RF Transceiver Self-Calibration for Second-Order Intermodulation Distortion

Solution Overview

Problem

Current calibration methods for second-order intermodulation distortion in wireless communication systems are time-consuming and costly, leading to reduced product competitiveness due to inefficiencies in minimizing second-order crossover components caused by non-linearity in RF transceivers.

Innovation Solution

A calibration apparatus and method that utilizes a logic circuit in an RF transceiver to generate and up-convert modulation signals with different frequencies, combining them into an RF transmission signal to adjust and minimize second-order crossover components within the receiver, leveraging native devices and reducing the need for external equipment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional external calibration equipment is used to minimize second-order crossover components, then calibration accuracy is improved, but calibration time and cost increase significantly

Engineering Contradiction:

Improvecalibration accuracyVSAvoidcalibration time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The RF transceiver performs self-calibration by utilizing its own internal logic circuit and transmission paths to generate test signals and measure second-order crossover components, eliminating the need for external calibration equipment and significantly reducing calibration time while maintaining accuracy

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The logic circuit and transmission paths are designed to serve dual purposes: normal signal transmission and calibration testing. The same components used for communication functions are also used to generate calibration test signals and measure distortion, thereby reducing overall system complexity and calibration costs

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Measurement precision

If traditional external calibration equipment is used to minimize second-order crossover components, then calibration accuracy is improved, but calibration cost increases

Engineering Contradiction:

Improvecalibration accuracyVSAvoidcalibration cost

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The RF transceiver performs self-calibration by utilizing its own internal logic circuit and transmission paths to generate test signals and measure second-order crossover components, eliminating the need for external calibration equipment and significantly reducing calibration time while maintaining accuracy

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The logic circuit and transmission paths are designed to serve dual purposes: normal signal transmission and calibration testing. The same components used for communication functions are also used to generate calibration test signals and measure distortion, thereby reducing overall system complexity and calibration costs

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Device complexity

If second-order intermodulation distortion is not calibrated, then device complexity is reduced, but signal sensitivity deteriorates

Engineering Contradiction:

Improvesystem complexityVSAvoidsignal sensitivity

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The RF transceiver performs self-calibration by utilizing its own internal logic circuit and transmission paths to generate test signals and measure second-order crossover components, eliminating the need for external calibration equipment and significantly reducing calibration time while maintaining accuracy

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The calibration process is performed in advance during manufacturing or initialization, adjusting the receiver's non-linearity characteristics before normal operation begins. This preliminary calibration ensures optimal signal sensitivity is achieved without adding complexity to the ongoing communication operations

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS9337940B2Second-order intermodulation distortion calibration apparatus, system and method

Publication Date: 2016.05.10 MEDIATEK INC

AI summary

A second-order intermodulation distortion calibration apparatus is provided. The calibration apparatus is applied to a radio-frequency (RF) transceiver, which includes a transmitter for providing an RF signal, and a receiver that is at the same time a target to be calibrated. The calibration apparatus includes a calibrator. The calibrator utilizes a logic circuit in the transmitter to generate two modulation signals having different frequencies, and utilizes two transmission paths to up-convert and combine the two modulation signals to an RF transmission signal. The calibrator further channels the RF transmission signal to the receiver to accordingly adjust second-order non-linear behaviors of the receiver and to detect a signal strength of a second-order crossover component caused by the receiver due to the second-order non-linearity. After the calibration process, the calibrator provides a control signal to minimize the signal strength of the second-order crossover component.