AD8307 as RF Demodulator to recover Audio from RF input

ello,

I need some help please. I am a Hobbyist with no engineering or math background and I like to build Receiver and Transceivers from projects I find in publications and on line, one I would like to build uses an AD8307 to recover audio from 0-18 MHz. It doesn’t list much details but I find the concept interesting if it can demodulate AM, SSB, CW signals and since I purchased more than 10 from mouser I’d really like to know how this works. I have not built the plans yet but if it works really well I will be happy. Also I’ve read other places it can also function as an IF Amp with AGC, if so can you help with that? I really need examples just not theory, and how high can this device function? I have several MC 1550 IF amps and plenty of circuits but that whole series is out of production.

My request may sound strange but I suffered severe Traumatic Brain injury in Combat so my math and theory skills are greatly reduced now, that’s why I’m seeking help.

i can include the schematics of a simple 0-18 MHz receiver if it would help.

Thank You,

Jim

PDF

  • 0
    •  Analog Employees 
    on Jul 14, 2020 1:39 AM

    Greetings Jim,

    Sorry about the delayed response to your inquiry. I'm just now getting the notification. Perhaps there was some system delay at this end.

    About your AD8307 circuit: The circuit in the PDF looks good to me. These types of simple circuits are how many people get started in radio. You should find this circuit in the PDF will demodulate AM such as for shortwave radio listening. The only problem I notice is the image frequency range of the input mixer is 90 to 108 MHz, which is the US FM broadcast band. To avoid interference from the FM broadcast, you might need a lot better filter on the input, not just the simple single inductor described in the PDF. This type of AD8307 demodulator circuit will not demodulate SSB.

    We're happy to help out here with the more specific questions about individual Analog Devices parts. For general help regarding simple RF circuits like this, you might want to reach out to a ham radio club in your area. Just a friendly suggestion. You can likely find one by a Google search. The ham radio community is generally very happy to help others when it comes to the art of radio. Perhaps try to attend one of their club meetings if possible. Although most in-person meetings are cancelled these days because of COVID-19, many ham radio clubs have online meetings instead.

    Hope that helps!  -Bruce