Signal Processing System Applied To Remove Otdr Noise

A signal processing system applied to remove OTDR noise characterized in comprising an analog-to-digital converter, a laser and driving unit, a sequence accumulator, a preprocessing counter, a pulse generator, a dual-port memory, an adaptive filter, an event decision device, and a preprocessing data decision device;

• wherein the pulse generator includes a digital circuit for generating an electric pulse which corresponds to an optical pulse required by an OTDR measurement, q electric pulses being generated during one OTDR measurement;
• wherein the laser and driving unit are used to convert the electric pulse generated by the pulse generator into an optical pulse signal without distortion;
• wherein the analog-to-digital converter is used to convert an analog electrical signal indicating an OTDR test result into a digital signal forming a measurement sequence SERi which indicates a measurement sequence SER obtained from an i-th optical pulse;
• wherein the sequence accumulator is used to accumulate and preprocess every n received measurement sequences SER to obtain a group of preprocessing data, thus m groups of preprocessing data are obtained during one OTDR measurement, m*n=q;
• wherein one port of the dual-port memory is a write-only port which is connected to the sequence accumulator to read each group of preprocessing data obtained by the sequence accumulator, and the other port of the dual-port memory is a read-only port which is used to take data away for subsequent noise processing;
• wherein the preprocessing counter is used to count a number of groups of preprocessing data obtained by the sequence accumulator, and generating an interrupt signal at obtaining a group of preprocessing data each time to notify the adaptive filter to read a new group of preprocessing data from the read-only port of the dual-port memory;
• wherein the adaptive filter reads the preprocessing data from the read-only port of the dual-port memory, and performs noise processing on the read preprocessing data by using an adaptive filtering process of wavelet transform;
• wherein the event decision device performs an event decision on filtered data output from the adaptive filter;
• wherein the preprocessing data decision device decides whether a certain group of preprocessing data of the m groups of preprocessing data is correct data or high signal-to-noise data according to a difference of the m groups of preprocessing data after passing through the event decision device.