circuit using cmos to mutiply frequency?

Question

i need a circuit using cmos to multiply frequency

Answer 1

ok...

Answer 2

It seems such as you pick to calibrate an inner RC clock to the mains frequency. Atmel has an utility notice on the thank you to try this (see source). as a fashion to "discover" the mains frequency you first verify a era between to different factors on the sine wave. The era is a count quantity from a timer it fairly is began and stopped using the different factors on the sine wave or a ingredient of the sine wave such via fact the constructive a million/2. there are various different techniques (i.e. circuits) to end this and what you pick upon will remember upon various factors collectively with fee, present circuitry, ability grant , EMC subject concerns, protection and so forth... the finest technique makes use of two resistors to style a voltage divider it fairly is straight away linked around the biggest and to the micro controller, its very decrease priced yet no longer very secure. The technique works with the help of sensing the era of the constructive a million/2 of the sine wave. you could make this device extra robust and safer with the help of including factors (increasing fee) collectively with a transformer for isolation and clipping diodes to cut back utilized voltages to the uC. 0 crossing detectors can be used. in case you're using a transformerless ability grant you could already be waiting to %. off a 0 go sign. an entire wave bridge factors pulsating DC to the backside of a transistor . The transistor controls the enter to an opto isolator which factors isolation betewwen teh mains and uC.

Answer 3

Phase-lock loop is what you want, good ol' 4046 -

http://www.fairchildsemi.com/ds/MM%2FMM74HC4046.pdf

In case you're not familiar w/these, the idea is to build a divider that divides the PLL output by the same number that you want to multiply your source frequency. The frequency (& phase) of the 2 is compared by the 4046, and if not equal, drives the output appropriately until it is.

I've built a few circuits using these, drop me a line if you need more detail.