[William Sommerwerck]

As friendly professor Peter Schickele once said... "Truth is truth. You can't
have opinions about truth."

I'm accused of having obsessions no one else cares about. (I'm willing to
confess to an excessive fondness for gerbils.) But I do care about the truth,
and make no apologies for it.

Part of the reason for this obsession is that, as an under-employed technical
writer and editor, I see technically incompetent people with little or no
ability to write or edit /being paid/ to do so. * Is it any wonder I blow my
stack over errors that a competent editor would have caught?

Anyhow...

Here are the excerpts from Frenzel's "Electronics Explained" that disturbed
me. I believe in encouraging people to think for themselves, so instead of
explaining what's wrong, I invite people to say what /they/ think is wrong
(including "important stuff" that's been left out). I might prompt a little,
but I prefer that people figure out these things on their own.

The purpose of this exercise is not to start arguments, but to get people
thinking about what they understand or don't understand.

(Frenzel is a master of tautological writing. He says the same thing over and
over in a slightly different way each time, rather than expressing it once,
simply. He would have had a great career as a paid-by-the-word pulp-fiction
writer.)

----------------------------------------------
p89

Recall that there are two basic types of electronic signals -- analog and
digital. A digital signal is one that varies in discrete steps. Unlike an
analog signal, which varies continuously, a digital signal has two levels or
states. The signal switches or changes abruptly from one state to the other.

Figure 5.1 shows a DC digital signal that switches between two known levels
such as zero volts or close to it (0.1 volts) or 0V and +3.3V. The positive
voltage can be anything between about 1 volt and 12 volts with 3.3 and 5 being
the most common.

[Those who can get p89 to appear might ask themselves whether the figure
actually shows a digital signal. How do you know it's digital and not analog?
Can a pulsed signal be analog? Can a sine wave be digital?]

Digital signals with two discrete levels are also referred to as binary
signals. Binary means two -- two states or two discrete levels of voltage.

Humans use the decimal number system that represents quantities with digits 0
through 9. However, digital equipment and computers do not. Internally,
digital equipment processes binary data.
----------------------------------------------
p118ff

Analog-to-Digital Conversion

The process of converting an analog signal into a digital one is called
analog-to-digital conversion, and is performed by an analog-to-digital
converter (ADC). The process, also referred to as sampling, is illustrated in
Figure 5-26. The ADC looks at the analog input and periodically takes a sample
of the voltage at that instant, captures it, then converts it into a
proportional binary number. We say that we are digitizing the signal. The
sample points are shown by the dots on the analog curve. The binary value of
the sample is shown to the right of the curve. The conversion process actually
results in a sequence of binary numbers that represent the analog waveform.
These values are usually stored in a RAM or transmitted to other circuits as
shown in Figure 5-27. Note the symbol for an ADC.

Digital-to-Analog Conversion

To recover the original signal, we put the data sequence previously captured
by the ADC into a digital-to-analog converter (DAC) (see Figure 5.28). The
output is a version of the analog signal. The DAC output is not a perfect
reproduction, but just an approximation. This is shown in more detail in
Figure 5.29. Each binary input results in a constant voltage output from the
DAC during the sample period. The result is a stepped approximation to the
original signal. The rate at which the binary data is [sic] sent to the DAC
must be the same as the sampling interval to recover the original frequency
information in the signal.

Resolution and Sampling Interval

The key to good data conversion is to use greater resolution and faster
sampling rates. Resolution refers t the number of bits used in the data
conversion. In Figure 5.27, only 4 bits are used, so the resolution is poor.
The voltage range is only divided into 16 intervals, meaning that amplitude
variations at [sic] less than 0.625 volt are missed. This problem can be
corrected by using more bits. ADCs are available in many bit sizes. The most
common are 8, 10,, and 12 bits, but 14 and 16 bits are available. Some methods
of ADC produce resolutions of 20 to 26 bits. The result is a finer conversion
of amplitude detail. As an example, if the 0- to 10-volt range in Figure 5.27
was [sic] a 12-bit ADC, the individual smallest voltage increment that can be
detected is 10/2^12 = 10/4096 = 2.44mV instead of the 0.625 volt[s] in the
figure.

Another critical specification is sampling rate. To retain all the frequency
detail in a signal, the sampling rate must be at least twice the highest
frequency in the signal. This called the Nyquist criterion. For example, when
digitizing music with a frequency range of 20 Hz to 20 kHz, the sampling rate
must be at least double the 20-kHz frequency. In most systems, a rate of 44.1
kHz or 48 kHz is used.

----------------------------------------------

For those who haven't fallen asleep (or died), here's part of my review of
another bad book, "Signals and Systems Using MATLAB".

I wrote "...on p9, he confuses "analog" with "continuous time" -- which is NOT
correct. One can have analog data that are discrete-time."

One reader responded "...it is impossible to have an analog signal that is
discrete time. An analog signal can be represented by a discrete time signal
very well, but an analog signal IS continuous, where a discrete time signal is
defined as being discontinuous. Since it is impossible to have a continuous
signal be equal to a discontinuous signal, your argument is invalid."

This confusion of time and amplitude remains common. (Note also the confusion
between "signal" and "data".) You might want to chew on it a bit. (ar-ar)


Thanks for your interest. Have at it!


* Several years ago I complained to a Wiley editor about a miserable book on
the history of radio. He was a very nice person -- but admitted he had almost
no technical knowledge. So what made him think he could edit technical books?
He'd applied for and taken a job he was unqualified for. I think I have a
right to be outraged.

"'We already know the answers -- we just haven't asked the right questions."
-- Edwin Land

[PStamler]

It's obvious that Frenzel has a muddled understanding of what's going on. I also suspect that English is not his first language; it's possible that this book was written in another language, then translated -- usually a bad idea for a technical work.

Peace,
Paul

[Mike Rivers[_2_]]

On 6/17/2013 2:17 PM, William Sommerwerck wrote:

Here are the excerpts from Frenzel's "Electronics Explained" that
disturbed me. I believe in encouraging people to think for themselves,
so instead of explaining what's wrong, I invite people to say what
/they/ think is wrong (including "important stuff" that's been left
out). I might prompt a little, but I prefer that people figure out these
things on their own.

