FREMGANGSMAADE VED SIGNALBEHANDLING AF EN MODTAGET IMPULSRAEKKE, ISAER VED MAALING AF DISPERSION I OPTISK FIBER, SAMT MODTAGER TIL UDOEVELSE AF FREMGANGSMAADEN

摘要

A method in signal processing of a train of pulses with a stable, high repetition frequency fr, in particular in connection with dispersion measurements of optical fibers, comprises sampling (1) of the received signal at a sampling frequency fs, where �$�\; (n\; is\; an\; integer\; and\; DELTA\; f\; is\; several\; magnitudes\; smaller\; than\; fr).\; When\; the\; sampling\; frequency\; is\; generated\; by\; a\; pulse\; generator\; (2),\; which,\; through\; a\; phase-detecting\; circuit\; (4),\; depends\; on\; partly\; a\; reference\; signal\; (from\; the\; oscillator\; 6)\; and\; partly\; a\; low\; frequency\; signal\; derived\; (via\; 5)\; from\; the\; signal\; received\; and\; sampled\; at\; the\; frequency\; fs,\; a\; stable\; sampling\; frequency\; is\; obtained\; even\; though\; the\; signal/noise\; ratio\; on\; the\; input\; of\; the\; receiver\; is\; significantly\; smaller\; than\; was\; permissible\; in\; the\; past.\; When\; the\; method\; is\; to\; be\; carried\; out\; within\; a\; relatively\; narrow\; repetition\; frequency\; range,\; the\; oscillator\; (6)\; is\; preferably\; replaced\; by\; a\; frequency\; dividing\; circuit\; designed\; to\; generate\; a\; reference\; signal\; by\; division\; of\; the\; sampling\; frequency.$