| 摘要 |
<p>The present invention is directed to a system for use with equipment designed for transmitting a relatively wideband signal over two or more relatively narrowband circuits so as to provide good overall system reliability even though the reliability of the individual narrowband circuits is poor. If systems, which transmit two or more relatively narrowband circuits to transmit quality greater than toll circuit quality (approximately 300 hertz to 3,000 hertz), are properly designed, only a failure of one transmission circuit will severely degrade the transmission of intelligible speech. For example, if the system is designed with frequencies between say, 50 hertz and 2,500 hertz, passing through a first transmission circuit and frequencies between 2,500 hertz and 5,000 hertz passing through the second line, there will be little loss of intelligibility if the second transmission circuit fails. However, loss of the first transmission circuit would be catastrophic. The present invention provides method and means to further improve reliability by detecting failures in the operation of the first line and to activate line switching means of both the transmitter and the receiver so as to switch transmission of the high intelligibility component of the signal through another line providing intelligible speech transmission. The detection of the failure and the activation of the transmitter and receiver line switching circuits is designed to provide rapid corrective measures to avoid serious interruptions of service. This invention is subject to a wide range of applications, however, it is especially suited for transmission of broadcast programs from remote sites to broadcast studios.</p> |
