[Probably fixed] White noise after changing slot

ea3ihi
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Location: Barcelona, Spain

[Probably fixed] White noise after changing slot

Post by ea3ihi » Fri Jan 24, 2020 6:57 pm

If you are listening to DMR in a slot and there is audio signal, if you press the star key to change slot and in the new slot there is no audio, a white noise can be heard. Should audio be turned off when changing slot? (maybe by calling terminate_digital()?)

VK3KYY
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Joined: Sat Nov 16, 2019 3:25 am
Location: Melbourne, Australia

Re: White noise after changing slot

Post by VK3KYY » Fri Jan 24, 2020 9:39 pm

I never hear this in normal operation

But if I change some optimisation settings it always has very loud white noise on all DMR signals.
Hence this sounds like another optimisation issue, but only in the version you have built yourself

ea3ihi
Posts: 87
Joined: Fri Jan 10, 2020 9:28 pm
Location: Barcelona, Spain

Re: White noise after changing slot

Post by ea3ihi » Sat Jan 25, 2020 9:39 am

I can confirm the same happens with your latest build from the 22nd of January

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EA5SW
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Location: Valencia, Spain

Re: White noise after changing slot

Post by EA5SW » Sat Jan 25, 2020 11:24 pm

The sound noise are low.. but I confirm this also in my own compilation.

Tested in duplex hotspot
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VK3KYY
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Joined: Sat Nov 16, 2019 3:25 am
Location: Melbourne, Australia

Re: White noise after changing slot

Post by VK3KYY » Sat Jan 25, 2020 11:38 pm

I tested this on several radios and I don't hear it at all.

So it seems that it only happens on some radios.

VK3KYY
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Location: Melbourne, Australia

Re: White noise after changing slot

Post by VK3KYY » Sun Feb 16, 2020 10:08 am

Does this occur in the latest version ?

VK3KYY
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Joined: Sat Nov 16, 2019 3:25 am
Location: Melbourne, Australia

Re: White noise after changing slot

Post by VK3KYY » Sun Feb 16, 2020 11:22 am

Ok

I will investigate

ea3ihi
Posts: 87
Joined: Fri Jan 10, 2020 9:28 pm
Location: Barcelona, Spain

Re: White noise after changing slot

Post by ea3ihi » Sun Feb 16, 2020 12:21 pm

It still happens to me too.

I have tried using the methods init_sound() and init_digital() when changing slot. Both methods are used when changing the channel. Using them when changing the slot did not produce the expected results.

it is not really anoying at all, I can only hear it when at home in a quiet room, but can it have some impact in the battery life?

ea3ihi
Posts: 87
Joined: Fri Jan 10, 2020 9:28 pm
Location: Barcelona, Spain

Re: White noise after changing slot

Post by ea3ihi » Sun Feb 16, 2020 3:13 pm

Interesting theory, something worth investigating, maybe we need to add a close audio call after the key beep

VK3KYY
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Location: Melbourne, Australia

Re: White noise after changing slot

Post by VK3KYY » Sun Feb 16, 2020 8:15 pm

I think there are several bugs.

1. I noticed that the audio amp gets turned on even if there is a signal on the other TG.
I tried to do a fix for this, on 15th Feb, but it had bad side effects for some people

I will need to find a better solution to prevent the amp turning on under that condition.

2. The beep system does not store the status of the audio amp prior to enabling the beep, and I think it probably does not turn the amp off after the beep I played.

However simply remembering the status of the audio amp prior to the beep enabling it, and restoring the state at the end of the beep would not work, because the DRM audio may be received during a beep, so the audio amp should not be always set back to the state prior to the beep.

Probably what is needed is 2 variables

One for the DMR system audio amp enable status and one of the beep system audio amp enable.

And only turn the amp off when both of those variables show that neither the DMR or beep system , needs the speaker to be enabled.

Also,
there is some code which I think reads the state of the audio amp enable pin, and uses it to determine if there is any audio.
This may be in the scanning code, but I can’t remember
This is not ideal, and it should instead use the new variable that just contains whether the DMR or FM system has enabled the audio amp

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