[Elecraft] P3 Measurements with new K3SYNA Boards

[Jim Brown]

On Tue,7/28/2015 7:38 AM, Alan Bloom wrote:
> On 07/27/2015 10:46 PM, Jim Brown wrote:
>> On Mon,7/27/2015 10:28 PM, Phil Wheeler wrote:
>>> Oh oh, Jim: We need a P3A :-) Good you took this on.
>>
>> Perhaps P3 firmware can be re-written to allow display of greater
>> dynamic range to the extent that electronics headroom supports it?
>
> The limit is the 32-bit arithmetic in the DSP firmware.  32 bits gives 
> you 96 dB less some headroom to allow for the averaging function.  I 
> tried floating-point arithmetic but it increased the computation time 
> by more than an order of magnitude.

Understood, and clearly the right design compromise.  My data is the 
accumulation of peaks, without averaging.  Might it be possible for a 
special "measurement version of the firmware that would squeeze another 
10 dB?

> As you said, you can see the improved phase noise performance of the 
> new synthesizer by simply cranking up the reference level and allowing 
> the carrier to go off the top of the screen.  Perhaps someone will do 
> that when upgrading to the new synthesizer and post before and after 
> plots. (Didn't somebody already do that?)

I did see some work like that posted done with an analyzer with less 
frequency resolution, and the results clearly showed the improvement.

Thanks and 73, Jim