Thanks. In order to play editor here, I'd need more context. If this was
an audio book, I'd treat the subject differently than if it was a
general electronics book, which I infer from the title. But either way,
it looks like the author is either confused about the digital
representation of an analog signal or else he just edited himself too
brutally (or an editor who didn't get it did) and over-simplified to the
point that it's incomplete.



--
For a good time, call http://mikeriversaudio.wordpress.com

[William Sommerwerck]

"PStamler" wrote in message
...

It's obvious that Frenzel has a muddled understanding
of what's going on.

You caught that? grin

I also suspect that English is not his first language; it's
possible that this book was written in another language,
then translated -- usually a bad idea for a technical work.

Frenzel has been with "Electronic Design" for some years. I don't think he's a
"furriner". Given how cheap most publishers are, it's unlikely they would pay
to have something translated.

I'm currently studying Merhaut's "Theory of Electroacoustics", which was
written in Czech. The English version -- which was translated by a physics
teacher and has the author's approval -- is a pretty clear read.

[William Sommerwerck]

"Mike Rivers" wrote in message ...
On 6/17/2013 2:17 PM, William Sommerwerck wrote:

Here are the excerpts from Frenzel's "Electronics Explained" that
disturbed me. I believe in encouraging people to think for themselves,
so instead of explaining what's wrong, I invite people to say what
/they/ think is wrong (including "important stuff" that's been left
out). I might prompt a little, but I prefer that people figure out these
things on their own.

Thanks. In order to play editor here, I'd need more context. If this was an
audio book, I'd treat the subject differently than if it was a general
electronics book, which I infer from the title. But either way, it looks
like the author is either confused about the digital representation of an
analog signal or else he just edited himself too brutally (or an editor who
didn't get it did) and over-simplified to the point that it's incomplete.

This book is an introduction to electronics for the "unknowing". (I use that
in both senses of the word.)

The book reads throughout like an unedited first draft. I suspect Frenzel was
trying to be "quick and breezy" without regard for the little (and sometimes
big) details.

The other day I started to write an explanation of "digital" from scratch --
and it is not easy. There is so much preliminary material to present (such as
why one would want to represent information as quantized values, rather than
continuous variation) it can be daunting. That, however, is no excuse for
getting so much wrong.

[PStamler]

On Monday, June 17, 2013 5:52:14 PM UTC-5, William Sommerwerck wrote:

This book is an introduction to electronics for the "unknowing". (I use that

in both senses of the word.)

Not an easy task. I do that for a living myself, as does Mike Rivers (and as you used to do back in the Stereophile days), and it's always a fine line to walk. In this case I think the author fell off the line.

The book reads throughout like an unedited first draft. I suspect Frenzel was

trying to be "quick and breezy" without regard for the little (and sometimes

big) details.

He also writes an endless string of short declarative sentences. That's deadly. Maybe Hemingway got away with it, but he wrote *good* short sentences.

The other day I started to write an explanation of "digital" from scratch --

and it is not easy. There is so much preliminary material to present (such as

why one would want to represent information as quantized values, rather than

continuous variation) it can be daunting. That, however, is no excuse for

getting so much wrong.

No, it's not easy. At the beginning of this discussion I offered my definitions of "analog" and "digital", and I found I had to use many weasel words, to cover the many ambiguities. And yes, it's important for the reader to know the "prior art" -- the explanations for the explanations, if you will, or the foundational material we take for granted but most "civilians" have never been exposed to.

Peace,
Paul

[William Sommerwerck]

"PStamler" wrote in message
...

The other day I started to write an explanation of "digital" from
scratch --
and it is not easy. There is so much preliminary material to present (such
as why one would want to represent information as quantized values,
rather than continuous variation) it can be daunting. That, however,
is no excuse for getting so much wrong.

No, it's not easy. At the beginning of this discussion I offered my
definitions
of "analog" and "digital", and I found I had to use many weasel words, to
cover the many ambiguities.

You're touching on an issue that hasn't been discussed yet.

The word "signal" has two meanings -- the waveform coming out of or going into
a circuit, and the information carried by that waveform. The failure to
recognize this causes writers to talk about analog or digital signals
(waveforms), when in reality, there are no such things. "Analog" and "digital"
refer to the way the data is represented or "coded" -- not the waveform that
carries that representation or coding.

You thus have writers stating that pulsed signals (waveforms) represent
digital information, when in reality the waveform has nothing whatever to do
with "analog" or "digital" information.

[None]

"William Sommerwerck" wrote in message
...
"PStamler" wrote in message
...

The other day I started to write an explanation of "digital" from
scratch --
and it is not easy. There is so much preliminary material to
present (such
as why one would want to represent information as quantized
values,
rather than continuous variation) it can be daunting. That,
however,
is no excuse for getting so much wrong.

No, it's not easy. At the beginning of this discussion I offered my
definitions
of "analog" and "digital", and I found I had to use many weasel
words, to
cover the many ambiguities.

You're touching on an issue that hasn't been discussed yet.

Of course it's been discussed. You've gone through this whole
rigmarole in the past, and you're rehashing it. Do you have a
short memory? None of this is new to many of us, and it seems
that none of it new even to the newsgroup.

The word "signal" has two meanings -- the waveform coming out of or
going into a circuit, and the information carried by that waveform.

Actually, it has even more meanings. "Continuous" also has
multiple meanings, and your failure to distinguish between them
caught you up last time. You called a discrete-time signal
"continuous", although in the mathematical sense usually
used in Signals and Systems, a discrete-time signal cannot
be continuous, as it is a series of discontinuous points with
no continuity anywhere.

Perhaps this kind of careless writing in technical discussions
is part of the reason for people disagreeing with you, despite
your ridiculous claim that you are (almost) always right. In
fact, you have shown yourself to be wrong, ambiguous, and
unclear in many cases here in RAP.

