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US 2001/0022790 A1Published application
Method of, and receiver for, detecting the presence of data
AssigneeKoninklijke Philips Electronics N.V.
InventorDomenico G. Porcino
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AssigneeKoninklijke Philips Electronics N.V.
InventorDomenico G. Porcino
Estimating the term…
A method of, and a receiver for, detecting the presence of digitally modulated data signals in which the receiver is periodically energised to detect the presence of the signals. The received signals/noise are converted using a quadrature frequency translation stage (16, 17, 18) into a complex signal which after differential decoding (28) contain n samples for each transmitted bit. A running sum of successive groups of m samples, where m<n, is obtained and an absolute value (Xi) of each group is derived. A weighting value (Wi) is selected by comparing each absolute value with predetermined statistics of expected values and the weighting value selected is multiplied by the associated absolute value to produce a product (S). The product is compared in a comparator (56) with a further threshold level (58) to derive an indication of the presence of data in the received signals. If the indication is negative the receiver is powered down to save power.
A method of detecting the presence of digitally modulated data signals, the method including differentially decoding the digitally modulated signals into oversampled complex signals comprising n samples per bit, forming a running sum of successive groups of m samples, where m is less than n, deriving an absolute value for the successive running sums, weighting the absolute value and determining the presence of data by comparing the weighted absolute value with a threshold level.
A receiver comprising means for receiving a digitally modulated signal, means for forming the digitally modulated signal into an oversampled, differentially decoded complex signal comprising a stream of n samples per bit, means for forming a running sum of successive groups of m samples, where m is less than n, means for deriving an absolute value for successive running sums, weighting means for weighting the respective absolute values, and a comparator for comparing the weighted absolute value with a threshold level and providing an output indicative of the presence of data in the received signals.
Dependencies are inferred from the claim text.