Fremgangsmåte for utjevning av gruppeforsinkelse mellom en senders analoge filtre og dem i en mottager for signaler i fasekvadratur, samt tilsvarende anordning og transmisjonssystem

摘要

The method involves providing compensation for propagation time differences between first and second analogue filters (5',5") of a signal transmitter operating in quadrature, and between third and fourth analogue filters (10',10") of a receiver for signals in quadrature. The output signals from the first and second filters are applied to the third and fourth filters respectively in order to measure a time difference (delta-1) equal to (Tx+Rx) - (Ty+Ry), with Tx, Rx, Ty, Ry being the respective propagation times of the four filters. The connections are then reversed so the first and second filter outputs are applied to the fourth and third filters respectively and a time difference (delta-2) is calculated on the same basis. On the basis of the two time difference values, weighting coefficients are determined for application to digital filters in series with the analogue filters to compensate for the time differences.