The whole point of this redundant charade seems to be to
fail, once again, to prove how wonderful you are. QED. Long
ago, not so long ago, and now, once again. When you're
wrong, you simple deny it. No doubt, after the dust settles,
you'll be back again with the same horse****.

If anyone wants to jump ahead to the punch line, they can
simply search for the previous re-runs of the Willie Thinks He's
Always Right Comedy Hour.

[Mike Rivers[_2_]]

On 6/17/2013 6:52 PM, William Sommerwerck wrote:

The other day I started to write an explanation of "digital" from
scratch -- and it is not easy. There is so much preliminary material to
present (such as why one would want to represent information as
quantized values, rather than continuous variation) it can be daunting.

That's why I didn't attempt a rewrite. At $100/hour, I don't think that
rec.audio.pro can afford it.

It's possible that the book only got a grammatical edit, not a technical
one, and it's really hard to edit your own writing. I did the technical
editing for Ethan Winer's book The Audio Expert. It wasn't all that
difficult because Ethan knows his stuff and didn't really make any
errors. The sort of things that i contributed were changes that made the
language easier to understand, and occasionally suggest an different
example that made the point clearer than what he used. But I knew the
subject matter. If I was handed, say, a book about using Pro Tools to
produce hip hop, I couldn't have done as good a job.

My own writing tends to be pretty breezy and informal, but at least I
try to get the technical parts correct. A brutal editor could probably
cut my word count by 25 to 50 percent, but I can't.

--
For a good time, call http://mikeriversaudio.wordpress.com

[None]

"William Sommerwerck" wrote in message
...
The purpose of this exercise is not to start arguments,

Of course it is. Are you now writing Monty Python skits?

but to get people thinking about what they understand or don't
understand.

No, it's for you to engage in an auto-erotic display of egotism.

He says the same thing over and over in a slightly different way
each time, rather than expressing it once, simply. He would have had
a great career as a paid-by-the-word pulp-fiction writer.

If you have any self-awareness left, you should stand in
front of a mirror, and read that to yourself until it sinks in.
You might want to clear your calendar.

[William Sommerwerck]

The word "signal" has two meanings -- the waveform coming out of or going
into a circuit, and the information carried by that waveform.

Actually, it has even more meanings. "Continuous" also has
multiple meanings, and your failure to distinguish between them
caught you up last time. You called a discrete-time signal
"continuous", although in the mathematical sense usually
used in Signals and Systems, a discrete-time signal cannot
be continuous, as it is a series of discontinuous points with
no continuity anywhere.

I never said anything of the sort. You either can't read (likely) or you're
lying (not so likely).

A discrete-time signal can be analog. Analog and continuous do not mean the
same thing.

Sorry, but I am always always right. Sorry about that.

[William Sommerwerck]

"Mike Rivers" wrote in message ...

My own writing tends to be pretty breezy and informal, but at least I
try to get the technical parts correct. A brutal editor could probably
cut my word count by 25 to 50 percent, but I can't.

I have the same problem. You can learn to do this but it's difficult.

[Paul[_13_]]

On 6/17/2013 6:28 PM, None wrote:
"William Sommerwerck" wrote in message
...
The purpose of this exercise is not to start arguments,

Of course it is. Are you now writing Monty Python skits?

but to get people thinking about what they understand or don't
understand.

No, it's for you to engage in an auto-erotic display of egotism.

He says the same thing over and over in a slightly different way each
time, rather than expressing it once, simply. He would have had a
great career as a paid-by-the-word pulp-fiction writer.

If you have any self-awareness left, you should stand in
front of a mirror, and read that to yourself until it sinks in.
You might want to clear your calendar.


100% Agreed.

Nobody who wants to learn about electronics is going to
rely on one book anyways. For anyone who will end up designing
circuits, it all sinks in eventually.

Maybe if William was actually duly employed, he'd have less time
to tear down the work of others. I'm still waiting for his
magically lucid description of the "truth".

[None]

"William Sommerwerck" wrote in message
...
The word "signal" has two meanings -- the waveform coming out of
or going into a circuit, and the information carried by that
waveform.

Actually, it has even more meanings. "Continuous" also has
multiple meanings, and your failure to distinguish between them
caught you up last time. You called a discrete-time signal
"continuous", although in the mathematical sense usually
used in Signals and Systems, a discrete-time signal cannot
be continuous, as it is a series of discontinuous points with
no continuity anywhere.

I never said anything of the sort. You either can't read (likely) or
you're lying (not so likely).

A discrete-time signal can be analog. Analog and continuous do not
mean the same thing.

Sorry, but I am always always right. Sorry about that.

Masturbating in public is impolite, but I guess you really
crave the attention that you can't get in real life. I'm sure
you're accustomed to being ignored and reviled, because
that's what you demand.

And you have confirmed what most of us already knew:
you don't mean it when you apologize. Your recent sham
apology was not sincere, which you have confirmed at least
four time now, since you puked it onto Usenet.

[Ron C[_2_]]

On 6/17/2013 10:14 PM, Paul wrote:
On 6/17/2013 6:28 PM, None wrote:
"William Sommerwerck" wrote in message
...
The purpose of this exercise is not to start arguments,

Of course it is. Are you now writing Monty Python skits?

but to get people thinking about what they understand or don't
understand.

No, it's for you to engage in an auto-erotic display of egotism.

He says the same thing over and over in a slightly different way each
time, rather than expressing it once, simply. He would have had a
great career as a paid-by-the-word pulp-fiction writer.

If you have any self-awareness left, you should stand in
front of a mirror, and read that to yourself until it sinks in.
You might want to clear your calendar.


100% Agreed.

Nobody who wants to learn about electronics is going to
rely on one book anyways. For anyone who will end up designing
circuits, it all sinks in eventually.

Maybe if William was actually duly employed, he'd have less time
to tear down the work of others. I'm still waiting for his
magically lucid description of the "truth".



Were I truly cynical I might tend to think that he's waiting
to review our responses before he (contrives) and presents
his spin of the absolute truth.

