performing frequency sweep in stimulus profile editor

[oeua.uoeuoau]

Hello all,

I am trying to figure out what the easiest way of doing this is.

I have a output signal. I want to start with a 5V signal, then I want to make it into a sinewave with an amplitude of 0.05V starting at 1Hz and gradualy increase the frequnecy, sweeping it up to 500Hz. I know there is a sine wave function in stimulus profile editor, but it seems to want to hold the frequency fixed.

Thanks.

[Jarrod_S. · Accepted solution]

There are a few options:

1. Make your own sinewave sequence that will sweep the frequency as it plays. The built-in sinewave function is just a sequence that you can view and copy to modify however you want. Double click it in the palette to view the sequence.

2. Use multi-tasking and the built-in sine wave sequence. The SineWave sequence does take in a parameter for Frequency, but it takes that value in by reference. This means that if the value mapped to the Frequency parameter changes while the SineWave sequence is executing, the frequency of the sine wave will update, too. This allows you to use a multi-task structure to run two parallel tasks: one to call SineWave and one to ramp the frequency variable.

Attached is an example to help you make some sense of this. This may not be the exact logic you want, but should help you get some ideas going. Hope this helps!

[Devin_K]

A while back, I made some point-by-point sinewave functions, including one for perforning a frequency sweep of a sinewave.  To execute the function, you provide th normal sinewave parameters (amplitude, frequency, etc...) as well as a starting frequency and a sweep rate.  This function would then be called repeatedly from another sequence which is responsible for incrementing the Time arguement.

In the attached example, the "PlayWfm" sequence will generate a signal for a fixed duration.  The signal generated depends on the "Function" input (set Function = 2 for a linearly swept sine wave).  Note that you could create your own caller for the SweptSine function which stopped when the frequency reached 500 Hz, instead of lasting for a fixed duration like the example.

[oeua.uoeuoau]

Thank you to both replies. They were both very helpful.