On Sun, 10 Aug 2003 15:16:03 -0000, you wrote:
If you need a linear frequency response from an RC network look up op-
amp integrators.
Hi again Bernard - I altered my circuit, without too much sucess. The
response is still slightly curved. I've posted a file called pwmv.pdf
with a couple of graphs of voltage output versus speed selection. As
you can see altering the pwm rate makes no difference, increasing the
voltage gives a more linear top end, but its still not quite there. It
would appear that from browsing various articles that it is a commom
phenomina and in a lot of commercial systems the top and bottom and of
the scale is discarded.
It would also appear that maybe my assumption of PWM and Art's
implementation is flawed? I incorrectly assumed that RMS values are
proportional to duty on/off cycles, until I read this article
Comments?
--
Steve Blackmore
