Abstract: A frequency characteristic measuring apparatus measures a device under test in which the frequency of an input signal and the frequency of an output signal differ from each other, simplifying the configuration of a tracking generator and peripheral circuits associated with the tracking generator, and simultaneously measuring the characteristics of the input signal and the output signal of the device under test. A spectrum analyzer has mixers, local oscillators and IF sections as first and second measuring units for measuring frequency characteristics of two input signals by performing frequency sweep in correspondence with a first or second frequency range, a mixer and an oscillator as a tracking generator section which operates by being linked to the frequency sweep operation in the first measuring unit, and a section which generates a trigger signal designating measurement start timing.

Abstract: It is possible to provide a frequency component measuring device capable of narrowing the range of transmission frequency of a local oscillator, preventing degradation of the level measurement accuracy, and measuring the level of a modulation wave. The device includes: a local oscillator (24) capable of performing sweep in a predetermined frequency range; a mixer (22) for mixing a local oscillation signal outputted from the local oscillator (24) and a measured signal so as to subject the measured signal to a frequency conversion; a plurality of intermediate-frequency filters (44, 46) for extracting and outputting components of different intermediate frequencies from a signal outputted from the mixer (22); and an image removal processing section (66) for performing image removal according to the plurality of intermediate-frequency signals separately outputted from the intermediate-frequency filters (44, 46) corresponding to frequency sweep operations performed by the local oscillator (24) more than once.

Abstract: A frequency characteristic measuring apparatus capable of measuring a frequency characteristic of a device under test in which the frequency of an input signal and the frequency of an output signal differ from each other, capable of simplifying the configuration of a tracking generator and peripheral circuits associated with the tracking generator, and capable of simultaneously measuring the characteristics of the input signal and the output signal of the device under test.

Abstract: It is possible to provide a frequency component measuring device capable of narrowing the range of transmission frequency of a local oscillator, preventing degradation of the level measurement accuracy, and measuring the level of a modulation wave. The device includes: a local oscillator (24) capable of performing sweep in a predetermined frequency range; a mixer (22) for mixing a local oscillation signal outputted from the local oscillator (24) and a measured signal so as to subject the measured signal to a frequency conversion; a plurality of intermediate-frequency filters (44, 46) for extracting and outputting components of different intermediate frequencies from a signal outputted from the mixer (22); and an image removal processing section (66) for performing image removal according to the plurality of intermediate-frequency signals separately outputted from the intermediate-frequency filters (44, 46) corresponding to frequency sweep operations performed by the local oscillator (24) more than once.

Abstract: The device of the present invention is used to measure the intensity of a disturbing wave and measures an average value of impulsive noise. The invention permits accurate and short-time measurements. Impulsive noise, which is input via a variable attenuator, a frequency converter, an intermediate-frequency amplifier and a band-pass filter of a 9 or 120 kHz pass frequency, is provided to a linear detector. The detected output is applied to a low-pass filter which is composed of CR elements and whose cut-off frequency is tens of kilohertz. By the low-pass filter, the peak value of the detected output is lowered and its width is increased. The filter output is converted by an A-D converter to a digital signal. Digital values at respective sample points in the digital signal of one frame are added by an arithmetic circuit, and the added value is divided by the number of samples to obtain an average value, which is displayed.

Abstract: A synchronizing gate signal is generated in synchronism with an input signal or a clock signal, and first and second gates are opened by the synchronizing gate signal. The input signal having passed through the first gate is counted by a first counter circuit, and the clock signal having passed through the second gate is frequency-divided by a divide-by-10.sup.n frequency divider. An output from the frequency divider is counted by a second counter means. The synchronizing gate signal is generated under the control of a control circuit, and is prevented from being generated when the output from the frequency divider is applied to the control circuit. The n in the frequency-division ratio 1/10.sup.n of the frequency divider and a maximum count P of a third counter circuit are determined from a count of the third counter circuit, a preset measurement accuracy, and a period of the clock signal at the time one output is produced from the frequency divider, the n being set in the frequency divider.

Abstract: A sweep voltage from a sweep voltage generator is provided to sweep start and stop adjusting means, the outputs of which are summed by a summing circuit and, by the summed output, the oscillation frequency of a voltage controller oscillator is controlled. The oscillation frequency of the voltage controlled oscillator and the output frequency of a reference signal generator set to a sweep start frequency are compared by comparing means. The output of the sweep voltage generator is put in a sweep start state and sweep start adjusting means is adjusted in accordance with the output of the comparing means, thereby to cause the oscillation frequency of the voltage controlled oscillator to agree with a set sweep start frequency. The output of the sweep voltage generator is put in a sweep stop state and sweep stop adjusting means is adjusted in accordance with the output of the comparing means, thereby to cause the oscillation frequency of the voltage controlled oscillator to agree with a set sweep stop frequency.