Question

You are using a D/A converter to generate a Sine wave. When you look at the output on an oscilloscope the signal looks too "jagged". What can you do to make it smoother?

Answer 1

1) the d-a convertion in the 6212 is 16 bits and you have a 20 volt range so each bit reprents a discrete 0.305mV step (+/- conversion errors). so you really aren't producing a pure sine wave just steps.

2) The larger portion of what you are observing on the oscilloscope is due to the o'scope. Essentially an O'scope is meant to be read by an operator so vertical accuracy is as good as an operator need. The standard is +/- 1/2 minor division. With 50 minor divisions on any range an acuracy of 1% is as good as a scope really needs to be- so the typical digital scope uses an 8bit ADC. Assume you have a 20V vertical scale this means the smallest change you can see is 78mV. Try looking at only a portion of the signal (use a finer vertical scale) and the resolution of what remains on the screen will improve.