| 摘要 |
<p>A multiple signal carrier transmission apparatus and method for broadcasting stereo sounds to an audio output device uses three related carrier frequencies on which are modulated the sum of first and second stereo channel signals (24) and the first and second stereo channel signals (26) themselves. The composite multiple carrier frequency signal is transmitted to a receiver which separates the three carrier frequency signals to generate a separate left channel signal (84), a right channel signal (94) and a composite center channel (102), monophonic, signal which is the sum of the first and second channel signals. A detector monitors the signal strength of each separate left and right channel signal to detect a decrease in either channel output below a threshold.</p> |
