Audio played back on the air

JJ4SDR
Posts: 436
Joined: Fri Jul 30, 2021 10:09 pm
Location: TEXAS, USA

Audio played back on the air

Postby JJ4SDR » Sun Jan 16, 2022 11:46 pm

Hi,

Been quite happy with my 7k DLE MKII radio, but wondered if someone could shine some light on a question that someone posed after I played back their transmission that I had recorded. The fellow was suggesting that the audio played back may not necessarily be an accurate representation of what he sounds like as my radio will impart the sound qualities that it didn't have going out his transmitter.

Is there a block diagram that shows how and what processing kind of processing the ANAN puts on recorded signals that played back on the air? The TX is flat is the first requirement which the ANAN meets but how does the TX in the ANAN "process" such recorded audio? In addition to audio processing that ANAN does I also have audio processing that my Digital Audio Workstation does for my own TS signal.

Would appreciate information on this!
Best!
Juha
NI2M
PC: 8 Core i7-10700 CPU @ 2.90GHz, NVMe SK Hynix 512 GB SSD, 32GB RAM
Windows 10 Home, Version 22H2
Thetis v2.10.4.3 x64
Protocol 2 v2.1.18
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kc2rgw
Posts: 165
Joined: Mon Jun 22, 2020 5:44 pm

Re: Audio played back on the air

Postby kc2rgw » Mon Jan 17, 2022 12:44 pm

The signal is recorded as you heard it, after it's propagated, so the frequency response will shift.

Then when you transmit it, it will propagate again and the frequency response will shift again.

So the received recorded signal has your noise floor, and whatever signal strength it was as you heard it and the atmospheric effects on it from the path it took. Then you are repeating those layers again, back to the listener and then through whatever way they hear things, their noise floor, their pass band, their speakers or whatever.

It's always an approximation at best, though these rigs do a pretty nice job of it.
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w-u-2-o
Posts: 5540
Joined: Fri Mar 10, 2017 1:47 pm

Re: Audio played back on the air

Postby w-u-2-o » Mon Jan 17, 2022 5:05 pm

All audio processing is disabled on Quick Playback.

At one time there was a bug whereby CFC was not disabled properly during playback.

That bug was fixed in the initial release of Thetis 2.8.11
JJ4SDR
Posts: 436
Joined: Fri Jul 30, 2021 10:09 pm
Location: TEXAS, USA

Re: Audio played back on the air

Postby JJ4SDR » Fri Jan 21, 2022 12:36 am

Thanks for the responses. It seems to me that it may do justice to email a recording rather than play it back over the air. Obviously, the audio set-up at the station where the recorded file is played back will impact the sound, depending on the quality of the speakers and/or headphones.

Juha
NI2M
PC: 8 Core i7-10700 CPU @ 2.90GHz, NVMe SK Hynix 512 GB SSD, 32GB RAM
Windows 10 Home, Version 22H2
Thetis v2.10.4.3 x64
Protocol 2 v2.1.18

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