Preamplifier for digital phosphor oscilloscope

Abstract

The invention provides a 1.5GHz preamplifier for a digital phosphor oscilloscope. The preamplifier comprises a high-resistance attenuator, an impedance transformer, a low-resistance step programmable attenuator, a high-speed differential amplifier, a high and low resistance selector and the like. High and low resistance are selected for an input signal; when the low resistance is selected, the signal passes through a radio frequency relay and directly enters the low-resistance step programmable attenuator; and when the high resistance is selected, the signal passes through the high-resistance attenuator and an impedance transformation circuit, is converted from high-resistance input to low-resistance output, and then enters the low-resistance step programmable attenuator through a radio frequency two-way selective switch, and the tasks of performing fine gain tuning, converting a single-ended signal into a differential signal and performing level conversion are finished by using the high-speed differential amplifier. The circuit successfully achieves a large effect of pushing the research and development of corresponding measuring instruments, particularly the design of digital oscilloscopes, and can effectively fill in a gap in the research and development of domestic middle and high-end digital oscilloscopes.

Description

technical field [0001] The invention belongs to the technical field of signal amplification, transmission and processing, and mainly relates to a design method of a 1.5GHz preamplifier of a digital fluorescent oscilloscope. Background technique [0002] Traditional oscilloscope preamplifier circuits are basically composed of discrete components and ordinary patch components, and the highest analog bandwidth is generally 200MHz to 500MHz (-3dB), which greatly limits the application range of oscilloscopes and becomes a bottleneck for the development of oscilloscopes. In recent years, foreign digital oscilloscopes have developed rapidly, and the high-end digital oscilloscope market is basically occupied by American Tektronix, Agilent, and LeCroy. American Tektronix first launched digital phosphor oscilloscopes in the early 21st century, pushing the development of digital oscilloscopes to a new platform. Compared with ordinary oscilloscopes, broadband oscilloscopes can understan...

AI Technical Summary

Problems solved by technology

[0002] Traditional oscilloscope preamplifier circuits are basically composed of discrete components and ordinary patch components, and the highest analog bandwidth is generally 200MHz to 500MHz (-3dB), which greatly limits the scope of application of oscilloscopes and becomes a bottleneck for the development of oscilloscopes.

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