Apparatus and method for optimum decision threshold setting
OwnerMichael H. Eiselt, Lara Garrett +1inventors
InventorsMichael H. Eiselt, Lara Garrett, Samir Sheth
Life of this patent
Estimating the term…
Abstract
The invention pertains to optical fiber transmission systems, and is particularly relevant to transmission of large volumes of data over long distances at high rates. An apparatus and method for improved bit-error-rate (BER) performance when transmitting optical data over long distances using is disclosed. In particular, the improvement teaches the proper decision threshold setting of the optical signal at the receiver module.
Claims19
An optical signal receiver comprising:
- a photodetector for receiving the optical signal and converting it into an electrical signal;
- an electronic amplifier for amplifying the electrical signal;
- a decision circuit for discretising the electrical signal into logical ones and logical zeros based on a decision threshold;
- a forward error correction circuit for counting a number of errors in the logical ones and a number of errors in the logical zeros;
- a feedback circuit for setting the threshold based on an optimization parameter related to the number of errors in the number of logical ones and the number of errors in the number of logical zeros.
A method of optimizing a decision threshold in an optical receiver comprising the steps of:
- setting a target ratio value;
- measuring a number of erred ones in the signal;
- measuring a number of erred zeros in the signal;
- adjusting the decision threshold to close on the target ratio.
An optical signal receiver comprising:
- a receiver unit receiving the optical signal and converting it into an electronic signal;
- a decision circuit connected to the inverting receiver, interpreting the electronic signal into logical ones and logical zeros based on a threshold;
- a counting circuit connected to the decision circuit, tabulating the number of erred ones and erred zeros in the logical ones and zeros;
- a controller connected to the counting circuit and the decision circuit whereby a ratio of erred ones to erred zeros is used to calculate the threshold.
Dependencies are inferred from the claim text.