Ah, but can anyone actually be that cynical?
==
Later...
Ron Capik cynic--training
--

[William Sommerwerck]

"Paul" wrote in message ...

Maybe if William was actually duly employed, he'd have
less time to tear down the work of others.

If I were duly employed, that's what I'd be paid to do.

It might not bother you that most technical books are overpriced toilet paper,
but it bothers me.

[William Sommerwerck]

I'm still waiting for his magically lucid description of the "truth".

I started writing it, but (as I said to Mike), it's not easy. I'll complete it
if you (Ron) agree to give it a //serious// review in this group.

I doubt you would, because it would be too easy to call it everything in it
wrong and say I didn't know what I was talking about.

I'm calling you out on this.

[Ron C[_2_]]

On 6/17/2013 10:41 PM, William Sommerwerck wrote:
"Paul" wrote in message ...

Maybe if William was actually duly employed, he'd have
less time to tear down the work of others.

If I were duly employed, that's what I'd be paid to do.

It might not bother you that most technical books are overpriced toilet
paper, but it bothers me.

However it seems the free market isn't buying
what you're selling. You may sit and stew, change
your marketing, or change your product. Seems
you've opted for the first state.

I opted for retirement, thus have no dogs in the fight.

[OK, I may still care about accuracy ...at some level.]
==
Later...
Ron Capik
--

[Paul[_13_]]

On 6/17/2013 7:23 PM, None wrote:


"William Sommerwerck" wrote in message
...
The word "signal" has two meanings -- the waveform coming out of or
going into a circuit, and the information carried by that waveform.

Actually, it has even more meanings. "Continuous" also has
multiple meanings, and your failure to distinguish between them
caught you up last time. You called a discrete-time signal
"continuous", although in the mathematical sense usually
used in Signals and Systems, a discrete-time signal cannot
be continuous, as it is a series of discontinuous points with
no continuity anywhere.

I never said anything of the sort. You either can't read (likely) or
you're lying (not so likely).

A discrete-time signal can be analog. Analog and continuous do not
mean the same thing.

Sorry, but I am always always right. Sorry about that.

Masturbating in public is impolite, but I guess you really
crave the attention that you can't get in real life. I'm sure
you're accustomed to being ignored and reviled, because
that's what you demand.

And you have confirmed what most of us already knew:
you don't mean it when you apologize. Your recent sham
apology was not sincere, which you have confirmed at least
four time now, since you puked it onto Usenet.


100% agreed.

William is like most "know-it-all" personalities: only he
knows the truth, and everyone else is a dumb****.

Get over yourself, William, you've got the attention you wanted...
now put your dick back in your pants....

[None]

"William Sommerwerck" wrote in message
...
I'm still waiting for his magically lucid description of the
"truth".

I started writing it, but (as I said to Mike), it's not easy. I'll
complete it if you (Ron) agree to give it a //serious// review in
this group.

I doubt you would, because it would be too easy to call it
everything in it wrong and say I didn't know what I was talking
about.

I'm calling you out on this.

LOL! "Calling you out". What a ****ing asshole! In a world
where you could invent your own definitions, and no other
definitions ever have any validity, you could probably make
a case that you're always right. But in the real world, where
definitions exist by common understanding, your refusal
to accept common understanding just leaves you behind
as an unemployable loser.

You repeatedly come here and pretend that you and you
alone know the one and only true definition of some term
or other, and then you pretend that it makes you superior.
The truth is, that your inability to engage in productive
communication,
and your condescending attitude that your pig-headedness
makes you superior, is one of the reasons that you deserve
the mockery and contempt that you get.

When you are proven wrong, you simply refuse to hear it,
because your head is so far up your asshole that you can
see your back teeth. And now, like a petulant bratty child,
you demand that others dance to your tune. But in fact,
you can't play a tune, and nobody wants to dance with
you.

[Paul[_13_]]

On 6/17/2013 8:08 PM, None wrote:
"William Sommerwerck" wrote in message
...
I'm still waiting for his magically lucid description of the "truth".

I started writing it, but (as I said to Mike), it's not easy. I'll
complete it if you (Ron) agree to give it a //serious// review in this
group.

I doubt you would, because it would be too easy to call it everything
in it wrong and say I didn't know what I was talking about.

I'm calling you out on this.

LOL! "Calling you out". What a ****ing asshole! In a world
where you could invent your own definitions, and no other
definitions ever have any validity, you could probably make
a case that you're always right. But in the real world, where
definitions exist by common understanding, your refusal
to accept common understanding just leaves you behind
as an unemployable loser.

You repeatedly come here and pretend that you and you
alone know the one and only true definition of some term
or other, and then you pretend that it makes you superior.
The truth is, that your inability to engage in productive communication,
and your condescending attitude that your pig-headedness
makes you superior, is one of the reasons that you deserve
the mockery and contempt that you get.

When you are proven wrong, you simply refuse to hear it,
because your head is so far up your asshole that you can
see your back teeth. And now, like a petulant bratty child,
you demand that others dance to your tune. But in fact,
you can't play a tune, and nobody wants to dance with
you.

Jesus, I couldn't agree more.

No wonder no one wants to hire this idiot.....

[Gary Eickmeier]

Well, if no one else is going to answer you I will try.

The biggest problem that I see in the text is that he thinks the digital
file will not be a perfect copy of the analog input, and that digital
waveforms are a connect the dots stair stepped approximation of the analog.
That would be a serious error.

Gary Eickmeier

William Sommerwerck wrote:
As friendly professor Peter Schickele once said... "Truth is truth.
You can't have opinions about truth."

I'm accused of having obsessions no one else cares about. (I'm
willing to confess to an excessive fondness for gerbils.) But I do
care about the truth, and make no apologies for it.

Part of the reason for this obsession is that, as an under-employed
technical writer and editor, I see technically incompetent people
with little or no ability to write or edit /being paid/ to do so. *
Is it any wonder I blow my stack over errors that a competent editor
would have caught?
Anyhow...

