T
Tim Williams
- Jan 1, 1970
- 0
Type 2 phase detector I came up with over the weekend.
http://webpages.charter.net/dawill/Images/Phase Detector.gif
Detects phase from zero to 2pi (radians) from A to B, outputting a PWM
signal proportional to the angle (or voltage, after integration).
Speed is limited by the comparators (unless you already have squarewaves)
and overlap of the one-shot pulses. Feeding relatively slow RC slopes into
logic isn't the best idea, a schmitt trigger would help but the spare
inversion shown seems to square it up pretty well. A current-limiting
resistor on the gate input would be nice too, though for the 393 and 100pF
values, the fall rate of 10V/0.1us draws at most 10mA. And, of course, if
phase exceeds 0 or 2pi, you get a nasty discontinuity or unstable region,
but any type 2 detector behaves the same anyway.
Tim
http://webpages.charter.net/dawill/Images/Phase Detector.gif
Detects phase from zero to 2pi (radians) from A to B, outputting a PWM
signal proportional to the angle (or voltage, after integration).
Speed is limited by the comparators (unless you already have squarewaves)
and overlap of the one-shot pulses. Feeding relatively slow RC slopes into
logic isn't the best idea, a schmitt trigger would help but the spare
inversion shown seems to square it up pretty well. A current-limiting
resistor on the gate input would be nice too, though for the 393 and 100pF
values, the fall rate of 10V/0.1us draws at most 10mA. And, of course, if
phase exceeds 0 or 2pi, you get a nasty discontinuity or unstable region,
but any type 2 detector behaves the same anyway.
Tim
