trapezoidal waveform generation

[Lei Dai]

I am trying to generate trapezoidal waveforms that output in digital serial format (@ 10Mhz). I know that LabVIEW has a formula wave generator VI but a trapezoid can not be specied in the required format. Is there a way to modify the VI to accept multiple cases (ie. rise, flat, fall)? In case I have to write one from scratch, does anyone know how the LabVIEW waveform generation VI's control the frequency in real time? I had a look at the diagrams and couldn't make heads or tails of it. Any advice would be greatly appreciated.

Thanks.

[Matt_K]

You could probably string a few of the formula wave generators together to achieve the trapezoidal wave (rise,flat,fall..) but it would probably be just as easy to create the waveform yourself by creating an array of points in a loop. One of the nice features of the waveform generation VIs is their memory. They utilize uninitialized shift registers to keep track of things. You would probably want to implement something like this in your program.