Implementation of A 30-Channel PCM Telemetry Encoder

Abstract

The function of a PCM telemetry encoder, installed in moving vehicles such as automobiles, aircraft, missiles, and artillery projectiles, is to transform many physical variables, such as velocity, shock, temperature, vibration and pressure, into digital data. Also, the encoder is required to make a data frame composed of digital input signals and frame synchronous data. The framed data is supplied to the input of a transmitter. There are three critical considerations in developing a PCM telemetry encoder to be installed in an artillery projectile. The first is the performance consideration, such as sampling rate, data receiving rate and data transmission rate. The second is the size consideration due to the severely limited installation space in an artillery projectile and the last is the power consumption consideration due to limitations of the munition’s power supply. To meet these three considerations, the best alternative is a one-chip solution. Using a commercially available TMS320F2812 DSP chip, we have implemented a 30-channel PCM telemetry encoder to process randomized data frames, composed of 16-channel analog data, 14-channel digital data and 2 frame synchronization data per data frame, at 10Mbps transmission baud rate. This paper describes the structure of the 30-channel PCM telemetry encoder and its performance.