Abstract: A device for heat control in laser welding of dissimilar additively-manufactured parts includes a welding main body, a moving frame, a lifting frame, a laser welding head, a temperature control mechanism, a pressing mechanism, and a supporting and cleaning mechanism. The moving frame is mounted on the welding main body. The lifting frame is provided on the moving frame. The temperature control mechanism includes a welding platform designed to hold a laser metal deposition (LMD) printed part and a selective laser melting (SLM) printed part. The laser welding head is provided on the underside of the lifting frame for to weld the LMD part to the SLM part.

Abstract: An example system includes a signal generator to output signals based on multiple carrier frequencies; a wired transmission medium for carrying the signals, where the wired transmission medium is configured as open ended to produce reflections on the wired transmission medium of the signals; and a signal analyzer to receive the reflections and to determine a transmission time of a signal along the wired transmission medium based on the reflections. The signal analyzer is configured to perform operations that include performing a search based on an estimated transmission time of the signal along the wired transmission medium and the reflections to determine the transmission time. The search is to determine which of multiple candidate transmission times to select for the transmission time.

Abstract: An example method includes the following operations: (i) receiving a device signal from a device under test (DUT); (ii) setting an attenuation value; (iii) applying the attenuation value to the device signal to produce an attenuated device signal for a frequency spectrum analyzing device, where the frequency spectrum analyzing device produces a noise signal; (iv) obtaining a power spectral density value using the frequency spectrum analyzing device, where a power spectral density comprises a power, at a frequency value, of a combined signal that is based on the attenuated device signal and the noise signal; (v) repeating operations (ii), (iii), and (iv) one or more times to produce multiple power spectral density values; (vi) repeating operations (i), (ii), (iii), (iv), and (v) one or more times to add power spectral density values to the multiple power spectral density values; and (vii) obtaining a power spectral density of the device signal.

Abstract: An example method includes following operations: (i) receiving a device signal from a device under test (DUT); (ii) setting an attenuation value; (iii) applying the attenuation value to the device signal to produce an attenuated device signal for a frequency spectrum analyzing device, where the frequency spectrum analyzing device produces a noise signal and intermodulation interference; (iv) obtaining a power spectral density value, where the power spectral density value comprises a power, at a frequency value, of a combined signal that is based on the attenuated device signal, the noise signal, and the intermodulation interference; (v) repeating operations (ii), (iii), and (iv) one or more times to produce multiple power spectral density values; (vi) repeating operations (i), (ii), (iii), (iv), and (v) one or more times to add power spectral density values to the multiple power spectral density values; and (vii) obtaining a power spectral density of the device signal.

Abstract: A system and method for using a wireless radio frequency (RF) data packet signaling link to enable non-link control of testing of a data packet signal transceiver device under test (DUT) in which a communication session between a tester and a DUT for purposes of testing the DUT may first be initiated by a separate, commonly available, and lower cost, communication device. Following its establishment, the tester may monitor the communication session, e.g., via wireless signal sniffing, to acquire and use associated device identification information to join the session and transmit trigger based test (TBT) data packets for initiating a test sequence within the DUT. Hence, use of a non-link capable tester to perform parametric testing of a DUT at the lowest network architecture layer, e.g., the physical (PHY) layer, may be enabled.

Abstract: An example process determines a first error vector magnitude (EVM) of a signal output by a device under test (DUT). The process includes adding attenuation on a signal path between the DUT and a vector signal analyzer (VSA), where the attenuation is changeable: measuring, at the VSA, at least two second EVMs for different values of attenuation of the signal output by the DUT, where the at least two second EVMs are corrupted by noise from the VSA, and where each of the at least two second EVMs is based on two or more measurements; and determining the first EVM based on a linear relationship that is based on the first EVM, the at least two second EVMs, and a function based on the attenuation, where the first EVM is without at least some of the noise from the VSA.

Abstract: An example process determines a first error vector magnitude (EVM) of a signal output by a device under test (DUT). The process includes adding attenuation on a signal path between the DUT and a vector signal analyzer (VSA), where the attenuation is changeable: measuring, at the VSA, at least two second EVMs for different values of attenuation of the signal output by the DUT, where the at least two second EVMs are corrupted by noise from the VSA, and where each of the at least two second EVMs is based on two or more measurements; and determining the first EVM based on a linear relationship that is based on the first EVM, the at least two second EVMs, and a function based on the attenuation, where the first EVM is without at least some of the noise from the VSA.

Abstract: An example test system includes memory (e.g., one or more memory devices) storing (i) instructions that are executable, and (ii) a mapping function that relates first error vector magnitudes (EVMs) for first symbols to second EVMs for the first symbols, where the first EVMs are corrupted by radio frequency (RF) noise and the second EVMs are corrupted by both RF noise and symbol decoding errors. The test system also includes a decoder to receive a signal from a device under test, and to obtain a third EVM for a second symbol that is based on the signal, where the third EVM is corrupted by both RF noise and a symbol decoding error. One or more processing devices are configured to execute the instructions to adjust the third EVM using the mapping function to correct the symbol decoding error in the third EVM.

Abstract: A system and method for using a wireless radio frequency (RF) data packet signaling link to enable non-link control of testing of a data packet signal transceiver device under test (DUT) in which a communication session between a tester and a DUT for purposes of testing the DUT may first be initiated by a separate, commonly available, and lower cost, communication device. Following its establishment, the tester may monitor the communication session, e.g., via wireless signal sniffing, to acquire and use associated device identification information to join the session and transmit trigger based test (TBT) data packets for initiating a test sequence within the DUT. Hence, use of a non-link capable tester to perform parametric testing of a DUT at the lowest network architecture layer, e.g., the physical (PHY) layer, may be enabled.

