Microphone Transceiver: TX filter bandwidth is 6kHz. Should be 3kHz maximum

[ly2ss]

Describe the bug.

HackRF One r4. Portapack H2+ fw: Mayhem n_240608. USB/LSB transmit filter bandwidth is 6 kHz. Should be 3kHz maximum. Combined with low cut off frequency 300 Hz would fit as designator 2K70J3E as per Recommendation ITU-R M.1732-3 (02/2023) "Characteristics of systems operating in the amateur and amateur-satellite services for use in sharing studies"

More details: http://www.rfcec.com/RFCEC/Section-3%20-%20Fundamentals%20of%20RF%20Communication-Electronics/33%20-%20TRANSCEIVER/Transceiver%20-%20ARS%20Approximate%20BW%20of%20a%20SSBSC-AM%20RTPY%20Signal%20Emission%20Designator%202K70J3E.pdf

Zilvis (LY2SS)

Reproduction

The audio sweep test. https://youtu.be/o7e-1pjucLg

Expected behavior

Should be 3kHz maximum. Combined with low cut off frequency 300 Hz would fit as designator 2K70J3E as per Recommendation ITU-R M.1732-3 (02/2023).

Environment/versions

HackRF One r4. Portapack H2+ fw: Mayhem n_240608

Anything else?

No response

[Brumi-2021]

Hi @ly2ss, you are right, the max SSB bandwidth should be 3khz . Those switching filters are working well in RX side . I will have a look in TX side if we can reduce easily.
73 cheers

[Brumi-2021]

We can close now this issue with above merged commit . Later I will also update the Mic Transceiver wiki with that new feature .