Proper

Abstract

The transmitter and the receiver of the two parts is an important part of wireless communication system. Transmitter is divided into two kinds according to the modulation method, one kind is to simulate the transmitter another kind is the digital transmitter. Simulation principle of the transmitter can be modulated by controlling the signal in the voltage controlled oscillator varactor its capacitance change, so caused the oscillation frequency of the vco changes, thus to realize the frequency modulation. But analog transmitter has many shortcomings and the insufficiency, such as single function or single carrier frequency in the system is not easy to change, so can't guarantee the effect of variable frequency, and due to the characteristics of varactor constraint, the smaller the modulation frequency. With the rapid development of wireless technology, and now the number of large scale, such as ultra-high speed digital integrated circuit transmitter because it has the following advantages and gradually becomes the direction for the future of transmitter, adjustable carrier frequency, symbol rate, high frequency programmable, modulation mode can be restructured. In this paper, design of nc FM transmitter can be in 80.0 MHZ to 80.0 MHZ 0 arbitrarily set frequency, 11 channels can be preset, so avoid the frequency of the oneness.