counter circuit

Published:2011/6/8 20:51:00 Author:chopper | Keyword: counter | From:SeekIC

Measuring phase angle adopts hardware counting mode instead of singlechip direct counting mode.Because hardware counting mode can improve the precision.We make 256 scale successive carry counting mode by using two pieces of 74HC161 in series.The external frequency reference selects a high-speed pulse generated by 10MHz active crystal oscillator to count the width of signal Fi output by phase-locked loop.Therefore,it can make the measuring absolute error of transadmittance angle less than 5% of theoretic calculation.The principle of circuit is as follows.



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