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# Decreasing frequency of TTL signal

## Decreasing frequency of TTL signal

(OP)

I have a TTL pulse from a camera which I want to use to trigger a laser off.  The problem I have is that the signal from the camera is 1kHz, and I only want to trigger the laser at a frequency of 1Hz.  So basically I need a device that takes the 1kHz signal and outputs a 1Hz signal (which is in step with the 1kHz input).

Any advice on a divice Which could do this would be most appreciated.

Tom
Replies continue below

### RE: Decreasing frequency of TTL signal

Why can't you use 3 BCD counters?

### RE: Decreasing frequency of TTL signal

(OP)

Thanks for the suggestion.  Will investigage 3 BCD counters...

### RE: Decreasing frequency of TTL signal

What you need is a frequency divider, or clock divider circuit. Such circuits can be constructed by using several digital logic divider or counter ICs. NOTE - there are other types of divider circuits that may not be fully synchronous, which would not meet your need to be "in step".

Example, a 74HCT4017 IC is a divider chip that can divide by 10 if connected properly. String three of these together and you have your 1Hz signal from a 1KHz input. The data sheets for these devices give basic application circuits. This is just a quick example out of a dozen common digital divider/counter chips readily available.

### RE: Decreasing frequency of TTL signal

A 1 Hz signal that is in step with a 1 kHz signal.

Does it matter with which of the 1000 pulses in the 1 kHz signal your 1 Hz is "in step"?

First one, 345th or last?

Gunnar Englund
www.gke.org
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

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