"gareth" wrote in message
...
"gareth" wrote in message
...
"Brian Howie" wrote in message
...
http://www.radioelementi.it/public/saqrx.pdf
https://sites.google.com/site/sm6lkm/saqrx/

Wow! Wow! Wow!

Dev-C++ a free C++ compiler for Windows thrown in, and much
smaller than MicroBloat's products!

Having now had time to persuse the C code, I have the answers to
all my questions!

I'd like to recommend to ALL readers of these NGs that they download
the source code and the free C compiler whilst they are available, even
if not immediately using them.

Within the AudioCallBack routine is where it all happens, including the
phase accumulation making the DDS for the local VFO, and the FFT.

It's some years aince I've seen a Windows program done at the knife-and-fork
level and so that takes me back before the times of Visual Basic, and TCL.

As Brian said, it is easy to recompile and build the program again, thus
giving
the opportunity to dabble with the code by trying out minor edits, even if
limited to the colours (colors for the yanks) of the Windows.

The program clearly relies on the speed of a PC, for example, the DDS
calculates
sin and cos on the fly from the phase accumulator rather than using a
look-up table, and
I'm afraid the dinosaur in me keeps harking back to my days of assembler
programming
on a PDP11/20 where the slowest instruction (save for RESET at 50 mSecs) was

BICB @(R1)+, @(R2)+, taking about 17 uSecs.


All-in-all, this revelation by Brian is to be recommended to those who
wish to see an example of DSP programming to run on a PC.

Well done, Brian, and many thanks!