GB1227363A - - Google Patents

Abstract

1,227,363. Pilot gain control. SIEMENS A.G. 26 July, 1968 [28 July, 1967], No. 35751/68. Heading H4R. In a pilot-controlled line-communication system including controlled repeaters and intermediate preset repeaters in which the output signal level of at least some of the controlled repeaters is varied to compensate for changes in line temperature, said some of the controlled repeaters each being provided with a pilot receiver which controls the amplification or attenuation of a four terminal network in the repeater in such a way that the transmitting level of the respective repeaters deviates from a predetermined nominal value by a value that is equal to the error in the received level but of opposite sign. The level at the terminal transmitter is determined by a temperature or resistance measurement of media in the vicinity of the line or by the level of the signal received from the distant end, or alternatively it may be stabilized at the nominal value and have a controlled repeater giving a deviated output level after an interval of a half of the controlled repeater interval. The pilot receiver 8, Fig. 7, may control a network 7 through a differential amplifier 10 and a memory 9 the latter being responsive to a monitor 11 to maintain the existing level in the event of pilot failure. A second network 12 may also be controlled in a manner identical with network 7 the attenuation of the respective networks may in this case and at some stations be set by a variable attenuator 13 to change the ratio of level lead to level-error in the input signal. Level diagrams, including one for universely spaced repeaters are incorporated.