Anritsu Corporation

Seiya Suzuki

Ken Mochizuki

Takashi Murakami

Takashi Aoki

Naosuke Tsuchiya

A frequency synthesizeroutputs a periodic signal r(t) at a frequency detuned by a predetermined frequency &#x394;f [Hz] from a frequency of 1/integer of a frequency of a reference clock signal f0 synchronized with a signal to be measured ws. A first sampler unitsamples the signal to be measured ws at a timing of the trigger signal CLK. A second sampler unitsamples an I signal I(t) at the timing of the trigger signal CLK. A phase shifteroutputs a Q signal Q(t) obtained by shifting a phase of the reference clock signal f0 by 90&#xb0;. A third sampler unitsamples the Q signal at the timing of the trigger signal CLK. A correction value calculation unitcalculates a correction value &#x394;t(n) based on sampling data I(n) and Q(n) and a set value t(n) of a sampling time.

Sampling circuit, sampling method, sampling oscilloscope, and waveform display method

An apparatus for rapidly measuring jitter transfer characteristics is provided. A modulation signal generator generates a modulation signal M including a plurality of sinusoidal components having known amplitudes mto mand different frequencies fto f, and outputs the modulation signal M to a jitter generator. A clock signal C phase-modulated by the modulation signal M is input to a data signal generator, a data signal D synchronized with the clock signal C is provided to a measurement object, a data signal D' output from the measurement object is input to a clock recovery unit to recover a clock signal component C&#x2032;, and the clock signal component C&#x2032; is phase-detected by a phase detector. A signal amplitude detector detects the amplitudes of the plurality of sinusoidal components included in the modulation signal M from an output signal M&#x2032; of the phase detector, and an operation processor calculates a ratio of the detected amplitudes and the known amplitudes for each of the sinusoidal components, respectively.

Apparatus for measuring jitter transfer characteristic

It is an object of the invention to correctly display the waveform of a demodulation signal with a single apparatus. A jitter demodulator which demodulates a jitter component of a digital signal input from the outside, a jitter amount detector which detects the amplitude value of a demodulation signal output from the jitter demodulator, an interpolator which measures a period of the demodulation signal output from the jitter demodulator and interpolates the demodulation signal processing with a rate corresponding to the measured period, a display unit, and a display control section which displays on the display unit the value detected by the jitter amount detector and a waveform of the demodulation signal interpolated by the interpolator are provided in a single housing.

Jitter measuring apparatus

The present invention provides a measuring device which extracts, from an inputted data signal, a clock signal in which there is little internal occurrence of absence or phase fluctuations, and correctly carries out measurement of an error ratio or jitter or wander accompanying transmission of the data signal by using the clock signal. A band-pass filter extracts, from the inputted data signal, a signal component having a same frequency as that of a clock signal to be regenerated. A binarizing circuit binarizes the extracted signal component at a predetermined threshold value, and outputs it as a regenerated clock signal. At this time, the binarizing circuit is configured such that, when there is a same code continuing period in the data signal, the binarizing circuit binarizes the signal outputted during the period by relaxation vibration at an interior of the band-pass filter, so as to compensate for absence of the clock signal during the period. A calculating module calculates at least one of the error ratio, the jitter, and the wander based on the regenerated clock signal from the binarizing circuit.

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Atsugi, Japan

Seiya Suzuki