On Thu, Jun 17, 2010 at 10:53:31PM +0200, Nick Copeland wrote: > > How do the other scopes work? If you really want to get a good image of > a waveform on a screen then you might want to totally divorce the sampling > rate from the screen drawing:
Yes. For a soft scope you have two options: a horizontal scale caibrated in 'samples' (a pixel corresponds to an integer number of samples), or one that maps to time (in ms or us). > To actually see a waveform and how it develops then you really need the scope > to sync to it. The way the oscilloscopes worked was a detection level at > which > to start painting (positive edge zero crossing for example but other levels > are > equally acceptable) and a delay time before searching again (blanking period, > more or less). In a digital scope finding the sync point requires upsampling by a least a factor of four, then you can interpolate linearly. After that, to display the actual waveform correctly aligned to the sync point you may have to interpolate even to a finer level. It's not at all a simple thing. Ciao, -- FA O tu, che porte, correndo si ? E guerra e morte ! _______________________________________________ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev