spikes in square wave, help!

[ritch_by_nature]

Hello,

     I am running the built in function generator vi from labview in my server to generate different waveforms. I modified it and add a DC noise + sinewave  and a random noise case. On my client side, the sinewave looks normal but the squarewave and sawtooth have some spikes and noise riding on em and I cant figure out why because while troubleshooting, I checked the waveform in my server before it is being written to the client. All the waveforms look fine. but on the client side only some of them works fine. 

Please help, pics and vi attached.

[smoores]

Are you referring to the spike that occurs at approximately the 1:44:48.750 PM mark?

It looks like there may be a problem here where your function generator is not producing an integer number of cycles.  When trying to concatinate waveforms, you should always have an integer number of cycles created so that the waveforms will match up.  Try double checking that waveform frequency * number of samples (#s) / sample rate (Fs) is equal to some integer value.  You may also consider lining up your concatinated waveforms at a location where you expect to see little to no noise.  In the case of a square wave, that could be a 90 degree phase shift.