ADC Encoder Interface for Low-Latency Redundant Code Transmission

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Solution Overview

Problem

Existing analog-to-digital converter (ADC) systems face significant latency issues due to the time required to transmit digital representations from the ADC circuit to receiving digital circuits, especially when interface circuits perform substantial computations or when transmission occurs after the A/D conversion process is complete.

Innovation Solution

The implementation of an encoder interface circuit that generates a redundant digital representation during the A/D conversion process, allowing for the transmission of partial codes before the conversion is complete, using a numerical successive-approximation algorithm to gradually narrow the uncertainty range and reduce overall latency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the ADC system waits for the complete A/D conversion process before transmitting digital representations, then the accuracy and completeness of the digital data is improved, but the latency increases significantly

Engineering Contradiction:
Improvedigital representation accuracyVSAvoidsystem latency
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The encoder interface circuit begins encoding digital representations into redundant format during the A/D conversion process itself, rather than waiting for completion. This preliminary encoding action allows transmission to start before conversion finishes, reducing latency while maintaining accuracy through the redundant encoding scheme that can handle incomplete conversion data

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The digital representation transmission is segmented into multiple parts: the redundant digital representation is transmitted during conversion, and the compact digital representation is transmitted after conversion completes. This segmentation allows partial results to be utilized earlier, reducing overall system latency while ensuring final accuracy

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If the interface circuit performs substantial computations to derive compact digital representations, then the data processing accuracy is improved, but the transmission time and latency increase

Engineering Contradiction:
Improvedigital representation accuracyVSAvoidcomputation time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The interface circuit performs preliminary encoding into redundant digital representation format during the A/D conversion process, preparing data for transmission without waiting for complete conversion. This preliminary action reduces the computational burden at transmission time and allows earlier data utilization

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system transmits a redundant digital representation (excessive action) that contains more information than the final compact representation needs. This partial transmission during conversion, followed by refinement to compact format after conversion, allows earlier transmission while ensuring final accuracy through the refinement process

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP2388922B1Method and circuit for encoding and transmitting numerical values from an analog-to-digital conversion process
Publication Date: 2014.07.09 LINEAR TECHNOLOGY CORP
  • EP2388922B1 patent drawingFigure 1~2
  • EP2388922B1 patent drawingFigure 3~4
  • EP2388922B1 patent drawingFigure 5~6

AI summary

An analog-to-digital converter system and methodology comprising an analog-to-digital converter circuit configured to provide sequentially a plurality of codes designating a numerical value in a first number system. The analog-to-digital converter system further comprising an encoder interface circuit configured to receive the plurality of codes and to derive a redundant digital representation. A portion of the redundant digital representation is transmitted during the conversion period. The encoder interface circuit may be configured to use a numerical successive-approximation algorithm to derive the redundant digital representation. A substantial portion of the redundant digital representation may be transmitted via a serial interface during the conversion period to reduce an overall latency.