Apple Inc.

David A Donovan

Justin Lawrence Gregg

Wassim El-Hassan

Vishwanath Venkataraman

Gary Lang Do

Adil Syed

Tomoki Takeya

Thomas W Chang

Gurusubrahmaniyan Subrahmaniyan Radhakrishnan

Vishuanath Venkataraman

A calibration system may be provided for calibrating wireless communications circuitry in an electronic device during manufacturing. The calibration system may include data acquisition equipment and calibration computing equipment for receiving and processing test and calibration signals from wireless communications circuitry to be calibrated. During testing and calibration operations, a device may be provided with initial pre-distortion calibration values. The initial pre-distortion calibration values may be generated at least in part based on calibration operations performed for other wireless electronic devices. The device may generate a test signal using the initial pre-distortion calibration values. The calibration system may determine whether the test signal is within an acceptable range of a known reference signal. If the test signal is outside of the acceptable range, the calibration system may generate a set of corrected pre-distortion calibration values to be used in generating wireless communications signals during normal operation of the device.

Systems for calibration of wireless electronic devices

Electronic devices with wireless communications capabilities are provided. The electronic device may include storage and processing circuitry, power amplifier circuitry, power supply circuitry, etc. The storage and processing circuitry may direct the power amplifier circuitry to operate using a desired gain mode, in a particular radio channel, and at a given output power level. The power supply circuitry may bias the power amplifier circuitry with a power supply voltage. The performance of the power amplifier circuitry may be characterized by an adjacent channel leakage ratio (ACLR) margin. The power consumption of the power amplifier circuitry may be characterized by a current savings ratio. A cost function may be calculated by taking the product of the ACLR margin and current savings ratio. A minimum point for each cost function curve may be determined. It is desirable to bias the power amplifier circuitry with a supply voltage corresponding to the minimum point.

Methods for determining optimum power supply voltages for radio-frequency power amplifier circuitry

A calibration system for calibrating wireless circuitry in an electronic device is provided. The test system may include test equipment, a computer, and a device under test (DUT). The test equipment may measure the output power of the DUT. The DUT may include power amplifier circuitry that is provided with a power supply voltage supplied by power supply circuitry. A list mode sequence of commands may be provided to the DUT and the test equipment to calibrate the power amplifier circuitry. The list of commands may be processed by the DUT to produce radio-frequency signals. The list of commands may be simultaneously processed by the test equipment to perform measurements on the radio-frequency signals. The computer may retrieve measurement data from the test equipment after testing is complete. The computer may subsequently determine calibrated control settings for the DUT that reduce power consumption while ensuring satisfactory adjacent channel leakage performance.

Method for determining optimum power amplifier configurations using list mode testing

A method for testing wireless devices under test (DUTs) in a wireless test station is provided. Each test station may include a test unit, a test chamber with an antenna, and a radio-frequency (RF) cable that connects the test unit to the test chamber. Reference DUTs may be used to calibrate each test station to compute a corrected linear equation based on a nominal path loss value. Over-the-air (OTA) path loss of each test station may not be directly measured. Once calibrated, the test chambers may be used during product testing to test factory DUTs to determine whether a particular factory DUT satisfies pass/fail criteria. During product testing, measured output power levels may be compared with expected output power levels computed using the corrected linear equation. The amount of error between the measured and expected output power levels will determine whether a production DUT satisfies the pass/fail criteria.

Methods of testing wireless devices in over-the-air radio-frequency test systems without path loss characterization

Calibration equipment for calibrating multiple test stations in a test system is provided. Each test station may include a test unit, a test chamber with an over-the-air antenna, and a radio-frequency (RF) cable that connects the test unit to the test chamber. Reference devices under test (DUTs) may be used to calibrate uplink and downlink path loss (e.g., OTA path loss, RF cable path loss, and variations of the test unit) associated with each test station. The reference DUTs may calibrate each test station at desired frequencies to generate a path loss table. Once calibrated, the test chambers may be used during production testing to test factory DUTs. During production testing, the transmit/receive power efficiency of each factory DUT may be calculated based on values in the path loss table to determine whether a particular production DUT is a passing or failing DUT according to pass/fail criteria.

Methods for calibrating over-the-air path loss in over-the-air radio-frequency test systems

Test systems are provided for performing testing and calibration operations on wireless circuitry in electronic devices. The electronic devices may include cellular telephones and other portable electronic devices. Wireless circuitry in a device may include a radio-frequency transceiver that is controlled based on radio-frequency transceiver control signals. The wireless circuitry may also include power amplifier circuitry. The power amplifier circuitry may receive radio-frequency signals from the transceiver and may produce correspondingly amplified radio-frequency output signals for wireless transmission with an antenna. The power amplifier circuitry may be powered by a bias voltage. The test systems may provide the electronic device with a transmit power request that directs the electronic device to produce a desired output power. The test systems may measure the actual resulting power. After sufficient measurements have been made, the test systems may calibrate the transceiver and power amplifier settings.

Wireless transmitter calibration using absolute power requests

Wireless circuitry in an electronic device may contain radio-frequency transceiver circuitry and power amplifier circuitry that transmits radio-frequency signals through an antenna. A tap and power detector that are interposed in the radio-frequency signal path between the power amplifier circuitry and the antenna may be used to make output power measurements. Control circuitry may control the wireless circuitry in an open-loop control regime in which output power adjustments are based on a requested power without using the output power measurements. The control circuitry may also control the wireless circuitry in a closed-loop control regime in which the output power measurements serve as a source of real time feedback to determine whether to increase or decrease the output power. The output power may be controlled using linear transition zone power control curves in a transition zone between the open-loop regime and the closed-loop regime.

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Oakland, CA, United States of America

David A Donovan