Here are the excerpts from Frenzel's "Electronics Explained" that
disturbed me. I believe in encouraging people to think for
themselves, so instead of explaining what's wrong, I invite people to
say what /they/ think is wrong (including "important stuff" that's
been left out). I might prompt a little, but I prefer that people
figure out these things on their own.
The purpose of this exercise is not to start arguments, but to get
people thinking about what they understand or don't understand.

(Frenzel is a master of tautological writing. He says the same thing
over and over in a slightly different way each time, rather than
expressing it once, simply. He would have had a great career as a
paid-by-the-word pulp-fiction writer.)

----------------------------------------------
p89

Recall that there are two basic types of electronic signals -- analog
and digital. A digital signal is one that varies in discrete steps.
Unlike an analog signal, which varies continuously, a digital signal
has two levels or states. The signal switches or changes abruptly
from one state to the other.
Figure 5.1 shows a DC digital signal that switches between two known
levels such as zero volts or close to it (0.1 volts) or 0V and
+3.3V. The positive voltage can be anything between about 1 volt and
12 volts with 3.3 and 5 being the most common.

[Those who can get p89 to appear might ask themselves whether the
figure actually shows a digital signal. How do you know it's digital
and not analog? Can a pulsed signal be analog? Can a sine wave be
digital?]
Digital signals with two discrete levels are also referred to as
binary signals. Binary means two -- two states or two discrete levels
of voltage.
Humans use the decimal number system that represents quantities with
digits 0 through 9. However, digital equipment and computers do not.
Internally, digital equipment processes binary data.
----------------------------------------------
p118ff

Analog-to-Digital Conversion

The process of converting an analog signal into a digital one is
called analog-to-digital conversion, and is performed by an
analog-to-digital converter (ADC). The process, also referred to as
sampling, is illustrated in Figure 5-26. The ADC looks at the analog
input and periodically takes a sample of the voltage at that instant,
captures it, then converts it into a proportional binary number. We
say that we are digitizing the signal. The sample points are shown by
the dots on the analog curve. The binary value of the sample is shown
to the right of the curve. The conversion process actually results in
a sequence of binary numbers that represent the analog waveform.
These values are usually stored in a RAM or transmitted to other
circuits as shown in Figure 5-27. Note the symbol for an ADC.
Digital-to-Analog Conversion

To recover the original signal, we put the data sequence previously
captured by the ADC into a digital-to-analog converter (DAC) (see
Figure 5.28). The output is a version of the analog signal. The DAC
output is not a perfect reproduction, but just an approximation. This
is shown in more detail in Figure 5.29. Each binary input results in
a constant voltage output from the DAC during the sample period. The
result is a stepped approximation to the original signal. The rate at
which the binary data is [sic] sent to the DAC must be the same as
the sampling interval to recover the original frequency information
in the signal.
Resolution and Sampling Interval

The key to good data conversion is to use greater resolution and
faster sampling rates. Resolution refers t the number of bits used in
the data conversion. In Figure 5.27, only 4 bits are used, so the
resolution is poor. The voltage range is only divided into 16
intervals, meaning that amplitude variations at [sic] less than 0.625
volt are missed. This problem can be corrected by using more bits.
ADCs are available in many bit sizes. The most common are 8, 10,, and
12 bits, but 14 and 16 bits are available. Some methods of ADC
produce resolutions of 20 to 26 bits. The result is a finer
conversion of amplitude detail. As an example, if the 0- to 10-volt
range in Figure 5.27 was [sic] a 12-bit ADC, the individual smallest
voltage increment that can be detected is 10/2^12 = 10/4096 = 2.44mV
instead of the 0.625 volt[s] in the figure.
Another critical specification is sampling rate. To retain all the
frequency detail in a signal, the sampling rate must be at least
twice the highest frequency in the signal. This called the Nyquist
criterion. For example, when digitizing music with a frequency range
of 20 Hz to 20 kHz, the sampling rate must be at least double the
20-kHz frequency. In most systems, a rate of 44.1 kHz or 48 kHz is
used.
----------------------------------------------

For those who haven't fallen asleep (or died), here's part of my
review of another bad book, "Signals and Systems Using MATLAB".

I wrote "...on p9, he confuses "analog" with "continuous time" --
which is NOT correct. One can have analog data that are
discrete-time."
One reader responded "...it is impossible to have an analog signal
that is discrete time. An analog signal can be represented by a
discrete time signal very well, but an analog signal IS continuous,
where a discrete time signal is defined as being discontinuous. Since
it is impossible to have a continuous signal be equal to a
discontinuous signal, your argument is invalid."
This confusion of time and amplitude remains common. (Note also the
confusion between "signal" and "data".) You might want to chew on it
a bit. (ar-ar)

Thanks for your interest. Have at it!


* Several years ago I complained to a Wiley editor about a miserable
book on the history of radio. He was a very nice person -- but
admitted he had almost no technical knowledge. So what made him think
he could edit technical books? He'd applied for and taken a job he
was unqualified for. I think I have a right to be outraged.

"'We already know the answers -- we just haven't asked the right
questions." -- Edwin Land

[Mike Rivers[_2_]]

On 6/17/2013 10:41 PM, William Sommerwerck wrote:

It might not bother you that most technical books are overpriced toilet
paper, but it bothers me.

Not very good toilet paper. The covers are too slick, and the pictures
aren't very interesting.

I suspect that the problem is with the publishing industry rather than
with the authors. Publishers don't want a thick book with a lot of
details about a very small range of topics because they'd only sell a
handful. They want a book that covers a wider scope.

For example, I've been thinking for a couple of years about writing a
book, probably 100-150 pages, about connections between elements of a PA
system. But who'd buy it if it didn't tell them how to mic a drum kit or
compress a bass?


--
For a good time, call http://mikeriversaudio.wordpress.com

[Mike Rivers[_2_]]

On 6/18/2013 2:01 AM, Gary Eickmeier wrote:
Well, if no one else is going to answer you I will try.

