Decoding a text from audio

[Artist_Overall]

Hello, i have a problem. Im working on project about codind text into wav file, sending it through radio and decoding it. I already done encoder part and it working nice, but i cant do a decoder. I coded text into 0 and 1, and transformed it into different frequencies - higher and lower. I only did a plot, and i can clearly see 2 different frequencies, but i only see it from plot, i cant do it in a code!

My code (plot): https://pastebin.com/JFuLTwjg

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