[hpsdr] Mercury update

[pvharman at arach.net.au]

We are now very close to a working Ozy board and the software necessary to 
interface to PowerSDR.  I had suspended the work I was doing on Mercury until 
the larger FPGA on the Ozy board was available since I was unable to cram all 
the code into the small Cyclone FPGA used on the Xylo evaluation board.  

Since I should be able to start on this again shortly I thought that I would 
do a little math and see what potential performance we may be able to achieve 
with the LT2208 ADC. 

I’ve posted my calculations on the Wiki so others can see how the figures were 
obtained (and correct them!).  Assuming we are able to achiever the 
specifications of the LT2208 then the Mercury board is starting to look like a 
very useful receiver indeed.

73's Phil...VK6APH