University of Electronic Science and Technology of China

Huiqing Pan

Feng Tan

Hao Zeng

Lianping Guo

Peng Ye

Qinchuan Zhang

Duyu Qiu

Jun Jiang

Kuojun Yang

Wuhuang Huang

Yong Zhao

Xingqi Liu

Luonan Zheng

Shuhao Wu

The present invention provides a method and apparatus for automatically adjusting the hold-off time of a DSO based on real-time cycle measurements of the system trigger signal: obtaining a cycle sequence by measuring the system trigger signal, the maximum cycle and minimum cycle, then judging the difference of the maximum cycle and minimum cycle: if the difference is greater than a threshold set by user, setting the hold-off time to the maximum cycle, the minimum cycle or the median cycle, then returning; otherwise terminating the adjustment of the hold-off time. At this point, the hold-off time is correctly set. Therefore, the present invention reduces the complexity and time consumption of the hold-off adjustment, and allows the test signal to be quickly and stably displayed on screen of DSO, meanwhile, which makes the trigger adjustment of DSO more convenient.

Method and apparatus for automatically adjusting the hold-off time of a DSO

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

The present invention provides a method for a method for measuring the properties of liquid based on a quartz crystal microbalance sensor, which employs two measurements to obtain two frequency shifts of the QCM sensor induced by two different volume of the sample liquid. The present invention creatively established the relationship between the density and viscosity of sample liquid and the frequency shifts of QCM sensor. With present invention, the density and viscosity of sample liquid can be obtained through two frequency shifts. Comparing to the conventional liquid property measurement. The measuring procedure of present invention are more simple, and the measuring results are more accurate. Moreover, the present invention consumes less volume of sample liquid, and has the features such as online, real time and quantitative.

Method for measuring the properties of liquid based on a quartz crystal microbalance sensor

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Chengdu, China

Huiqing Pan