Data receiver comprising a control loop with reduced sampling frequency

Data receiver comprising:

• a) an input coupled to receive a data signal having data symbols occurring at a rate of 1/T symbols/sec., wherein T is a rational fraction (.ltoreq.1) of an interval between received symbols of the data signal,
• b) an adaptive system for estimating at least one measure of a characteristic quantity of the data signal applied to the input of the data receiver, said adaptive system comprising:
• i) error determining means for determining an error in the estimate of the measure of the characteristic quantity of the data signal, said error determining means having first and second inputs and an output;
• ii) adapting means for adapting at discrete instants the estimate of the measure of the characteristic quantity of the data signal, said adapting means having an input and an output;
• iii) means connecting the input of the data receiver to the first input of the error determining means;
• iv) means coupling the output of the error determining means to an input of the adapting means for periodically conveying thereto the error with a period nT, where n is an integer;
• v) means coupling the output of the adapting means to the second input of the error determining means, the signal at said output of the adapting means forming the measure of the characteristic quantity of the data signal, said adapting means functioning to adapt its output signal at discrete instants in order to minimize the error;
• c) said input signal to the data receiver giving rise to a cyclostationary data signal having a cyclostationary period mT, where m is an integer;
• d) the integer n being selected such that the greatest common divisor of n and m is equal to 1.