I would like to implement a signal on a pwm signal, what is the requirements and limitation through this?

 

The main requirement is that the PWM frequency be higher than the Nyquist limit of twice the highest modulation frequency. For good response a value at least 10 times the highest dither frequency or ≥3000Hz is recommended..

 

The main requirement is that the PWM frequency be higher than the Nyquist limit of twice the highest modulation frequency. For good response a value at least 10 times the highest dither frequency or ≥3000Hz is recommended..

dear friend, I should take this requirement as a report to my presentation, where can I find this requirements, I mean a text or book or ...?

 

Look up Nyquist sample rate. This applies to all sampling systems including PWM.

 

I wonder if you tell me what should I do?

 

But my servo valve current is so high (about 1 amp) to be applicable due to 3000Hz PWM, I wnoder if you tell me what should I do?

The servo likely has inductance which will smooth and average the PWM pulses into a steady current, which is what you want. A higher frequency actually helps, since there is less ripple in the average current value.
The PWM driver just needs sufficient current capacity to provide the 1 amp current.

Do you understand how PWM works?

 

The servo likely has inductance which will smooth and average the PWM pulses into a steady current, which is what you want. A higher frequency actually helps, since there is less ripple in the average current value.
The PWM driver just needs sufficient current capacity to provide the 1 amp current.

Do you understand how PWM works?

yes, i got it.