Question

0. Why does the bandwidth of the amplifier play a role in determining the reso- lution of the system?

Answer 1

Resolution Gain

Bandwidth is like a frequency range with which signal can be transmitted and recovered reasonably {Note : it is different in different contexts, but basically, it's a frequency range}.

For example, a certain wire with a bandwidth of 10kHz, meaning it can be used to transmit anything within that 0kHz to 10kHz range say... will be communicated across and recovered well without very much signal deterioration. In amplifiers such as Op-Amp (741) it has a bandwidth of XYkhz, which decreases with increasing gain. This is because as the gain increases, and as the frequency of the input gets increasingly higher beyond the bandwidth, signals within the CMOS itself interferes (you know what I mean? like cancelling each other out) with each other. So, this means the effective gain is decreased. So this means signals beyond the bandwidth is no so well "recovered" so to speak. Less gain, means signals within the CMOS don't "intefere" with each other as much at higher frequencies, because they're not as "strong".

Hence, bandwidth is the frequency at which the gain starts to drop when frequency increases. So, if lowering the gain (using feedback) moves that point (where the gain starts to drop) to a higher frequency then the bandwidth has increased.

Sorry Sir, that might sound a bit confusing..but im sure you'll get there !

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