Telemetry System Parameters and Bit Error Performance of NRZ and DM PCM/FM
PACIFIC MISSILE TEST CENTER POINT MUGU CA
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The work reported herein involved the experimental determination of optimum telemetry system parameters for the transmission of NRZ and DM PCMFM. The objective was to compare the efficiency of the two PCM formats and to evaluate rules of thumb for determining system parameters. A PCMFM telemetry system was simulated and optimum receiver IF bandwidth, RF transmitter deviation, and premodulation filter bandwidth for the transmission of NRZ and DM were determined so that NRZ and DM performance could be compared on an equivalent basis. NRZ and DM rules of thumb were examined to determine the system performance loss due to nonoptimum operation. The experiment verified other reported conclusions that show NRZ to be 3 dB better than DM for equivalent bit rates under their respective optimum conditions. Thus DM is not recommended for applications of maximum data transfer in a bandlimited RF system where noisy signals may be received.