I got a xtal controle VHF commercial radio at Ham Fair Japan. I would like to use this for multi channel amateur band receiver. So I tried to make up the oscillator for 144MHz band.
(1) Configuration
-Oscillator
Using 2SK241 for oscillator circuit and Motrolla's MC145163 for synthesizer.
-Pre-scaler uPB565
This is a NEC made pre-scaler usable up to 1GHz. It has 4 kinds of dividing mode;2, 4, 8, 16. This time selected dividing 4.
-MC145163
This MOT's LSI is very suitable for designing ham rigs' VFO, which has 4 digit BCD preset counters from 3 to 3999. And also there is standard Xtal frequency oscillator and preset dividers. This LSI's input nodes are pull down in the LSI. You should supply 5V level for setting 1.
The maker said that this LSI is usable up to 15MHz input. However this time using at 38MHz (divided 4 from 154MHz), and you may supply 8V on the Vcc. I heard that at 8V of Vcc this IC could work up to about 50MHz input.
-Lag-lead filter
I adopted simple lag-lead filter followed OP-amp.
(2) Parts list
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(3) Assembled
I assembled digital portion on the universal PCB, and all of those are mounted and soldered on the bare board .
(4) Spectrum
I checked the spectrum using summary spectrum analyzer of amateur's. (6dB PAD inserted)
Refferences
-CQ HAM RADIO July 1992 P.230 "144MHz PLL Oscillator" By JA3KPA
-Sougo Denshi Publishing "PLL Application circuit" Dr.Ken Yanagisawa Sep 1977
Copyright 2004-2006 by JA3KPA/1, nob
12/04/10 ,2005/08/13,2005/5/03 updated
