ITU-R - International Telecommunication Union/ITU Radiocommunication Sector
Scope
Introduction The RF signal-to-noise ratio at the receiver input depends@ apart from other factors@ on audio frequency S/N ratio for a defined grade of performance. Since the majority of the physiological and psychological factors ultimately influence only the AF signal-to-noise ratio@ a series of subjective listening tests were carried out in India and the USSR to assess the minimum acceptable value of this ratio@ from which the equivalent RF signal-to-noise ratio at the input of the receiver may also be derived.