Abstract: System and method for testing a wireless data packet signal transceiver device under test (DUT) in which external control circuitry manages initiation of execution by a tester of test program instructions defining multiple self-terminating test control sequences in one or more desired sequences. The test control sequences may be pre-stored in a tester for subsequent execution under control of control signals sourced externally by the external control circuitry via separate control signals.

Abstract: System and method for testing transmission and reception performance of a data packet signal transceiver device under test (DUT). Data packet signals transmitted by a tester with a tester transmit output power (TTOP) contain trigger frames that include data corresponding to a reported tester transmit power (RTTP) of the data packet signals, and a desired received signal strength (TRSS) of DUT data packet signals to be received by the tester. Based on received signal strength of the tester data packet signals reported by the DUT (DRSS), responsive DUT data packet signals having a DUT transmit output power of RTTP?DRSS+TRSS. Successive repetitions of such tester and DUT data packet signals for multiple combinations of values of the TTOP, RTTP and DRSS enable testing transmission and reception performance of the DUT, including determining minimum and maximum DUT transmission power levels, with minimal signal interactions between tester and DUT.

Abstract: System and method for testing transmission and reception performance of a data packet signal transceiver device under test (DUT). Data packet signals transmitted by a tester with a tester transmit output power (TTOP) contain trigger frames that include data corresponding to a reported tester transmit power (RTTP) of the data packet signals, and a desired received signal strength (TRSS) of DUT data packet signals to be received by the tester. Based on received signal strength of the tester data packet signals reported by the DUT (DRSS), responsive DUT data packet signals having a DUT transmit output power of RTTP-DRSS+TRSS. Successive repetitions of such tester and DUT data packet signals for multiple combinations of values of the TTOP, RTTP and DRSS enable testing transmission and reception performance of the DUT, including determining minimum and maximum DUT transmission power levels, with minimal signal interactions between tester and DUT.

Abstract: System and method of testing performance of a data packet signal transceiver (DUT). Multiple DUT signals, with each having a respective DUT transmit power (RDTPn) received by the tester and corresponding to one (IDTPn) of multiple intended DUT transmit powers, for n=1, . . . , m, with a power equal to a minimum IDTP, maximum IDTP, or intermediate IDTP therebetween. Following association of each RDTPn with its IDTPn, a tester signal is sent having a trigger frame and tester transmit output power (TTOP). The trigger frame includes data corresponding to a reported tester transmit power (RTTP), and a desired signal strength (TRSS) of a DUT data packet signal to be received by the tester. A return DUT signal having a RDTPn is received, from which an IDTPn corresponding to the RDTPn is determined and compared to RTTP-TTOP+TRSS.

Abstract: A method for controlling block error rate (BLER) testing of a cellular communication device for a system having a fixed number of BLER data packets. Alternating sequences of downlink (DL) data packets have packet identifiers with a first state, and are separated by additional sequences of DL data packets having packet identifiers with a second state, thereby enabling control of BLER testing of the device to ensure a reliable accumulated count of DL data packets received by the device having packet identifiers only with the second state.

Abstract: A method for controlling block error rate (BLER) testing of a cellular communication device for a system having a fixed number of BLER data packets. Alternating sequences of downlink (DL) data packets have packet identifiers with first and second states, and are separated by additional sequences of DL data packets having packet identifiers with the first state, thereby enabling control of BLER testing of the device to ensure a reliable accumulated count of DL data packets received by the device having packet identifiers only with the second state.

Abstract: A method for testing a data packet signal transceiver device under test (DUT). Following initial signal communications with a DUT, timing of further transmissions by the DUT may be effectively controlled by transmitting congestive communication channel signals to cause the DUT to detect apparent communication channel activity and in response thereto delay its own signal transmissions.

Abstract: A method for testing a data packet signal transceiver device under test (DUT). Following initial signal communications with a DUT, timing of further transmissions by the DUT may be effectively controlled by transmitting congestive communication channel signals to cause the DUT to detect apparent communication channel activity and in response thereto delay its own signal transmissions.

Abstract: A method for coordinating testing of a wireless device under test (DUT) using non-link testing resources. Coordination between the tester and DUT is achieved by transmitting, from the tester to the DUT, predetermined numbers of data packets associated with predetermined tester identification data (e.g., MAC addresses identifying the tester transmitter). During test phases involving measurement and/or calibration of DUT transmit signals, the tester sends a number of data packets associated with one or more versions of tester identification data, in response to which the DUT performs internal operations (e.g., revising transmit power offsets). During later test phases involving validation of DUT performance, the tester sends another number of data packets associated with one or more versions of the tester identification data to inform the DUT that its testing has passed or failed, and/or is to be repeated.

Abstract: A method for improving accuracy of power measurements of low power radio frequency (RF) signals received by a RF signal receiver in which power measurement accuracy taken at a low resolution is compensated with use of multiple RF signal attenuations at a finer resolution. In accordance with exemplary embodiments, incremental RF signal attenuations are applied to the received RF signal. An average of the power measurements, including those with the applied signal attenuations, has a net measurement error less than that of a direct power measurement.

Abstract: A method for communicating test results from a wireless device under test (DUT) using non-link testing resources. Test data resulting from testing one or more operations of the DUT are combined with other data to form one or more data packets for transmission to a tester. The test data occupies, e.g., via encoding, a portion of the one or more data packets designated for data identifying the DUT or a tester.