Ultrafast edge step pulse generating method and generator thereof

Abstract

The invention relates to the technical field of electrical equipment and in particular relates to an ultrafast edge step pulse generating method and a generator thereof. In the invention, a high-precision clock reference source is used for generating a clock excitation signal exciting a high-speed comparator to generate a pulse signal of a faster edge, and a pulse amplitude adjustment circuit is used for amplifying and pre-shaping the amplitude of the pulse signal of the faster edge; then the pulse signal enters a pulse rising edge accelerating circuit, and the rising edge of the pulse signal after amplitude adjustment is further accelerated by utilizing the step recovery effect of a step recovery diode; meanwhile, the waveform of the output pulse signal is subjected to shaping and amplitude control so as to meet the requirements on the rising time, the amplitude and the overshoot pulse of a characteristic impedance tester; and finally, the pulse signal is output by using a pulse output interface. The output pulse rising time is 150ps, the amplitude is larger than 500mV, the overshoot pulse is smaller than 10 percent, and the prepulse can be ignored. The invention can discover or sense smaller impedance discontinuous distances.

Description

Technical field: [0001] The invention relates to the technical field of electrical equipment, in particular to an ultrafast edge step pulse generation method and a generator for a characteristic impedance tester. Background technique: [0002] Time Domain Reflectometer (TDR) is an important time-domain testing instrument. A typical TDR device consists of a broadband sampling oscilloscope and an external high-speed step pulse generator. It has been widely used in PCBs, ICs, cables and connectors. and other test areas. In the circuit board industry, TDR is the main test equipment to detect whether the characteristic impedance of PCB traces meets the design requirements, and is usually called a characteristic impedance tester. The most important performance index of TDR equipment is the system rise time T sys , which represents the ability of the TDR device to detect or perceive the smallest (ie shortest) impedance discontinuity distance. The system rise time (reflected rise...

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Problems solved by technology

[0011] According to the theory of signal integrity, if the time interval from the transmission of an electrical signal to the reflection back through the impedance discontinuity point is less than the rise time of the incident electrical signal, then this part of the reflected signal will be annihilated by the rising incident signal, so TDR It is also impossible to distinguish the reflected signal, that is to say, the TDR equipment cannot distinguish the impedance discontinuity point

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