Okay, this is weird. The PWM waveform (a modified triangle) itself is 88 kHz. But the PWM output is at 255 kHz ???
It must be picking up some noise from somewhere or oscillating.
I was looking at this phototransistor: http://www.rapidonline.com/pdf/58-0115.pdf
Rated 50ns rise/fall time, which is very fast.
I'll have to use these with the peak detector to detect the minimum amplitude, so I can compare against that, because a phototransistor in a normal open collector configuration would invert the signal. Then again, is there anything stopping me using these in an open emitter configuration, given the base is not referenced to ground?
It must be picking up some noise from somewhere or oscillating.
I was looking at this phototransistor: http://www.rapidonline.com/pdf/58-0115.pdf
Rated 50ns rise/fall time, which is very fast.
I'll have to use these with the peak detector to detect the minimum amplitude, so I can compare against that, because a phototransistor in a normal open collector configuration would invert the signal. Then again, is there anything stopping me using these in an open emitter configuration, given the base is not referenced to ground?