Signalwaveform offset Problem

[RchB]

Hi all,

I've a problem during the  geneartion of a signal wave(Sine,Square) on FPGA (PXIe-7868R).

I'm able to generate a signal with the right frequency and amplitude but when I change the Offset (1V to 5V) the signal remains the same and does not change and when i put a high value  the signal is distorted

Any suggestion?
Thanks

[billko]

When you introduce a DC offset to a signal, it does just that - it offsets the signal by that amount.  Let's say you have a signal that varies from +5 Volts to -5 Volts.  With an offset of zero Volts, you will have a signal that varies from +5 Volts to -5 Volts.  Introduce an offset of +5V and now your signal varies from +10 Volts to zero Volts.

I'm pretty sure the reason you are getting distortion is because, by offsetting the signal by +5 Volts, whatever is producing the signal can't go that high - it is clipping on the high side.  It's generally not a good idea to run a source in this fashion.

[RchB]

Thanks for your reply 

I agree with you. the signal distroy when I put a big value in the Offset for exemple 15.

my problem when i put a value betwin (0 to 10) the signal does not change that what Im trying to figure out