Design And Implementation Of Missile-borne Miniaturized S-band Telemetry Transmitter

The telemetry system plays a very important role in our national defense weapon experiment.At present,the domestic telemetry equipment is developing towards the direction of small volume,low power consumption and high stability.The goal of this paper is to develop a miniaturized S band telemetering transmitter.Its volume is smaller than 30 mm × 30 mm × 30 mm,and it has a wide range of application scenarios.PCM/FM is the most commonly used telemetry system in the field of telemetry in China,with high stability and mature technology.The transmitter is divided into three parts: PCM encoder,FM modulator and power amplifier filter.PCM/FM telemetry system is adopted in this paper.In order to ensure that the signal of 0 or 1 of continuous 128 bit does not appear in the telemetry process,the code type used in this paper is pseudorandom non-zero flat code RNRZ_L,and channel coding is TPC code in the coding link at the same time.The channel gain of 4dB can be obtained at BER of 10^-5.Based on the study of frequency synthesizer and FM modulation,this paper finally adopts a more practical quasi-two-point injection phase-locked frequency modulation method based on two-point injection phase-locked frequency modulation technology.The basic principle of this modulation mode is expounded,its superiority and feasibility are demonstrated.In the design of power amplifier filter,a voltage-controlled oscillator with a certain output gain is used in the design of FM modulator,so a single-stage amplifier can be adopted.In this paper,we select the appropriate bandpass filter to filter noise and avoid affecting other frequency points.The problems that should be paid attention to in the PCB design of RF circuit are studied emphatically.In the end,the small telemetry transmitter in S band has been successfully developed,which has been successfully verified by indoor static telemetry transceiver test and flight test of telemetry system.