Suppressed-Carrier SSB Demodulator

This technic is know as demodulation by subsampling. The disadvantage is the sharp bandpass filter you would need, cuz you do a directconversion from RF into audio base band. Every carrier near by does get also demodulated.

Do you know of a technique that doesn’t demodulate nearby carriers?

I just realized that as long as the nearby signals are more than 20kHz away then only people with exceptional hearing will be able to hear them.

250kHz +- is also demodulated

Or 1MHz +- http://everycircuit.com/circuit/5411578806796288

No it isn’t. The “demodulation” of 250kHz +- will be averaged by the low pass filter to 0V+noise. 270kHz/230kHz won’t result in a 20kHz signal. It will still result in 0V+noise. What is demodulated other than the main signal is the harmonics of the main signal. 1MHz, 1.5MHz, 2MHz, etc. will be demodulated. However, this shouldn’t matter much since virtually any band pass filter could filter those signals out easily. As long as the stations near 500kHz never broadcast signals at 480/520kHz or closer, then the low pass filter at the output will filter out the unwanted signal and if that doesn’t work then our ears will do the filtering since we can’t hear frequencies above 20kHz. If the low pass filter restricts the highest frequency signal at the output to 3-4kHz, then the stations could be positioned quite close to each other in frequency without much issue.

Oh, sorry. When I wrote the last comment I hadn’t seen your most recent comment yet. Just the one about 250kHz.