how to extract 45 cycles from bunch of waveforms I want to extract 45 number of cycles from the bunch of cycle which is similar to sine wave of varying amplitude. please help me to do so. in this picture i have capture only 45 cycles but i have continuous wave forms.i.e after each 45 cycles the signal is repeating.

thanking you,
For best performance in the presence of noise, I recommend "locking" onto the cyclical signal using a Phase-Lock-Loop (PLL) approach. Then you can feed the PLL output (which will be a cleaner representation of your signal and can be a digital square wave if desired) into a digital counter, which you can then count to 45 after resetting the counter at any position desired.