Normalized Delay Polar Modulator for Low-Spur Phase Shifting

Solution Overview

Problem

Existing RF communication technologies face challenges with polar modulation, including error vector magnitude issues in Cartesian modulation and the generation of spurious frequencies in polar modulation, especially with large phase shifts exceeding 360°.

Innovation Solution

A polar phase or frequency modulator is developed, utilizing a normalized delay circuit and calculator to generate digital delay control values based on phase or frequency samples, which are used to delay carrier signal edges, thereby modulating the signal effectively without exceeding 360° phase shifts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If polar modulation is used to directly modulate the phase of the carrier frequency, then amplitude and phase are processed separately leading to low cost implementation, but spurious frequencies are generated particularly when phase shift exceeds 360°

Engineering Contradiction:

Improveimplementation costVSAvoidspurious frequencies

Core Design Contradiction:

Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The patent implements dynamic phase unwrapping that continuously tracks and adjusts the phase trajectory to prevent exceeding 360° shifts. The system dynamically modifies the phase modulation approach based on real-time conditions, switching between direct polar modulation and alternative strategies when phase accumulation approaches critical thresholds, thereby eliminating spurious frequencies while maintaining implementation simplicity.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent employs feedback mechanisms that monitor the accumulated phase shift and provide control signals to prevent phase excursions beyond 360°. The system uses feedback from the modulated signal characteristics to adjust the modulation depth and timing, ensuring that phase shifts remain within the safe range while maintaining the cost-effective polar modulation architecture.

Inventive Principle:

Principle #23Feedback

2Loss of information

If the number of phase symbols exceeds a certain limit in Cartesian modulation, then more phase information can be transmitted, but Error Vector Magnitude errors occur

Engineering Contradiction:

Improvephase information transmission capacityVSAvoidError Vector Magnitude

Core Design Contradiction:

Loss of informationVSReliability

Solution Approach 1:

The patent implements dynamic phase unwrapping that continuously tracks and adjusts the phase trajectory to prevent exceeding 360° shifts. The system dynamically modifies the phase modulation approach based on real-time conditions, switching between direct polar modulation and alternative strategies when phase accumulation approaches critical thresholds, thereby eliminating spurious frequencies while maintaining implementation simplicity.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent employs feedback mechanisms that monitor the accumulated phase shift and provide control signals to prevent phase excursions beyond 360°. The system uses feedback from the modulated signal characteristics to adjust the modulation depth and timing, ensuring that phase shifts remain within the safe range while maintaining the cost-effective polar modulation architecture.

Inventive Principle:

Principle #23Feedback

3Productivity

If large phase shifts exceeding 360° are applied in polar modulation, then greater modulation capacity is achieved, but spurious frequencies are generated

Engineering Contradiction:

Improvemodulation capacityVSAvoidspurious frequencies

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent implements dynamic phase unwrapping that continuously tracks and adjusts the phase trajectory to prevent exceeding 360° shifts. The system dynamically modifies the phase modulation approach based on real-time conditions, switching between direct polar modulation and alternative strategies when phase accumulation approaches critical thresholds, thereby eliminating spurious frequencies while maintaining implementation simplicity.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent employs feedback mechanisms that monitor the accumulated phase shift and provide control signals to prevent phase excursions beyond 360°. The system uses feedback from the modulated signal characteristics to adjust the modulation depth and timing, ensuring that phase shifts remain within the safe range while maintaining the cost-effective polar modulation architecture.

Inventive Principle:

Principle #23Feedback

Data Source

PatentEP3790188B1Polar phase or frequency modulation circuit and method

Publication Date: 2023.05.31 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES

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AI summary

The present disclosure relates to a polar phase or frequency modulator comprising: a normalized delay circuit (602) configured to delay edges of an input carrier signal (CLK_IN) based on normalized delay control values (ϕi) to generate a modulated output signal (RF_OUT); and a normalized delay calculator (604) configured to receive the modulated output signal (RF_OUT) and to generate the normalized delay control values (ϕi).