What is noise factor & Snr?

The ratio of the available signal power to the unwanted available noise power (SNR) is an obvious performance metric quantifying the degree to which the noise is corrupting the coexisting desired signal. The noise factor (F) of a circuit is another metric and is probably the most frequently used parameter to describe the behavior of a circuit.

What is a noise factor?

It is defined as the signal-to-noise ratio at the input to the circuit divided by the signal-to-noise ratio at the output. The noise factor is always greater than unity, as long as the measurement bandwidth is the same for the input and output data. A network without any noise sources will have a noise factor of one.

What is noise contribution in a circuit?

The noise contribution from individual circuit components is usually defined in statistical terms. If we look at a noisy signal, we see a random variation in voltage or current amplitude over a range of frequencies.