U.S. Philips Corporation

Antonius J Bogers

Johannes W Bergmans

Marc Victor Arends

Eric Kathmann

Steven J Van Lerberghe

Gerardus C Gielis

Mark A Russell

Paulo M Castello Da Costa

Guido K Willi

Johannes M Verbakel

A digital cordless telephony system comprises a radio base station and a plurality of portable radio stations. The radio base station comprises a single digital signal processor for performing standard radio base station functions, and further for supporting all kinds of connections between different parties such as portable parties, network parties, and local base station parties. The single digital signal processor executes party profiles corresponding to a desired connection configuration.

Digital cordless telephony system, a radio base station, and a

For avoiding error propagation as a result of decision feedback equalization, the data to be transmitted are coded with a coder 2 which has a transfer function substantially inverse to the transfer function of the channel 4. Consequently, instantaneous decisions about the received symbol may be made at the receiver 6 without intersymbol interference causing a disturbance. If the channel transfer function differs from the transfer function of the precoder 2, intersymbol interference will again occur, so that the symbol error rate will increase. In order to restrict this increase of the symbol error rate as much as possible, the receiver comprises a cascaded circuit of an adaptive filter 18 which has an inverse transfer function to that of the channel and a decoder 21 which has an inverse transfer function to that of the precoder 2.

Data transmission system with reduced error propagation

In order to decide on the logic value of the output signal corresponding to a received multivalued digital signal, the receiver includes a comparator circuit (3) for comparing the amplitude of the output signal with a plurality of decision thresholds produced by an integrator (24). Based on such comparison, a regenerated signal is produced having the decided logic value and an amplitude which is proportional to the decision thresholds. An adaptation circuit (17) compares the regenerated signal amplitude with that of the output signal, and based on such comparison produces a control signal (z) for either increasing or decreasing the decision thresholds so as to conform the regenerated signal with the output signal, such adaptation being effected by selectively supplying either a positive or a negative voltage to the input of the integrator (24). To prevent erroneous decisions on the logic value of the output signal due to misadaptations of the decision thresholds, adaptation is prevented in the case of output signals which can only result in one direction (increase or decrease) of erroneous adaptation. Such signals are those for which the corresponding regenerated signals have either the lowest or the highest absolute logic values.

Receiver for multivalued digital signals

A digital lattice filter, comprising a plurality of identical stages each having a pair of inputs for receiving input signals and a pair of outputs for supplying output signals, these stages being connected in a cascade arrangement, each stage consisting in two mutually linked branches and no less than one of these branches comprising delay means, and in that always an even number of successive cascaded filter stages forms a group, in which both branches of each group of filter stages comprise a delay elements such that the time delay in the first branch is equal to the time delay in the second branch.

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Eindhoven, Netherlands

Antonius J Bogers