Digital filtering for data compression in telemetry systems
Abstract
There are many obstacles to using data compression in a telemetry system. Nonlinear quantization is often too lossy, and the data is too highly structured to make variablelength entropy codes practical. This paper describes a lossless telemetry data compression system that was built using digital FIR filters. The method of compression takes advantage of the fact that the optimal Nyquist sampling rate is rarely achievable due to two factors: (1) Sensor/transducers are not bandlimited to the frequencies of interest, and (2) Accurate, highorder analog filters are not available to perform effective band limiting and prevent aliasing. Realtime digital filtering can enhance the performance of a typical sampling system so that it approaches Nyquist sampling rates, effectively compressing the amount of data and reducing transmission bandwidth. The system that was built reduced the sampling rate of 14 highfrequency vibration channels by a factor of two, and reduced the bandwidth of thedata link from 1.8 Mbps to 1.28 Mbps. The entire circuit uses seven functionspecific, digitalfilter DSP`s operating in parallel (two 128tap FIR filters can be implemented on each Motorola DSP56200), one EPROM and a Programmable Logic Device as the controller.
 Authors:
 Publication Date:
 Research Org.:
 Sandia National Labs., Livermore, CA (United States)
 Sponsoring Org.:
 USDOE, Washington, DC (United States)
 OSTI Identifier:
 10173701
 Report Number(s):
 SAND948613C; CONF94101643
ON: DE94016611; BR: GB0103012
 DOE Contract Number:
 AC0494AL85000
 Resource Type:
 Conference
 Resource Relation:
 Conference: ICSPAT 94: signal procession applications and technology,Dallas, TX (United States),1821 Oct 1994; Other Information: PBD: [1994]
 Country of Publication:
 United States
 Language:
 English
 Subject:
 42 ENGINEERING; 99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE; TELEMETRY; DATA PROCESSING; DIGITAL FILTERS; DATA ACQUISITION; SAMPLING; REAL TIME SYSTEMS; COMPUTER ARCHITECTURE; 426002; 990200; LASERS AND MASERS; MATHEMATICS AND COMPUTERS
Citation Formats
Bell, R.M.. Digital filtering for data compression in telemetry systems. United States: N. p., 1994.
Web.
Bell, R.M.. Digital filtering for data compression in telemetry systems. United States.
Bell, R.M.. 1994.
"Digital filtering for data compression in telemetry systems". United States.
doi:. https://www.osti.gov/servlets/purl/10173701.
@article{osti_10173701,
title = {Digital filtering for data compression in telemetry systems},
author = {Bell, R.M.},
abstractNote = {There are many obstacles to using data compression in a telemetry system. Nonlinear quantization is often too lossy, and the data is too highly structured to make variablelength entropy codes practical. This paper describes a lossless telemetry data compression system that was built using digital FIR filters. The method of compression takes advantage of the fact that the optimal Nyquist sampling rate is rarely achievable due to two factors: (1) Sensor/transducers are not bandlimited to the frequencies of interest, and (2) Accurate, highorder analog filters are not available to perform effective band limiting and prevent aliasing. Realtime digital filtering can enhance the performance of a typical sampling system so that it approaches Nyquist sampling rates, effectively compressing the amount of data and reducing transmission bandwidth. The system that was built reduced the sampling rate of 14 highfrequency vibration channels by a factor of two, and reduced the bandwidth of thedata link from 1.8 Mbps to 1.28 Mbps. The entire circuit uses seven functionspecific, digitalfilter DSP`s operating in parallel (two 128tap FIR filters can be implemented on each Motorola DSP56200), one EPROM and a Programmable Logic Device as the controller.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 1994,
month = 8
}

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