[icecube]

HI

first off all i don't know if this is the correct forum for this type
of question

I'm trying to find away filter a signal with a weighting filter called
CCIR 468-4 (ITU-R 468-4)

and AES17

so what i'm looking for in the math behind the weighting type so i can
use them

if this isn't the correct forum can anbody direct me to the correct

rgds

[[email protected]]

On May 19, 2:45 pm, icecube wrote:
HI

first off all i don't know if this is the correct forum for this type
of question

I'm trying to find away filter a signal with a weighting filter called
CCIR 468-4 (ITU-R 468-4)

and AES17

so what i'm looking for in the math behind the weighting type so i can
use them

if this isn't the correct forum can anbody direct me to the correct

rgds


I believe ITU468-4 is the same as the old ANSI A weighting,
in which case, from:

http://www.ptpart.co.uk/show.php?con...r acteristics

A-weighting

The A-weighting characteristic is ideally realised by a filter with
the following characteristics:

* Four differentiating zeros
* Two poles at -20.6 Hz (-129.4 /s)
* One pole at -107.7 Hz (-676.7 /s)
* One pole at -737.9 Hz (-4636 /s)
* Two poles at -12200 Hz (-76655 /s)

and therefore has the following transfer function:

see the link above

[icecube]

On 19 Maj, 21:00, wrote:
On May 19, 2:45 pm, icecube wrote:





HI

first off all i don't know if this is the correct forum for this type
of question

I'm trying to find away filter a signal with a weighting filter called
CCIR 468-4 (ITU-R 468-4)

and AES17

so what i'm looking for in the math behind the weighting type so i can
use them

if this isn't the correct forum can anbody direct me to the correct

rgds

I believe ITU468-4 is the same as the old ANSI A weighting,
in which case, from:

http://www.ptpart.co.uk/show.php?con...WeightingFilte...

A-weighting

The A-weighting characteristic is ideally realised by a filter with
the following characteristics:

* * * Four differentiating zeros
* * * Two poles at -20.6 Hz (-129.4 /s)
* * * One pole at -107.7 Hz (-676.7 /s)
* * * One pole at -737.9 Hz (-4636 /s)
* * * Two poles at -12200 Hz (-76655 /s)

and therefore has the following transfer function:

see the link above- Skjul tekst i anførselstegn -

- Vis tekst i anførselstegn -

not to my understanding.

the ITU468-4 has more gain from 1 to 9kHz than the A weighting filter.

[John Phillips[_2_]]

On 2008-05-19,
wrote:
On May 19, 2:45 pm, icecube wrote:
I'm trying to find away filter a signal with a weighting filter called
CCIR 468-4 (ITU-R 468-4) and AES17

so what i'm looking for in the math behind the weighting type so i can
use them

I believe ITU468-4 is the same as the old ANSI A weighting,
in which case, from:

Not as far as I can see. See, for example:

http://en.wikipedia.org/wiki/ITU-R_468_noise_weighting

The ITU-R standard BS.468-4 (not available for free, I think):

http://en.wikipedia.org/wiki/Standard:ITU-R_468

shows a fairly simple (600 Ohm impedance, two inductors, five capacitors)
weighting network and a more complex constant resistance weighting
network.

However these networks aren't reproduced in the URLs above although the
weights are, which may help the OP.

--
John Phillips

[icecube]

On 20 Maj, 10:11, John Phillips
wrote:
On 2008-05-19,

wrote:
On May 19, 2:45 pm, icecube wrote:
I'm trying to find away filter a signal with a weighting filter called
CCIR 468-4 (ITU-R 468-4) and AES17

so what i'm looking for in the math behind the weighting type so i can
use them

I believe ITU468-4 is the same as the old ANSI A weighting,
in which case, from:

Not as far as I can see. *See, for example:

* *http://en.wikipedia.org/wiki/ITU-R_468_noise_weighting

The ITU-R standard BS.468-4 (not available for free, I think):

* *http://en.wikipedia.org/wiki/Standard:ITU-R_468

shows a fairly simple (600 Ohm impedance, two inductors, five capacitors)
weighting network and a more complex constant resistance weighting
network. *

However these networks aren't reproduced in the URLs above although the
weights are, which may help the OP.

--
John Phillips

i was more looking the filter coef. but i'll try and see what i can do
with what i have which the information in the link