24-Bit, 204.8 kS/s Dynamic Signal Acquisition and Generation

Overview

The National Instruments 4461 and 4462 are high-accuracy data acquisition

devices specifically designed for sound and vibration applications. The

devices include the hardware and software needed to make precision

measurements with microphones, accelerometers, and other transducers

that have very large dynamic ranges. Common applications for the

NI 446x include audio test, automotive test, noise, vibration, and

harshness (NVH) analysis, and machine condition monitoring (MCM).

The NI 446x devices offer a complete range of functionality for sound

and vibration monitoring and analysis applications. With either two inputs

and two outputs, or four inputs, they are ideal for applications where

simultaneous generation and acquisition of noise, vibration, and acoustic

signals are required. You can synchronize the acquisition clock of your

NI 446x with other instruments in your system for mixed-signal

applications. Both analog and digital triggering are available on an NI 446x.

Hardware

Applications

• Audio Test

• Noise, Vibration, and Harshness Test

• Machine Condition Monitoring

• Sound Power

• Structural Vibration

• Pass-by Noise

Analog Inputs

The analog input channels of NI 446x devices have 24-bit resolution ADCs

that are simultaneously sampled at software-programmable rates for

standard audio applications, such as 44.1 kS/s (the standard rate used in

CD players), 48.0 kS/s (the rate used in digital audio tape (DAT) recorders

and other digital audio equipment), 96.0 kS/s, and 192 kS/s. An NI 446x is

well-suited for audio, sound, and vibration analysis applications.

The analog inputs offer programmable AC/DC coupling. A programmable

gain amplifier stage on the inputs gives gain selection from -20 to +30 dB

in 10 dB steps. Furthermore, to provide you with the quietest and

highest-quality analog measurements, the input stage accepts

differential or single-ended signal connections.

• 2 or 4 simultaneously sampled

analog inputs

• 2 simultaneously updated

analog outputs (NI 4461 only)

• 118 dB dynamic range, 24-bit resolution

• 204.8 kS/s maximum sampling rate

• 92 kHz alias-free bandwidth

• Input range from ±316 mV to 42.4 V

• 6 gain settings

• AC/DC coupling

• Antialiasing and anti-imaging protection

• IEPE conditioning – software-configurable

• Multimodule synchronization

Operating Systems

• Windows 2000/NT/XP

Recommended Software

• LabVIEW

• LabVIEW Real-Time Module

• LabVIEW Sound and

Vibration Toolkit

• LabVIEW Order Analysis Toolkit

• LabWindows/CVI

• Measurement Studio

Measurement Services Software

(included)

• NI-DAQmx

Calibration Certificate Available

NI 4461, NI 4462

Product

Bus

Analog

Inputs

Input

Resolution

Sampling

Rate

Input

Range

Input

Configuration

Analog

Outputs

Output

Resolution

Update

Rate

Output

Range

Triggering

NI 4461

PXI, PCI

2

24 bits

204.8 kS/s

±316 mV to 42.4 V

Differential/pseudodifferential

2

24 bits

204.8 kS/s

±100 mV to 10 V Analog/digital

NI 4462

PXI, PCI

4

24 bits

204.8 kS/s

±316 mV to 42.4 V

Differential/pseudodifferential

0

–

–

–

Analog/digital

Table 1. NI 446x Channel, Speed, and Resolution Specifications

Figure 1. These 24-bit delta-sigma converters deliver outstanding dynamic range.