One of the problem come up, one of the 2FSK frequency waveform will decrease its amplitude due to long distance transmission , the project Is aiming to suing 2 LM567 IC's to select the specific range of the input frequency , ideally the output of LM567 the square wave can works like a (maybe CD4006)switch control to put the sine wave back on, so that I can able to adjust the amplitude of that select frequency.

I use the circuit as show below and calculation of the R1 C1 and C2, when input a pure sine wave with a selected frequency its works. but when input a 2FSK single the form is show below. I don't know what happed it seems all random

I use the circuit as show below and calculation of the R1 C1 and C2, when input a pure sine wave with a selected frequency its works. but when input a 2FSK single the form is show below. I don't know what happed it seems all random

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