The Time Source and AD/DA Interface

For many application it is necessary to have a synchronous time with the input and output of samples on the computer. Since oscillators on AD/DA can differ from the system-clock, it is better to use the AD/DA as time source. Also the time can float a little bit because of Audio I/O Buffers, so the computation for the sound is correct.

Here the C-Library libADDA is used, which can handle Audio on PCs running Linux OSS or ALSA and SGI-Audio (in future also NT), which provides the time source. If no AD/DA-card is used, the library uses the system clock as Time-Source.

For more details see the documentation on the libADDA.

Since more than one AD/DA-channel can be used, there is the possibility to use them in parallel, whereby the User has to guarantee that the AD/DAs are synchronized (by hardware). The Operation DAC or ADC can be used to get the data from this to/from the SDFGraph.

As parameter also the sample-rate, format and Buffer sizes (which are the advance) can be adjusted, but has to be probed if the the hardware support these.