[hpsdr] More Mercury

[KD5NWA]

What is the deal with not providing a real link to the photo, all this
CGI stuff is great if it doing something useful but for a link to a
photo, why not just put the link to the photo itself rather to download
a program that then goes out and gets the picture (Rube Goldberg). The
program can be one of hundreds and if it's not loaded on your PC? You
get nothing.. Linux, Windows XP, 4 different browsers and nada.

Very frustrating, I have not seen a single picture posted on
www.hamsdr.com ever.

Anyone care to share the secret of what the CGI in that server is
expecting in your PC?

Grumble, Grumble


On Mon, 2006-06-12 at 22:25 +0800, Phil Harman wrote:
> ***** High Performance Software Defined Radio Discussion List *****
> 
> I've been able to interface the LT2208 demo board to the Xylo and hence to 
> PowerSDR. The screen shot at
> 
> http://www.hamsdr.com/dnld.aspx?id=328
> 
> show a +10dBm signal at 25MHz directly into the LT2208.  With the image 
> amplitude and phase controls at 0 and 0 respectively there is no visible 
> image.
> 
> The FPGA interface to the LT2208 is very crude at the moment. I've using a 
> fixed NCO at 25MHz followed by a CIC filter decimating by 2048 since this 
> gives ~48kHz from the 100MHz clock. You can see the sinx/x shape of the 
> noise floor, the CIC needs following with a compensating FIR to flatten 
> this.
> 
> The CIC is also very simple, this is the design file from MatLab
> 
> // Discrete-Time FIR Multirate Filter (real)
> // -----------------------------------------
> // Filter Structure        : Cascaded Integrator-Comb Decimator
> // Decimation Factor       : 2048
> // Differential Delay      : 1
> // Number of Sections      : 3
> 
> I've chosen the input frequency on the screen shot to get rid of all of the 
> spurs - there are still lots of them but I guess a better CIC and FIR will 
> clean a lot of them up.  The bandscope vertical scale is wrong since I am 
> sending 16 bits from the LT2208 and PowerSDR is expecting 24. Still it 
> lools like we are getting the full 16 bits from the LT2208 since you can see 
> about 96dB of DR.  What is intersting is that with no signal input the 
> output from the LT2208 is 0, the LSB never moves, so the internal noise 
> looks very good.
> 
> We are going to need a decent pre-amp for the high bands but even so the 
> initial results look quite good.
> 
> Must sleep!!
> 
> 73's Phil...VK6APH
> 
> 
> 
> 
-- 

Cecil
KD5NWA
www.qrpradio.com


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