What happens to the SNR if you average a set of signals together?

When averaging a set of signals together, the signal-to-noise ratio (SNR) typically improves. This improvement occurs because the random noise tends to average out over multiple measurements, while the actual signal, which is consistent across the samples, reinforces itself.

In more detail, noise is generally a random process, meaning it will vary in amplitude from sample to sample. When you take the average of multiple signals, the random variations in noise can cancel each other out, leading to a more stable and clearer representation of the underlying signal. On the other hand, the actual signal, assuming it remains consistent across the measurements, contributes positively in a way that allows its strength to remain or become more pronounced after averaging.

This process effectively increases the ratio of the signal's energy relative to the noise's energy, leading to better clarity and accuracy in the measurement of the signal. Therefore, the SNR improves when you average signals together.