SCHALTUNGSANORDNUNG ZUR KOMPENSATION

摘要

The circuit for compensating third-order distortion caused by a laser (3) in a signal to be transmitted contains a pre-equaliser (2) ahead of the laser (3) and an evaluating circuit (4) which senses the distortion in the signal at the output of the laser (3) and controls the pre-equaliser (2). A test signal generator (5) feeds a first out of band test signal (fo) into the pre-equaliser (2), and the third-order distortion of this signal at the output of the laser (3) is compared in the evaluating circuit (4) with a second test signal (3fo) having three times the frequency of the first test signal (fo). The comparison gives a manipulated variable (I) for the pre-equaliser (2).