[hpsdr] Meaning of ADC-L and ADC-R metering in PowerSDR

[Warren C. Pratt]

Hi Brian,

These values return the total signal into the "slice" BEFORE the 
bandpass filter.  So, they do not vary based upon the bandpass filter; 
however, of course, they do vary depending upon what is within the total 
bandwidth of the slice.

As far as I recall, there is no return of total ADC reading from 
hardware to software.  The closest thing is just the ADC Overload bit.

In brief, no they don't allow you to see the total ADC input.

73,
Warren  NR0V

On 2/22/2014 11:05 AM, Brian Lloyd wrote:
> ***** High Performance Software Defined Radio Discussion List *****
>
>
>
> Today I was using my ANAN-10 to get an idea of the total power coming 
> in from my Pixelsat loop. This is a broad-band untuned loop with a 
> preamp, good pretty much from DC to 30MHz. (Really it is useful from 
> about 50kHz to 20MHz but it does have significant output above and 
> below that range.) My assumption was ADC-L and ADC-R represented the 
> actual ADC values relative to full-scale, based on the fact that 
> PowerSDR labels the value in dBFS (decibels relative to full-scale).
>
> You can imagine my surprise when I discovered that this value changed 
> as I "tuned" the radio. (Yes I did check the attenuator and made sure 
> it was set to 0dB for these tests.) Now my supposition is that what 
> ADC-L and ADC-R are reporting are the values of the samples in a given 
> RX "slice" rather than the actual ADC values. If this is the case, 
> perhaps a new label is in order in PowerSDR? May I suggest, "Not Very 
> Useful - L" and "Not Very Useful - R". Or perhaps, "Slice - I" and 
> "Slice - Q".
>
> But a reading of how close the input is to saturating the ADC(s) would 
> be very useful.
>
> -- 
> Brian Lloyd, WB6RQN/J79BPL
> 706 Flightline Drive
> Spring Branch, TX 78070
> brian at lloyd.com <mailto:brian at lloyd.com>
> +1.916.877.5067
>
>
> _______________________________________________
> HPSDR Discussion List
> To post msg: hpsdr at openhpsdr.org
> Subscription help: http://lists.openhpsdr.org/listinfo.cgi/hpsdr-openhpsdr.org
> HPSDR web page: http://openhpsdr.org
> Archives: http://lists.openhpsdr.org/pipermail/hpsdr-openhpsdr.org/

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openhpsdr.org/pipermail/hpsdr-openhpsdr.org/attachments/20140222/d8e49461/attachment-0004.htm>