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.

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html