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80Hz - 200µs signal

Posted: Sat Mar 03, 2018 10:09 am
Hi,
Does somebody can explain me if it's possible to create in Audacity a signal of 80Hz with a pulse width of 200µs?
I suppose it is not a sinusoidal wave and the generate square signal menu does not display a pulse width parameter.

Re: 80Hz - 200µs signal

Posted: Sat Mar 03, 2018 10:45 am
patrickp78 wrote:to create in Audacity a signal of 80Hz with a pulse width of 200µs?
If you mean that you want a pulse wave with a pulse width of 200 µs and a pulse repetition frequency of 80 Hz, then running this code in the Nyquist Prompt effect will do that:

Code: Select all

``````(osc-pulse 8 -0.997)
``````
Note that this is a digital signal between -1 and +1. If you intend to convert this to an analogue signal, there will aliasing and overshoot, which may or may not matter for your application.

Re: 80Hz - 200µs signal

Posted: Sat Mar 03, 2018 5:17 pm
Thanks for these informations.
In fact, I try to reproduce on Audacity the same signal as that of muscle strengthening devices, but I do not know what is the shape of the current and the only indications are for example:
- Frequency: 80 Hz
- Pulse width: 200 μs
And there is no indication regarding the pulse duration ...

Re: 80Hz - 200µs signal

Posted: Sun Mar 04, 2018 12:01 pm
On such a device, you can safely assume a 50% duty cycle, imho.

Re: 80Hz - 200µs signal

Posted: Sun Mar 04, 2018 2:16 pm
cyrano wrote:On such a device, you can safely assume a 50% duty cycle, imho.
How does that work with the specified "80Hz with a pulse width of 200µs"?
Wouldn't the pulse width at 80 Hz with 50% duty cycle be 625 µs?

Re: 80Hz - 200µs signal

Posted: Mon Mar 05, 2018 10:10 am
I would expect such a device to have specs written by the marketing dept...

Re: 80Hz - 200µs signal

Posted: Mon Mar 05, 2018 10:41 am
Sorry, it's in french!
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