[Qt-interest] Signal Generator Software Audio Enable

[Brad Howes]

On Nov 2, 2009, at 10:14 AM, Srdjan Todorovic wrote:

> Curious... did you use a QDial, or some special widget for the
> Freq/Amplitude/Phase dials?

Stock QDial.

> What's the highest frequency you can achieve on the PC you used, and
> does the process scheduler cause problems when your application is
> task-switched ?

As I mentioned, I calculate most values ahead of time and for my  
application it is not critical to be real-time when a dial changes,  
just close-to-real-time. For each generator, I create a lookup table  
for sine over 0 - PI, with spacing between samples dependent on the  
resolution of the messages. For instance, if I'm sending out 10K  
samples per message, with a message frequency of 400 Hz, then I get my  
per sample resolution and I can scale the lookup tables accordingly.  
Building the output messages is simply a sum of all generator lookup  
tables at each sample index, so your throughput limitation is really  
how fast one can sequence through your sample size. Of course you are  
limited by Shannon on how high a frequency you can generate without  
aliasing.

Brad

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Brad Howes
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