Design And Implementation Of The Short Wave Frequency Synthesizer Of DF100A Transmitter

DF100A100KW transmitter is a short pulse step modulator analog broadcasting transmitters in the country has been widely used in high-power shortwave station, a high market share, usage of nearly100units. DF100A shortwave transmitter carrier frequency generated by the short-wave frequency synthesizer, is a major component of the transmitter frequency synthesizer stability determines the stability of the whole work; quality of frequency synthesizers indicators will decide on the entire transmitter the quality of machine indicators. This article focuses on the benefits of short-wave frequency synthesizer based on DDS technology and to study the implementation of DDS technology, the overall design of the DDS technology shortwave frequency synthesizer technology, and to achieve the core functionality through DDS, FPGA, ARM chip, control switch and interactive functions. Focused on the short-wave frequency bands within the frequency generation and control switching sinusoidal signal and the original transmitter frequency monitoring alarm function, automatic gain control functions are integrated together. The product is fully able to realize all of the features shortwave frequency synthesizer with adjustable output amplitude, stable performance, easy switching advantages. Meanwhile, the frequency synthesizer can also be input in advance the function diagram, according to the product in order to achieve automatic switching frequency diagram; be complete and accurate display of the output frequency detection; output amplitude can be adjusted manually to achieve automatic control. Currently, the frequency synthesizer has DF100A shortwave transmitter applications, stable performance, good.This paper DF100A shortwave transmitter shortwave frequency synthesizer design to introduce the following aspects:Starting from the shortwave frequency synthesizer design requirements and program selection, the relevant aspects related to the technical points focuses on the theory and circuit design DDS, selection and circuit design of the filter, AGC partially integrated and FPGA frequency measurement method and circuit implementation, and results of the design and performance simulation and verification.