ARCHIVE: Australian Ham Radio Discussion Forum ( AHRDF )

Is it possible to detect audio clipping on a sideband signal?

I've just recently obtained a bluetooth headset and adaptor. The bluetooth adaptor connects to my Yaesu FTDX3000. I've found that normal mic gains are far too high, so I've had to wind the mic gain back to about 7 to allow for this. Problem is, how do I know when the audio is clipping? Obviously, I want to get full modulation without clipping. I am feeding into a dummy load and monitoring on a RTL-SDR.com device, but it's hard to see if there is clipping or not.

See attachment. There seems to be lot's of harmonics. I've wound back the mic gain and there is less harmonics, but how do I know if I'm modulating 100%?

In your set up is it possible to route the audio out of the bluetooth adapter and then from the RTL-SDR into a DAW (digital audio workstation such as Cakewalk, Reaper, Audacity etc etc) as separate tracks, then compare the waveform traces?

Keep in mind that bluetooth has some real drawbacks if you are interested in clean and fast audio.

First up, bluetooth has enormous latency, generally thought to be between 34-200 milliseconds depending on the equipment and the usual RF issues, which can seriously screw with audio performance. Does this latency matter in an SSB audio set up? I have no idea, but in recording and mixing with a DAW it all but makes bluetooth headphones and microphones unusable.

The other thing to consider that using bluetooth means that the audio stream is encoded and decoded by various components along its journey (which is part of the latency issue) so each transformation makes its own changes to the stream.

HTH

Colin VK5CSW

Thanks Colin!
Sorry I didn't answer your post earlier (how rude of me!). Yes, I have Audacity and I am quite familiar with it. Making comparisons between the waveforms make sense.

I did connect my bluetooth headset to my computer and checked the waveform like this in Audacity and it was very clean. I am yet to do it through my rig. Had lots of things on since I posted this and just haven't got around to it

Ahhh life. It gets in the way of radio....