Accession Number : ADA193324

Title :   A Notch Filter Instrument for Measuring ELF (Extremely Low Frequency) MSK (Minimum Shift Keying) Signals.

Descriptive Note : Technical rept.,

Corporate Author : IIT RESEARCH INST CHICAGO IL

Personal Author(s) : Drexler, R G ; Gauger, J R

PDF Url : ADA193324

Report Date : Jan 1988

Pagination or Media Count : 101

Abstract : This report presents a notch filter technique for measuring extremely low frequency (ELF) signals in the presence of other higher-level, low frequency voltages, specifically 60 Hz and harmonics, on public utility systems. The report also describes the design, development, and operation of a special-purpose notch filter instrument that allows the practical realization of this measurement technique. The instrument, called the Notch Box III, is compact (2.75 x 10 x 9 in.), lightweight (less than 4 lb), and battery operated for complete electrical isolation and portability of its electronic circuitry. It features input buffering and selectable attenuation, input overload warning, a narrow-band 60 Hz notch filter with greater than 80 dB of attenuation, a Chebyshev low-pass filter providing sharp roll-off above 100 Hz, output signal buffering, and battery charge status indication. The Notch Box III can operate 150 hours on a single battery charge. Keywords: Extremely low frequency; Interference mitigation; Active filter; Notch filter; Interference measurement; Noise measurement; Instrumentation.

Descriptors :   *EXTREMELY LOW FREQUENCY, *FREQUENCY SHIFT KEYERS, *NOISE(RADIO), *ELECTROMAGNETIC WAVE FILTERS, ATTENUATION, CIRCUITS, ELECTRICAL INSULATION, ELECTRONICS, HARMONICS, INPUT, INSTRUMENTATION, INTERFERENCE, LOW FREQUENCY, LOW PASS FILTERS, LOW VOLTAGE, MEASUREMENT, OUTPUT, OVERLOAD, PUBLIC UTILITIES, SIGNALS, WARNING SYSTEMS, BANDSTOP FILTERS, NARROWBAND, TRANSFER FUNCTIONS

Subject Categories : Electricity and Magnetism
      Radio Communications

Distribution Statement : APPROVED FOR PUBLIC RELEASE