Serial Transmitter Phase Pre-Emphasis for Isolated Pulse Integrity

Solution Overview

Problem

Amplitude pre-emphasis is insufficient for compensating high-frequency loss in non-linear channels, particularly affecting isolated pulses which experience significant attenuation and increased bit errors due to Pulse Width Shrinkage in optical networks.

Innovation Solution

Phase pre-emphasis is applied by widening isolated pulses in time before transmission, using a modulator and pattern detector to modify the duty cycle of the clock signal, ensuring that isolated pulses are not attenuated as severely, thereby maintaining signal integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If amplitude pre-emphasis is used to boost high frequency content, then high frequency loss compensation is improved, but isolated pulses are still severely attenuated in non-linear channels

Engineering Contradiction:

Improvehigh frequency loss compensationVSAvoidisolated pulse transmission reliability

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The patent changes the temporal parameter of isolated pulses by widening their duration before transmission. This parameter change transforms the pulse characteristics so that after channel transmission and slicing, the pulses maintain sufficient amplitude and width for reliable detection, resolving the contradiction between high frequency loss compensation and isolated pulse reliability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies preliminary pulse widening action before transmission through the channel. By pre-widening isolated pulses before they enter the non-linear channel, the system proactively compensates for the expected attenuation and slicing effects, ensuring reliable reception despite the channel's harmful characteristics

Inventive Principle:

Principle #10Preliminary action

2Ease of operation

If the channel has a low-pass response, then high frequency content is attenuated, but isolated pulses lose both amplitude and width after transmission

Engineering Contradiction:

Improvechannel transmission simplicityVSAvoidisolated pulse shape preservation

Core Design Contradiction:

Ease of operationVSShape

Solution Approach 1:

The patent applies preliminary anti-action by widening isolated pulses before transmission to counteract the low-pass channel's tendency to attenuate and narrow them. This pre-compensation ensures that even after the channel's low-pass filtering effect, the pulses maintain sufficient shape integrity for reliable detection

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The patent changes the temporal parameter of isolated pulses by widening their duration before transmission. This parameter change transforms the pulse characteristics so that after channel transmission and slicing, the pulses maintain sufficient amplitude and width for reliable detection, resolving the contradiction between high frequency loss compensation and isolated pulse reliability

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS8315303B1Phase pre-emphasis for a serial data transmitter

Publication Date: 2012.11.20 MICROSEMI STORAGE SOLUTIONS INC

AI summary

Apparatus and methods apply pre-emphasis to the phase rather of a signal than to the amplitude of a single. This approach can provide superior pre-emphasis performance than the conventional amplitude pre-emphasis techniques in certain situations, such as when a non-linear slicer is present in the signal path. For example, electrical-to-optical (E/O) and optical-to-electrical (O/E) converters can effectively slice a signal.