Digital oscilloscope with impedance matching function

Abstract

The invention provides a digital oscilloscope with an impedance matching function. The digital oscilloscope comprises an input part for receiving a tested signal, a measurement part for measuring the tested signal, a control part, a first circuit, a second circuit and a selector, wherein the first circuit is used for outputting the signal to the measurement part when the control part transmits a third control signal; the second circuit is used for outputting the signal to the measurement part when the control part transmits a fourth control signal; and the selector is used for ensuring that the input part is connected in series with the first circuit through a 50-omega impedance attenuation module when the control part transmits a first control signal, and the input part is connected in series with the second circuit through a 1M-omega attenuation module when the control part transmits a second control signal. The digital oscilloscope has the characteristics of simplifying the front-end circuit designing difficulty of the oscilloscope, improving the frequency limit of the 50-omega impedance input mode, increasing the bandwidth, improving the characteristics and reducing noise, and is particularly suitable for the high-frequency section digital oscilloscope.

Description

technical field [0001] A digital oscilloscope with impedance matching function of the present invention relates to the field of measuring devices for displaying waveforms, in particular to the field of oscilloscopes. Background technique [0002] Digital oscilloscopes are the most common general-purpose measurement equipment. There are many types and division methods. For example, in terms of structure, the most common ones are desktop oscilloscopes, portable oscilloscopes, and virtual oscilloscopes used in conjunction with computers. In terms of functions, they can be divided into It is divided into general-purpose oscilloscopes and special-purpose oscilloscopes. From the perspective of display capabilities, some people also divide oscilloscopes into fluorescent display oscilloscopes or storage display oscilloscopes. [0003] In the prior art, a digital oscilloscope usually includes an input analog front-end circuit, a digital-to-analog conversion circuit, and a control cir...

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Problems solved by technology

[0014] Although the oscilloscope in the prior art can provide two different input modes, that is, a high-impedance input mode and a 50Ω input resistance mode, due to the high impedance of the high-impedance attenuation network 105 and the 1MΩ resistor R102, the parasitic parameters ( Such as parasitic capacitance, inductance) is very sensitive, and the bandwidth is small

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