An iteration of my last QAM circuit. This circuit theoretically takes the 4 QAM signal, seen in blue, and extracts the two separate binary digits by mixing the signal with local oscillators in quadrature. These oscillators must be synced with the signal carrier in order to properly read the data without skipping or duplicating data, or producing erroneous results.
In this case, the two results of the mixed signal are then filtered to remove the carrier frequency. Now to extract the most significant bit, the sum of the results is taken. For the least significant bit, the difference of the results is taken.
Feel free to comment and make suggestions!