Wave Shaping Circuit for Clockless Precursor and Post-Cursor Equalization
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Solution Overview
Problem
In high-speed digital transmission, existing signal conditioning methods fail to effectively combine precursor, main, and post cursor signals independently of a clock signal, leading to distortion and frequency content imbalance in signals transmitted at high data rates.
Innovation Solution
A wave shaping circuit combines precursor, main, and post cursor signals independently of a clock signal, using delay blocks and a combiner circuit to provide a conditioned output signal, with the main signal delayed relative to the precursor signal and the post cursor signal delayed relative to the main signal, to compensate for signal losses and distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional pre-emphasis and de-emphasis methods are used, then signal distortion is reduced, but the methods cannot effectively combine precursor, main, and post cursor signals independently of a clock signal
Solution Approach 1:
The patent segments the signal conditioning process into three distinct components: precursor signal (pre-emphasis), main signal (transition), and post cursor signal (de-emphasis). Each component is processed through separate delay blocks and then combined, allowing independent optimization of each function while achieving comprehensive signal conditioning without requiring complex clock-based coordination.
2Productivity
If high-speed digital transmission is used, then data transfer rate increases, but signal distortion and loss of high-frequency content occur due to transmission medium
Solution Approach 1:
The patent applies preliminary action by generating the precursor signal through pre-emphasis before the main signal transitions. This pre-conditioning of the signal compensates for anticipated distortion in the transmission medium, ensuring that high-frequency content is preserved and signal integrity is maintained even at high data transfer rates like PCIe 3.0's 8 GT/s.
3Reliability
If bits with high frequency content are emphasized, then pre-conditioning for compensation is achieved, but bits with lower frequency content are de-emphasized
Solution Approach 1:
The patent applies local quality by treating different portions of the signal waveform differently at different times. The precursor signal provides pre-emphasis for upcoming transitions, the main signal handles the actual transition, and the post cursor signal provides de-emphasis after the transition. This localized processing ensures that each frequency component receives appropriate emphasis or de-emphasis at the correct moment, achieving overall signal equalization without creating harmful frequency imbalances.
Data Source
AI summary
Embodiments of an apparatus for signal conditioning, a serial data interface, and a method for a programmable delay filter are disclosed. In an embodiment of an apparatus for signal conditioning, a wave shaping circuit has a precursor signal, a post cursor signal, and a main signal combined to provide an output signal. The precursor signal, the post cursor signal, and the main signal are provided for combination independently of a clock signal. The main signal is delayed relative to the precursor signal, and the post cursor signal is delayed relative to the main signal.