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J. Roger

Publications and source records attributed to J. Roger.

2 recordsLinked to original sources
USGS1978

A prototype design for microprocessor based digital telemetry transmitter for low frequency data

A prototype microprocessor based digital transmitter with low power requirements has been designed and built for use in dial-up telemetry applications. The processor used is the 8 bit RCA COSMAC. Input data is an analog signal in the range of -5 volts to +5 volts which is digitized to 12-bit precision. The transmitted data is a serialized and encoded frequency-shift-keyed signal suitable for transmission over phone lines or radio. Over 500 16-bit words can be stored in the data buffer for transmission with expansion up to 8k words possible. Average power consumption is less than 100 ma at 5 volts.

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USGS1977

A multi-channel digital telemetry system for low frequency geophysical data

An inexpensive general purpose digital telemetry system for collection of low frequency geophysical data from U.S. Geological Survey instruments (eg. tilt, strain, gravity, creep, water level, radon, magnetic field, resistivity, telluric current, temperature, etc.) has been designed and built. This system provides data for a more general interactive data acquisition, retrieval and analysis system. The field stations are self-contained, battery operated and housed in weather proof containers. Each accepts up to 15 analog data inputs in the range of -5 to +5 volts. The dynamic range is 70db. The units transmit information as FSK (Frequency Shift Keyed) tones onto either a phone line or radio link with up to 150 transmitters sharing one line. The average power consumption is 0.06 nR watts where n is the 1 number of input channels transmitted and R is the sample rate in minutes -1 . The central receiver-recorder unit accepts and decodes the FSK tones and converts, formats and records the digital data together with time information and station identification on IBM combatible magnetic tape. The digital data are also converted and recorded in analog form for visual monitoring.

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