Simplest way to delay/retard a square wave?

[sss]

yup , as the title says , need the simplest sircuit to delay a pulsed wave with not constant freq.
any ideas?

[I_Forgot]

How long do you need to delay it? Do you need to delay rising edge, falling edge, or both? Voltage swing? Fanout/current source/sink capability?

I_F

[sss]

Originally posted by I_Forgot
How long do you need to delay it? Do you need to delay rising edge, falling edge, or both? Voltage swing? Fanout/current source/sink capability?

I_F

i need to delay it in a millisec range ,something that can be controlled (increased or reduced)
need to delay the whole signal.

[fizzard]

How much variation in frequency? Is the delay constant or fixed? How much resolution do you need?

I PLL might work, maybe a shift register with a clock.

[sss]

Originally posted by fizzard
How much variation in frequency? Is the delay constant or fixed? How much resolution do you need?

I PLL might work, maybe a shift register with a clock.

hmm , audio freq range , the delay is constant , but i want to be able to change it with a pot or something.
thanx guys

[fizzard]

Are you trying to delay a digital audio signal, or a digital signal in the audio frequency range?

Is this a clock signal or digital data?

You could use a series of latches, and adjust the delay by changing where you tap the signal from. This won't be practical for long delays unless you have an FPGA.

You might want to look at a microcontroller (AVR, PIC, etc.). They have a built in analog to digital converter for a potentiometer input.

[gootee]

If it is an "externally-produced" (i.e. not under your control) signal, then it seems like the easiest way to delay it would be to use a bunch of digital memory and make a buffer big enough to hold at least the maximum delay's-worth of signal.

Make the buffer "circular" and have two memory address "pointers", one for the write location and one for the read location, that both increment around the circular buffer, separated by your delay.

If the pulses are strictly binary information (i.e. just "a pulse" or "not a pulse"), then the hardware could be almost trivial.

But if you need to also keep the amplitude information, then you'll have to have an analog-to-digital converter for the input and a digital-to-analog converter for the output, and use bytes of memory for each sample instead of bits, and maybe sample much more often, and worry about some other stuff, too.

My lab partner and I did one just like that, for audio signals, in an EE lab course, back around 1976 or so. But my lab partner had just made his own microprocessor system from scratch (for fun), and I think he pretty-much "carried me" on that particular project. :-)

Good luck.

- Tom Gootee

http://www.fullnet.com/~tomg/index.html

[sss]

oh , u guys make it sound complicated
its not a digital audio signal , got nothing to do with audio ...
its a simple square wave in audio freq range .
i dont want to use memory ,this makes it complicated.
what if i'll need to delay the rising edge only , can it be done without memory?
thanx again.

[dnsey]

Can you use the pulse to trigger a monostable, and take the output fro the other 'side'? (Would only work if the input frequency is constant or unimportant).

[sss]

Originally posted by dnsey
Can you use the pulse to trigger a monostable, and take the output fro the other 'side'? (Would only work if the input frequency is constant or unimportant).

imput freq is not constant