April 23rd 05, 04:48 PM
To hear Arny Krueger and others tell the story, the common comodisumo
PC with a sound card has wholly obsoleted all lgitimate test gear. So
the product described herein-which requires a backplane chassis and a
CPU card each of which also cost considerably more than the commodisumo
PC-must be a scam and all those companies buying them a bunch of
tweakos, gullibards, and dumb****s.
Plug-in digitizer card lets you trade resolution for speed
By Alex Mendelsohn, eeProductCenter
Mar 23 2005 (16:59 PM)
URL:
http://www.electronics-express.com/showArticle.jhtml?articleID=3D159905001
National Instruments Introduces Universal Instrument for Dynamic
Measurements
PXI-Based Flexible Resolution Digitizer Delivers Industry's Highest
Dynamic Range
Austin, Texas-Design and test engineers now can use a single modular
instrument to make a wide range of dynamic measurements with the new
National Instruments flexible resolution digitizer. Just as the digital
multimeter brought universal measurement capability to DC measurements,
the NI PXI-5922 flexible resolution digitizer revolutionizes dynamic
measurements with a universal measurement device. Engineers can combine
the module with NI LabVIEW 7.1 to create numerous types of instruments,
such as AC voltmeters, audio analyzers, frequency counters, spectrum
analyzers or I/Q modulation analyzers that often exceed the measurement
performance of high-end traditional instruments with similar
functionality.
"Virtual instrumentation redefined how test and measurement systems
were built," said Dr. James Truchard, NI president and CEO. "The NI
PXI-5922 flexible resolution digitizer redefines how the hardware for
virtual instrumentation is built by providing a device that spans many
different applications. The module ensures error-free measurements for
the broadest set of applications of any digitizer and takes us a long
way toward our goal of a universal instrument measurement platform."
Unlike traditional measurement devices that have a fixed resolution for
all sample rates, the NI PXI-5922 digitizer uses the NI FlexII ADC that
has flexible resolution and can sample anywhere from 16 bits at 15 Ms/s
to 24 bits at 500 ks/s. The NI FlexII ADC incorporates patented NI
methods for reducing the linearity and temperature drift errors
inherent to multi-bit sigma-delta converters to achieve unprecedented
dynamic range at high sample rates. With the module's large dynamic
range and low noise, design and test engineers can directly digitize
low-level signals without the need for external signal conditioning,
such as filters and low-noise amplifiers. Reduced signal conditioning
improves measurement accuracy and reliability while also saving test
system development time.
The combination of measurement flexibility and high dynamic range make
the NI PXI-5922 module ideal for a wide range of applications. With
performance exceeding the best commercially available ADCs, for
example, engineers can use the module to characterize and test the
latest DACs. For precision audio applications, the digitizer's
unparalleled ability to acquire signals with 24-bit resolution at up to
500 kS/s means engineers can capture high-order harmonics with wide
dynamic range. The module's 18-bit resolution at 10 MS/s makes it an
excellent digitizer for acquiring baseband I/Q signals used in digital
communications systems.
The NI PXI-5922 module is built on the Synchronization and Memory Core
(SMC) architecture for tight synchronization with other SMC-based
products such as high-speed digitizers, arbitrary waveform generators
and digital waveform generator/analyzers. This gives the module
multiple instrument synchronization with module-to-module skew of less
than 1 ns typical; deep, flexible onboard memory up to 256 MB per
channel; and high-speed data streaming. Engineers can use the module to
create mixed-signal stimulus response measurements or to expand the
number of acquisition channels up to 1,632 channels by synchronizing
multiple NI PXI-5922 modules.
Pricing and Contact Information
Priced from $6,495.
Ernest Martinez, National Instruments, 11500 N Mopac Expwy, Austin,
Texas 78759-3504. Tel: (800) 258-7022. (800) 258-7022, Fax: (512)
683-9300. E-mail: . Web: www.ni.com/modularinstruments
This latest National Instruments (NI) flexible-resolution digitizer has
been five years in the making. It also embodies no less than a dozen NI
patents.
Arguably, it offers the highest dynamic range of any digitizer on the
market. Offering a 120 dB SFDR (spurious-free dynamic range), the
PXI-5922 runs two simultaneously sampled channels, and has =B11-V and
=B15-V input ranges.
