Importance

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Abstract

The invention relates to a method in connection with a QAM receiver wherein, particularly when making use of a 32QAM, 64QAM demodulator lator a like, a digital transmission signal (1) to be transmitted is down-converted in a tuner and band-filtered with a first filter to a preferably fixed, standard intermediate frequency (5). This is followed by a further subsequent down-conversion by a first oscillator and filtering with a second filter to a so-called low intermediate frequency (6) which is equal to the symbol rate used in image transmission or its low odd multiple, whereafter an AD converter (7) is used under the synchronization of a second oscillator (8) for picking up samples (X) from the symbol sequence of a processed signal (6) to a demodulator (9), capable of regulating the above-mentioned, preferably voltage-controlled oscillators. Particularly in order to provide a variable-rate transmission signal, said low intermediate frequency signal (6), such as the mean frequency and bandwidth of its spectrum, is measured by of a measuring system (11), the measuring results thereof being used for controlling the oscillators (4, 8) in such a manner that the fixed-rate demodulator (9) can be locked to the signal. The invention relates also to a QAM receiver operating in accordance with the method.

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First Claim