Dear sir,What is the source of the PWM signal, and what can you tell us about it?
I often regard a monostable multivibrator followed by a low pass filter as a F-to-V converter, but if that's the case, what PLC do to the signal, other than to possibly add noise.Indeed Cruts is right! Unless the signal is coming from the scope connection we need a lot more information.
In addition, the explanation, " I used frequency to voltage converter circuit ,it's input is pwm signal through plc. "does not make sense. Th output of a frequency to voltage converter is a DC level, not a square wave.
DC, please read what Bob Pease had to say about F to V and V to F converters. He was brilliant in that area as well as many others.I often regard a monostable multivibrator followed by a low pass filter as a F-to-V converter, but if that's the case, what PLC do to the signal, other than to possibly add noise.
Agree: We can't help much because we don't know much about the circuit.