Inputs can be single-ended or unbalanced differential or operate as one
differential channel. Inputs can be low-Z or high-Z as well, under
software control. The PXI card's 50-ohm input provides correct BNC
cable termination. It's useful where frequency response is paramount,
such as in RF applications. The card's 1-Mohm input is for signal
sources that can't drive typical 50-ohm loads without saturation or
linearity degradation.
DC accuracy, for both 50-Ohm and 1-Megohm inputs, is =B1500-ppm (0.05%)
of input plus 50-=B5V on the =B11-V range. For the =B15-V range, DC
accuracy is also =B1500-ppm of input, plus 100-=B5V.
The Cat's Meow In Memory
All of that is backed up by as much as 256 Mbytes/channel of on-card
storage, depending on options. The deepest memory option lets one of
these digitizers acquire almost 420,000 triggered waveforms without
software intervention, in a multiple-record acquisition mode. That's
the cat's meow in applications such as radar where short trigger re-arm
times are the rule.
In use, a PXI-5922 can stream data continuously from its memory array
to host memory for longer acquisitions and for streaming to disk.
Moreover, the use of the PXI bus and scatter-gather bus mastering, let
you move data to your PC at speeds up to 100 times faster than most
instrument interfaces.
Resolution Vs Speed Tradeoffs
A PXI-5922 can sample at rates up to 500-ksamples/s for 24-bit
resolution, but---without making any changes---you can trade off
resolution for sampling speed, and sample much faster at up to 15
Msamples/s but at lower (16-bit) resolution. As NI notes in its press
release (on the left), that's why the card can substitute for a range
of high-end instruments.
Key to the PXI-5922 dynamic range performance is NI's proprietary Flex
II A/D analog-to-digital converter. It's part of an analog ASIC that
uses patented linearization to reduce harmonics that are inherent in
multi-bit delta-sigma A/D converters. The Flex II ensures dynamic
performance over a range of sampling rates.
What's more, the PXI-5922, like other so-called virtual instruments,
uses your host PC to run algorithms for linearization and calibration
to eliminate temperature drift and other non-linearity errors.
In a demo session I recently enjoyed with NI director of product
marketing Eric Starkloff, he emphasized that single-bit delta-sigma A/D
converters typically offer high resolution and high dynamic range, but
they're limited to low-frequency applications. "Because of limited
sampling speeds, they're not good for applications involving dynamic
signals greater than a few hundred kilohertz in frequency," he says.
"On the other hand, multi-bit delta-sigma A/Ds can give you high
dynamic range at high frequencies, but they must be linearized."
Starkloff also points out that conventional instrumentation usually
offers incremental performance improvements. "Those kinds of
instruments are not able to keep pace with the range of resolution and
dynamic range requirements a lot of people want."
Click on this chart to see the relationship of the speed at which a
signal is digitized versus the resolution (accuracy) with which it can
be acquired; the graph shows the relationship for conventional
instruments, NI's digitizers to date, and the new NI plug-in.
Click for larger graph
Not mentioned in NI's press statement is the fact that the PXI-5922's
are shipped factory-calibrated and are NIST-traceable (National
Institute of Standards and Technology).
Environmental Correction
The plug-in's on-board calibration circuit also corrects for
environmental effects on linearity, gain, offset, and input-bias
current, and you can run self-calibration at any time. Starkloff also
notes that the digitizer has a 2-year calibration cycle as well, which
should bode well as far as keeping cost-of-ownership under control.
If you do desire to have a lab calibrate one of these boards, you can
return it to NI, or you can send it to a qualified metrology lab for
its routine calibration.
NI now has a number of PXI digitizers, some with resolution up to 24
bits, and sampling rates to 200-Msamples/s. These complement the
company's signal generators that can use 16-bit data converters
operating at similar sample rates, as well as NI's digital waveform
generator/analyzers that work to 400-Mbits/s, and its RF vector signal
generators and analyzers that work out to 2.7-GHz.
With the addition of this PXI-5922 flexible-resolution digitizer you
can make NI's popular LabVIEW 7.1 graphical programming environment
create just about any kind of voltmeter or analyzer you can dream
up---even exotic quadrature modulation analyzers as found in today's
wireless communications systems. For less than $6500, that sounds like
a good deal to me.
