Abstract: An amplifier circuit arrangement for amplifying at least one input signal to an output signal for delivery to a load. The amplifier circuit arrangement includes at least one four-port hybrid coupler, a main amplifier having an input terminal for receiving a first input signal and coupled to a first port of the hybrid coupler, an auxiliary amplifier having an input terminal for receiving a second input signal and coupled to the second port of the hybrid coupler, a negative resistance amplifier circuit coupled to the third port of the hybrid coupler. The negative resistance amplifier circuit receives a signal from the hybrid coupler via the third port and returns an amplified signal back to the third port of the hybrid coupler. At least one of the auxiliary amplifier and negative resistance amplifier circuit selectively operates in combination with the main amplifier circuit.

Abstract: A method and a system for determining at least one contribution of at least one device under test (DUT) are described. The DUT may be part of a radio frequency (RF) device chain. The method includes capturing a first signal portion at a first node associated with an input of the DUT and capturing a second signal portion at a second node associated with an output of the DUT. The first signal portion and the second signal portion are captured quasi-simultaneously. The method may also include aligning the captured first signal portion and the captured second signal portion with each other temporally, and determining the contribution of the DUT by comparing the first signal portion and the second signal portion.

Abstract: A method and a system for determining at least one contribution of at least one device under test (DUT) are described. The DUT may be part of a radio frequency (RF) device chain. The method includes capturing a first signal portion at a first node associated with an input of the DUT and capturing a second signal portion at a second node associated with an output of the DUT. The first signal portion and the second signal portion are captured quasi-simultaneously. The method may also include aligning the captured first signal portion and the captured second signal portion with each other temporally, and determining the contribution of the DUT by comparing the first signal portion and the second signal portion.

Abstract: A comb signal generator that includes at least two signal sources that each provide a signal, wherein the signals provided by the at least two signal sources are shaped similarly. The com signal generator also has a combining circuit connected with the at least two signal sources, wherein the combining circuit is configured to combine the signals provided by the at least two signal sources, thereby generating a combined signal. Further, the com signal generator includes a clipping circuit connected with the combining circuit, wherein the clipping circuit is configured to receive and process the combined signal, thereby generating a comb signal. Further, a method of providing a phase and amplitude reference is described.

Abstract: A comb signal generator that includes at least two signal sources that each provide a signal, wherein the signals provided by the at least two signal sources are shaped similarly. The comb signal generator also has a combining circuit connected with the at least two signal sources, wherein the combining circuit is configured to combine the signals provided by the at least two signal sources, thereby generating a combined signal. Further, the comb signal generator includes a clipping circuit connected with the combining circuit, wherein the clipping circuit is configured to receive and process the combined signal, thereby generating a comb signal. Further, a method of providing a phase and amplitude reference is described.

Abstract: A performance testing method for determining a performance of a device under test having non-linear characteristics is disclosed. The performance testing method comprises the following steps: generating a hard clipper model of said device under test; generating a test signal having predefined properties; forwarding said test signal to the device under test, wherein the device under test generates an output signal based on said test signal; feeding said hard clipper model with said test signal, thereby generating a model output signal; and comparing said output signal to said model output signal in order to determine the performance of the device under test. Moreover, a measurement system for determining a performance of a device under test having non-linear characteristics is disclosed.

Abstract: A device for converting a digital input signal into an analog output signal is provided. The device includes a first digital to analog converter configured to generate a first analog signal, and a second digital to analog converter configured to generate a second analog signal. The device further includes a signal splitter configured to couple out a feedback signal from the second analog signal. The device further includes a first signal combiner configured to subtract the feedback signal from the first analog signal to generate an error signal. The device further includes an amplifier configured to amplify the error signal, resulting in an amplified error signal. The device further includes a second signal combiner configured to combine the amplified error signal and a signal derived from the second analog signal, resulting in the analog output signal.

Abstract: A performance testing method for determining a performance of a device under test having non-linear characteristics is disclosed. The performance testing method comprises the following steps: generating a hard clipper model of said device under test; generating a test signal having predefined properties; forwarding said test signal to the device under test, wherein the device under test generates an output signal based on said test signal; feeding said hard clipper model with said test signal, thereby generating a model output signal; and comparing said output signal to said model output signal in order to determine the performance of the device under test. Moreover, a measurement system for determining a performance of a device under test having non-linear characteristics is disclosed.

Abstract: A measuring system for determining phase differences of antenna element signals of antenna elements of an antenna array under test is provided. The measuring system comprises a signal generating means, which is configured to provide a measuring signal to the antenna array under test over the air and receiving means configured to measure the antenna element signals, resulting from receiving the measuring signal by the antenna elements of the antenna array under test and determine the phase difference of the antenna element signals.

Abstract: A calibration apparatus for calibrating at least one of a signal generator and a signal analyzer is described, wherein the calibration apparatus comprises an input terminal for establishing a connection with the signal generator, an output terminal for establishing a connection with the signal analyzer, a reference signal source for providing a reference signal, and a combiner circuit for combining signals received. The combiner circuit has a first input connected to the reference signal source and a second input assigned to the input terminal, the combiner circuit having an output assigned to the output terminal. Further, a calibration system and a method for calibrating at least one of a signal generator and a signal analyzer are described.

