GB1129624A - Radio transmitter supervisory devices - Google Patents

Abstract

1,129,624. Monitoring radio transmitters. STANDARD TELEPHONES & CABLES Ltd. 11 Feb., 1966, No. 6095/66. Heading H4L. In an arrangement for monitoring the output stage of a radio transmitter, the modulated R/F wave is fed via input 2 and switch 3 to the transmitter 1 whose output is fed via a switch 4 to the normal transmitting aerial. A second output from transmitter 1 may be fed via switch 4 to a spare aerial. The switch 3 connects a number of inputs such as 2 to a corresponding number of transmitters and the switch 4 switches the outputs from each of the transmitters to a suitable aerial or alternatively to the spare aerial. The monitor is provided with amplitude detectors 7 and 8 supplying signals to a control unit 9. A further amplitude detector 12 (operation not described) is connected to the control unit 9, and a lead 14 supplies a signal to unit 9 when the spare aerial is in use. The amplitude detectors 7, 8 supply signals which operate corresponding triggers in the unit 9 if the input to or output from transmitter 1 falls below a predetermined level for more than a specified time. The unit 9, Fig. 2 (not shown) is a logic circuit arranged so that if a fault is detected only at 8 a transmitter fault is indicated, and if a fault is detected at 7 an input (service) fault is indicated but this fault also detected at 8 is prevented from indicating a transmitter fault.