Home |
Search |
Today's Posts |
#11
|
|||
|
|||
An SDR or DDS question?
"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! |
Thread Tools | Search this Thread |
Display Modes | |
|
|