Acoustics Applications | Spectrum
The measurement and analysis of sound waves traveling in air, solids and liquids is important to a number of industries involved in production test, machine/engine performance and process control. Signals detected by sensors such as microphones and accelerators can reveal critical information about an objects behavior and action. Sound waves can also be used for acoustic location with active techniques employing sound generation and studying echo responses while passive methods listen for generated sounds or vibrations and then endeavor to determine the direction and location of the source. Perhaps the most famous acoustic location method is SONAR where hydrophones are be used to monitor waveforms traveling in water. However, acoustic location is also employed in other mediums and plays a key role in material science and geology.
Using the latest PC based technology, Spectrum digitizers and arbitrary waveform generators make excellent tools for use in the development, testing and operation of acoustic systems. Small and compact they offer a wide range of bandwidths and sampling rates so that they can best match the measurement needs. High-resolution digitizers offer 16 bit performance with very high precision and low noise. The cards deliver outstanding signal-to-noise ratio's (up to 90 dB) and spurious free dynamic range (up to 115 dB) so that the smallest signal variations can be detected and analyzed. Dynamic range is further extended by a front-end design which provides up to eight different full scale ranges (from ± 50 mV up to ± 10 V) and wide input offset.
Each digitizer card can have from one to sixteen channels and up to sixteen cards can be linked together with Spectrum's StarHub system to create instruments with up to 256 fully synchronous channels making them suited to applications with multiple sensors and sensor arrays. If necessary even larger systems can be created by connecting StarHub systems together making it possible to build systems with thousands of fully synchronized channels. The cards also come with large on-board memories (up to 1 Gsamples/card) and advanced streaming and readout modes for capturing and transferring signals. Streaming over the cards fast PCIe or PCI bus to a RAID based storage array allows the capture and storage of days of information. Spectrum's S Bench 6 software can also be used to view and qualify signals. FFT's are available for frequency domain analysis and power measurements while parametric calculations help to determine key signal characteristics like amplitude, frequency, pulse width and period.
Typical acoustic applications include acoustic ranging, acoustic location, SONAR, seismology, acoustic emission, vibration analysis, engine testing, process control, ocean acoustic tomography and bio-acoustics.
Spectrum Product Features
- Sampling rates from 100 kS/s to 3 MS/s
- Very low SNR and SFDR
- 8 input ranges from ±50 mV to ±10 V full scale
- Segmented Memory with FIFO Readout
- Star-Hub for high channel count systems with full synchronization
- SBench 6 for control display and analysis
Matching Card Families
- M2i.46xx: 16 Bit 3 MS/s to 200 kS/s Digitizer
- M2i.47xx: 16 Bit 1.33 MS/s to 100 kS/s Digitizer with 16 synchronous channels
- DN2.46x: 16 Bit 3 MS/s to 200 kS/s digitizerNETBOX LXI/Ethernet Digitizer
- M2i.601x: 14 Bit 20 MS/s to 60 MS/s Arbitrary Waveform Generator
Modular digitizers allow accurate, high resolution data acquisition that can be quickly transferred to a host computer. Signal processing functions, applied in the digitizer or in the host computer, permit the enhancement of the acquired data or the extraction of extremely useful information from a simple measurement.
Measurements on mechanical devices and systems using a modular digitizer requires the use of a variety of transducers or sensors in order to convert mechanical parameters such as force, acceleration, pressure, rotational speed, and their kindred into electrical signals you can measure. This article is a primer on making such measurements using a modular digitizer.