Hey all, "In AM synchronous demodulation, Why we don't divide m(t)coswt by cos(wt) instead of multiplying by cos(wt), since this can be easily implemented by a simple divider circuit?" If it's all about thinking mathematically, then it seems like it's more intuitive and a whole lot easier if we just divide by coswt, why we go through all the trouble and multiply then we have to know the trig identity of (cos(a)cos(b)) and then put a LPF after the output... I asked this question to two professors and I got different answers: #Professor 1 Reply: "For your scheme to work you must know exactly what the frequency w is that the transmitter is using, which tends to drift. So try your scheme with dividing by cos (w+delta)t and see whether you can recover the signal." #Professor 2 reply was: "we don't use the division scheme for two reasons: a- In the real world, noise is added to the received signal and it is going to look like this, m(t)coswt+n(t). If you then divide by coswt, you will get, m(t)+n(t)/coswt, and since the cosine function ranges from -1 to 1, thus for values of cosine less than 1, the noise term will increase much more, so you will get poor SNR. b- When the cosine function goes to zero, you will divide by zero and this will cause amplitude spikes which leads to circuit saturation." I am now confused more than ever. which one is true?