Hello I am trying to find a peak detection circuit that is as passive as possible (ideally no battery needed) that takes an input signal of around 700 microvolts pk-pk. All of the passive peak detector circuits that I have found use diodes making it impossible for me to use them with how small my input signals amplitude is. Are there any other options that work for envelope detection of very small signals without having to use a diode or amplifier? Any references on where I could start would be appreciated as I am having trouble with where I could begin.
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what impedance and frequency? what output? – Tony Stewart EE75 May 14 '17 at 23:48
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The frequency of the carrier wave is 1-10Mhz and modulation wave is about 0.3 Hz. I am not sure on the impedance. – Samuel May 14 '17 at 23:54
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Well Schottky diodes work to such levels but depends on current. But seems like a poor requirement to operate without voltage. Even a CMOS gate is only uA as a high gain linear detector. – Tony Stewart EE75 May 14 '17 at 23:56
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What do you expect as an output? Maybe you could steal power from that? – Spehro Pefhany May 15 '17 at 00:13
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"ideally no battery needed" - why? – Bruce Abbott May 15 '17 at 01:10
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You might want to google "RF detector. Just because a diode needs 700 mV to turn on doesn't mean it can't be used for this application. – The Photon May 15 '17 at 02:30
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@Samuel you can't use ampilifier for that signal? – I.Omar Apr 22 '18 at 21:15
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How about this? (from RF Design magazine of decades ago)
simulate this circuit – Schematic created using CircuitLab
analogsystemsrf
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1By pre-biasing the diode to be "ON", microVolts PP at top node of diode will be rectified (or should we say ---- distorted) to cause a change in voltage across the Rout. – analogsystemsrf May 18 '19 at 11:09