| 摘要 |
PROBLEM TO BE SOLVED: To provide a current adjusting circuit where a plurality of circuit characteristics can be adjusted simultaneously with a one-time zapping. SOLUTION: In this current adjusting circuit, a VCO1 , a VCO2 and a VCO3 which have the same circuit constitution on the same integrated circuit are constituted. Switching circuits 61-66, containing Zener diodes for zapping, current-supplying transistors 51-56 which output a reference current which is adjusted according to the signals from the switching circuits 61-66, and current mirror circuits 10, 20 which supply the same current as the reference current to the VCO1 , the VCO2 , and the VCO3 are installed. Thereby a fundamental oscillating frequency f0 of the VCO2 and the VCO3 can be adjusted simultaneously, by adjusting the fundamental oscillating frequency f0 of the VCO1 by zapping.
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