24-Bit, 102.4 kS/s, 8 and 4-Channel
Dynamic Signal Acquisition
NI 4472 Series, NI PCI-4474
• 24-bit resolution
• 110 dB dynamic range
• 102.4 kS/s maximum
sampling rate
• 45 kHz alias-free bandwidth
• ±10 V range
• AC/DC coupling
• IEPE conditioning –
software configurable
• Multiple-device synchronization
Operating Systems
• Windows 2000/NT/XP
• LabVIEW Real-Time
• Mac OS X
Recommended Software
• LabVIEW
• LabVIEW Sound and
Vibration Analysis Toolkit
• LabVIEW Order
Analysis Toolkit
• LabWindows/CVI
• Measurement Studio
Measurement Services
Software (included)
• NI-DAQmx
Device
NI 4472
NI 4472B
NI 4474
Bus
PCI, PXI
PXI
PCI
Analog
Inputs
8
8
4
Resolution
24 bits
24 bits
24 bits
Sampling
Rate
102.4 kS/s
102.4 kS/S
102.4 kS/S
Input
AC Cutoff
Range
Triggering
Frequency
±10 V Analog and digital
3.4 Hz
±10 V Analog and digital
0.5 Hz
±10 V Analog and digital
3.4 Hz
Table 1. NI 447x Channel, Speed, and Resolution Specifications
Overview
The National Instruments PCI-4472 and PXI-4472 are 8-channel
dynamic signal acquisition devices for making high-accuracy audio-
frequency measurements. The NI PCI-4474 is a similar 4-channel
board. The vibration-optimized PXI-4472B offers a lower AC
cutoff frequency of 0.5 Hz. Input channels incorporate Integrated
Electronic Piezoelectric (IEPE) signal conditioning for
accelerometers and microphones. The input channels of an NI 447x
simultaneously digitize input signals over a bandwidth from DC to
45 kHz. You can synchronize multiple NI 447x devices for high-
channel-count applications, or with other modules using the PXI star
trigger bus or the RTSI bus on PCI. When used with the Sound and
Vibration Toolkit or other software analysis tools, an NI 447x can
obtain a variety of accurate time and frequency measurements for
your application.
dynamic range greater than 110 dB can be
Applications
Noise and vibration diagnostics
achieved. Using state-of-the-art delta-sigma
Audio test and measurement
modulating ADCs, the NI 447x devices
Machine condition monitoring
Sound power
achieve low noise and low distortion.
Telecommunications testing
Because these ADCs use a 1-bit quantizer
Structural vibration
Pass-by noise
oversampled at a multiple of the specified
sampling rate, they produce extraordinary linearity. Extremely flat,
linear-phase, lowpass digital filters then remove aliases and shape the
quantization noise from the band of interest. Using the delta-sigma
modulating ADCs, an NI 447x is immune to the DNL distortion
associated with conventional data acquisition devices.
>110 dB (24-bit)
Hardware
Analog Inputs
NI 447x devices have four or eight analog inputs with 24-bit
resolution ADCs that are simultaneously sampled at a software-
programmable rate. The high resolution provides the necessary
accuracy to make NI 447x devices well suited for audio and vibration
analysis applications.
Outstanding measurements can be achieved with an NI 447x.
For example, when sampling at 51.2 kS/s and using a 16 k FFT, a
Figure 1. The 24-bit architecture of the NI 447x devices deliver more than 110 dB dynamic
range and a significantly lower noise floor than 12, 16, and comparable 24-bit products.
Antialiasing
The analog inputs have both analog and real-time digital filters
implemented in hardware to prevent aliasing. Input signals are first
passed through fixed analog filters to remove any signals with
frequency components beyond the range of the ADCs; then digital
NI [ NATIONAL INSTRUMENTS CORPORATION ]
