Re: Simulation Device... Keyed Peak Detector
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Posted by Michael A. Terrell on May 28, 2008, 8:46 pm
Please log in for more thread options Jim Thompson wrote: That sounds like the old 'Keyed AGC' on TVs. A pulse from the flyback set a reference once each line, then the detected signal level was used to set the RF & IF gain. -- http://improve-usenet.org/index.html If you have broadband, your ISP may have a NNTP news server included in your account: http://www.usenettools.net/ISP.htm Sporadic E is the Earth's aluminum foil beanie for the 'global warming' sheep. | ||||||||||||||||
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Posted by Joerg on May 28, 2008, 8:53 pm
Please log in for more thread options > Jim Thompson wrote:
>> I want to build an ideal device for use in PSpice simulations, a Keyed
>> Peak Detector... >> >> Finds the maximum peak value of an input voltage while it's enabled >> ("keyed"), and "dumps"/outputs zero when not enabled. >> >> Any ideas? >
> > That sounds like the old 'Keyed AGC' on TVs. A pulse from the flyback > set a reference once each line, then the detected signal level was used > to set the RF & IF gain. > It's the other way around, like the fast-attack/slow-release AGC in single sideband receivers. Except that Jim wants to reset it when keyed off. I rarely have to use that in SPICE but stuff like this I mostly fudge out of real parts with the important values at the extremes, where the computer doesn't beep and the results are still reasonably accurate. -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM. | ||||||||||||||||
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Posted by Michael A. Terrell on May 29, 2008, 2:02 am
Please log in for more thread options
Joerg wrote: >
> Michael A. Terrell wrote: > >
> > That sounds like the old 'Keyed AGC' on TVs. A pulse from the flyback > > set a reference once each line, then the detected signal level was used > > to set the RF & IF gain. >
> It's the other way around, like the fast-attack/slow-release AGC in > single sideband receivers. Except that Jim wants to reset it when keyed off. The concept was the same though. You had a fixed reference level to compare the signal to, and used the recovered peak as needed. > I rarely have to use that in SPICE but stuff like this I mostly fudge
> out of real parts with the important values at the extremes, where the > computer doesn't beep and the results are still reasonably accurate. -- http://improve-usenet.org/index.html If you have broadband, your ISP may have a NNTP news server included in your account: http://www.usenettools.net/ISP.htm Sporadic E is the Earth's aluminum foil beanie for the 'global warming' sheep. | ||||||||||||||||
> I want to build an ideal device for use in PSpice simulations, a Keyed
> Peak Detector...
>
> Finds the maximum peak value of an input voltage while it's enabled
> ("keyed"), and "dumps"/outputs zero when not enabled.
>
> Any ideas?