DDS芯片及单片机设计.pdf

a AN-557 APPLICATION NOTE One Technology Way • P.O. Box 9106 • Norwood, MA 02062-9106 • 781/329-4700 • World Wide Web Site: An Experimenter’s Project for Incorporating the AD9850 Complete-DDS Device as a Digital LO Function in an Amateur Radio Transceiver* PIC “N” MIX DIGITAL INJECTION SYSTEM By Peter Rhodes, BSc, G3XJP (email pirrhodes@) PART 1 OF 5 CONVERGING THEMES This construction project brings together a number of Discounting the value of your time, I would argue that themes which I have been kicking around for some time. for years it has been viable to build multiband HF trans- But first, why PIC “N” MIX? ceivers which outperform their commercial counter- parts at any point on the price versus performance TWO ESSENTIAL TERMS graph—from the cheap and cheerful through to the truly PIC—A range of microcontrollers produced by Arizona exotic. Except, that is, for one critical element—the Microchip Inc. In this application, the PIC16C84. injection oscillator. DDS—Direct Digital Synthesis. The technique of digi- I have been build