Abstract
The frequency synthesizer has been widely used in information communications and FM broadcasting. With digital technology in the rapid development of frequency synthesis technology to a new level.
The issue of using direct digital synthesis method to complete frequency synthesis. Hardware from the baseline frequency module production costs, frequency synthesizer module, keyboard input module, the module has four major components. Specific measures for implementation are : AT89C51 as the core, through the keyboard input to the microcontroller designated frequency, by SCM algorithm programmed control programmable counter 8254 and consisting of 4,046 PLL synthesis module, specified output frequency; Meanwhile, SCM will be sent to the frequency synthesis module displayed.
In the design process, in the hardware design has used the tool PROTEL99SE manufacture schematic diagram and the PCB board chart, in the software design has used the method which the module programs. In the debugging process has used the oscilloscope, the avonmeter, Top2005 programming, simulation software of Chaoxiang 3000.
Key words: Single-chip；the frequency synthesis； the keyboard entry； LED demonstrated
