Re: 10MHz peak measurement
From: Yukio (yano_at_shaw.ca)
Date: 12/07/04
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Date: Tue, 07 Dec 2004 07:38:24 GMT
You are describing the function of a AM RF detector operating ~ 10 MHZ , a
little pickier than a garden variety 455 KC AM Detector . Your requirements
for a Wide-Bandwidth is contrary to several generations of Ultra narrow band
designs, so you must back-engineer any modern circuit to increase the
bandwidth. Things like TRF amplifiers come to mind as opposed to HiQ IF
amplifiers. Just build an AM detector that will demodulate the local AM
station and go from there. Most OP Amps I've seen quit around 100KC so you
would have to find one that would work to around 20 MHZ . Diode Detectors
can be found that will work all the way into the GigaHertz range, the output
of which should in the ~ subsonic range ie 10's of seconds per Cycle, duck
soup for standard garden variety OP amps. Would a Voltage controlled
Amplifier help ? ie take the error Voltage from a PLL circuit monitoring
the Incoming Signal Frequency to adjust the gain of the Output amplifier to
track the frequency shift and flatten the output response
Yukio VE5YS
<jwodin@gmail.com> wrote in message
news:1102387589.710462.294510@z14g2000cwz.googlegroups.com...
>I have the simple problem of trying build a circuit that turns a
> ~8-15Mhz, ~100mV-2V sine wave into a DC level (for read out by an ADC).
> I've tried just rectifying and putting an RC to hold the DC level, but
> I don't seem to get a flat response over the specified frequency
> range. The sine wave will change amplitude over seconds, but no faster
> than that. Any ideas, or am I just not good enough at making
> rectifiers with caps (which is very possible).
>
> Jesse
>
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