What happens to SNR as receive bandwidth increases?

As the receive bandwidth increases, the signal-to-noise ratio (SNR) tends to decrease. This occurs because widening the bandwidth allows more noise signals from the surrounding environment to be captured along with the desired signal. Essentially, while increasing bandwidth can capture more signal energy, it also increases the amount of noise energy, leading to a comparatively lower SNR.

A narrow bandwidth filters out many of the unwanted noise components, allowing for a clearer distinction between the signal and noise. However, as bandwidth is increased, the added noise can overpower the signal, resulting in decreased SNR.

This illustrates an important trade-off in signal processing: while broader bandwidths can enhance speed and resolution in some contexts, they can also dilute the clarity of the signal due to the accompanying noise, thereby leading to a lower SNR.