The biggest problem that I see in the text is that he thinks the digital
file will not be a perfect copy of the analog input, and that digital
waveforms are a connect the dots stair stepped approximation of the analog.
That would be a serious error.

I don't think he even got far enough to make that error. When you know
that this is what most people who aren't about to present the sampling
theorem will say about digital representation of an analog signal, it's
easy to infer even from an incomplete explanation, that he's telling you
that the digital representation isn't smooth.

And in fact, it isn't smooth. It's a series of binary numbers that
represent analog levels sampled at discrete intervals. It's only an
accurate representation of the analog signal when you take a further
step and remove information that is out of bounds of the sampling theory.

And that's a very simplified and not entirely precise explanation.

--
For a good time, call http://mikeriversaudio.wordpress.com

[Arny Krueger[_5_]]

"William Sommerwerck" wrote in message
...
/
The other day I started to write an explanation of "digital" from
scratch -- and it is not easy. There is so much preliminary material to
present (such as why one would want to represent information as quantized
values, rather than continuous variation) it can be daunting. That,
however, is no excuse for getting so much wrong.

Part of the problem may be that the word digital is a word that is something
like the word fridge. Everybody thinks they know what it means but tend to
forget that when you start formulating formal definitions, fuzz around the
edges becomes intolerable.

When I think of the word digital what I really mean is "Discrete value,
discrete time" or "Quantized value, quantized time". Once you agree with
that, life seems to become considerably easier. Those definitions also
admits what I find to be an amazingly large number of different kinds of
signals and brings in a lot of history. I lived through a lot of it. For
example, binary signals are only a subset of all of the possible kinds of
digital signals.

[John Williamson]

Arny Krueger wrote:
"William Sommerwerck" wrote in message
...
/
The other day I started to write an explanation of "digital" from
scratch -- and it is not easy. There is so much preliminary material to
present (such as why one would want to represent information as quantized
values, rather than continuous variation) it can be daunting. That,
however, is no excuse for getting so much wrong.

Part of the problem may be that the word digital is a word that is something
like the word fridge. Everybody thinks they know what it means but tend to
forget that when you start formulating formal definitions, fuzz around the
edges becomes intolerable.

When I think of the word digital what I really mean is "Discrete value,
discrete time"

Which I would define as "Taking the nearest value of the signal,
selected from a number of such, encoded as a number, at the instant when
the clock ticks". The way a normal ADC works.

or "Quantized value, quantized time".

Which I would take as meaning "Taking a known value at a known instant".
The known value is not necessarily encoded, but could, for instance, be
represented as the amount of charge on a capacitor as measured by an
analogue meter, and the time can be arbitrary, not exactly defined by a
clock. The way a "Sample and hold" circuit works. If the timing is set
by a clock ticking and you have a number of sample and hold circuits, in
series, then you have the principle of a bucket brigade delay.

At the ultimate resolution, though, all signal values are quantised by
the charge of an electron, and the time resolution is limited by the
Planck time, which is (5.39106(32) × 10-44 s).

--
Tciao for Now!

John.

[William Sommerwerck]

"Gary Eickmeier" wrote in message ...

Well, if no one else is going to answer you I will try.

The biggest problem that I see in the text is that he thinks the digital
file will not be a perfect copy of the analog input, and that digital
waveforms are a connect the dots stair stepped approximation of the analog.
That would be a serious error.

That seems to be what he's saying, and it /is/ a serious error. There are
others.

Frenzel doesn't properly address -- even in passing -- the issue of how
accurate a quantized representation can be. Indeed, he says that faster
sampling and a deeper bit depth give a better representation -- but this isn't
necessarily true.

[William Sommerwerck]

"Arny Krueger" wrote in message
...
"William Sommerwerck" wrote in message
...

The other day I started to write an explanation of "digital" from
scratch -- and it is not easy. There is so much preliminary material
to present (such as why one would want to represent information
as quantized values, rather than continuous variation) it can be
daunting. That, however, is no excuse for getting so much wrong.

Part of the problem may be that the word digital is a word that is
something like the word fridge. Everybody thinks they know what it
means, but tend to forget that when you start formulating formal
definitions, fuzz around the edges becomes intolerable.

You mean... A fridge isn't a Frigidaire? And if it's not an Amana, it's not a
Radarange? (I shouldn't have to mark this as a joke, but it seems necessary.)


When I think of the word digital what I really mean is "Discrete value,
discrete time" or "Quantized value, quantized time". Once you agree with
that, life seems to become considerably easier. Those definitions also
admits what I find to be an amazingly large number of different kinds
of signals and brings in a lot of history. I lived through a lot of it.
For
example, binary signals are only a subset of all of the possible kinds of
digital signals.

What he said. It's all correct. Thank you.

[William Sommerwerck]

"No wonder no one wants to hire this idiot..."

Those who have hired me, and let me do my job without telling me how to do it,
have been happy with my work.

At Data I/O I rewrote the horrible user manual for the schematic-capture
software Data I/O had recently purchased. When the product went out the door,
it immediately received kudos from customers who'd had trouble with the
previous manuals.

At Microsoft, I rewrote material I was told /not/ to rewrite -- and got
uninvited compliments.

I rewrote Software Bisque's user manuals. SB got compliments from customers --
and fewer phone calls.

At AccessLine, I had a "love affair" with my boss. If you've ever had a
manager who demands your best work, and supports you in achieving it, you know
how great going to work can be.

I'm "sorry", Mr No-Name, but as a technical writer, I usually know what I'm
doing. I don't need your approval, nor will I grovel in front of you asking
for permission to speak in public on subjects I know something about.

[William Sommerwerck]

"None" wrote in message
m...
"William Sommerwerck" wrote in message
...

LOL! "Calling you out". What a ****ing asshole! In a world
where you could invent your own definitions, and no other
definitions ever have any validity, you could probably make
a case that you're always right. But in the real world, where
definitions exist by common understanding, your refusal
to accept common understanding just leaves you behind
as an unemployable loser.

And in all your long, rich existence, you have never had the experience of
reading or hearing some "expert" say something. and reacting "Wait. That's
wrong."?

