Occupied Bandwidth and Signal to Noise Ratio in AM Stereophonic Broadcasting

Abstract

This paper deals with the theoretical analysis and the experimental results of the occupied bandwidth and signal to noise ratio in five AM stereophonic broadcast systems, Belar, Magnavox, Motorola, Harris and Kahn, which have been proposed in the United States.
Computation of the spectrum and the out-of-band radiation in the five systems are carried out with various input levels and frequencies, and the results are applied to the regulations in Japan.
The relative noise increace, for the case of comparatively low receiver-input level to which the noise output due to RF white noise is inversely propotional, is theoretically calculated, and is measured in five systems, showing that the signal to noise ratio of stereophonic broadcasting is about 3 to 4 dB worse than that of monophonic broadcasting.