Method and apparatus for measuring a filtering characteristic, pre-equalizer and communication equipment

Patent metadata

Field	Value
Publication number	US-10225010-B2
Application number	US-201615375732-A
Country	US
Kind code	B2
Filing date	Dec 12, 2016
Priority date	Dec 11, 2015
Publication date	Mar 5, 2019
Grant date	Mar 5, 2019

Abstract

A method and apparatus for measuring a filtering characteristic, pre-equalizer and communication equipment. The apparatus for measuring a filtering characteristic includes: a first processing unit configured to determine a filtering characteristic of a receiving end according to an amplitude of a receiving signal obtained after a measurement signal passes through a transmitting end filtering module and a receiving end filtering module at provided different frequency offsets of a transmitting laser of a transmitting end and a local laser of the receiving end.

First claim

What is claimed is:

1. An apparatus for measuring a filtering characteristic, comprising:
a memory that stores a plurality of instructions; and
a processor coupled to the memory and configured to execute the instructions to:
determine a first filtering characteristic of a receiving end according to an amplitude of a received signal obtained after a measurement signal passes through a transmitting end filtering module and a receiving end filtering module at different frequency offsets of a transmitting laser of a transmitting end and a local laser of the receiving end,
wherein, the processor configured to execute the instructions to:
determine amplitudes of the received signal at the different frequency offsets, and take the amplitude of the receiving signal at each frequency offset as the first filtering characteristic of the receiving end at a frequency point to which each frequency offset corresponds; and
determine the first filtering characteristic of the receiving end according to the determined first filtering characteristic of the receiving end at the frequency point to which each frequency offset corresponds.

2. The apparatus according to claim 1 , wherein the processor further configured to execute the instructions to:
measure a second filtering characteristic of the transmitting end;
measure a joint response of the first filtering characteristic of the receiving end and the second filtering characteristic of the transmitting end; and
determine the second filtering characteristic of the transmitting end according to the first filtering characteristic of the receiving end and the joint response.

3. The apparatus according to claim 1 , wherein the processor further configured to execute the instructions to:
set one of a frequency of the transmitting laser and the frequency of the local laser to obtain the different frequency offsets.

4. The apparatus according to claim 1 , wherein the processor further configured to execute the instructions to:
one of determine each frequency according to the receiving signal and calculate each frequency offset according to frequencies of the transmitting laser and the local laser.

5. The apparatus according to claim 1 , wherein the measurement signal is a narrowband signal.

6. The apparatus according to claim 5 , wherein the narrowband signal is one of a direct current signal, a single-frequency signal, and a pseudo-random signal of a low Baud rate.

7. The apparatus according to claim 1 , wherein the processor further configured to execute the instructions to:
perform power calibration on the transmitting laser and the local laser.

8. The apparatus according to claim 1 , wherein the apparatus further comprises:
a transmitter configured to transmit the measurement signal.

9. A pre-equalizer, comprising:
a memory that stores a plurality of instructions; and
a processor coupled to the memory and configured to execute the instructions to:
determine amplitudes of a received signal at different frequency offsets of a transmitting laser of a transmitting end and a local laser of a receiving end, and take the amplitude of the receiving signal at each frequency offset as a first filtering characteristic of the receiving end at a frequency point to which each frequency offset corresponds;
determine the first filtering characteristic of the receiving end according to the determined first filtering characteristic of the receiving end at the frequency point to which each frequency offset corresponds;
determine a second filtering characteristic of the transmitting end according to the first filtering characteristic of the receiving end and a joint response of the first filtering characteristic of the receiving end and the second filtering characteristic of the transmitting end; and
determine a coefficient of the pre-equalizer according to the second filtering characteristic of the transmitting end, and perform pre-equalization on a transmission signal by using the coefficient of the pre-equalizer.

10. The pre-equalizer according to claim 9 , wherein the pre-equalizer further comprises:
a transmitter configured to transmit the measurement signal.

11. An optical communication equipment, comprising the apparatus for measuring a filtering characteristic as claimed in claim 1 .

Assignees

• Fujitsu Ltd

Inventors

• Tao Zhenning
• Fan Yangyang
• Dou Liang

Classifications

• H04B10/07955 Primary

  Monitoring or measuring power · CPC title

• H04L27/01

  Equalisers {(baseband equalizers at the transmitter end H04L25/03343; in analogue transmission systems H04B3/04, H04B7/005)} · CPC title

• H04B10/5161

  Combination of different modulation schemes · CPC title

• H04B10/0731 Primary

  Testing or characterisation of optical devices, e.g. amplifiers · CPC title

• H04L25/03878

  Line equalisers; line build-out devices · CPC title