Current-Pump Analog Signal Generation With Noise-Shaped Integration

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Solution Overview

Problem

Existing methods for generating analog signals, such as those used in software radio for 5G mobile telephony, face limitations in flexibility, reconfigurability, and energy efficiency, particularly due to non-linearities in amplifiers and limitations in frequency range generation.

Innovation Solution

A device comprising a current pump controlled by a digital control code, with a module for calculating the digital code that includes noise shaping and quantization error compensation, and a differential amplifier with capacitive input impedance, allowing for the generation of arbitrary analog signals by temporal integration of switched currents, while minimizing energy consumption and reducing non-linearities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If frequency raising is performed in the analog domain by multiplying by a carrier signal, then radiofrequency signals can be generated, but the non-linearities of the amplifier cannot be compensated in the digital domain and the system lacks flexibility

Engineering Contradiction:

Improvesignal qualityVSAvoidreconfigurability

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent inverts the conventional approach by performing frequency raising in the digital domain before analog conversion, rather than in the analog domain after conversion. This allows digital signal processing techniques to be applied to compensate for non-linearities and enables flexible reconfiguration of carrier frequencies through software control of the digital code generator.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent replaces the analog domain frequency multiplication operation with a digital domain operation. Instead of using analog mixers and carriers, the system uses digital code generation and processing to achieve frequency raising, which can then be converted to analog form. This substitution enables precise digital control and compensation of amplifier non-linearities.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If Direct Digital Synthesis (DDS) is used to raise frequency in the digital domain, then flexibility is improved, but the carrier frequency range is limited to multiples of the working frequency

Engineering Contradiction:

Improvefrequency rangeVSAvoidfrequency accuracy

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent changes the fundamental parameter of frequency generation by using a digital code generator that can produce arbitrary frequency values not constrained to multiples of a base frequency. The system varies digital control codes to directly set carrier frequencies, enabling continuous frequency tuning across a wide range while maintaining precision through digital control mechanisms.

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If zero-order integration is used for analog signal generation, then the system is simple to implement, but sizable errors are produced compared to first-order integration

Engineering Contradiction:

Improveimplementation simplicityVSAvoidsignal accuracy

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent implements a feedback mechanism where the output of the integration stage is fed back to correct quantization errors. This feedback loop enables first-order integration behavior that compensates for quantization inaccuracies, significantly improving signal accuracy while maintaining a relatively simple implementation structure through the use of feedback control.

Inventive Principle:

Principle #23Feedback

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution enables the generation of high-quality analog signals with reduced energy consumption and improved flexibility, allowing for arbitrary signal generation while minimizing errors and non-linearities, thus addressing the limitations of existing technologies.

Implementation Method 1

a differential amplifier exhibiting a predominantly capacitive input impedance

Methodology Applied

Scientific EffectCapacitive integration: Capacitance

Data Source

PatentUS10340942B2Device for generating analogue signals and associated use

Publication Date: 2019.07.02 THALES SA

AI summary

An analog signals generating device comprises a current pump controlled by a control code generated by a module for calculating the digital code with shaping of noise. The calculation module receives as input a digital signal representative of the analog signal to be generated and comprises at least one quantizer and a quantization error compensating stage. The current pump comprises two groups of at least one electric current generator and two groups of at least one switching means, the switching facilities being controlled by the control signal and causing the electric currents to flow between the electric current generators and the inputs of a differential amplifier exhibiting a predominantly capacitive input impedance and connected in series between the two groups of switching means.