Adv Antest Corporation

The University of Tokyo

Toudai Tlo, Ltd.

Koji Asami

Tetsuya Iizuka

Yasuo Furukawa

Zolboo Byambadorj

Takahiro Kudo

Haruo Kobayashi

Shin Masuda

Juichi Nakada

Shinsuke Tajiri

Kiyoshi Hashiba

Tetsuya Taura

Takahide Suzuki

Hiroyuki Miyajima

N (N≥2) D/A converters convert respective input data at a sampling frequency F. A digital signal processing unit generates N items of sub-band waveform data. Each of N items of sub-band waveform data is generated by frequency-shifting corresponding one of N sub-band components included in digital waveform data that represents the analog output signal, such that each sub-band waveform data has its maximum frequency below F/2. A local signal generating circuit generates N local signals having different frequencies.

Signal generator

A test apparatus inspects an antenna element or a device including the antenna element as a DUT by OTA. A front-end unit includes a plurality of electric field detection elements provided to face a plurality of points on a radiation surface of the antenna element of the DUT. The plurality of electric field detection elements can simultaneously detect the electric fields formed at the corresponding points by the DUT, respectively. A tester body receives a plurality of detection signals from the front-end unit and evaluates the DUT.

Test apparatus of antenna array

There is provided a calibration device including: a calibration signal supply unit configured to supply, as a calibration input signal, a multitone signal having tones at a plurality of frequency bands to a converter configured to multiply an input signal by each of a plurality of signal patterns and limit a band to obtain each of a plurality of bandpass signals, and reconstruct an output signal in accordance with the input signal from the plurality of bandpass signals; a calibration bandpass signal acquisition unit configured to acquire a plurality of calibration bandpass signals obtained by the converter in response to the multitone signal; and a calibration processing unit configured to calibrate a parameter for the reconstruction in the converter based on the plurality of calibration bandpass signals.

Calibration device, conversion device, calibration method, and non-transitory computer-readable medium having recorded thereon calibration program

There is provided a calibration device including: a calibration signal supply unit configured to supply, as a calibration input signal, a multitone signal having tones in a plurality of frequency bands to a converter configured to multiply an input signal by each of a plurality of signal patterns and limit a band to obtain each of a plurality of bandpass signals, and reconstruct an output signal in accordance with an input signal from the plurality of bandpass signals; a calibration bandpass signal acquisition unit configured to acquire a plurality of calibration bandpass signals obtained by the converter in response to the multitone signal; and a calibration processing unit configured to calibrate a parameter for the reconstruction in the converter based on the plurality of calibration bandpass signals.

Calibration device, conversion device, calibration method, and computer-readable medium having recorded thereon calibration program

A front-end circuit is used to test an RF signal from an RF device. The RF signal is generated by modulating a carrier signal having a carrier frequency with a wideband baseband signal. A variable frequency oscillator generates a local signal having a variable local frequency. The first frequency mixer frequency mixes a local signal and an RF signal to generate an IF signal having a frequency. A band-pass type first filter filters the IF signal. The local frequency can be selected from a plurality of frequencies having a frequency interval equal to or narrower than a bandwidth of the first filter.

Front-end circuit

Provided is a measurement apparatus that measures a characteristic of an AD converter, comprising a signal supplying section that supplies the AD converter with an analog input signal having a prescribed waveform; an acquiring section that acquires a digital output signal output by the AD converter as a result of sampling the analog input signal; a measured histogram generating section that generates a histogram of the digital output signal; and a range calculating section that calculates at least one of an analog value corresponding to a lower limit and an analog value corresponding to an upper limit of a prescribed digital range, based on at least one of (i) a frequency corresponding to digital values, in a measured histogram obtained by measuring the digital output signal, that are less than or equal to the digital range and (ii) a frequency corresponding to digital values in the measured histogram that are greater than or equal to the digital range.

Measurement apparatus, program, recording medium, and measurement method

Provided is a signal processing apparatus for compensating for a non-linear distortion of a digital signal, including: an analysis signal generating section that converts the digital signal into a analysis signal of a complex number, using a digital filter; and a compensation section that compensates for the analysis signal, using a compensation coefficient of a complex number corresponding to the non-linear distortion, where the digital filter divides data of the digital signal into 'n' data sequences, assigns (n*L+k)th data of the digital signal to a k-th data sequence, performs filtering on each of the data sequences using a same filter coefficient, and combines each of the data sequences after the filtering, thereby generating an imaginary number portion of the analysis signal, where 'n' is an integer equal to or greater than 2, L=0, 1, . . . , and k=1, 2, . . . , n.

Signal processing apparatus, digital filter and recording medium

A test apparatus configured to test an N-bit (N represents an integer) A/D converter is provided. A voltage generating unit outputs a 2-valued analog voltage to the A/D converter. A capture unit captures an output code of the A/D converter for each level. A signal processing unit compares the output code captured for each level with the corresponding expected value code, corrects the value of the analog voltage for each level based upon the comparison result, and outputs the corrected analog voltage to the voltage generating unit.

