SCNR stands for signal to effective clipping noise ratio. It measures the degradation of a signal when its peaks are cut off by an amplifier or converter hitting its maximum voltage limit. Engineers use this ratio to determine how much headroom a system needs before clipping distortion drowns out the valid data.
We pushed the input too hard and the SCNR dropped off a cliff once the ADC started clipping.
Unlike standard SNR which measures background thermal noise, SCNR specifically targets the harsh harmonic distortion created when a signal hits the voltage rails.
Related terms
ADC
An analog-to-digital converter transforms continuous physical signals into discrete digital numbers.
Headroom
The margin between the nominal operating level of a signal and the absolute maximum limit before clipping occurs.
Limiter
A circuit that prevents an electrical signal from exceeding a predetermined amplitude.