Telemetry system with phase-locking noise suppressing receiver

A telemetry system for transmitting data from a remote device to a receiving device, said system having a transmitter in said remote device and a receiver in said receiving device, said transmitter comprising

• a carrier generator for generating a high frequency carrier signal;
• data means for providing pulse data;
• symbol means for generating a relatively low frequency symbol clock signal;
• modulating means for modulating said carrier signal to encode it with said data at a rate corresponding to said clock signal so as to provide pulsatile high frequency signals, and transmitting means for transmitting said pulsatile high frequency signals;
• said receiver comprising demodulate means for demodulating said transmitted pulsatile high frequency signals, said demodulate means having, circuit means for receiving a feedback signal carrying information used in demodulating said pulsatile high frequency signals;
• phase lock means for deriving from said demodulated signals a synchronized signal which is synchronized with said symbol clock signal;
• and
• symbol feedback means for generating a feedback signal in sync with said symbol clock signal and inputting it to said demodulate means.

A telemetry receiver for receiving and detecting transmitted pulsatile high frequency signals, said pulsatile high frequency signals being in the form of a high frequency signal modulated with a train of data symbols generated coincident with a symbol clock having a symbol rate less than said high frequency, and wherein the presence of a said symbol produces a said high frequency signal, comprising:

• High Frequency (hf) means for receiving said high frequency signals;
• detection means for detecting the occurrence of said high frequency signals, said detection means having enabling means for enabling its operation substantially coincident with each received pulsatile high frequency signal;
• phase means for determining the phase of said high frequency signals at the time of detection of each said signal;
• Phase Locked Loop (pll) means for generating a continuous signal which is phase-locked to the determined phase of said signals;
• calculating means for determining from said continuous phase-locked signal substantially when the next symbol is due to be generated;
• and
• said enabling means having demodulate means for generating a demodulating signal in phase with each received high frequency signal symbol.