Fractional Pre-emphasis for Multi-mode Interconnect Signal Loss
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Solution Overview
Problem
Conventional methods for signal transmission in multi-mode interconnect systems face signal loss and frequency limitations, as they require specific code words for each bit interval, leading to incorrect signal perception and data rate constraints.
Innovation Solution
A system implementing fractional pre-emphasis, where multiple bits of binary data are encoded into scalar values, and a comparator module generates difference signals to apply pre-emphasis to analog signals, adjusting the emphasis for a fraction of the period based on these differences, ensuring accurate signal transmission across multi-mode interconnects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional overdrive or waveform shaping is applied to multi-mode interconnect systems, then signal loss can be compensated, but the code word accuracy deteriorates causing incorrect signal perception
Solution Approach 1:
The patent applies different pre-emphasis strategies to different interconnect channels based on their individual impedance characteristics. Each channel receives customized pre-emphasis adjustments rather than uniform treatment, allowing accurate code word transmission while compensating for signal loss specific to each channel's impedance properties
Solution Approach 2:
The system performs pre-emphasis adjustments before the signal reaches the interconnect, proactively compensating for expected impedance losses. The pre-emphasis circuit modifies the waveform in advance based on the source impedance and channel characteristics, ensuring accurate signal delivery without requiring post-processing or feedback corrections
2Reliability
If conventional equalization requiring code word changes is applied, then signal transmission can be maintained, but the system complexity increases due to dependency on preceding values
Solution Approach 1:
The patent extracts the pre-emphasis function from the complex feedback-based equalization process. By using a simple pre-emphasis circuit that operates independently on each channel based on impedance characteristics, the system achieves reliable signal transmission without requiring complex processing of preceding code words or feedback loops
Solution Approach 2:
The pre-emphasis circuit is designed to automatically adapt to different channel conditions based on their impedance characteristics without requiring external control or feedback. Each channel's pre-emphasis is determined by its own impedance properties, making the system self-adjusting and eliminating the need for complex centralized equalization control
3Speed
If steeper waveform slope is applied at the source end, then the maximum frequency is improved, but the signal transition time at the destination end increases
Solution Approach 1:
The patent changes the waveform parameters (amplitude and shape) at the source end based on the interconnect's impedance characteristics and length. By adjusting these parameters proactively, the system achieves fast transitions at the destination without suffering from excessive transition times, resolving the contradiction between maximum frequency and transition time
Data Source
AI summary
Systems, methods, and computer readable media for fractional pre-emphasis of multi-mode interconnect are disclosed. According to one aspect, the subject matter described herein includes a method for fractional pre-emphasis of multi-mode interconnect. Multiple bits of binary data are periodically received. For each period, the multiple bits of binary data are encoded into multiple scalar values, each value representing a level of an analog signal to be output over a multi-mode interconnect system during the current period. Multiple analog signal outputs are generated corresponding to multiple scalar values, each signal output being driven to a level according to its corresponding scalar value. For each representative scalar value, a difference between the scalar value generated during the current period and the scalar value generated during the previous period is determined, and a pre-emphasis signal that is proportional to the difference is generated. Pre-emphasize each analog signal output according to the respective pre-emphasis signal, where the analog signal is pre-emphasized for a fraction of a period that is less than the entire period.