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Design >> RF Design >> 3MHz rectifier
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Message started by joc on May 5^th, 2010, 10:09am

Title: 3MHz rectifier
Post by joc on May 5^th, 2010, 10:09am

Hi there!
I need to rectify a 3MHz signal, with 30mVpp. I tried with an opamp LM318, but the bandwidth is not enough. I tried with a transistor 2n3904, in a common emiter configuration but I almost got an unity gain. I did this on a protoboard. Can I still use protoboard at this frequencies?. Any advice will be appreciated.
Thanks :o

Title: Re: 3MHz rectifier
Post by RFICDUDE on May 15^th, 2010, 4:58pm

Are you trying to demodulate a 3MHz signal, or are you trying to rectify a 3MHz carrier to perform power conversion (or are you trying to do something completely different)?

Title: Re: 3MHz rectifier
Post by rfcooltools.com on May 17^th, 2010, 10:35am

joc,

use two npns hooked as a differential pair tie one base to a voltage reference (AC short) then apply your 3 MHz signal to the other base (bias it correctly of course) your rectified signal will be at the emitter.

2n3904 will work at these frequencies.

Can I still use protoboard at this frequencies? Probably not an issue unless your trace is a meter or more.
Jeremy