PWM - Dutycycle affecting frequency?

[flotulopex]

Hi,

I'm just playing around with PWM (...and PicMultiCalc).

While making some experiments, I notice that changing the dutycycle will affect the Period's duration (frequency).

First, I set dutycylce to 127 (=50%). The frequency is 92,24kHz.
<img src="http://www.picbasic.co.uk/forum/attachment.php?attachmentid=1640&stc=1&d=117939319 7">

Second, same test at 64 (=25%) dutycycle. The frequency is now 46,02kHz.
<img src="http://www.picbasic.co.uk/forum/attachment.php?attachmentid=1639&stc=1&d=117939319 7">

In my comprehension of PWM, dutycycle would affect only the ratio of the HIGH against the LOW signal.

Is this okay or am I measuring something wrong?