FM SCA Rejection
FM SCA rejection measures how well a tuner keeps a subsidiary broadcast carrier out of its audio output.
SCA carries an additional service alongside the main FM programme. This specification concerns suppression of the 67 kHz subsidiary carrier, expressed in decibels. A larger comparable figure means less unwanted contribution from that signal under the test conditions.
FM SCA Rejection — Tuner
The tuner must recover the main programme while excluding signals intended for other services. SCA rejection describes that separation at the audio output. It can matter when the received broadcast carries the subsidiary signal, but the number does not establish the tuner's overall noise or distortion performance.
Compare results using the same test arrangement and subsidiary-carrier conditions. Do not substitute suppression of the 19 kHz stereo pilot or 38 kHz stereo subcarrier: those are different signals. Nor does high SCA rejection indicate stronger reception of a weak station or better separation of adjacent stations.