摘要 |
This invention relates to slave controlled forward, reverse or third point measurements of at least one of group delay and attenuation distortions of any of a number of transmission sections connected in a measuring loop between a local transmitter and a local receiver. A swept test carrier frequency signal and a fixed reference carrier frequency signal are amplitude modulated by the same modulating frequency and are applied to the transmission section under test in a periodically alternating sequence. After passing through the transmission section under test, the thus generated envelopes of both signals will have suffered a time delay as well as an amplitude degradation caused by the frequency dependent group delay and attenuation characteristics of the transmission section under test. If a remote transmission section should be measured, a remote control signal is supplied from the local transmitter to the remote receiver-transmitter set, which specifies parameters of the test signal to be delivered by said slave controlled remote transmitter. If an envelope signal detected by a remote receiver should be retransmitted to the local receiver, a second control signal is supplied from the local transmitter to enable the respective remote transmitter to remodulate said envelope signal onto a carrier signal, the frequency whereof is the reference carrier frequency and the amplitude whereof is constant. The selection between remote control and remodulation modes of any remote receiver-transmitter set is solely made by means of those two control signals from the local transmitter without the need of any operator in any remote receiver-transmitter set.
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