Abstract: A measuring system for determining a beamforming quality of an antenna array signal of an antenna array of a device under test. The measuring system comprises a measuring device configured to receive an antenna array signal, and to measure the antenna array signal and to determine a beamforming signal quality thereof. The antenna array signal is wirelessly transmitted to the receiver by the antenna array of a device under test. The measuring system further comprises a positioning unit configured to position the device under test in successive predefined orientations. The measuring device is configured to receive and measure the antenna array signal successively in each of the predefined orientations.

Abstract: A test system for testing an array antenna under test with at least two antenna elements comprises a signal generator that generates a test signal, a signal splitter that splits the test signal into a plurality of antenna source signals for the single antenna elements, and a vector multiplier for each one of the antenna source signals, wherein the vector multipliers each adjust the amplitude and/or phase of the respective antenna source signal according to predetermined adjustment parameters and wherein output ports of the vector multipliers are connected to respective ones of the antenna elements.

Abstract: A calibration apparatus for calibrating at least one of a signal generator and a signal analyzer is described, wherein the calibration apparatus comprises an input terminal for establishing a connection with the signal generator, an output terminal for establishing a connection with the signal analyzer, a reference signal source for providing a reference signal, and a combiner circuit for combining signals received. The combiner circuit has a first input connected to the reference signal source and a second input assigned to the input terminal, the combiner circuit having an output assigned to the output terminal. Further, a calibration system and a method for calibrating at least one of a signal generator and a signal analyzer are described.

Abstract: A system for measuring or characterizing a multi-element antenna having at least two antenna elements comprises a vector network analyzer with at least two input/output ports. Each input/output port of the vector network analyzer is connected to one antenna element of the multi-element antenna. The vector network analyzer has generator means for generating waves at each of its input/output ports, which are coherent to each other.

Abstract: A device for converting a digital input signal into an analog output signal is provided. The device includes a first digital to analog converter configured to generate a first analog signal, and a second digital to analog converter configured to generate a second analog signal. The device further includes a signal splitter configured to couple out a feedback signal from the second analog signal. The device further includes a first signal combiner configured to subtract the feedback signal from the first analog signal to generate an error signal. The device further includes an amplifier configured to amplify the error signal, resulting in an amplified error signal. The device further includes a second signal combiner configured to combine the amplified error signal and a signal derived from the second analog signal, resulting in the analog output signal.

Abstract: A test system for testing an array antenna under test with at least two antenna elements comprises a signal generator that generates a test signal, a signal splitter that splits the test signal into a plurality of antenna source signals for the single antenna elements, and a vector multiplier for each one of the antenna source signals, wherein the vector multipliers each adjust the amplitude and/or phase of the respective antenna source signal according to predetermined adjustment parameters and wherein output ports of the vector multipliers are connected to respective ones of the antenna elements.

Abstract: A design method for designing a multi-path amplifier involves connecting an amplifier stage having at least two amplifier branches to a combiner stage; feeding a plurality of testing signals with one or more of a plurality of sweeping variables to the amplifier stage; measuring output signals at the output of the combiner stage depending on the plurality of testing signals; designing a structure of an input network stage for the amplifier stage on the basis of the measured output signals; and combining the designed input network stage with the amplifier stage to create an efficiency-optimized multi-path amplifier.

Abstract: A method for measuring characteristics of a transmitter unit of a device under test is described. A signal generator is provided that comprises a baseband processing unit having at least a digital pre-distortion sub-unit. A device under test is provided that has a transmitter unit. A measuring unit is provided. Said signal generator and said device under test are connected with each other via an interface. At least one input signal is generated by using said signal generator, said input signal is forwarded to said device under test. An output signal of said device under test is measured by using said measuring unit. A first pre-distortion parameter for an increasing input amplitude is determined by using said digital pre-distortion sub-unit. A second pre-distortion parameter for a decreasing input amplitude is determined by using said digital pre-distortion sub-unit. Said first and second pre-distortion parameters are determined such that said output signal has a high fidelity.

Abstract: A method for measuring characteristics of a transmitter unit of a device under test is described. A signal generator is provided that comprises a baseband processing unit having at least a digital pre-distortion sub-unit. A device under test is provided that has a transmitter unit. A measuring unit is provided. Said signal generator and said device under test are connected with each other via an interface. At least one input signal is generated by using said signal generator, said input signal is forwarded to said device under test. An output signal of said device under test is measured by using said measuring unit. A first pre-distortion parameter for an increasing input amplitude is determined by using said digital pre-distortion sub-unit. A second pre-distortion parameter for a decreasing input amplitude is determined by using said digital pre-distortion sub-unit. Said first and second pre-distortion parameters are determined such that said output signal has a high fidelity.

Abstract: A measuring system for determining phase differences of antenna element signals of antenna elements of an antenna array under test is provided. The measuring system comprises a signal generating means, which is configured to provide a measuring signal to the antenna array under test over the air and receiving means configured to measure the antenna element signals, resulting from receiving the measuring signal by the antenna elements of the antenna array under test and determine the phase difference of the antenna element signals.