Circuit for the reception of digital signals which have been transmitted over a dispersive optical waveguide

摘要

In the optical transmission of a digital signal via an optical waveguide (3) which is dispersive at the operating wavelength, by means of an optical transmitter (2), the output signal of which is frequency modulated (FSK-modulated in this case) by the digital signal, there is at the end of the optical waveguide link a difference DELTA tau in the delay of the two wave trains which occur in the FSK modulation. The electrical output signal V of an opto-electrical transducer (5) at the receiving end is intensity-modulated and passes through three value ranges. To retrieve the digital signal from this, a circuit (6) according to the invention is used, the output of which assumes a first state when a sample is in the first value range, the output of which assumes a second stage when a sample is in the second value range and the output of which assumes the state which occurred N bits previously at the same output when a sample is in the third value range.