Abstract: In an oscilloscope having a video signal input, a video signal and the like can be monitored in addition to the normal waveform monitoring operation as the oscilloscope.

Abstract: An acquisition memory for storing therein and reading out digital waveform data received from an A/D converter is made up of a dual port serial access memory which stores therein the waveform data in response to a first write clock and reads out the waveform data therefrom in response to a first read clock. A display memory for writing therein and reading out therefrom the waveform data read out from the acquisition memory is made up of a dual port serial access memory which stores therein the data in response to a second write clock different from the first write clock and read out the data therefrom in response to a second read clock different from the first read clock.

Abstract: In a digital oscilloscope, a sharp and fine line can be displayed at high horizontal resolution. The digital oscilloscope includes a memory for storing waveform data to be displayed; a display data output unit including sync signal generating unit for generating a sync signal and an output unit for reading the waveform data from the memory in synchronism with the sync signal to output said read waveform data; and an audio/visual color dot matrix plane display device including a display unit having dots arranged in a matrix form for color representation. The scan clock signal generator generating the scan clock signal in synchronism with the sync signal produced from sync signal generating unit, and the dot scan control unit sequentially supplying the display data outputted from the output unit in synchronism with the scanning clock signal to the dots of the display unit, whereby the content of the waveform data is displayed on the display unit.

Abstract: A reference analog signal is supplied to an analog-to-digital converter via a sample-and-hold circuit and an amplifier so as to obtain digital data corresponding to the reference analog signal. The obtained digital data corresponding to the reference analog signal is compared with predetermined reference data. The gain and the offset voltage of the amplifier is corrected so as to make the difference between the digital data corresponding to the reference analog signal and the reference data smaller than a predetermined allowance on the basis of the comparison result.

Abstract: A wide-band amplifier for driving a capacitive load includes an amplifier of a complementary push-pull circuit receiving and amplifying an input signal to produce an output signal for driving the capacitive load, and a controller for controlling bias current of the amplifier in response to a detected output derived from a high frequency component in the output signal of the amplifier. The controller makes the bias current of the amplifier variable with frequency and amplitude of the input signal.