Abstract: A flash translation layer with a rewind feature, and a method of operation. In some embodiments, the method includes: receiving, by a storage device, a first write command, for a first logical address; performing, by the storage device, a write to flash memory at a first physical address, corresponding to the first logical address; receiving, by the storage device, a first bookmarking command, for the first logical address; receiving, by the storage device, a second write command, for the first logical address; performing, by the storage device, a write to flash memory at a second physical address, corresponding to the first logical address; receiving, by the storage device, a first rewind command, for the first logical address; receiving, by the storage device, a read command, for the first logical address; and retrieving, by the storage device, in response to the read command, data from the first physical address.

Abstract: A system and method for performing visual inspection using synthetically generated images is disclosed. An example embodiment is configured to: receive one or more images of a compliant manufactured component; receive images of component defects; use the images of component defects to produce a variety of different synthetically-generated images of defects; combine the synthetically-generated images of defects with the one or more images of the compliant manufactured component to produce synthetically-generated images of a non-compliant manufactured component; and collect the one or more images of the compliant manufactured component with the synthetically-generated images of the non-compliant manufactured component into a training dataset to train a machine learning system.

Abstract: Radio-frequency performance of wireless communications circuitry on an electronic device under test (DUT) may be tested without external test equipment such as signal analyzers or signal generators. A first DUT may transmit test signals to a second DUT. External attenuator circuitry interposed between the DUTs may attenuate the test signals to desired power levels. The second DUT may characterize and/or calibrate receiver performance by generating wireless performance metric data based on the attenuated test signals. A single DUT may transmit test signals to itself via corresponding transmit and receive ports coupled together through the attenuator. The DUT may generate performance metric data based on the test signals. The DUT may include feedback receiver circuitry coupled to an output of a transmitter via a feedback path and may characterize and/or calibrate transmit performance using test signals transmitted by the transmitter and received by the feedback receiver.

Abstract: A test system is provided for performing radio-frequency tests on an electronic device under test (DUT) having multiple antennas. The test system may include a test unit for generating radio-frequency test signals, a test enclosure, and a test antenna fixture. The test fixture may include tunable antenna circuitry, antenna tuning elements, a test sensor, a microcontroller, a battery, and a solar cell that charges the battery, each of which is mounted on a test fixture within the test enclosure. The test sensor may be used to detect stimuli issued by the DUT. In response to detecting the stimuli, the microcontroller may send control signals to the antenna tuning elements to configure the antenna circuitry in different modes. Each of the different modes may be optimized to test a selected one of the multiple antennas in the DUT when operating using different radio access technologies and at different frequencies.

Abstract: Radio-frequency performance of wireless communications circuitry on an electronic device under test (DUT) may be tested without external test equipment such as signal analyzers or signal generators. A first DUT may transmit test signals to a second DUT. External attenuator circuitry interposed between the DUTs may attenuate the test signals to desired power levels. The second DUT may characterize and/or calibrate receiver performance by generating wireless performance metric data based on the attenuated test signals. A single DUT may transmit test signals to itself via corresponding transmit and receive ports coupled together through the attenuator. The DUT may generate performance metric data based on the test signals. The DUT may include feedback receiver circuitry coupled to an output of a transmitter via a feedback, path and may characterize and/or calibrate transmit performance using test signals transmitted by the transmitter and received by the feedback receiver.

Abstract: A device under test (DUT) may be tested using a test station having a test host, a non-signaling tester, and a test cell. During testing, the DUT may be placed within the test cell, and the DUT may be coupled to the test host and the tester. In one suitable arrangement, the DUT may be loaded with a predetermined test sequence. The predetermined test sequence may configure the DUT to transmit test signals using different network access technologies without synchronizing with the tester. The tester may receive corresponding test signals and perform desired radio-frequency measurements. In another suitable arrangement, the tester may be loaded with the predetermined test sequence. The predetermined test sequence may configure the tester to generate test signals using different network access technologies without establishing a protocol-compliant data link with the DUT. The DUT may receive corresponding test signals and compute receive signal quality.

Abstract: 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.

Abstract: A wireless electronic device may contain at least one adjustable antenna tuning element for use in tuning the operating frequency range of the device. The antenna tuning element may include radio-frequency switches, continuously/semi-continuously adjustable components such as tunable resistors, inductors, and capacitors, and other load circuits that provide desired impedance characteristics. A test system that is used for performing passive radio-frequency (RF) testing on antenna tuning elements in partially assembled devices is provided. The test system may include an RF tester and a test host. The tester may be used to gather scattering parameter measurements from the antenna tuning element. The test host may be used to ensure that power and appropriate control signals are being supplied to the antenna tuning element so that the antenna tuning element is placed in desired tuning states during testing.

Abstract: A test system is provided for performing radio-frequency tests on an electronic device under test (DUT) having multiple antennas. The test system may include a test unit for generating radio-frequency test signals, a test enclosure, and a test antenna fixture. The test fixture may include tunable antenna circuitry, antenna tuning elements, a test sensor, a microcontroller, a battery, and a solar cell that charges the battery, each of which is mounted on a test fixture within the test enclosure. The test sensor may be used to detect stimuli issued by the DUT. In response to detecting the stimuli, the microcontroller may send control signals to the antenna tuning elements to configure the antenna circuitry in different modes. Each of the different modes may be optimized to test a selected one of the multiple antennas in the DUT when operating using different radio access technologies and at different frequencies.

