Hi,
I've been experimenting with the PWM signal, and connected it to my soundcard to see what is happening. What I've found is that the PWM signal is some sort of sinus, and if I change the duty cycle the amplitude goes up.
I was expecting a block form signal.. and the duty cycle varies the on width time of the block.
Is my soundcard fooling me (I kwow I should get a scope) or is the signal a sinus wave?
Thanks
PWM shape
Started by Flores, Aug 23 2010 01:02 PM
3 replies to this topic
#2
Chris Seto
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Posted 23 August 2010 - 01:28 PM
I can't vouch for any weird PC oscilloscope software, but that's not right. I have a real O-Scope and the signal looks perfectly fine. I know because I did a lot of testing with it when I did the ESC and servo drivers I posted. 
EDIT: The PWM signal will always be either a 'pulse wave' or a 'square wave'. It will never be a sine wave or anything like that.
EDIT: The PWM signal will always be either a 'pulse wave' or a 'square wave'. It will never be a sine wave or anything like that.
#3
Flores
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Posted 23 August 2010 - 02:05 PM
he he.. okay thanks.. gonna buy a scope.. I promise.
#4
Chris Seto
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Posted 23 August 2010 - 02:14 PM
Rigol and Picoscope both make very nice scopes (with probes) for under $400 from Saelig.com. I'd just go with them and be done it with. It's not even worth trying to use any of those PC sound card scopes. You aren't going to get good data from them anyway.
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