Monitoring unit for optical burst mode signals

• US 20030016412A1
• Filed: 07/15/2002
• Published: 01/23/2003
• Est. Priority Date: 07/17/2001
• Status: Active Grant

• Current Assignee: RPX Corporation
• Original Assignee: Alcatel SA (Nokia Corporation)
• Inventors: Eilenberger, Gert, Bigalk, Uwe
• Granted Patent: US 7,031,616 B2
• Time in Patent Office: Days
• US Class Current: 398/5
• CPC Class Codes: H04B 10/07953 Monitoring or measuring OSNR, BER or Q
• CPC Class Codes: H04L 1/20 using signal quality detector

Abstract

The invention has for its object to provide a monitoring unit, particularly for optical burst mode signals in asynchronous optical networks based on, e.g., Internet or ATM (ATM=asynchronous transfer mode). The monitoring unit for burst mode signals comprises a detector for performing a Q-factor measurement in dependence on at least one variable and at least one fixed amplitude threshold value and on at lest one variable and at least one fixed phase value. This detector contains a burst mode amplitude detector for generating a fixed amplitude threshold value for each burst, a burst mode clock recovery circuit for generating a fixed phase value for each burst, a burst detector for detecting the beginning of each burst, and a control logic for generating a variable amplitude threshold value and a variable phase value for each burst.

Claims

1. A monitoring unit for burst mode signals, comprising a detector for performing a Q-factor measurement in dependence on at least one variable and at least one fixed amplitude threshold value and on at least one variable and at least one fixed phase value, said detector comprising a burst mode amplitude detector for generating a fixed amplitude threshold value for each burst mode signal to be included in the measurement, a burst mode clock recovery circuit for generating a fixed phase value for each burst mode signal to be included in the measurement, a burst detector for detecting the respective beginnings of burst mode signals, and a control logic for generating a variable amplitude threshold value and a variable phase value for each burst mode signal to be included in the measurement.

2. A monitoring unit as set forth in claim 1, further comprising a first comparator for comparing received burst mode signals with associated variable amplitude threshold values, a second comparator for comparing the received burst mode signals with associated fixed amplitude threshold values, a first decision circuit, following the first comparator, for passing on the output signals of the first comparator in dependence on generated, variable phase values belonging to the burst mode signals, a second decision circuit, following the second comparator, for passing on the output signals of the second comparator in dependence on generated, fixed phase values belonging to the burst mode signals, and an EXOR gate for combining the output signals of the first and second decision circuits.

3. A monitoring unit as set forth in claim 2, further comprising a burst synchronization logic following the burst detector for determining the respective beginnings of the payloads of burst mode signals and a gate following the EXOR gate and controlled by the burst synchronization logic for passing error signals to a processing unit which serves to estimate a Q factor.

4. A monitoring unit as set forth in claim 3, further comprising an extraction unit following the burst synchronization logic for extracting header and/or control information for the selective measurement of specific burst mode control signals and a switch which is connected between the extraction unit, the burst synchronization logic, and the gate and controlled by the control logic.

5. A monitoring unit as set forth in claim 1, serving to monitor optical burst mode signals and comprising an optical-to-electrical converter for generating electric input signals for the burst mode amplitude detector, the burst mode clock recovery circuit, and the burst detector.