Re: FG 504 function generator odd behaviour


Dave Daniel
 

The first thing to do is measure the power rails to make sure that the voltages are in spec and clean.

DaveD

On Jul 10, 2020, at 13:04, Colin Herbert via groups.io <colingherbert=blueyonder.co.uk@groups.io> wrote:

I have an FG 504 which is showing some odd behaviour. The triangle-wave shows asymmetry in that the negative peaks of the wave are rounded-off at any frequency and the positive ones have a similar but lesser problem at higher frequencies. This also seems to manifest itself as what looks like cut-off on the negative peaks of the sine-wave and lesser cut-off on positive peaks. While the triangle-waves are more-or-less symmetrical, the sine-waves are definitely not so, showing a nearly three-to-one voltage ratio in favour of positive peaks. There is also noticeably overshoot on the square-waves at anything above 1kHz and only a DC offset at frequencies below 80Hz.
I am totally ignorant of how this function generator produces triangle-waves, but I do understand that the square-waves and sine-waves are derived from the triangle-wave. Does anyone have any help that they can offer? I would be grateful to get this useful function-generator working properly.
Colin.


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