An all Transistor PDM Telemetry Coder

摘要

This report describes an all transistor PDM telemetry coder that is very linear, is unaffected by variations in signal-voltage during the information pulse, and is free from the micro¬phonic effects encountered in vacuum tube circuits. The complete circuit includes an a stable blocking oscillator pulse-rate generator, a voltage-controlled delay multivibrator (DMV) encoder, and a gated memory circuit which prevents variations in signal voltage from appearing at the input to the DMV during the information pulse. The coder operates at a pulse rate of 900 ± 5 pps, exhibits a transfer function linear to within ±0.5%, and can be calibrated to 0.1%. Seven silicon transistors are utilized.