Design And Implementation Of 140MHz If Transceiver

With the development of electronic technology,satellite communication has been more and more used into many areas of society.IF transceiver as an important part of satellite communication IF receiver,is moving in the direction of high frequency,large dynamic range,high sensitivity,high linearity and high resolution.This paper is aimed at the actual demand of satellite communication 140 MHz IF transceiver.First of all,through the comparison of the scheme of various receiver and transmitter,the intermediate frequency transceiver scheme of this paper is determined,and then the working principle and key function components of the transceiver channel are deeply analyzed.On this basis,ADS(Advanced Design System)simulation software and the actual debugging are combined to meet the actual needs of the IF transceiver.In this paper,the 140 MHz transceiver requires the receiver to receive the frequency of 140 MHz ± 5MHz,the power of-30 dBm ~ 60 dBm signal,and produce the frequency of 14.96 MHz ± 5MHz,power 0dBm ± 1dB of the IF signal;and require the launch channel will be 25 MHz ± 5MHz,0dBm The modulation signal is upconverted to 140 MHz ± 5MHz and output at-20 dBm ± 1dB.This article has got following resultFirstly,the receiver uses the superheterodyne scheme and the voltage-controlled gain amplifier circuit.When the input signal frequency is 140 MHz ± 5MHz and the power is-30 d Bm ~-60 dBm large dynamic range,the output signal power unevenness is realized at 9.96 MHz ~ 19.96 MHz less than 1dB of design requirements.Secondly,the noise figure of each functional component and the cascade noise figure of each component are analyzed,and the low noise design of the receiving channel is realized by the calculation.Thirdly,according to the transmitter requirements,the design of transmitter has two output channels both emitting 140 MHz ± 5MHz,-20 dBm ± 1dB signal.Finally,the test results show that the noise figure of the receiving channel is 3.5dB when the small signal(-60dBm)is input,the noise figure of the receiving channel is 9.8dB when the large signal(-30dBm)is input,which meets the requirement of less than 10 dB The Other test indicators also meet the design requirements.