Question 3-78L4

Receiver sensitivity is commonly and precisely determined by measuring the input signal level required to achieve a 12 dB SINAD (Signal-to-Noise And Distortion) ratio. SINAD is a critical metric because it quantifies the purity of the recovered audio, comparing the power of the desired signal to the combined power of noise and distortion components. A 12 dB SINAD level is an widely accepted industry standard for specifying the minimum discernible signal (MDS) sensitivity of a receiver. It represents the point where the received signal is clearly intelligible above the background noise and any inherent distortion generated within the receiver, making it a robust and objective measurement for comparing different receivers. While "quieting" methods (like 10 dB or 25 dB quieting) measure the reduction in noise output when a signal is present, they do not account for distortion. Therefore, quieting measurements are less comprehensive and less precise for a complete "exact sensitivity specification" than SINAD, which includes distortion in its calculation. Furthermore, 10 dB SINAD is not the commonly accepted standard threshold; 12 dB SINAD is.