University of Electronic Science and Technology of China

Kuojun Yang

Hao Zeng

Qinchuan Zhang

Peng Ye

Lianping Guo

Jun Jiang

Duyu Qiu

Wuhuang Huang

Feng Tan

Huiqing Pan

Shulin Tian

Guang Yang

Jia Zhao

Jian Gao

Houjun Wang

Pan Wang

Jinpeng Song

Chuanyun Xiang

Shuo Wang

Xingqi Liu

The present invention provides a method for 3D waveform mapping of full-parallel structure, first, a 3D waveform mapping database is created according to the size of a 3D waveform image, the number of bits of probability value and the ADC's resolution of data acquisition module, then the 3D waveform mapping database is divided into M&#xd7;Mindependent mapping storage areas along the time axis and the amplitude axis, and each independent mapping storage area is assigned a RAM, then RAMs are selected and addresses are calculated based on the sampling values and the structure of created 3D waveform mapping database, finally, parallel mappings are performed simultaneously on the time axis and the amplitude axis according to the selected RAMs and calculated addresses. Thus, the mapping time are shorten, especially in vector mapping mode, several RAMs are used for mapping, so the WCR of DSO is improved.

Method for 3D waveform mapping of full-parallel structure

A method for oscilloscope 3D mapping in scan mode. The input signal is acquired using a real-time sampling rate which is Dtimes higher, thus more sampling points, i.e. Dacquired data can be obtained during the time interval between two consecutive horizontal pixels. The Dacquired data are mapped into a same column of the screen to implement fluorescent waveform display. In addition, to realize the scanning display, a flag X is introduced into the three-dimensional database, when the screen refresh signal arrives, the first Dacquired data are read out from the unread acquired data in FIFO memory. The three-dimensional database is updated from the flag X, which make the leftmost waveform always be the oldest waveform, the rightmost waveform always be the newest waveform. Thus the 3D mapping is realized in scan mode, letting the DSO have a fluorescent waveform display at slow time-base.

Method for oscilloscope 3D mapping in scan mode

The present invention provides a temperature-compensated crystal oscillator based on digital circuit, a closed-loop compensation architecture is employed to realize the high precision compensation of the crystal oscillator. The output frequency f(T) of the TCXO to be compensated is directly connected with the compensation voltage Vc(T) in real time, and the compensation voltage is fed back to the voltage control terminal of the VCXO to be compensated to compensate, so that the output frequency after compensation is equal to the target frequency signal, thus avoiding the frequency shift of output signal caused by temperature hysteresis, i.e. the discrepancy between the temperature acquired by a temperature sensor and the real temperature of the resonant wafer in the prior art.

Temperature-compensated crystal oscillator based on digital circuit

A method for measuring waveform capture rate (WRC) of DSO based on average dead time measurement. First generating ramp signal or symmetric triangular wave signal as base signal, a trigger signal, the frequency which is higher than the nominal maximum waveform capture rate of the DSO under measurement; secondly, setting the parameters of DSO for measuring; then obtaining a plurality of test signals by delaying base signal K times with different delay time, for each test signal, inputting it the trigger signal simultaneously to DSO, calculating dead time between two adjacent captured waveforms according to their initial voltages, finally calculating waveform capture rate based on average dead times. The waveform capture rate obtained can effectively reflect the overall capturing capacity of DSO, more tellingly, the waveform capturing capacity of acquisition system of DSO.

Method for measuring the waveform capture rate of a digital storage oscilloscope based on average dead time measurement

The present invention provides a method for measuring the waveform capture rate of parallel digital storage oscilloscope. On the basis of double pulse measurement, and in consideration of the asymmetry of acquisition and the refreshing time of parallel DSO, the present invention provides a step amplitude-frequency combined pulse measurement to measure the time for waveform acquisition and mapping T, the number of captured waveforms before LCD refreshing Wand the dead time caused by LCD refreshing T, and then calculates the measured average WCR of parallel DSO, according to the measured data, so that the WCR of parallel can be measured.

Method for measuring the waveform capture rate of parallel digital storage oscilloscope

For the signal under acquisition which varies monotonically before and after the trigger time, a method for full-digital random sampling employs first sampled data before the trigger time and first sampled data after the trigger time to fit a curve, and obtains an intersection point of triggering level and the fitted curve, then, calculates the time interval between sampled data after the trigger time and the intersection point in the end, reconstructs the original signal, i.e. the signal under acquisition by a time interval of each acquisition. Thus, an analog trigger circuit and a time measurement circuit of conventional random sampling system can be eliminated, that simplifies the circuit design of data acquisition system and decreases its hardware complexity. Moreover, the higher sampling rate for the signal under acquisition is attained, and more waveform details are obtained.

Method for full-digital random sampling

A method for adjusting the waveform brightness for a waveform formatted to be displayed on a digital three-dimensional (3D) oscilloscope having M brightness gradation levels to display the waveform on a digital 3D oscilloscope having L brightness gradation levels is includes, creating a ROM in an FPGA and storing a look-up table of screen display brightness value of LCD that is corresponding to the waveform occurrence N(T,A) at the current brightness gradation L. The ROM is divided into 2sub ROMs, each sub ROM has the capacity of 2&#xd7;d bits. A value of round(p&#xb7;N(T,A) is assigned to waveform brightness value D(T,A) and is stored correspondingly into the subROMof 2&#xd7;d bits by ascending order of the b bits of binary data of waveform occurrence N(T,A). In this way, using the b bits of binary data of waveform occurrence N(T,A) as the binary address of the subROM, corresponding waveform brightness value D(T,A) at the current brightness gradation L can be obtained through look-up table in the subROM.

Method for quickly adjusting the waveform brightness of digital three-dimensional oscilloscope

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Chengdu, China

Kuojun Yang