(I guess it's like a $2000 line cord, Shakti Stones, or a toob amp
then.)
PC with a sound card has wholly obsoleted all lgitimate test gear. So
the product described herein-which requires a backplane chassis and a
CPU card each of which also cost considerably more than the commodisumo
PC-must be a scam and all those companies buying them a bunch of
tweakos, gullibards, and dumb****s.
Plug-in digitizer card lets you trade resolution for speed
By Alex Mendelsohn, eeProductCenter
Mar 23 2005 (16:59 PM)
URL:
http://www.electronics-express.com/showArticle.jhtml?articleID=3D159905001
National Instruments Introduces Universal Instrument for Dynamic
Measurements
PXI-Based Flexible Resolution Digitizer Delivers Industry's Highest
Dynamic Range
Austin, Texas-Design and test engineers now can use a single modular
instrument to make a wide range of dynamic measurements with the new
National Instruments flexible resolution digitizer. Just as the digital
multimeter brought universal measurement capability to DC measurements,
the NI PXI-5922 flexible resolution digitizer revolutionizes dynamic
measurements with a universal measurement device. Engineers can combine
the module with NI LabVIEW 7.1 to create numerous types of instruments,
such as AC voltmeters, audio analyzers, frequency counters, spectrum
analyzers or I/Q modulation analyzers that often exceed the measurement
performance of high-end traditional instruments with similar
functionality.
"Virtual instrumentation redefined how test and measurement systems
were built," said Dr. James Truchard, NI president and CEO. "The NI
PXI-5922 flexible resolution digitizer redefines how the hardware for
virtual instrumentation is built by providing a device that spans many
different applications. The module ensures error-free measurements for
the broadest set of applications of any digitizer and takes us a long
way toward our goal of a universal instrument measurement platform."
Unlike traditional measurement devices that have a fixed resolution for
all sample rates, the NI PXI-5922 digitizer uses the NI FlexII ADC that
has flexible resolution and can sample anywhere from 16 bits at 15 Ms/s
to 24 bits at 500 ks/s. The NI FlexII ADC incorporates patented NI
methods for reducing the linearity and temperature drift errors
inherent to multi-bit sigma-delta converters to achieve unprecedented
dynamic range at high sample rates. With the module's large dynamic
range and low noise, design and test engineers can directly digitize
low-level signals without the need for external signal conditioning,
such as filters and low-noise amplifiers. Reduced signal conditioning
improves measurement accuracy and reliability while also saving test
system development time.
The combination of measurement flexibility and high dynamic range make
the NI PXI-5922 module ideal for a wide range of applications. With
performance exceeding the best commercially available ADCs, for
example, engineers can use the module to characterize and test the
latest DACs. For precision audio applications, the digitizer's
unparalleled ability to acquire signals with 24-bit resolution at up to
500 kS/s means engineers can capture high-order harmonics with wide
dynamic range. The module's 18-bit resolution at 10 MS/s makes it an
excellent digitizer for acquiring baseband I/Q signals used in digital
communications systems.
The NI PXI-5922 module is built on the Synchronization and Memory Core
(SMC) architecture for tight synchronization with other SMC-based
products such as high-speed digitizers, arbitrary waveform generators
and digital waveform generator/analyzers. This gives the module
multiple instrument synchronization with module-to-module skew of less
than 1 ns typical; deep, flexible onboard memory up to 256 MB per
channel; and high-speed data streaming. Engineers can use the module to
create mixed-signal stimulus response measurements or to expand the
number of acquisition channels up to 1,632 channels by synchronizing
multiple NI PXI-5922 modules.
Pricing and Contact Information
Priced from $6,495.
Ernest Martinez, National Instruments, 11500 N Mopac Expwy, Austin,
Texas 78759-3504. Tel: (800) 258-7022. (800) 258-7022, Fax: (512)
683-9300. E-mail: . Web: www.ni.com/modularinstruments
This latest National Instruments (NI) flexible-resolution digitizer has
been five years in the making. It also embodies no less than a dozen NI
patents.
Arguably, it offers the highest dynamic range of any digitizer on the
market. Offering a 120 dB SFDR (spurious-free dynamic range), the
PXI-5922 runs two simultaneously sampled channels, and has =B11-V and
=B15-V input ranges.
