Abstract:The purpose of the article is to design a small S-band USB transponder on the basis of ZYNQ to reduce the size of the transponder and ruduce the power consumption of the transponder; This paper firstly introduces the advantage of ZYNQ,and puts forward the design scheme of a standard USB transponder based on ZYNQ 7000,and discusses the key technology and the principle of modulation and demodulation of the transponder.The working process of the transponder is as follows:when the satelite enters the on-orbit flight stage,the transponder receives the uplink remote control subcarrier signal transmitted from the ground monitoring station,and after demodulation,transmits the remote control PCM sream to the relevant equipment through the interface with other satellite subsystems;the transponder receives the uplink ranging signal transmitted from the ground monitoring station,the ranging baseband signal is transmitted to the ground after local frequency upconversion;the PCM remote data is received through the UART serial port,and the modulated telemetry data is sent to the ground station through the telemetry subcarrier;the internal telemetry information is sent to other subsystems through the serial port.That is,the transponder has the function of transmit distance、demodulate remote control commands and transmit telemetry subcarrier in non spread spectrum mode; The transponder’s up conversion part and down conversion part use the integrated chip,to simplify the circuit.The use of the ZYNQ and the integrated chip greatly reduced the volume of the transponder and ruduce the power consumption of the transponder.