It's interesting that Mike Rivers and Ron Capik -- who have writing
experience -- aren't so quick to dump on me. (I'm /not/ saying they approve of
everything I say or do.) Could it be they know you can't write well about
things you don't understand?


"But in the real world, where definitions exist by common understanding..."

Which is another way of saying that common belief is fact -- which it isn't.

Most people believe what they're told by their parents or "experts", without
questioning it. More than anything, this is what I'm fighting.

I've always been weak on acoustics. I've just started studying Merhaut's
"Theory of Electroacoustics", and this time I seem to be understanding it.

[William Sommerwerck]

"Mike Rivers" wrote in message ...
On 6/17/2013 10:41 PM, William Sommerwerck wrote:

It might not bother you that most technical books are overpriced
toilet paper, but it bothers me.

Not very good toilet paper. The covers are too slick, and the pictures
aren't very interesting.

I suspect that the problem is with the publishing industry rather than with
the authors. Publishers don't want a thick book with a lot of details about
a very small range of topics because they'd only sell a handful. They want a
book that covers a wider scope.

For example, I've been thinking for a couple of years about writing a
book, probably 100-150 pages, about connections between elements
of a PA system. But who'd buy it if it didn't tell them how to mic a
drum kit or compress a bass?

How about a book titled "Installing and Maintaining PA Systems"? Wouldn't
there be a market for that?

[William Sommerwerck]

"Ron C" wrote in message
...
On 6/17/2013 10:41 PM, William Sommerwerck wrote:
"Paul" wrote in message ...

Maybe if William was actually duly employed, he'd have
less time to tear down the work of others.

If I were duly employed, that's what I'd be paid to do.
It might not bother you that most technical books are
overpriced toilet paper, but it bothers me.

However it seems the free market isn't buying what you're
selling. You may sit and stew, change your marketing, or
change your product. Seems you've opted for the first state.
I opted for retirement, thus have no dogs in the fight.
[OK, I may still care about accuracy ...at some level.]

I sincerely thank Ron for (more or less) agreeing with me.

My marketing approach has always been "I can help you provide better customer
support and improve customer satisfaction". It has worked in only one case
that I remember.

Isn't anyone bothered that the expensive books they buy are often poorly
written and organized? Or that they have only rarely been edited for technical
accuracy?

[Mike Rivers[_2_]]

On 6/18/2013 9:49 AM, William Sommerwerck wrote:

How about a book titled "Installing and Maintaining PA Systems"?
Wouldn't there be a market for that?

There are already a couple of books that cover that subject pretty well,
the Yamaha Sound Reinforcement Handbook and Sound System Engineering
(the Don Davis bunch).

A title like that would scare away the people I want to write for. This
would be a book for the person who posts on a fourm: "I just bought a
new mixer. Can someone tell me the best way to hook it up?"


--
For a good time, call http://mikeriversaudio.wordpress.com

[William Sommerwerck]

"Mike Rivers" wrote in message ...
On 6/18/2013 9:49 AM, William Sommerwerck wrote:

How about a book titled "Installing and Maintaining PA Systems"?
Wouldn't there be a market for that?

There are already a couple of books that cover that subject
pretty well, the Yamaha Sound Reinforcement Handbook
and Sound System Engineering (the Don Davis bunch).
A title like that would scare away the people I want to write
for. This would be a book for the person who posts on a fourm:
"I just bought a new mixer. Can someone tell me the best way
to hook it up?"

I see a couple of issues... A mixer is necessarily /part of/ a larger system.
Is it possible to explain how to hook it up without the context of the system
as a whole? I'm not sure it is.

To put it a slightly different way... It's usually assumed that if you
understand how trees work, you won't have trouble assembling them into a
forest. That is rarely true for a newcomer -- they often don't even understand
the trees.

I once tried to twist Mr Mackie's arm into letting me rewrite the mixer
manual. It was /locally/ well-written, but poorly organized. It needed to be
laid out from the perspective of someone who had no practical experience with
mixers, and had to be instructed from the ground up, starting with the
simplest things (ie, where do you plug in a mic and how do you set its
level?).

Basically, it's the manufacturers' responsibility to provide this sort of
documentation. To the extent they don't, you have a market.

How about "The Big Dummy's Guide to Installing and Using a Mixer"?

[Frank Stearns]

Mike Rivers writes:

On 6/18/2013 9:49 AM, William Sommerwerck wrote:

How about a book titled "Installing and Maintaining PA Systems"?
Wouldn't there be a market for that?

There are already a couple of books that cover that subject pretty well,
the Yamaha Sound Reinforcement Handbook and Sound System Engineering
(the Don Davis bunch).

A title like that would scare away the people I want to write for. This
would be a book for the person who posts on a fourm: "I just bought a
new mixer. Can someone tell me the best way to hook it up?"

How about joining the "Idiots Guide" franchise? I've seen some surprising topics in
that area (sorry, escapes me now; something like the "Idiot's Guide to Funerals", or
some such was one; there are some other arcane topics as well).

So, "The Idiot's Guide to Small PA Systems"...

Personally, the entire franchise is somewhat annoying to me, but hey, if you can
sell them on your writing in your field but using their editorial guidelines, why
not?

Frank
Mobile Audio
--

[Mike Rivers[_2_]]

On 6/18/2013 12:28 PM, William Sommerwerck wrote:

I see a couple of issues... A mixer is necessarily /part of/ a larger
system. Is it possible to explain how to hook it up without the context
of the system as a whole? I'm not sure it is.

The question, of course, is naive. What they really mean to ask, and
what I would answer in the book, is to how to hook up the sort of sound
system that a person who would ask a question that way would be likely
to buy.

To put it a slightly different way... It's usually assumed that if you
understand how trees work, you won't have trouble assembling them into a
forest. That is rarely true for a newcomer -- they often don't even
understand the trees.

