Part Number: TMS570LC4357
Tool/software:
Hello,
I want to measure the frequency of a sine wave (around 5KHz) using the TMS570LC4357. I know that the eCAP module can be used to measure the frequency of a square wave accurately. Can the same eCAP module be used for a sine wave? If so, will it provide accurate frequency measurements? If not, what other methods can be used to measure the sine wave frequency with some tolerance?
Regards,
Karthik Rao
Hi Karthik Rao,
It is not possible to directly connect sinewave to the TMS570LC4357, we can only connect PWM signals (square waves) and can measure their frequencies.
One way to measure the sinewave frequency is that, using of zero crossing detection circuit.
Zero crossing detection using comparator circuit
As mentioned in above note, we can use the external comparator circuit for zero cross detection. So that means we can convert the sine wave into the square wave as shown below.
So, if we give the output of this zero-cross detector to the eCAP module then we can measure the sinewave frequency from there.
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Thanks & regards,
Jagadish.
