PWM Decoder Pulse Filtering for High-Gear Data Recovery

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Solution Overview

Problem

Existing pulse-width modulated (PWM) decoders, particularly those used in M-PHY communication links, face challenges in accurately decoding data at higher gears due to oversampling limitations, which results in inefficiencies and inaccuracies.

Innovation Solution

A decoder comprising a one-sided pulse filter that shortens the durations of high pulses and a flip-flop that latches the filtered signal on trailing edges, allowing for precise decoding of PWM data by suppressing short pulses and maintaining long pulses, thereby improving data recovery across varying data rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If oversampling is used to recover data in PWM decoders, then data can be recovered at lower gears, but the decoder becomes unsuitable for higher gears due to inefficiencies and inaccuracies

Engineering Contradiction:
Improvedata recovery accuracyVSAvoiddecoding efficiency at higher gears
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The one-sided pulse filter performs preliminary action by shortening high pulses before the data recovery process. This pre-processing step modifies the PWM signal characteristics in advance, making the subsequent decoding operation more efficient and accurate across all gear ranges, particularly at higher gears where oversampling fails.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention changes the temporal parameter of the PWM signal by shortening the duration of high pulses through the one-sided pulse filter. This parameter transformation converts the wide pulses into narrower pulses that can be accurately decoded without oversampling, enabling efficient operation at higher data rates while maintaining measurement precision.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If pulse durations are not shortened, then the original PWM signal characteristics are preserved, but decoding accuracy deteriorates at higher gears

Engineering Contradiction:
ImprovePWM signal characteristicsVSAvoiddecoding accuracy
Core Design Contradiction:
Stability of the object's compositionVSMeasurement precision

Solution Approach 1:

The one-sided pulse filter applies preliminary action by preprocessing the PWM signal to shorten pulse durations before decoding. This pre-modification of pulse characteristics enables accurate decoding at higher gears while maintaining the essential PWM structure, effectively resolving the conflict between preserving signal characteristics and achieving decoding accuracy.

Inventive Principle:
Principle #10Preliminary action

3Ease of manufacture

If traditional oversampling decoding is used, then implementation is simple, but the decoder cannot handle higher gears effectively

Engineering Contradiction:
Improvedecoder implementation simplicityVSAvoidgear range compatibility
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The invention merges the pulse shortening function with the existing PWM decoder structure. The one-sided pulse filter is integrated into the decoding path, combining a simple preprocessing stage with the existing flip-flop-based decoding logic. This merged approach maintains implementation simplicity while dramatically improving adaptability to higher gears.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The one-sided pulse filter acts as an intermediary component between the PWM input signal and the decoding logic. This intermediary element transforms the input signal characteristics without complicating the overall system, enabling the simple flip-flop-based decoder to handle higher gears effectively by preprocessing the signal to appropriate pulse widths.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3134818B1Pulse-width modulation data decoder
Publication Date: 2018.05.02 QUALCOMM INC
  • EP3134818B1 patent drawingFigure 1~3
  • EP3134818B1 patent drawingFigure 4~6

AI summary

Systems and methods for decoding pulse-width modulated (PWM) data are disclosed. An example decoder filters a data input signal with a one-sided pulse filter. The one-sided pulse filter suppresses short pulses on the data input signal and passes long pulses. The example decoder latch the filtered data signal at the end of each bit time of the data input signal. The duration of pulses that are suppressed by the one-sided pulse filter can be calibrated to compensate for circuit variations and to allow the decoder to operate at various data rates. The decoder can be implemented in a small integrated circuit area and can be power efficient.