What is Signal-to-Noise Ratio (SNR)?

Signal-to-Noise Ratio (SNR) is the ratio of the power of the desired signal to the power of background noise, typically expressed in decibels (dB). SNR(dB) = 10log10(Psignal/Pnoise). A higher SNR indicates a cleaner signal with less noise corruption. In wireless communications, SNR determines the achievable data rate (Shannon-Hartley theorem: C = B × log2(1 + SNR)) and bit error rate. Typical requirements: voice calls need ~10 dB SNR, while high-speed data needs >20 dB SNR for low error rates.