[hpsdr] ADC negative clip

[MDS Info]

John,

Yes, I had read that, thanks.

The ADC near negative clip and negative clip leds come on immediately upon powering up the SDK and Hermes lite.

No setting changes in PowerSDR cause them to go out.  I have tried all setting of dither on and off with all settings
of the step attenuator.  The noise floor rises and falls with the step attenuator settings.

With a S-ATT of zero the noise floor is around -138, and at 31 the floor is at -110.


One thing, though, if I hit TUNE, I see what looks like a tune carrier in the spectrum display, but when tune is turned
off the rx does not return.  The carrier goes away.  Leds 3 and 4 go off.  It looks like it is still in xmit mode, with
no rx at all.  The overload message disappears, I think because the rx is not functioning.  Nothing brings the rx back
except to power off the Hermes and SDK.

73's

Glen K4KV


-----Original Message-----
From: hermes-lite at googlegroups.com
[mailto:hermes-lite at googlegroups.com]On Behalf Of John Williams
Sent: Saturday, April 25, 2015 10:53 AM
To: hermes-lite at googlegroups.com
Subject: Re: ADC negative clip


https://github.com/softerhardware/Hermes-Lite/wiki/Software

Read the sections on shutting off dither and using the step attenuator.

On 4/24/2015 10:04 PM, MDS Info wrote:
> Hello,
>
> I have read that since I have leds3 and 4 on at power up, I have ADC
> Negative clip and ADC near negative clip.
>
> What does this mean, and what should I look for on the board?
>
> I am assuming this is causing the adc1 overload message in PSDR.
>
> 73's
>
> Glen K4KV
>

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