Design And Implementation Of The Uhf-band Radio Transceiver Module

UHF radio communication has achieved wide and mature application in modern wireless communication, transceiver which is a base equipment of wireless communication, plays a decisive role in the quality of wireless communication. So, the design of UHF radio transceiver has a vast market demand and application.Following the development and the needs expansion of wireless communication, every part of UHF transceiver has spring up many matured products. In the low-end applications, we can find large number of semi-integrated or integrated wireless IC, which provide more choice and convenient for my design. Besides antenna, Radio transceiver consists of preselection filter, low noise amplifiers, mixer, IF filter, IF amplifiers, AGC, local oscillator circuit, modulation and demodulation, power amplifiers.This project chooses TH7122 wireless IC as a basic component, with LNA, filters, T/R switch, PA and other peripheral circuits make up of a small transceiver, which is used for audio or digital work in the UHF band. Data modulation adopts MSK, there are two frequency points in data modulation, 1200Hz and 1800Hz. Receiver employs one superheterodyne structure, signal via T/R switch, external LNA, filters, with the help of external LNA and filters, the image rejection and reduce noise figure is improved. Then the signal enters into internal LNA, Mixer and modulation. Transmit part uses a varactor diode which is connected with a cap to modulate the crystal, the frequency of VCO of PLL will change because of reference frequency (output of crystal), this signal is amplified by power enlarge circuits. Finally, the signal is transmitted by low pass filer and antenna. This design has advantages of inexpensive, miniaturization, modularize and trying to bring down the power dissipation.This paper contains a classic scheme of radio transceiver, all the qualification, radio's propagation model, qualification demonstration and analyze??. After that, we analyzed IC th7122 and its structure, designed its circuit. Besides, we provided other peripheral circuits, simulation and test results about the design.