I have a signal around 500Hz that is roughly sinusoidal and has a peak voltage of around 4v when all things are well. When things go wrong every 6th peak is low at about 2v. I am trying to detect this low peak and activate an LED (also if 2 peaks every 6 are low a second LED is lit).
One problem is the whole siganl can be down to half its value or anywhere in between, so a good peak may be 2v and a bad one 1v. So I have tried to extract the DC level of the rectified signal to use as a floating referance to compare the peaks to. If a peak falls below the DC threshold it should light a LED.
However I am not able to detect the low peak yet.
Any ideas would be most welcomed.
The circuit at the moment is:-
One problem is the whole siganl can be down to half its value or anywhere in between, so a good peak may be 2v and a bad one 1v. So I have tried to extract the DC level of the rectified signal to use as a floating referance to compare the peaks to. If a peak falls below the DC threshold it should light a LED.
However I am not able to detect the low peak yet.
Any ideas would be most welcomed.
The circuit at the moment is:-
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