Asynchronous excitation phenomena in oscillatory circuit containing periodically operating analog switch

Author(s):  
Michitaka Matsuki ◽  
Shinsaku Mori
Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1048
Author(s):  
Muhammad Nasir Ullah ◽  
Yuseung Park ◽  
Gyeong Beom Kim ◽  
Chanho Kim ◽  
Chansun Park ◽  
...  

We propose an integrated front-end data acquisition circuit for a hybrid ultrasound (US)-gamma probe. The proposed circuit consists of three main parts: (1) a preamplifier for the gamma probe, (2) a preprocessing analog circuit for the US, and (3) a digitally controlled analog switch. By exploiting the long idle time of the US system, an analog switch can be used to acquire data of both systems using a single output channel simultaneously. On the nuclear medicine (NM) gamma probe side, energy resolutions of 18.4% and 17.5% were acquired with the standalone system and with the proposed switching circuit, respectively, when irradiated with a Co-57 radiation source. Similarly, signal-to-noise ratios of 14.89 and 13.12 dB were achieved when US echo signals were acquired with the standalone system and with the proposed switching circuit, respectively. Lastly, a combined US-gamma probe was used to scan a glass target and a sealed radiation source placed in a water tank. The results confirmed that, by using a hybrid US-gamma probe system, it is possible to distinguish between the two objects and acquire structural information (ultrasound) alongside molecular information (gamma radiation source).


Author(s):  
Parfentiev Nikolay Andreevich

A special point was found in the frequency characteristics of the oscillatory circuit, which was not mentioned earlier in textbooks on electrical engineering and radio engineering. The module of complex resistance of the circuit does not depend on the value of the active resistance at a frequency less than  times that of the resonance. The material is of interest to all engineers and scientists specializing in electrical engineering. On its basis, new methods for measuring the parameters of electrical circuits can be developed. Physical interpretation of the phenomenon doesn't exist at the moment.


2019 ◽  
Vol 29 (07) ◽  
pp. 1950097 ◽  
Author(s):  
Yuman Zhang ◽  
Mei Guo ◽  
Gang Dou ◽  
Yuxia Li ◽  
Guanrong Chen

The [Formula: see text] (SBT) nanometer film can be used as a physical memristive component. Three oscillatory circuits built on the physical SBT memristor are proposed in this paper, one is self-excited oscillatory circuit and two are forced oscillatory circuits. These three oscillatory circuits have simple structures with complex dynamics. The self-excited oscillatory circuit can generate steady periodic oscillations; the first forced oscillatory circuit can generate relatively complex quasi-periodic oscillations, while the second can generate more complex dynamics such as chaotic oscillations. The impacts of the circuit parameter and initial state values of the SBT memristor on the dynamical behaviors of the three oscillatory circuits are investigated via numerical simulations. It is found that the SBT memristor can be used to design various memristor-based circuits. Specifically, in a flux-controlled memristor-based circuit, if an inductor is in parallel with the memristor, the order of the circuit is one less than the number of energy storage elements in the circuit. The equilibrium point of the circuit is different from the typical line equilibrium for autonomous circuits. The initial state value of the memristor has no impact on the steady state of the circuit. The same phenomena are observed for a charge-controlled memristor-based circuit, when a capacitor is in series with the memristor.


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