scholarly journals Modeling Pulsed High-Power Spikes to Drive Piezoelectric Broadband Transducers Improving SNR in Ultrasonic Imaging & NDE

2021 ◽  
Author(s):  
Antonio Ramos ◽  
Abelardo Ruiz ◽  
Enrique Riera
Keyword(s):  
High Power ◽  
Dynamic Range ◽  
Ultrasonic Imaging ◽  
Average Power ◽  
Pulsed Power ◽  
Moderate Intensity ◽  
Signal To Noise ◽  
Discharge Generator ◽  
Piezoelectric Devices ◽  
Very High

Ultrasonic imaging & NDE applications can greatly improve their signal-to-noise ratios (SNR) by driving each transducer (composing piezoelectric arrays) with a spike giving pulsed power of k-Watts, repetitively at a PRF = 5000 spikes/s, by using a HV capacitive-discharge generator. However very-high levels, of pulsed intensities (3-10 A) and voltages (300-700 V) must be considered for a rigorous spike modeling. Even though the consumed "average" power will be small, the intensity through each transducer achieves several amperes, so the pulsed powers delivered by each HV generator can attain levels higher than in CW high-power ultrasonic applications: e.g., up to 5 kW / spike. This is concluded here from a transient modeling of the loaded generator. Then, unforeseen phenomena rise: intense brief pulses of driving power & emitted force in transducers, and non-linearities in driver semiconductors, because their characteristic curves only include linear ranges. But fortunately, piezoelectric devices working in this intense regime do not show serious heating problems, because the average power remains being moderate. Intensity, power and voltage, driving a broadband transducer from a HV capacitive pulser, are calculated to drastically improve (in ≅ 40 dB) the ultrasonic net dynamic range available, with emitted forces ≅ 250 Newtons pp and E/R received pulses of 70 V pp.

Evaluation of High Power Experimental SiC SGTO Devices for Pulsed Power Applications

2012 ◽  
Vol 717-720 ◽  
pp. 1183-1186 ◽  
Author(s):  
Shelby Lacouture ◽  
Kevin Lawson ◽  
Stephen Bayne ◽  
Michael Giesslmann ◽  
Heather O'Brien ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
High Power ◽  
Real World ◽  
High Energy ◽  
Pulsed Power ◽  
Test Bed ◽  
Real World Application ◽  
Very High Energy ◽  
And Performance ◽  
Very High

The development of new semiconductor designs requires that extensive testing be completed in order to fully understand the device’s characteristics and performance capabilities. This paper describes the evaluation of experimental Silicon Carbide high power Super Gate Turn Off Thyristors (SiC SGTOs) in a unique test bed that is capable of stressing the devices with very high energy/power levels while at the same time mimicking a realistic, real world application for such devices.

A new technology for locating very low frequency and negative signal-to-noise ratio sound sources

2021 ◽  
Vol 263 (4) ◽  
pp. 2468-2475
Author(s):  
Yazhong Lu ◽  
Sean Wu ◽  
Zeyu Yuan ◽  
Wen He
Keyword(s):  
Spatial Resolution ◽  
Background Noise ◽  
Dynamic Range ◽  
New Technology ◽  
Low Frequency ◽  
Signal To Noise ◽  
Sound Sources ◽  
Very Low Frequency ◽  
Very High ◽  
Negative Signal

This paper presents a new technology that enables one to locate multiple sound sources with very a large dynamic range simultaneously, including very low frequency and negative signal-to-noise ration sound sources in a non-ideal environment, where there are random background noise and unknown interfering signals. In particular, spatial resolution of source localization is frequency independent. In other words, spatial resolution remains very high at very low as well as at very high frequencies. The underlying principle of this new technology is a hybrid methodology that includes a passive SODAR (nic etection nd anging), advanced signal processing and least-squares minimization. Using this technology, engineers will be able to visualize sound sources in both real time and post processing in an adversary test environment. Live videos of sound sources localization inside a crowd machine shop are shown, where there are unknown background noise, unspecified sound reflections and reverberation, and interfering signals.

An Over 120dB Dynamic Range Linear Response Single Exposure CMOS Image Sensor with Two-stage Lateral Overflow Integration Trench Capacitors

2020 ◽  
Vol 2020 (7) ◽  
pp. 143-1-143-6 ◽  
Author(s):  
Yasuyuki Fujihara ◽  
Maasa Murata ◽  
Shota Nakayama ◽  
Rihito Kuroda ◽  
Shigetoshi Sugawa
Keyword(s):  
Linear Response ◽  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Cmos Image Sensor ◽  
Image Sensor ◽  
Signal To Noise ◽  
Single Exposure ◽  
Two Stage ◽  
Noise Ratio ◽  
Maximum Signal

This paper presents a prototype linear response single exposure CMOS image sensor with two-stage lateral overflow integration trench capacitors (LOFITreCs) exhibiting over 120dB dynamic range with 11.4Me- full well capacity (FWC) and maximum signal-to-noise ratio (SNR) of 70dB. The measured SNR at all switching points were over 35dB thanks to the proposed two-stage LOFITreCs.

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