Research And Design On Local Oscillator Of S-Band Converter Based On CPCI Bus

This paper introduces the research and design of two local oscillators of S-Band converter based on CPCI Bus.CPCI BUS has characteristics such as high speed, reliable and being easy to manage, it also has good compatibility with PCI features. Combine the design of RF circuit and the CPCI BUS, could make the frequency source applicable in more fields.This paper talked about the design of a S-Band multi-channel microwave frequency changer based on CPCI Bus firstly, then we compare the difference between different frequency synthesis methods, choose the design program of the local oscillator used on S-Band microwave frequency changer. We use a charge pump PLL frequency synthesizer and a DDS-PLL frequency synthesizer to achieve LO1 and LO2. Considering the modularization, miniaturization and complex electromagnetic environment characteristics of the CPCI system, miniaturization and EMC design is necessary in circuit. The size of the two frequency sources is about 50?25mm and 40?50mm.In the design of this study, an amplifier is added compared to ordinary PLL. The topic becomes highly versatile with this practical value added in the loop, which effectively inhibited the phase frequency leakage. The test results show that the phase noise of the frequency output from LO1 is 2925~3020MHz, phase noise better than-90 dBc/Hz @ 1 kHz, the step frequency is 10 MHz, stray for-69 dBc; the frequency output from LO2 is 960.001~970MHz, the step frequency is 1KHz, phase Noise better than-99 dBc/Hz @ 1 kHz, and stray for-70 dBc.This study has highly versatile and practical value.