Design of modular approach based Ku-band telemetry transmitter for geostationary satellites

The Telemetry, Tracking and Command system is critical to the success of a satellite mission. Telemetry transmitter is a part of TT&C RF subsystem for telemetry downlink and ranging operations. Optimal utilization of frequency bands is of fundamental importance to communications systems. With the growing number of satellites, the frequency band allocated for space applications in S-band and C-band is becoming increasingly crowded. Therefore, in future, all communication satellites will have to use Ku-band or Ka-band for TT&C operations. A modular approach based Ku-band telemetry transmitter has been designed to cater this need. Telemetry transmitter downlinks telemetry data and ranging tones to ground station in phase modulated format on a carrier frequency chosen in the Kuband. It consists of a PLL synthesizer based highly stable carrier generator, a varactor diode based phase modulator, BJT and MESFET based active frequency multipliers and a MMIC based low power amplifier.