Programmable Digital Loopback Circuits for RF Signal Processing

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Solution Overview

Problem

Existing digital loopback circuits in RF systems lack flexibility and versatility, limiting their use for various purposes and applications.

Innovation Solution

Implementing programmable digital loopback circuits with combiners and weighting circuits between the digital domain processing of the receiver and transmitter, allowing for programmable combination and processing of RX and TX signals, enabling flexible implementation of digital loopback paths.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If fixed digital loopback circuits are used in RF systems, then the circuit structure is simple, but the flexibility and versatility are limited

Engineering Contradiction:
Improveflexibility and versatilityVSAvoidcircuit structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements a universal digital loopback circuit that can perform multiple functions including signal routing, combining, weighting, and processing. The circuit is designed to handle various signal paths (RX to TX, TX to RX, RX to RX, TX to TX) and support different applications (DRFM, electronic warfare, RF repeaters) through a single integrated structure, eliminating the need for separate dedicated circuits for each function.

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

Solution Approach 2:

The patent introduces programmable elements that allow the circuit configuration to be dynamically changed. Switches can be controlled to establish different signal paths, combiners can be programmed to adjust signal mixing ratios, and weighting circuits can be modified to change signal characteristics. This dynamic reconfigurability enables the same hardware to adapt to different operational requirements and applications.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If multiple dedicated loopback circuits are implemented for different applications, then the versatility is improved, but the device complexity increases

Engineering Contradiction:
Improveapplication coverageVSAvoidnumber of circuits
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges multiple dedicated loopback circuit functions into a single integrated circuit. By combining signal routing switches, combiners, weighting circuits, and processing elements into one unified structure, the patent achieves the functionality of multiple dedicated circuits while reducing the overall number of separate components. This consolidation maintains application-specific performance while simplifying the overall device architecture.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrated circuit is designed with universal capabilities to support multiple applications including DRFM, electronic warfare, and RF repeaters. Through programmable control, the same circuit infrastructure can be configured to meet the specific requirements of different applications, eliminating the need to implement separate dedicated circuits for each use case.

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

3Adaptability or versatility

If programmable elements are added to create flexible loopback paths, then the adaptability is improved, but the manufacturing complexity increases

Engineering Contradiction:
ImproveprogrammabilityVSAvoidcircuit implementation
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent introduces a controller as an intermediary element that manages the programmable switches, combiners, and weighting circuits. This controller serves as a mediator between the digital domain and the RF signal path, allowing complex programmable functionality to be implemented through software or firmware control rather than complex hardwired logic. This approach simplifies manufacturing by separating the control logic from the signal processing paths.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3930226B1Programmable digital loopback for RF applications
Publication Date: 2022.11.23 ANALOG DEVICES INC
  • EP3930226B1 patent drawingFigure 1
  • EP3930226B1 patent drawingFigure 2
  • EP3930226B1 patent drawingFigure 3

AI summary

Various approaches to implementing digital loopback in a radio frequency (RF) system are disclosed. An example RF system includes a receiver that includes an ADC and a transmitter that includes a DAC. The apparatus includes multiple digital loopback circuits provided at different points between the digital domain processing of the receiver and the transmitter. Each digital loopback circuit may include a combiner and one or more weighing circuits, which make the circuit programmable. The combiner of a given digital loopback circuit is configured to combine a RX signal and a TX signal at a particular point of the digital domain processing of the receiver and the transmitter where said digital loopback circuit is implemented. The one or more weighting circuits are configured to define the how much of the TX signal and/or RX signal is used for said combination.