Inputs can be single-ended or unbalanced differential or operate as one
differential channel. Inputs can be low-Z or high-Z as well, under
software control. The PXI card's 50-ohm input provides correct BNC
cable termination. It's useful where frequency response is paramount,
such as in RF applications. The card's 1-Mohm input is for signal
sources that can't drive typical 50-ohm loads without saturation or
linearity degradation.
DC accuracy, for both 50-Ohm and 1-Megohm inputs, is =B1500-ppm (0.05%)
of input plus 50-=B5V on the =B11-V range. For the =B15-V range, DC
accuracy is also =B1500-ppm of input, plus 100-=B5V.
The Cat's Meow In Memory
All of that is backed up by as much as 256 Mbytes/channel of on-card
storage, depending on options. The deepest memory option lets one of
these digitizers acquire almost 420,000 triggered waveforms without
software intervention, in a multiple-record acquisition mode. That's
the cat's meow in applications such as radar where short trigger re-arm
times are the rule.
In use, a PXI-5922 can stream data continuously from its memory array
to host memory for longer acquisitions and for streaming to disk.
Moreover, the use of the PXI bus and scatter-gather bus mastering, let
you move data to your PC at speeds up to 100 times faster than most
instrument interfaces.
Resolution Vs Speed Tradeoffs
A PXI-5922 can sample at rates up to 500-ksamples/s for 24-bit
resolution, but---without making any changes---you can trade off
resolution for sampling speed, and sample much faster at up to 15
Msamples/s but at lower (16-bit) resolution. As NI notes in its press
release (on the left), that's why the card can substitute for a range
of high-end instruments.
Key to the PXI-5922 dynamic range performance is NI's proprietary Flex
II A/D analog-to-digital converter. It's part of an analog ASIC that
uses patented linearization to reduce harmonics that are inherent in
multi-bit delta-sigma A/D converters. The Flex II ensures dynamic
performance over a range of sampling rates.
What's more, the PXI-5922, like other so-called virtual instruments,
uses your host PC to run algorithms for linearization and calibration
to eliminate temperature drift and other non-linearity errors.
In a demo session I recently enjoyed with NI director of product
marketing Eric Starkloff, he emphasized that single-bit delta-sigma A/D
converters typically offer high resolution and high dynamic range, but
they're limited to low-frequency applications. "Because of limited
sampling speeds, they're not good for applications involving dynamic
signals greater than a few hundred kilohertz in frequency," he says.
"On the other hand, multi-bit delta-sigma A/Ds can give you high
dynamic range at high frequencies, but they must be linearized."
Starkloff also points out that conventional instrumentation usually
offers incremental performance improvements. "Those kinds of
instruments are not able to keep pace with the range of resolution and
dynamic range requirements a lot of people want."
Click on this chart to see the relationship of the speed at which a
signal is digitized versus the resolution (accuracy) with which it can
be acquired; the graph shows the relationship for conventional
instruments, NI's digitizers to date, and the new NI plug-in.
Click for larger graph
Not mentioned in NI's press statement is the fact that the PXI-5922's
are shipped factory-calibrated and are NIST-traceable (National
Institute of Standards and Technology).
Environmental Correction
The plug-in's on-board calibration circuit also corrects for
environmental effects on linearity, gain, offset, and input-bias
current, and you can run self-calibration at any time. Starkloff also
notes that the digitizer has a 2-year calibration cycle as well, which
should bode well as far as keeping cost-of-ownership under control.
If you do desire to have a lab calibrate one of these boards, you can
return it to NI, or you can send it to a qualified metrology lab for
its routine calibration.
NI now has a number of PXI digitizers, some with resolution up to 24
bits, and sampling rates to 200-Msamples/s. These complement the
company's signal generators that can use 16-bit data converters
operating at similar sample rates, as well as NI's digital waveform
generator/analyzers that work to 400-Mbits/s, and its RF vector signal
generators and analyzers that work out to 2.7-GHz.
With the addition of this PXI-5922 flexible-resolution digitizer you
can make NI's popular LabVIEW 7.1 graphical programming environment
create just about any kind of voltmeter or analyzer you can dream
up---even exotic quadrature modulation analyzers as found in today's
wireless communications systems. For less than $6500, that sounds like
a good deal to me.
(I guess it's like a $2000 line cord, Shakti Stones, or a toob amp
then.)