[hpsdr] Janus Lives!!

[Gerald Youngblood]

Hi Phil,

The spectrum looks very clean.  Great work!  

There appears to be one problem with the measurements though.  The noise
floor in the screen shots cannot be accurately calibrated since the 500 Hz
RMS noise measures -159 dBm.  If you subtract 26 dB for the 500 Hz
bandwidth, you get a noise floor of -185 dBm/rt Hz.  This is below kTB of
-174 dBm/rt Hz.  That would equate to a negative NF (-11dB).  I would be
interested in seeing the 500 Hz bandwidth shot after calibration with the
radio attached.

73,
Gerald

Gerald Youngblood, K5SDR
FlexRadio Systems
Ph: 512-535-5266
Fax: 512-233-5143
Email: gerald at flex-radio.com
Web: www.flex-radio.com
 

> -----Original Message-----
> From: hpsdr-bounces at hpsdr.org 
> [mailto:hpsdr-bounces at hpsdr.org] On Behalf Of Phil Harman
> Sent: Monday, July 03, 2006 7:45 AM
> To: High Performance Software Defined Radio Discussion List
> Subject: [hpsdr] Janus Lives!!
> 
> ***** High Performance Software Defined Radio Discussion List *****
> 
> All,
> 
> I've just completed the CPLD software for the Alpha Janus 
> board and the results are spectacular.
> 
> The image below is of the Janus sampling at 48kHz.  As you 
> can see the noise floor is at a spectacular -159dBm (it 
> actually hovers around -160dBm but that is when I captured 
> the screen). As you can see there are absolutly no spurs in 
> the passband.
> 
> The file name is "Janus noise floor.jpg"  for those that have 
> a problem with getting files from www.hamsdr.com
> 
> http://www.hamsdr.com/personaldirectory.aspx?id=348
> 
> The second screen shot is at 48kHz in spectrum mode. Again no 
> spurs and the signal at 0Hz is -120dBm. This drops below the 
> band noise when I connect the SDR1000 hardware.
> 
> http://www.hamsdr.com/personaldirectory.aspx?id=349
> 
> The file name is "Janus spectrum.jpg"
> 
> I still have some more tests to do as well as testing  at 
> 96/192kHz but so far all is looking great.
> 
> There are a small number of minor changes to the prototype 
> PCB which will be addressed shortly.  My sincere thanks to 
> Lyle KK7P for doing such a great job on the PCB design, Bill 
> KD5TFD for the PowerSDR software modifictions so Janus will 
> work with it and help with the Verilog coding and all those 
> who helped me up the FPGA learning curve.
> 
> Onwards to OZY!!
> 
> 73's Phil...VK6APH
> 
> 
> 
> 
> 
> 
> 
> 
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