[SIZE=-1]Hey all,
[/SIZE][SIZE=-1]"In AM synchronous demodulation, Why we don't divide m(t)coswt by cos(wt)
instead of multiplying [/SIZE][SIZE=-1]by cos(wt)?"[/SIZE]
[SIZE=-1]
When I was taking a class in Analog Communication... I recall that I was watching one of the video lectures on signals and [/SIZE][SIZE=-1]systems from Berkeley University, the Professor was talking [/SIZE][SIZE=-1](in that video recording of the lecture) [/SIZE][SIZE=-1]about[/SIZE][SIZE=-1] amplitude modulation and why when we want to [/SIZE][SIZE=-1]demodulate an AM modulated signal , in [/SIZE][SIZE=-1]synchronous[/SIZE][SIZE=-1] detection, we multiply the AM modulated signal = m(t)cos(wt) by cos(wt)[/SIZE], where w is the carrier frequency, and why we don't just divide by cos(wt) to get m(t) back, since this can be easily implemented by a simple divider circuit.
well, he didn't answer that question in the lecture, may be he just left it as an assignment for his students, I don't know. but it just got me thinking about it, 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 BPF centered at w after the output...
[SIZE=-1]what are your thoughts on this?
[/SIZE]
[/SIZE][SIZE=-1]"In AM synchronous demodulation, Why we don't divide m(t)coswt by cos(wt)
instead of multiplying [/SIZE][SIZE=-1]by cos(wt)?"[/SIZE]
[SIZE=-1]
When I was taking a class in Analog Communication... I recall that I was watching one of the video lectures on signals and [/SIZE][SIZE=-1]systems from Berkeley University, the Professor was talking [/SIZE][SIZE=-1](in that video recording of the lecture) [/SIZE][SIZE=-1]about[/SIZE][SIZE=-1] amplitude modulation and why when we want to [/SIZE][SIZE=-1]demodulate an AM modulated signal , in [/SIZE][SIZE=-1]synchronous[/SIZE][SIZE=-1] detection, we multiply the AM modulated signal = m(t)cos(wt) by cos(wt)[/SIZE], where w is the carrier frequency, and why we don't just divide by cos(wt) to get m(t) back, since this can be easily implemented by a simple divider circuit.
well, he didn't answer that question in the lecture, may be he just left it as an assignment for his students, I don't know. but it just got me thinking about it, 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 BPF centered at w after the output...
[SIZE=-1]what are your thoughts on this?
[/SIZE]