PCM/FM+FM/FM Design Parameters for Telemetering Systems

International Telemetering Conference Proceedings / October 26-29, 1992 / Town and Country Hotel and Convention Center, San Diego, CaliforniaIn a PCM/FM+FM/FM system, the PCM data is added to the subcarriers at baseband and the composite signal is modulated onto the carrier. When the subcarrier messages are demodulated, part of the PCM signal's spectrum falls within the bandwidth of the subcarrier bandpass filters. This causes interference with the subcarrier messages, particularly those of the lower subcarrier frequencies. When designing a PCM/FM+FM/FM system, one is concerned with the placement of the subcarrier frequencies and the interference suffered by the subcarriers due to the PCM signal. This paper develops a relationship between the lowest frequency subcarrier, PCM bit rate and the resulting interference. The design procedure allows a bit rate or lowest frequency subcarrier to be selected for a specified interference ratio. The expression of the ratio is a complex integral which is reduced to a simple equation involving the system parameters.International Foundation for TelemeteringProceedings from the International Telemetering Conference are made available by the International Foundation for Telemetering and the University of Arizona Libraries. Visit http://www.telemetry.org/index.php/contact-us if you have questions about items in this collection