SNR in analog and digital domain

1. What is SNR in analog communication?
2. What is SNR in digital imaging?
3. How is SNR calculated in ADC?
4. What does SNR depend on?

What is SNR in analog communication?

In analog and digital communications, a signal-to-noise ratio, often written S/N or SNR, is a measure of the strength of the desired signal relative to background noise (undesired signal).

What is SNR in digital imaging?

Signal-to-noise ratio (SNR) is a generic term which, in radiology, is a measure of true signal (i.e. reflecting actual anatomy) to noise (e.g. random quantum mottle). A lower signal-to-noise ratio generally results in a grainy appearance to images.

How is SNR calculated in ADC?

ENOB is based on the equation for an ideal ADC's SNR: SNR = 6.02 × N + 1.76 dB, where N is the ADC's resolution. A real world ADC never achieves this SNR due to its own noise and errors. You can rearrange the equation to calculate an ADC's effective N, or ENOB as we commonly call it: ENOB = (SNR – 1.76)/6.02 dB.

What does SNR depend on?

SNR also depends on the number of transmitter and receiver elements within the RF coils. The higher the number of transmitter and receiver elements, the better the SNR eg. a 32-channel (receiver element) body coil will produce better SNR compared to a 4-channel body coil.