Hi ,
I designed a pulse generator which operate exactly the same way old computer mouse mechanism works. (IR emmiter-sensor ) the requirment is to count number of pulse from A to D converter. Is this possible with PWM and low pass filter arrangment ?
Thanks in advance.
As I understand PWM, it's a scheme to vary pulse width based on the value of an analog input. I don't see how that will help you to count pulses, but maybe there's a way. What did you have in mind?
It's not obvious, to me at least, what you even mean by counting the number of pulses out of an A/D converter. But . . .
If I wanted to count the number of pulses on a signal line, a counter like the SN74163 would be my first thought. It will give you a multibit binary representation of the number of pulses since the last reset. A variation on this scheme uses decade counters like the SN74160 to output BCD, more easily displayed on 7-segment LEDs.
If it's an analog voltage proportional to the pulse repeatition frequency that you're after, you could have the pulse trigger a one-shot and lowpass-filter the output to recover the average value. This only works well when the ratio of maximum frequency to minimum frequency is fairly low.
Hope this helps.
tnx for the info anyway, i desinged a data aquisition system which displays the values that coming from 5 different sensors thru the parallel port. this pulse generator is one of them. All i want is to interface that also into the same ADC0809 but it is coming as pulses not like rest of analog voltages.
Hope u will help me soon.
tnx in advance.
Blake wrote:
Hi, Tribble. Your best bet might be to have your pulse generator trigger a 555 in monostable mode. The 555 fixed width pulses can then go to a low pass filter. This will give you a DC voltage proportional to the frequency of pulses.
Good luck Chris
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