Apple Inc.

Tomoki Takeya

Justin Lawrence Gregg

Adil Syed

Ruben Caballero

Vishwanath Venkataraman

David A Donovan

Song Liu

A test system may include test equipment for testing the radio-frequency performance of wireless electronic devices. The test equipment may provide radio-frequency downlink signals to a wireless electronic device under test (DUT). The test equipment may perform a power sweep by stepping down the downlink signals in signal power level to test receiver sensitivity for the DUT. The DUT may gather measurement data from the downlink signals. The test equipment may retrieve measurement data from the DUT after downlink signal transmission has ended. The test equipment may identify a trigger in the retrieved measurement data to ensure that the data is synchronized with the power sweep in the transmitted downlink signals. The test equipment may identify path loss information associated with the test system. The test equipment may compute receiver sensitivity values for the DUT based on the path loss information and retrieved measurement data.

Methods for testing receiver sensitivity of wireless electronic devices

Calibration equipment for calibrating multiple test stations in a test system is provided. Each test station may include a test unit, a test fixture, and a radio-frequency (RF) cable that connects the test unit to the test fixture. A control test setup may be used to calibrate uplink and downlink characteristics associated with each test station (e.g., to determine path loss associated with the RF cable and test fixture and variations associated with the test unit). The control test setup may calibrate each test station at desired frequencies to generate a test station error (offset) table. The test unit of each test station may be individually configured based on the test station error table so that offset is minimized among the different stations and so that the test stations may reliably measure hundreds or thousands of wireless electronic devices during product testing.

Methods for calibration of radio-frequency path loss in radio-frequency test equipment

A wireless electronic device such as a portable electronic device may contain a baseband module. Power amplifier circuitry in the device may amplify radio-frequency signals for transmission. During calibration measurements, a computer directs the baseband module to generate control signals that adjust the gain of the power amplifier circuitry. The computer may also direct the baseband module to generate a series of modulated or unmodulated test tones at one or more communications channel frequencies. A power sensor may be connected to the output of the power amplifier circuitry using a transmission line path. The computer and power sensor may be used in making power measurements on radio-frequency signals at the output of the power amplifier while power amplifier gain and test tone frequency adjustments are being made. Power amplifier calibration data may be produced and stored in the electronic device based on the power measurements.

System for calibrating wireless communications devices

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

A test station may include a test host, a tester, and a test chamber. Multiple devices under test (DUTs) may be placed in the test chamber during device characterization operations. Radio-frequency signals may be conveyed from the tester to the multiple DUTs using a radiated arrangement through an antenna in the test chamber. The tester may broadcast downlink test signals in parallel to the multiple DUTs. The DUTs may simultaneously synchronize with the downlink test signals and measure radio-frequency performance levels while receiving the downlink test signals. The test host may direct the tester to gradually lower its output power level. The DUTs may be used to determine downlink sensitivity by monitoring the measured radio-frequency performance levels as the output power level of the tester is lowered. Simultaneously downlink sensitivity testing may be performed for multiple modulation schemes and data rates for any communications protocol.

Simultaneous downlink sensitivity testing for multiple modulation schemes in a wireless test system

A test system may include multiple test stations. Electronic devices may be tested using the test system. Each test station may include a test unit such as a radio-frequency tester that can make wireless and wired radio-frequency signal measurements on devices under test. The test stations may be configured to perform pass-fail testing on devices under test during manufacturing. One or more selected devices under test that have passed the pass-fail tests may be retested using the test stations. Multiple tests may be performed at a given test station using the same selected device under test. Gathered test data may be analyzed to determine whether the test stations have sufficient accuracy and precision or need to be recalibrated or taken offline.

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Santa Clara, CA, United States of America

Tomoki Takeya