Abstract: A test station may include a test host, a signal generator, and a test chamber. Multiple devices under test (DUTs) may be placed in the test chamber during production testing. Radio-frequency signals may be conveyed from the signal generator to the multiple DUTs using a conducted arrangement through a radio-frequency signal splitter circuit or using a radiated arrangement through an antenna in the test chamber. The signal generator may broadcast initialization downlink signals. The multiple DUTs may synchronize with the initialing downlink signals. The signal generator may broadcast test downlink signals at a target output power level. The multiple DUTs may receive the test downlink signals and compute a corresponding downlink transmission performance level based on the received downlink signals. A given DUT is marked as a passing DUT if the downlink performance level is satisfactory. A given DUT may be retested if the downlink performance level fails design criteria.

Abstract: 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.

Abstract: A wireless electronic device may contain at least one adjustable antenna tuning element for use in tuning the operating frequency range of the device. The antenna tuning element may include radio-frequency switches, continuously/semi-continuously adjustable components such as tunable resistors, inductors, and capacitors, and other load circuits that provide desired impedance characteristics. A test system that is used for performing passive radio-frequency (RF) testing on antenna tuning elements in partially assembled devices is provided. The test system may include an RF tester and a test host. The tester may be used to gather scattering parameter measurements from the antenna tuning element. The test host may be used to ensure that power and appropriate control signals are being supplied to the antenna tuning element so that the antenna tuning element is placed in desired tuning states during testing.

Abstract: 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.

Abstract: A test station may include a test host, a signal generator, 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 signal generator to the multiple DUTs using a radiated arrangement through an antenna in the test chamber. The signal generator may broadcast downlink test signals. The DUTs may synchronize with the downlink test signals and measure radio-frequency performance levels while receiving the downlink test signals. The test host may direct the signal generator 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 signal generator is lowered. Downlink sensitivity testing may be performed across any desired radio-frequency bands and channels.

Abstract: A device under test (DUT) may be tested using a radio-frequency test station. A test station may include a test host, a test unit coupled to the test host, and a shielded enclosure. The shielded enclosure may contain a test antenna that is coupled to the test unit via a radio-frequency cable. The DUT may be placed in the shielded enclosure during testing. The DUT may not be electrically wired to the test host. The test host may direct the test unit to transmit control signals in the form of a text message using Short Message Service (SMS) so that the DUT is placed into different desired configurations during testing. The DUT may also be configured to respond by sending SMS messages back to the test unit, where the SMS messages generated by the DUT includes radio-frequency performance metrics measured using the DUT.

Abstract: 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.

Abstract: A device under test (DUT) may be tested using a radio-frequency test station. A test station may include a test host, a test unit coupled to the test host, and a shielded enclosure. The shielded enclosure may contain a test antenna that is coupled to the test unit via a radio-frequency cable. The DUT may be placed in the shielded enclosure during testing. The DUT may not be electrically wired to the test host. The test host may direct the test unit to transmit control signals in the form of a text message using Short Message Service (SMS) so that the DUT is placed into different desired configurations during testing. The DUT may also be configured to respond by sending SMS messages back to the test unit, where the SMS messages generated by the DUT includes radio-frequency performance metrics measured using the DUT.

Abstract: A device under test (DUT) may be tested using a test station having a test host, a non-signaling tester, and a test cell. During testing, the DUT may be placed within the test cell, and the DUT may be coupled to the test host and the tester. In one suitable arrangement, the DUT may be loaded with a predetermined test sequence. The predetermined test sequence may configure the DUT to transmit test signals using different network access technologies without synchronizing with the tester. The tester may receive corresponding test signals and perform desired radio-frequency measurements. In another suitable arrangement, the tester may be loaded with the predetermined test sequence. The predetermined test sequence may configure the tester to generate test signals using different network access technologies without establishing a protocol-compliant data link with the DUT. The DUT may receive corresponding test signals and compute receive signal quality.

Abstract: A test station may include a test host, a signal generator, 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 signal generator to the multiple DUTs using a radiated arrangement through an antenna in the test chamber. The signal generator may broadcast downlink test signals. The DUTs may synchronize with the downlink test signals and measure radio-frequency performance levels while receiving the downlink test signals. The test host may direct the signal generator 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 signal generator is lowered. Downlink sensitivity testing may be performed across any desired radio-frequency bands and channels.

Abstract: A test station may include a test host, a test unit, and a test chamber. Multiple devices under test (DUTs) may be placed in the test chamber during wireless testing. Radio-frequency signals may be conveyed between the test unit and the multiple DUTs using a conducted arrangement through a splitter-combiner circuit or using a radiated arrangement through a test antenna in the test chamber. The multiple DUTs may be synced to the test unit one DUT at a time (in series) or in parallel. The test host may direct the test unit to broadcast downlink signals at a given channel. The test host my direct a selected DUT to transmit uplink signals at the given channel or at a selected channel that is different from the given channel. The test unit may be used to perform desired measurement on the uplink signals transmitted from the selected DUT.