How to Estimate Duty cycle of given pulse

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kalaianand

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Hi friends,

I want to find the Duty cycle of incoming pulse in terms of voltage. The frequency of pulse shall change at any given time in this case. Then how to find the Dutycycle in terms of voltage ranges from (0 - 5)V.
 

By measuring its DC (average) voltage, assuming the pulse voltage is limited by two fixed levels (high and low).
 

KerimF said:
By measuring its DC (average) voltage, assuming the pulse voltage is limited by two fixed levels (high and low).
Click to expand...

Hi,

I tried by averaging using simple RC network with very low cut-off frequency. But the problem i am facing in the hysterises band due to ripple in 5V supply. The voltage voltage difference for duty cycle bandwidth is much lesser. So, circuit doesn't work. I am looking for circuit with some logic gates (Especially TTL level).
 

Do you mean the high level (supposed being 5V) is not fixed (having a ripple)?
If this is the case, could you estimate this ripple (its max and min, for example)?
 

KerimF said:
Do you mean the high level (supposed being 5V) is not fixed (having a ripple)?
If this is the case, could you estimate this ripple (its max and min, for example)?
Click to expand...

max. peak to peak ripple is 80mV. Which disturbs the hysterisis set for Comparator.
Required excess duty cycle measurement is 20%. frequency shall vary from 1kHz to 20kHz.
 

You mention a comparator, is it before or after the incoming pulses?
 

kalaianand said:
Hi friends,
I want to find the Duty cycle of incoming pulse in terms of voltage. The frequency of pulse shall change at any given time in this case. Then how to find the Dutycycle in terms of voltage ranges from (0 - 5)V.
Click to expand...

The dc (average) voltage of a pulse train depends on the duty cycle AND (of course) on the pulse voltages.
Thus, one of both values must be known to you (fixed).
 

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