Jim Lesurf wrote:
In article , Fleetie
wrote:



In the real world, the output from the D-A converter running at 30kHz
(remember Nyquist) will not be a 15kHz sinusoid, but will be a 15kHz
square wave.


This assumes the DAC has a "sample and hold" method for asserting the
output in between the sampled instants. Probably a good
assumption/approximation in many cases, but the actual waveshape will
depend upon the DAC.

As you indicated, though, the final output will depend upon the filtering
employed to help reconstruct the waveform.


A DAC without a reconstruction filter is as daft as an ADC without an
anti-aliasing filter.

Ian