Resonance Low Frequency Sound Source With Extended Frequency Band

1995 ◽  
Author(s):  
Dimitri M. Donskoy ◽  
Jan Nazalewicz
Keyword(s):  
Frequency Band ◽  
Sound Source ◽  
Digital Signal Processor ◽  
Frequency Control ◽  
Low Cost ◽  
Reaction Force ◽  
Double Resonance ◽  
Low Frequency ◽  
Underwater Sound ◽  
Compact Size

Abstract A new concept of a low-frequency (< 1000-Hz) underwater sound source has been proposed and tested (Donskoy and Blue, 1994). The present work is a further development of the source. A full scale reaction force driver to power the source was developed, built, and tested. In order to extend frequency band of the source, a double resonance approach (resonating reaction mass and resonating radiation piston) was employed. This approach allows for a significant extension (up to 400%) of the frequency band without an increase in a vibromotive force. The driver consists of a brushless servomotor, a brushless resolver for feedback, a Digital Signal Processor (DSP) based servo amplifier, and an interface with a PC. Vibromotive force is created with an eccentric weight mounted to a resonating mechanical structure. The driver can generate up to 8.000 lbs force, it has a programmable frequency control in the range up to 117 Hz, high power output (3.3 kW), compact size, low weight, and relatively low cost.

Low Frequency Piezoelectric Synthetic Jets

2010 ◽  
Author(s):  
Charles E. Seeley ◽  
Mehmet Arik ◽  
Yogen Uttukar ◽  
Tunc Icoz
Keyword(s):  
Low Cost ◽  
Heated Surface ◽  
Fluid Structure Interaction ◽  
Low Frequency ◽  
Synthetic Jet ◽  
Synthetic Jets ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Active Cooling ◽  
Compact Size

Active cooling is often required for circuit boards with high heat generation densities. Synthetic jets driven with piezoelectric actuators offer interesting capabilities for localized active cooling of electronics due to their compact size, low cost and substantial cooling effectiveness. The design of synthetic jets for specific applications requires practical design tools that capture the strong fluid structure interaction without long run times. There is particular interest in synthetic jets that have a low operating frequency to reduce noise levels. This paper describes how common finite element (FE) and computational fluid dynamics (CFD) codes can be used to calculate parameters for a synthetic jet fluid structure interaction (FSI) model that only requires a limited number of degrees of freedom and is solved using a direct approach for low frequency synthetic jets. Tests are performed based on impinging on a heated surface to measure heat transfer enhancement. The test results are compared to the FSI model results for validation and agreement is found to be good in the frequency range of interest from 200 to 500 Hz.

scholarly journals A Compact Size Wideband RF-VGA Based on Second Generation Controlled Current Conveyors

Electronics ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1600
Author(s):  
J. del Pino ◽  
Sunil L. Khemchandani ◽  
D. Galante-Sempere ◽  
C. Luján-Martínez
Keyword(s):  
Power Consumption ◽  
Second Generation ◽  
Low Cost ◽  
Low Frequency ◽  
Low Noise ◽  
Low Noise Amplifiers ◽  
Current Conveyors ◽  
Compact Size ◽  
Sige Bicmos ◽  
Controlled Current Conveyors

This paper presents a methodology to design a wideband radio frequency variable gain amplifier (RF-VGA) in a low-cost SiGe BiCMOS 0.35 μm process. The circuit uses two Class A amplifiers based on second-generation controlled current conveyors (CCCII). The main feature of this circuit is the wideband input match along with a reduced NF (5.5–9.6 dB) and, to the authors’ knowledge, the lowest die footprint reported (62 × 44 μm2 area). The implementation of the RF-VGA based on CCCII allows a wideband input match without the need of passive elements. Due to the nature of the circuit, when the gain is increased, the power consumption is reduced. The architecture is suitable for designing wideband, low-power, and low-noise amplifiers. The proposed design achieves a tunable gain of 6.7–18 dB and a power consumption of 1.7 mA with a ±1.5 V DC supply. At maximum gain, the proposed RF-VGA covers from DC up to 1 GHz and can find application in software design radios (SDRs), the low frequency medical implant communication system (MICS) or industrial, scientific, and medical (ISM) bands.

scholarly journals Performance Evaluation of Low Cost Analog Feedback Active Noise Cancellation System

2019 ◽  
Vol 8 (3S) ◽  
pp. 142-145
Keyword(s):  
Digital Signal Processor ◽  
Acoustic Noise ◽  
Low Cost ◽  
Low Frequency ◽  
Digital Signal ◽  
Noise Cancellation ◽  
Frequency Noise ◽  
Active Noise Cancellation ◽  
Active Noise ◽  
The Cost

Acoustic noise can be reduced by active noise cancellation (ANC) and passive noise cancellation (PNC) algorithm. The PNC can effectively attenuate the noise with high frequency, but not the noise with low frequency. ANC is one of the promising solution to reduce the low frequency noise. Commercial ANC headphones often use the digital signal processor (DSP) to perform the noise cancellation algorithm to cancel the annoying acoustic noise, but the cost is relatively high. A low-cost ANC solution is urgently needed to reduce the acoustic noise. The relationship between the frequency, distance and degree of magnitude of the noise level are also evaluated in this paper.

A new concept of a low‐frequency underwater sound source

1994 ◽  
Vol 95 (4) ◽  
pp. 1977-1982 ◽  
Author(s):  
Dimitri M. Donskoy ◽  
Joseph E. Blue
Keyword(s):  
Sound Source ◽  
Low Frequency ◽  
Underwater Sound

A Low Frequency Underwater Sound Source with an Acoustic Reel Shape Resonator

1990 ◽  
Vol 29 (S1) ◽  
pp. 83
Author(s):  
Hiroyuki Hachiya ◽  
Shigeo Ohtsuki ◽  
Motoyoshi Okujima
Keyword(s):  
Sound Source ◽  
Low Frequency ◽  
Underwater Sound
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