Test apparatus and test method for A/D converter

An analog-digital converting method comprising measuring, in advance, frequency characteristics of each of a plurality of ADCs; intra-group correction of, for each of a plurality of groups obtained by dividing a plurality of measurement signals, generating measurement signals that would be obtained when the frequency characteristics of the corresponding ADCs are ideal by multiplying the measurement signals by a correction coefficient that is based on the frequency characteristics of all the ADCs in the group; and inter-group correction of correcting and combining the frequency characteristics of the groups based on a difference in the frequency characteristics between the groups formed during the intra-group correction, to generate a frequency spectrum of the digital signal.

Analog-digital converting method and analog-digital converting apparatus

Provided is a reference data converting section that rearranges each of a plurality of frequency components along the frequency axis such that (i) a fundamental wave component and harmonic wave components of a reference digital signal are within a first Nyquist region of a spectrum of the reference digital signal and (ii) image components of the fundamental wave component and the harmonic wave components are within a second Nyquist region of the spectrum; and a distortion detecting section that detects the non-linear distortion of the reference digital signal caused by each harmonic wave component, based on each harmonic wave component having a prescribed order number in the spectrum in which each frequency component has been rearranged by the reference data converting section.

Signal processing apparatus, test system, distortion detecting apparatus, signal compensation apparatus, analytic signal generating apparatus, recording medium and analytic signal generating method

Provided is a signal output control section that inputs to a digitizer a reference signal whose frequency changes at each prescribed measurement cycle; a data extracting section that extracts a number of pieces of data corresponding to an integer multiple of a period of the reference signal in each measurement cycle, from pieces of data of a reference digital signal output by the digitizer according to the reference signal that come after a prescribed wait interval has passed since an initiation timing of each measurement cycle; a distortion identifying section that calculates the non-linear distortion caused by the digitizer for each frequency of the reference signal, based on the data in each measurement cycle extracted by the data extracting section; and a distortion calculating section that calculates the non-linear distortion caused by the digitizer when the analog signal input to the digitizer has a frequency that differs from any of the plurality of frequencies at which the reference signal transitions, based on the non-linear distortion detected by the distortion identifying section for each frequency.

Distortion identification apparatus, test system, recording medium and distortion identification method

Provided is a measuring apparatus which measures a quadrature modulator, including a supplying section supplying the quadrature modulator with a reference I signal having a predetermined frequency and a reference Q signal whose phase is shifted by 90 degrees from the reference I signal, an extracting section extracting, from a modulation signal output from the quadrature modulator by applying quadrature modulation to the reference IQ signals, a main signal component as the reference IQ signals modulated, and an image signal component occurring at a position symmetric to the modulated reference IQ signals with respect to the carrier signal, and a measurement value calculating section calculating at least one of a carrier phase error and amplitude error which occur between I signal and Q signal sides of the quadrature modulator, and a skew between IQ signals of the quadrature modulator, based on the main signal component and image signal component.

Measuring apparatus, measuring method, recording medium, and test apparatus

Provided is a test apparatus that tests a device under test that outputs a plurality of modulated signals modulated with carrier signals having frequencies identical to each other, including a synthesizing section that synthesizes the plurality of modulated signals to output a synthesized signal; an AD converting section that samples the synthesized signal to output a digital signal corresponding to the synthesized signal; and a judging section that judges acceptability of the plurality of modulated signals output by the device under test, based on the digital signal.

Testing apparatus and testing method

An AD converting apparatus converts an analog input signal into a digital output signal. The apparatus includes a plurality of AD converters that are supplied with sampling clocks differing from each other by a prescribed phase and that each output an individual signal obtained by digitizing the input signal according to the sampling clock supplied thereto, a common compensating section that commonly compensates for prescribed common non-linear distortion in the individual signals, and a plurality of individual compensating sections that each individually compensate for individual non-linear distortion in a corresponding one of the individual signals. The individual non-linear distortion is obtained as a ratio between the non-linear distortion and the common non-linear distortion in each individual signal. The apparatus further includes a combining section that combines the individual signals to generate the output signal.

Analog digital converting apparatus, analog digital converting method, test apparatus, program and recording medium

Provided is an AD converting apparatus that converts an analog input signal into a digital output signal, comprising a plurality of AD converters supplied with sampling clocks differing from each other by prescribed phase amounts, each AD converter outputting an individual signal obtained by digitizing the input signal according to the supplied sampling clock; a plurality of amplitude-dependent characteristic correcting sections that are provided to correspond to the plurality of AD converters, each amplitude-dependent characteristic correcting section generating a corrected individual signal by correcting the individual signal output by the corresponding AD converter using a correction factor corresponding to an amplitude of the individual signal; and a combining section that generates the output signal by combining a plurality of the corrected individual signals.

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Tokyo, Japan

Koji Asami