How can I analyze this circuit?

Question

I am analyzing a circuit in which an audio is cleanly amplified. I am using PSPICE fo analyze it, but I am not sure how to show that the signal was amplified or that it stayed clean. Please help if you have any idea what I am talking about!

Answer 1

The amplification can be shown 2 ways. First, an AC analysis will show the gain vs frequency for the amplifier. Then, the transient analysis can show that the amplifier can handle the actual signal while remaining linear. Noise modeling is minuscule in Pspice.

Answer 2

I do not know PSPICE, but if you want to show that the signal is amplified, you could show that amplitude of the signal is larger on the output than the input.

If you want to show it is amplified cleanly, you could either show that the ratio of the input to the output stays constant throught out the frequency range that the circuit is designed for, or from low voltage to high voltage.

I am; of course, talking about frequency response and lineality. Two of the important factor of amplifiers.

In addition, both combined, you could show that IMD (inter-modulation distortion) is low on the output, when two-tone input is given. This test will conveniently show both frequency response and lineality in one test.

Another cleaness is low noise or S/N (signal to noise) ratio. To show this, you must show, when input is zero, there is no output. (there are other ways of doing this)

I have no idea how you would do this on simulation software, but this is how I would prove it on more conventional testing.