Pre-Emphasis Signal Level Adjustment for Transmission Line Equalization
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Solution Overview
Problem
Existing signal level adjustment methods for pre-emphasis in semiconductor integrated circuit devices fail to accurately adjust pre-emphasis intensity according to transmission line characteristics, leading to waveform distortion and data transmission errors due to inadequate control over de-emphasis processing.
Innovation Solution
A signal level adjustment method and circuit that adjusts pre-emphasis intensity by setting a threshold for the input buffer and varying the output level of the signal output circuit until the voltage falls within a given range, ensuring that the amplitude of high and low frequency components are equalized at the receiving end, using a control circuit that includes an input buffer threshold adjustment unit and a pre-emphasis intensity adjustment unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pre-emphasis intensity is increased to compensate for high frequency attenuation, then signal transmission quality improves, but waveform distortion increases due to improper de-emphasis control
Solution Approach 1:
The patent implements a feedback mechanism where the receiving side measures the amplitude relationship between high and low frequency components and feeds back this information to the transmitting side. The transmitting side then adjusts its pre-emphasis intensity based on this feedback, creating a closed-loop control system that automatically optimizes signal quality while preventing waveform distortion.
Solution Approach 2:
The patent dynamically adjusts the pre-emphasis intensity parameter based on measured transmission line characteristics. By changing this parameter in response to feedback information about frequency component amplitudes, the system optimizes compensation for high frequency attenuation while maintaining proper waveform shape at the receiving end.
2Ease of operation
If de-emphasis amplitude is determined according to emphasis amplitude, then processing simplicity is maintained, but pre-emphasis intensity cannot be accurately adjusted according to transmission line characteristics
Solution Approach 1:
The patent inverts the traditional control approach by having the receiving side measure the frequency component amplitudes and feed back this information to the transmitting side, which then determines the pre-emphasis intensity. This reversal of control direction enables accurate adjustment according to actual transmission line characteristics while maintaining processing simplicity through automated feedback-based control.
3Manufacturing precision
If stepwise adjustment of pre-emphasis intensity is performed, then amplitude equalization can be achieved, but adjustment time and complexity increase
Solution Approach 1:
The patent performs preliminary measurement of transmission line characteristics by transmitting test signals and measuring frequency component amplitudes before actual data transmission begins. This preliminary action allows the system to pre-calculate the optimal pre-emphasis intensity, eliminating the need for time-consuming stepwise adjustments during operation while ensuring accurate amplitude equalization.
Data Source
AI summary
A signal level adjustment system adjusting a level of signal outputted from a signal output circuit is realized. An input buffer threshold adjustment unit sets a threshold of a signal input circuit to a first variable value. A signal level adjustment unit adjusts an output level of a first signal at the signal output circuit until a voltage of the first signal outputted from the signal output circuit and inputted to the signal input circuit falls into a given range determined based on the threshold.