Abstract: A method and apparatus for fast response and distortion measurement of a signal transfer device. A computer processor generates a multitone test signal of predetermined duration and stores it in a memory. The test signal is read out, converted to analog form, if necessary, and applied to the input of a device under test. The output produced by the device under test in response to the test signal is acquired and digitized, if necessary, and a Fast Fourier Transform is performed on the acquired data to determine its spectral characteristics. Frequency response, harmonic distortion, intermodulation distortion, phase distortion, wow and flutter and other signal transfer characteristics are measured by the CPU by analysis of the output signal.

Abstract: A device for testing an amplifier. A plurality of PN modulators are provided corresponding to a plurality of oscillators at stages preceding or following them, or fluctuation is given to division ratios at the oscillators. Since each of n carriers combined by a combiner contains phase fluctuation, the possibility that the peaks will overlap each other or that the carriers having opposite phases will negate each other is very low. The peak power in signals supplied to the amplifier to be tested is unlikely to vary, enabling accurate evaluation or testing.

Abstract: In this digital signal measurement apparatus, an approach is employed to deliver a measurement signal from a measurement signal generator to a measured circuit to transform the signal on the time base through the measured circuit to a signal on the frequency base by a frequency base transform circuit and to further obtain a signal on the time base by a time base transform circuit. Thus, a difference between the signal on the time base through the measured circuit and the signal on the time base from the time base transform circuit is employed. Thus, for example, even if the measured circuit is a linear system, a measured result in the digital region and a result of the analog measurement can be in correspondence with each other. Accordingly, gain correction of a measurement signal is unnecessary, thus making it possible to prevent an increase in an error of a measured result of S/N.

Abstract: Waveform data read out of a memory is converted by a D/A converter into an analog waveform, and amplified by an amplifier to generate a waveform signal. To cancel a distortion generated in the amplifier, a composite waveform composed of a distortion canceling signal waveform and a fundamental frequency signal waveform to be generated is written into the memory. To determine a distortion canceling signal, the fundamental frequency component in the signal waveform is attenuated by a notch filter. The signal waveform is then converted by an A/D converter into a digital multi-sine waveform. This waveform is input to a computation and control part and subjected to a Fourier transform analysis to compute the amplitude and phase of each harmonic component. Further, the output of the amplifier the memory, is fed via the notch filter and the A/D is input to the computation and control part, where it is subjected to a Fourier transform analysis to compute the amplitude and phase of each distortion component.

Abstract: A vector network analyzer for performing swept frequency measurements on non-linear RF devices, using either an internal or external signal source. This simplifies and speeds linear and non-linear amplifier and mixer measurements, such as impedance, amplifier gain, and mixer conversion loss, on the one hand, and measurement of harmonics, on the other hand.

Abstract: A method and apparatus for determining the total harmonic distortion and the power factor of a non-linear load circuit coupled to an a.c. power source generating a.c. current and a.c. voltage, the a.c. current input to the load circuit being in phase with the a.c. voltage provided across the load circuit by the a.c. power source. The invention measures the total harmonic distortion of a.c. current and a.c. voltage at the non-linear load circuit and calculates the total harmonic distortion and the power factor as a function of both.

Abstract: For the reduction of noise signals, and particularly crosstalk signals, in measurement systems for analyzing emission or transmission processes and composed of a serial arrangement of a signal source (1), a measurement path (2) with or without a transmission test object (8), a detector (3), and a measurement and display circuit (5), an identification modulation is imparted to the signal component carried in the measurement path by means of repeated modulation (6, 9). The evaluation of the detector output signal may be performed with respect to a frequency which is free of the effects of the single modulation signals occurring in the detector output signal because of noise pick-up. Use of this method in homodyne systems for quadrupole parameter measurements further eliminates the effects of crosstalk reflections which typically occur in these systems.

Abstract: An instrument to determine, under actual field conditions, which type of VA demand meters are most appropriate for a particular consumer. The type of electrical load that the consumer places on an electrical supply system can introduce harmonics and phase distortion in the system resulting in VA meters producing incorrect readings. These VA meters are intended to measure the true apparent power S which is defined as S=V.sub.rms XI.sub.rms but, are generally designed to operate according to one of the following approximate formula:(1) S'=V.sub.rect XI.sub.rect X(1.11).sup.2 and(2) S"=.sqroot.P.sup.2 +Q.sup.2 where P is the active power and Q the reactive power.The instrument contains circuit to measure the rms values of the voltage and current waveforms from which the true apparent power S can be obtained as well as circuits to determine the value S' and S" according to the two approximate formula from which error signals e.sub.1 and e.sub.