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Design >> Analog Design >> Delay circuit for analog signal
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Message started by naina on Aug 16^th, 2017, 10:34pm

Title: Delay circuit for analog signal
Post by naina on Aug 16^th, 2017, 10:34pm

Hello
I am designing a delay circuit for my project which will delay an analog signal in nanosecond range. I have tried to do it using all pass filter but the design I am using is not working. Can anyone give some idea?

Title: Re: Delay circuit for analog signal
Post by neoflash on Aug 18^th, 2017, 4:29pm

I guess you need to be more specific:

1. nature of signal. linearity requirement on signal?
2. application of this delay? for what purpose?

naina wrote on Aug 16^th, 2017, 10:34pm:

Title: Re: Delay circuit for analog signal
Post by naina on Aug 19^th, 2017, 1:12pm

Actually I have to design a analog autocorrelator circuit and I was thinking to do it by mathematical formula. Means delay the signal then multiply them and then addition. I don't have all details. Can you tell me what are the specifications that I need to set. If you have any paper regarding it can you please send it?

Title: Re: Delay circuit for analog signal
Post by oge on Aug 21^st, 2017, 4:51pm

Not sure if this meets your spec, but for analog delays an easy way is current into cap delay. The way it works is you have a fixed current that charges a capacitor. Since i = C*(dv/dt), you can solve for dt which is the delay. dv/dt = i / C; dt = dv / (i / C); where 'i' is your constant current and 'C' is the size of your capacitor. dt is the time it takes for the voltage across the cap to change exactly 'dv' volts.

Example: I usually see this implemented as an inverter driving a capacitor. The output then drives another inverter or buffer that outputs a logic signal (ENABLE, or POWER_ON_RESET, etc.). The 'dv' in this case is the switching threshold of your next stage, for example.