An active single-ended probe and a test and measurement instrument

Abstract

The invention provides an active single-end probe and a testing and measuring instrument. The active single-end probe comprises a signal input end, a hand-held front end, a probe amplifier, a signal output end, and first and second balance resistors with the same resistance. One end of the first balance resistor is grounded, and the non-grounding end is connected to a serial connection line between the output end of an input impedance unit and the first input end of an amplifier unit. One end of the second balance resistor is grounded, and the non-grounding end is connected to a series connection line between the non-grounding end of a second resistor and the second input end of the amplifier unit, and the resistance after the parallel connection of the second balance resistor and the second resistor is smaller than the resistance of the second resistor. According to the active single-end probe and a testing and measuring instrument, since the equivalent resistance after the parallel connection decreases relative to the second resistance, the bias current of the amplifier unit is fixed and not changed, and thus the offset voltage generated by the equivalent resistance also decreases.

Description

technical field [0001] The invention relates to the technical field of test and measurement, in particular to an active single-ended probe and a test and measurement instrument. Background technique [0002] In the field of test and measurement, a probe is a device for collecting signals, which can input the collected measured signals into test and measurement instruments. The test and measurement instrument used in combination with the probe can be an oscilloscope, a spectrum analysis instrument, or a data acquisition device, etc. [0003] Probes usually include passive probes and active probes. According to different front-end circuits inside the probe, active probes are usually divided into differential probes and single-ended probes. According to different external structures of the probe, differential probes include hand-held differential probes and welded differential probes, and single-ended probes include hand-held single-ended probes and welded single-ended probes....

AI Technical Summary

Problems solved by technology

[0009] This structure of the active single-ended probe 200 has the following problems: when using the active single-ended probe 200, since the negative input end of the probe amplifier 202 is grounded through the resistor R2N, there will be a gap between the negative input end of the probe amplifier 202 and the ground. A bias current I is generated, and the bias current I will form an offset voltage on the resistor R2N, so that when the measured signal is measured, it will be seen on the test and measurement instrument that the measured signal has an obvious offset voltage signal. When the test The offset voltage signal is particularly obvious when the vertical scale of the measuring instrument is small

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