Alcatel

Erwin Schlag

Henning B&uuml;low

A method and a regenerative filter for equalizing an input digital signal is proposed, wherein the received input signals is processed by means of threshold decision elements, multiplexers, and a delay unit,, which regenerates a delayed signal for switching the multiplexer, wherein the input signal,passes in parallel through at least 4 threshold decision elements,and the output signals,of the threshold decision elements,are connected by at least one multiplexer,to the delay unit,and the delay unit,is comprised of at least two delay stages, whose delayed signals,switch the at least one multiplexer

Method and regenerative filter for equalizing digitally transmitted signals

In a digital optical transmission system, such as a passive optical distribution network, analog electric signals, e.g., video signals, are to be optically transmitted in such a way that they can be recovered in a receiver (BONT) in a simple manner. To accomplish this, the transmitter of the transmission system includes a delta-sigma modulator (MOD) and an electrical-to-optical transducer (EO). The delta-sigma modulator (MOD) digitizes the analog electric signals using the delta-sigma modulation method. The electrical-to-optical transducer (EO) then converts the digitized signals to optical signals, which are transmitted over optical fibers to a plurality of receivers (BONT). To recover the analog electric signals, each receiver (BONT) requires only one optical-to-electrical transducer (OE) and one passive electric filter (FIL). The filter (FIL) is a passive low-pass filter in one case and a passive bandpass filter in another. Appropriate selection of the sampling frequency for the delta-sigma modulation and utilization of image frequencies for transmission eliminate the need for frequency translators in the receivers (BONT).

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Vaihingen, Germany

Erwin Schlag