RF Receiver Calibration Using OTA CDMA Power Measurement

Solution Overview

Problem

Existing wireless test techniques are unable to accurately measure the radio-frequency signal power received at the receiver in electronic devices, as they either bypass the antenna or introduce interference with wired connections, and existing test equipment lacks the capability to measure received power levels directly.

Innovation Solution

A wireless test system that uses a call box to transmit protocol-compliant network messages to the device under test, directing it to measure the received radio-frequency signal power and return the measurement wirelessly, allowing the power value to be embedded in network messages or encoded in intercode handover commands.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If wired test probes are used to measure received power, then measurement capability is provided, but the cable introduces signal interference and distortion into the test environment

Engineering Contradiction:

Improvereceived power measurementVSAvoidsignal interference from cable

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the mechanical wired probe connection with a wireless measurement approach. The device under test performs self-measurement of received power using its own receiver, and the measurement data is transmitted wirelessly to the test equipment. This eliminates the cable that would otherwise introduce signal interference and distortion into the test environment.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The device under test performs the measurement function itself by using its own receiver to measure the received power of test signals. Instead of requiring external probe equipment to measure power at the antenna, the device's receiver internally measures the power and reports it back, making the device self-sufficient for the measurement task.

Inventive Principle:

Principle #25Self-service

2Measurement precision

If wired probes connect to connectors upstream from the receiver, then power measurement is possible, but the measurement does not reflect actual received power at the receiver input

Engineering Contradiction:

Improvereceived power measurement accuracyVSAvoidsignal power information distortion

Core Design Contradiction:

Measurement precisionVSLoss of information

Solution Approach 1:

The device under test performs the measurement function itself by using its own receiver to measure the received power of test signals. Instead of requiring external probe equipment to measure power at the antenna, the device's receiver internally measures the power and reports it back, making the device self-sufficient for the measurement task.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent uses the device's receiver as an intermediary measurement element. The receiver measures the actual received power at its input and then communicates this measurement data to the test equipment wirelessly. This intermediary approach ensures the measurement reflects true received power while avoiding direct wired connections that would introduce interference.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If existing wireless test equipment is used, then wireless testing avoids cable interference, but the equipment cannot measure received power levels in the device under test

Engineering Contradiction:

Improveelimination of cable interferenceVSAvoidreceived power measurement capability

Core Design Contradiction:

Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The device under test performs the measurement function itself by using its own receiver to measure the received power of test signals. Instead of requiring external probe equipment to measure power at the antenna, the device's receiver internally measures the power and reports it back, making the device self-sufficient for the measurement task.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent makes the device under test serve multiple functions: it acts as both the device being tested and as the measurement instrument. The receiver in the device performs both signal reception for normal operation and power measurement for testing purposes, eliminating the need for separate external measurement equipment.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS8718567B2Methods for calibrating radio-frequency receivers using code division multiple access test equipment

Publication Date: 2014.05.06 APPLE INC

AI summary

Wireless test equipment may be used to perform over-the-air testing of user equipment. The user equipment may contain an antenna and a receiver. The wireless test equipment may contain a call box that performs network-level testing by sending and receiving protocol-compliant network messages. The call box may transmit a radio-frequency test signal at a predetermined power. The antenna in the user equipment may receive the radio-frequency test signal and may provide the received radio-frequency test signal to the input of the receiver. The call box may send a network message such as a code-division-multiple-access intercode handover command to the user equipment to direct the user equipment to measure the received radio-frequency test signal power at the input of the receiver. The measured power may be transmitted to the call box as part of a pilot measurement message indicator, using an intercode handover command, or using other network messages.