SSB MODULATOR UPPER AND LOWER SIDEBAND

Hi Piero,

The Hilbert transform goes in the audio path, to provide 90-degree phase-related baseband signals. You still need a quadrature carrier as shown in your project -- it could be made with a second Hilbert although a Quadrature VCO is easier. Here's an example diagram:

Best regards,

Bob

Hi Bob,
I'm on vacation a few days and I saw your answer now.

As soon as I go back, I do some tests.

Thanks

Piero

Hi Bob,

today I tried the modulator that you advised me, with the addition of some extra filtering it works very well.

I suppose that demodulation happens in the same way ?.

You know if the 1701 has an FxLMS filter, or it only exists on more powerful DSPs, I can not find it.

Thanks

Piero

Hi Piero,

The Wikipedia SSB entry is helpful. Demodulation as typically done in communications receivers is typically done with a BFO (an oscillator) at the IF frequency where the carrier would be if present, driving a product detector (multiplier). Usually the BFO must be manually adjusted to the correct frequency with a control often called a "clarifier." If the SSB modulator by design allows some carrier through, it's possible to have the demodulator phase-lock to the carrier. If you're interested in this approach, try searching for "PLL" here in the SigmaStudio section of Engineer Zone.

The new FxLMS adaptive filter is not available on the ADAU1701 or -1761.

Bob