Multi-CDR Signal Acquisition and Tracking Across Modulation Schemes

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Solution Overview

Problem

Existing electronic systems face challenges in efficiently acquiring and tracking signals modulated by different schemes, such as 2-FSK, 3-FSK, and 4-FSK, due to the need for distinct clock recovery mechanisms and preamble detection, which can be inefficient and inflexible.

Innovation Solution

An integrated circuit with multiple clock and data recovery (CDR) modules that utilize a first CDR for acquisition and a second CDR for tracking, allowing for flexible clock rates and preamble detection across different modulation schemes by configuring clock multiplexers and serializers/deserializers to adapt to various preamble sequences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single CDR module is used for both acquisition and tracking across multiple modulation schemes, then device complexity is reduced, but acquisition time increases and flexibility decreases

Engineering Contradiction:
ImproveCDR module structureVSAvoidsignal acquisition time
Core Design Contradiction:
Device complexityVSLoss of time

Solution Approach 1:

The patent divides the CDR functionality into separate acquisition CDR and tracking CDR modules. The acquisition CDR is dedicated to signal acquisition with optimized parameters for detecting preamble sequences, while the tracking CDR handles continuous signal tracking. This segmentation allows each module to be optimized for its specific function, reducing overall acquisition time while maintaining manageable complexity through clear functional separation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements multiple CDR modules that can operate across different modulation schemes (2-FSK, 3-FSK, 4-FSK, etc.). Each CDR module is designed with universal capability to handle various preamble sequences and clock rates, allowing the system to adapt to different communication standards without requiring scheme-specific hardware, thus reducing acquisition time while keeping device complexity reasonable through standardized multi-functional design.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If distinct CDR mechanisms are used for each modulation scheme, then adaptability improves, but device complexity increases

Engineering Contradiction:
Improvesupport for multiple modulation schemesVSAvoidclock recovery mechanism
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent designs CDR modules with universal capability to support multiple modulation schemes (2-FSK, 3-FSK, 4-FSK, GFSK, MSK, etc.). The acquisition CDR and tracking CDR are configured to handle various preamble sequences and clock rates through programmable parameters rather than dedicated hardware for each scheme. This multi-functional design achieves high adaptability while controlling device complexity by avoiding proliferation of scheme-specific mechanisms.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent enables adaptability across modulation schemes by allowing dynamic configuration of CDR parameters such as clock rate, preamble sequence patterns, and detection thresholds. Instead of creating distinct hardware mechanisms for each scheme, the system achieves versatility through parameter reconfiguration of the same CDR modules, thereby maintaining manageable device complexity while supporting diverse modulation formats.

Inventive Principle:
Principle #35Parameter changes

3Speed

If higher clock rates are used for acquisition, then acquisition speed improves, but power consumption increases

Engineering Contradiction:
Improveacquisition speedVSAvoidpower consumption
Core Design Contradiction:
SpeedVSUse of energy by moving object

Solution Approach 1:

The patent segments the operational phases into acquisition and tracking, with the acquisition CDR operating at higher clock rates only during the brief acquisition phase to achieve fast preamble detection. Once acquisition is complete, the system transitions to the tracking CDR operating at lower, more energy-efficient clock rates for continuous signal tracking. This temporal segmentation of high-speed operation to only when necessary improves acquisition speed while minimizing overall power consumption.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements periodic acquisition attempts followed by continuous tracking phases. The high-power acquisition mode is activated periodically or on-demand when signal presence is detected, rather than continuously. This periodic activation of high-clock-rate acquisition functionality achieves fast acquisition when needed while significantly reducing average power consumption during the lower-power tracking phases in between.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP2947834B1Apparatus and method to acquire and track signals modulated by different modulation schemes
Publication Date: 2020.03.04 ANALOG DEVICES GLOBAL UNLTD
  • EP2947834B1 patent drawingFigure 1
  • EP2947834B1 patent drawingFigure 2A
  • EP2947834B1 patent drawingFigure 2B

AI summary

Apparatus and method for acquiring and tracking a data signal are disclosed. Two different CDR circuits are configured to acquire and track data based on two different modulation schemes. While in the acquisition mode, the first CDR circuit may acquire data signal by sampling the signal at a reduced clock rate and handover to the second CDR circuit when a preamble is found. Also in the acquisition mode, the data acquisition and tracking circuit may determine the power level of the preamble signal and dynamically adjust the threshold level for the tracking period upon finding of the preamble.