Research And Design Of The HF Wireless Transceiver

Wireless communication is a kind of communication manner which can exchange information using electromagnetic waves that propagate in free space. In recent years, the development of the wireless communication technology has made the correspondence among people become more convenient, and its application is more and more widely.In this thesis, a study is performed about the High frequency wireless transceiver, has produced this design detailed process and the final realization electric circuit, and the electric circuit principle of work is deeply studied. First of all, this paper gives a theoretical analysis of the modem, power amplifier, crystal oscillator, mixers and detectors and designs the corresponding circuit of each module based on the results of analysis of principles. Then PSPICE is used to simulate the circuit to optimize the circuit, according to the results of simulation make the circuit work in the best condition. Finally, a hardware circuit is fabricated by the results of theoretical analysis and designed schematics.The theory of ASK is used in the modulation system, and the circuit is realized by the high speed CMOS gate. A CMOS Pierce oscillator circuit is used for its excellent frequency stability, simple design, and high drive level, which meets the requirements of design. A high efficiency Class C amplifier is used in design. The latter class is a Butterworth low-pass filter which connects the antenna through the matching circuit after filtering and finally launches through the antenna. PREAMP is constituted by MC1350 and the amplified signal is mixed by the local oscillator circuit. The output of the IF signal is detected through the detector circuit and then transform the imitative signals into digital signals through a voltage comparator after detecting, thus completed the signal demodulation.The designed electric circuit is tested, and the result can satisfy the design specification. This electric circuit mentality is clear, simple, easy to realize also has a certain useful value.