And that's why there needs to be a good book. Every mixer instruction
manual tells you where the Auxiliary Send controls are, but few explain
that they feed signals to a bus and that bus is where you connect your
monitors (and why), or outboard effect processors. I'll leave the
rigging and line arrays for another book if I ever think I have enough
experience to write about them.

I once tried to twist Mr Mackie's arm into letting me rewrite the mixer
manual. It was /locally/ well-written, but poorly organized. It needed
to be laid out from the perspective of someone who had no practical
experience with mixers, and had to be instructed from the ground up,
starting with the simplest things (ie, where do you plug in a mic and
how do you set its level?).

Are you talking about my big mixer book, or the manual for one of their
mixers? I used to point people to the Mackie 1604 VLZ manual because it
had several suggested hook-up diagrams that covered real situations. The
first page or so of all of their manuals back then had "The Mackie Level
Setting Procedure" that offered one way of setting the channel trims so
that there was enough headroom in the mixer. Trouble was that people
looked at the meters and said "my mixer isn't hot enough." The problem
was one of gain structure in the system and a meter scale that covered
too wide of a range.

How about "The Big Dummy's Guide to Installing and Using a Mixer"?

I'd probably get sued by John Wiley, the folks who publish the "For
Dummies" books. I was thinking about "PA Systems For Drummers" but the
bass player might feel slighted.


--
For a good time, call http://mikeriversaudio.wordpress.com

[S. King]

On Tue, 18 Jun 2013 06:51:38 -0700, William Sommerwerck wrote:

"Ron C" wrote in message
...
On 6/17/2013 10:41 PM, William Sommerwerck wrote:
"Paul" wrote in message ...

Maybe if William was actually duly employed, he'd have less time to
tear down the work of others.

If I were duly employed, that's what I'd be paid to do.
It might not bother you that most technical books are overpriced
toilet paper, but it bothers me.

However it seems the free market isn't buying what you're selling. You
may sit and stew, change your marketing, or change your product. Seems
you've opted for the first state.
I opted for retirement, thus have no dogs in the fight. [OK, I may
still care about accuracy ...at some level.]

I sincerely thank Ron for (more or less) agreeing with me.

My marketing approach has always been "I can help you provide better
customer support and improve customer satisfaction". It has worked in
only one case that I remember.

SNIP

You're marketing approach is probably fine. I suspect that potential
employers spend a few minutes in conversation with you or in written
communication with you and conclude that you are trouble with a capital T,
unable to play or work effectively with others, and likely to harm the
enterprise more than you might help.

Steve King

[William Sommerwerck]

I'm answering this directly.

I once tried to twist Mr Mackie's arm into letting me rewrite the mixer
manual. It was /locally/ well-written, but poorly organized. It needed
to be laid out from the perspective of someone who had no practical
experience with mixers, and had to be instructed from the ground up,
starting with the simplest things (ie, where do you plug in a mic and
how do you set its level?).

Are you talking about my big mixer book, or the manual for one of their
mixers? I used to point people to the Mackie 1604 VLZ manual because it had
several suggested hook-up diagrams that covered real situations. The first
page or so of all of their manuals back then had "The Mackie Level Setting
Procedure" that offered one way of setting the channel trims so that there
was enough headroom in the mixer. Trouble was that people looked at the
meters and said "my mixer isn't hot enough." The problem was one of gain
structure in the system and a meter scale that covered too wide of a range.

I didn't know you'd written a mixer book. I was thinking of the manual.

I have an odd approach to learning things. I'm more interested in principles
than facts. With respect to mixers (I used to own a Mackie, which I used
solely as a mic preamp), I wanted to /understand/ how it worked and how it was
used. I don't like having to be dependent on a diagram.

In general, a manual should help the user understand the product sufficiently
that he rarely, if ever, has to refer to the manual.

[Les Cargill[_4_]]

William Sommerwerck wrote:
"PStamler" wrote in message
...

The other day I started to write an explanation of "digital" from
scratch --
and it is not easy. There is so much preliminary material to present
(such
as why one would want to represent information as quantized values,
rather than continuous variation) it can be daunting. That, however,
is no excuse for getting so much wrong.

No, it's not easy. At the beginning of this discussion I offered my
definitions
of "analog" and "digital", and I found I had to use many weasel words, to
cover the many ambiguities.

You're touching on an issue that hasn't been discussed yet.

The word "signal" has two meanings -- the waveform coming out of or
going into a circuit, and the information carried by that waveform.

Sort of...

The
failure to recognize this causes writers to talk about analog or digital
signals (waveforms), when in reality, there are no such things. "Analog"
and "digital" refer to the way the data is represented or "coded" -- not
the waveform that carries that representation or coding.



But these are a dual of each other - in the mathematical sense of
"dual". There's no metaphysical dualism; it's simply
a matter of the domain in which the signal is being discussed. There
exist devices or algorithms that perform a conversion between these
two domains.

There is a perfectly useful bijective mapping. A bijective mapping
can be construed as "equivalence". So...

Of course there are domains over which this distinction matters, but
those are much less likely than a general case. They mainly
matter to people implementing converters.


You thus have writers stating that pulsed signals (waveforms) represent
digital information, when in reality the waveform has nothing whatever
to do with "analog" or "digital" information.

When one takes measurements in the digital domains, one will see
classes of waveforms. Ditto analog domains.

--
Les Cargill

[William Sommerwerck]

My marketing approach has always been "I can help you provide
better customer support and improve customer satisfaction".
It has worked in only one case that I remember.

SNIP

Your marketing approach is probably fine. I suspect that potential
employers spend a few minutes in conversation with you or in written
communication with you and conclude that you are trouble with a
capital T, unable to play or work effectively with others, and likely
to harm the enterprise more than you might help.

You suspect far too much.

In many cases I have offered my services as an independent contractor who
would work off site.

What you don't understand is that most businesses aren't interested in
high-quality documentation, and don't go running after what they (think) they
don't need. Otherwise I and many other writers wouldn't be begging for work,
and you and I probably wouldn't be having this discussion.

When you buy a product with a lousy user manual, it's for one reason and one
reason only -- the manufacturer doesn't care.