Monday, 13 February 2012

Phase Locked Loop (PLL) Oscillator Circuit 860 MHz

Phase Locked Loop (PLL) Oscillator Circuit 860 MHz

This 860 MHz Phase Locked Loop (PLL) oscillator circuit is for 1200 MHz transverter's local oscillator with 435MHz rigs. The oscillator circuit uses PLL synthesizer IC's of Toshiba for PLL circuit. TC9122P is easy to use preset counter for determining request frequency value by patching. TC5081AP is phase comparator and TC5082P is binary counter for 2048 dividing. TC5082P has also been consited of Xtal oscillator circuit. 12.8MHz is divided by 2048 into 6.25Khz.

MB501 is a 64 dividing prescaler You must patch the input of TC9122P for 2150, and 6.25kHz*2150*64 comes to 860MHz. Parts VCO made by MURATA as MQC-302-856.

Circuit Diagram
The loop filter is simple lag-lead filter The output RF signal is boosted by MMIC. The uPC1675G is not suitable for this level, you may use MAR-3 instead. Because the uPC1675G's PiMAX is 0dBm and then Po:4dBm, MQC-302-856's output of over power. If you use MAR-3 instead you will get 11dBm of RF output.

I would like to use this LO for 1200 MHz to 435 MHz converter and combining with TUF-5 DBM. TUF-5 asks +7.5dBm LO input for MAX conversion gain. And on the input of DBM there should be placed PAD for decreasing distortion. 11dBm output level is adequate, so I think.

Assembled Circuit
Printed Circuit Board

Local Oscillator Parts

No comments:

Post a Comment