Oscilloscope with high-frequency path and low-frequency path separation circuit

Abstract

The invention discloses an oscilloscope with a high-frequency path and low-frequency path separation circuit, comprising a high-frequency path and low-frequency path separation circuit. The high-frequency path and low-frequency path separation circuit comprises an attenuation switch circuit, a high-frequency path circuit and a low-frequency path circuit, wherein the input signal of the oscilloscope enters the attenuation switch circuit and is switched by a double-pole-double-throw switch in the attenuation switch circuit; then the input signal enters the high-frequency path circuit and the low-frequency path circuit; the input signal of the oscilloscope is output respectively from the high-frequency path circuit and the low-frequency path, the ratio of a high-frequency output signal and a high-frequency input signal is 1:1, the ratio of a low-frequency output signal and a low-frequency input signal is 1:1, i.e. the ratio of signal input and signal output is 1:1 follow; and thus, the separation process of high-frequency components and low-frequency components is finished. The invention realizes an oscilloscope input circuit with high input resistance, low input capacitance, high DC(Direct Current) precision, high input pressurization, big bandwidth, low noise, large signal input shift range and good frequency response flatness.

Description

technical field [0001] The invention relates to an input analog circuit of an oscilloscope or other measuring instruments, in particular to an oscilloscope with a high-frequency and low-frequency path separation circuit. Background technique [0002] The input analog circuit of an oscilloscope or other measuring instruments determines key indicators such as its bandwidth. The measuring instrument will inevitably have an impact on the circuit under test. To minimize the impact, a high input resistance and a low input capacitance are required. , these two indicators are one of the important indicators of oscilloscope or measuring instrument. In addition to the functions of high input impedance and low input capacitance, the input analog circuit of the oscilloscope also completes functions such as AC coupling, DC coupling, large input bias voltage range, high input voltage, high DC measurement accuracy, high bandwidth, and low noise. These are the key indicators of the oscillo...

AI Technical Summary

Problems solved by technology

[0007] 1), DC precision is not high

Since the input pole is completely followed by the JFET circuit, the DC accuracy of the JFET circuit is not high

[0008] 2), input withstand voltage is low

[0009] 3), the input capacitance is large

[0010] 4), low bandwidth

Large input capacitance, resulting in low input bandwidth

[0011] 5), large interference and noise

The input capacitance is large, which makes it susceptible to interference and high noise

[0012] 6), the output driving ability is not enough

JFET is a source follower with limited output current

[0013] 7), the signal input offset range is small

[0014] 8) Poor frequency response flatness

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