A Phase-Locked UHF Telemetry Transponder for Missile Scoring Applications

Abstract

The Phase-Locked UHF Telemetry Transponder described in this article is part of the recently conceived Cooperative-Doppler Missile Scoring System. This system obtains the doppler curve of a missile relative to its target, without the use of special scoring equipment in the missile. This is accomplished through comparison of the telemetry information from the missile with a transponded signal from the target aircraft. The transponder is housed in the target aircraft and is responsible for transponding PAM/FM modulation from the telemetry band (2200-2290 MHz) to the scoring band (1760-1850 MHz), while preserving the phase of the modulation during the frequency translation. In order to accomplish this, true phase demodulation of the PAM/FM signal has been achieved through utilization, of the phase-lock technique. Included in this article is an analytical discussion of the phase-lock loop design with derivations of the closed-loop transfer function and response bandwidth; Root-Locus analysis; Bode diagram; and dynamic range and phase response considerations.