PSK08  Software for the 56002EVM       A Talbot  G4JNT

PSK08 is a data communications mode identical in operation to PSK31, but 
operating at one quarter the speed, ie. approximately 8 symbols per second.   My implementation for the 56002 EVM board uses the minimum modifications necessary to the PSK31 software written by G3PLX for this platform and is loaded and run in an identical manner.

The EVM software changes involved changing the 500 Hz data sampling to 
125 Hz and altering the decimation filter to a 1024 tap length narrow 
bandwidth one.

The software for the EVM is in the file   PSK08A.CLD

The Windows driver program for the PC  is PSK08EVM.EXE. This is functionally 
identical to PSK31EVM.EXE except that I have used a hex editor to change all 
references within the program code to PSK08 and PSK08A.CLD so that the 
program automatically loads the correct .CLD at start up and shows the 
correct title information

The one problem, however, is that clicking on the waterfall to set centre 
frequency no longer works properly.  As the functionality of the driver 
program has not changed, it cannot recognise that the EVM software is now 
running at one quarter rate and just means you will have to tune more 
carefully and pay attention to exact frequency setting.

If this mode becomes more popular I may try to persuade Peter G3PLX to 
actually modify the source code to correct the situation.  Hopefully this 
will be no more complicated than adding a divide by 4 in a couple of lines 
of code and changing file names.

I also have a crude version of PSK01, but based on an earlier implementation 
of PSK31 only for DOS.  This does not include the waterfall and will rely on 
users knowing and being able to set their precise frequency to within 0.1 Hz 
accuracy.    At the moment filtering is also a problem as the EVM will run 
out of space if I try to use a simple FIR filter.
