scholarly journals Derivation of the Equivalent Input Noise of Multiplicative Distributed Amplifiers for Wideband Optical Receiver Applications

2020 ◽  
Author(s):  
Temitope Odedeyi ◽  
Izzat Darwazeh
Keyword(s):  
Optical Receiver ◽  
Distributed Amplifiers ◽  
Input Noise ◽  
Equivalent Input Noise

Do Modern Hearing Aids Meet ANSI Standards?

2016 ◽  
Vol 27 (08) ◽  
pp. 619-627 ◽  
Author(s):  
Jourdan T. Holder ◽  
Erin M. Picou ◽  
Jill M. Gruenwald ◽  
Todd A. Ricketts
Keyword(s):  
Quality Control ◽  
Hearing Aids ◽  
Hearing Aid ◽  
Analysis Data ◽  
National Standards ◽  
Control Measures ◽  
Input Noise ◽  
Release Times ◽  
Quality Control Testing ◽  
Equivalent Input Noise

Background: The American National Standards Institute (ANSI) provides standards used to govern standardization of all hearing aids. If hearing aids do not meet specifications, there are potential negative implications for hearing aid users, professionals, and the industry. Recent literature has not investigated the proportion of new hearing aids in compliance with the ANSI specifications for quality control standards when they arrive in the clinic before dispensing. Purpose: The aims of this study were to determine the percentage of new hearing aids compliant with the relevant ANSI standard and to report trends in electroacoustic analysis data. Research Design: New hearing aids were evaluated for quality control via the ANSI S3.22-2009 standard. In addition, quality control of directional processing was also assessed. Study Sample: Seventy-three behind-the-ear hearing aids from four major manufacturers, that were purchased for clinical patients were evaluated before dispensing. Data Collection and Analysis: Audioscan Verifit (version 3.1) hearing instrument fitting system was used to complete electroacoustic analysis and directional processing evaluation of the hearing aids. Frye’s Fonix 8000 test box system (Fonix 8000) was also used to cross-check equivalent input noise (EIN) measurements. These measurements were then analyzed for trends across brands and specifications. Results: All of the hearing aids evaluated were found to be out of specification for at least one measure. EIN and attack and release times were the measures most frequently out of specification. EIN was found to be affected by test box isolation for two of the four brands tested. Systematic discrepancies accounted for ˜93% of the noncompliance issues, while unsystematic quality control issues accounted for the remaining 7%. Conclusions: The high number of systematic discrepancies between the data collected and the specifications published by the manufacturers suggests there are clear issues related to the specific protocols used for quality control testing. These issues present a significant barrier for hearing aid dispensers when attempting to accurately determine if a hearing aid is functioning appropriately. The significant number of unsystematic discrepancies supports the continued importance of quality control measures of new and repaired hearing aids to ensure that the device is functioning properly before it is dispensed and to avoid future negative implications of fitting a faulty device.

scholarly journals A Compact Low-Distortion Low-Power Instrumentation Amplifier

2010 ◽  
Vol 5 (1) ◽  
pp. 33-41
Author(s):  
Jader A. De Lima
Keyword(s):  
Low Frequency ◽  
Design Parameters ◽  
Instrumentation Amplifier ◽  
Cmos Process ◽  
Output Stage ◽  
Noise Spectral Density ◽  
Class Ab ◽  
Input Noise ◽  
Low Distortion ◽  
Equivalent Input Noise

A CMOS instrumentation amplifier based on a simple topology that comprises a double-input Gm-stage and a low-distortion class-AB output stage is presented. Sub-threshold design techniques are applied to attain high figures of differential-gain and rejection parameters. Analyses of input-referred noise and CMRR are comprehensively carried out and their dependence on design parameters determined. The prototype was fabricated in standard n-well CMOS process. For 5V-rail-to-rail supply and bias current of 100nA, stand-by consumption is only 16μW. Low-frequency parameters are ADM=86dB, CMRR=89.3dB, PSRR+=87dB, PSRR-=74dB. For a 6.5pF-damping capacitor, ΦM=73º and GBW=47KHz. The amplifier exhibits a THD of –64.5dB @100Hz for a 1Vpp-output swing. Input-noise spectral density is 5.2μV/ Hz @1Hz and 1.9μV/ Hz @10Hz, which gives an equivalent input-noise of 37.6μV, over 1Hz-200Hz bandwidth. This circuit may be employed for low-frequency, low-distortion signal processing, advantageously replacing the conventional 3-opamp approach for instrumentation amplifiers.

Consistency of Electroacoustic Characteristics Across Components of FM Systems

1991 ◽  
Vol 34 (3) ◽  
pp. 628-635 ◽  
Author(s):  
Linda M. Thibodeau ◽  
Kathryn A. Saucedo
Keyword(s):  
Sound Pressure Level ◽  
High Frequency ◽  
Sound Pressure ◽  
Pressure Level ◽  
Input Noise ◽  
The Individual ◽  
Equivalent Input Noise

In the absence of national or international electroacoustic standards for the evaluation of Frequency Modulated (FM) amplification systems, it becomes important to know the variability one may expect across similar models. Evaluation of thirty FM systems of the same model obtained from three different educational sites was performed to determine the variability that may occur as a result of the receiver, lapel microphone, or neckloop. There was a range as great as 20 dB in high frequency average saturation sound pressure level and equivalent input noise across receivers, lapel microphones, and neckloops. These results highlight the need for regular electroacoustic monitoring of not only the FM transmitter and receiver, but also the individual components, such as the lapel microphone and the neckloop.

A low-noise transistorized seismic amplifier

1964 ◽  
Vol 54 (1) ◽  
pp. 347-368
Author(s):  
Stamatios N. Thanos
Keyword(s):  
High Reliability ◽  
Low Noise ◽  
Ocean Bottom ◽  
Low Frequencies ◽  
Input Noise ◽  
Remote Operation ◽  
Source Impedance ◽  
Ocean Bottom Seismographs ◽  
Equivalent Input Noise ◽  
Remote Calibration

abstract The use of transistors for the amplification of fractional microvolt signals at extremely low frequencies is illustrated in the design of an amplifier developed for use in a lunar seismograph. The amplifier has an equivalent input noise voltage of 0.2 microvolts, p-p, with a source impedance of 2000 ohms and a 3 db bandwidth of 0.035 cps to 22 cps. The nominal input impedance is 1700 ohms. It is completely transistorized and performs satisfactorily over a specified temperature range of −20°C to +100°C. Low power requirements, high reliability, and capability for remote calibration and gain change make this amplifier especially suitable for any field or remote operation under extreme environmental conditions. This amplifier is presently being used in ocean bottom seismographs and magnetic variometers.

Signal Detection Technology for Giant Magnetoresistance Sensors

2013 ◽  
Vol 303-306 ◽  
pp. 270-273 ◽  
Author(s):  
Jing Hua Hu ◽  
Meng Chun Pan ◽  
Wu Gang Tian ◽  
Jia Fei Hu
Keyword(s):  
Signal Processing ◽  
Signal Detection ◽  
Giant Magnetoresistance ◽  
Low Noise ◽  
Output Data ◽  
Input Noise ◽  
Algorithm Efficiency ◽  
Detection Technology ◽  
Equivalent Input Noise ◽  
Signal Processing Methods

Presently, many attentions have been paid on low-noise pre-amplifier circuits and steady signal processing methods, but seldom on the combination of two technologies. In this paper, a small size low noise pre-amplifier circuit with 110dB Common Mode Rejection Ratio（CMRR）has been developed for giant magnetoresistance sensors(GMR) and its equivalent input noise voltage density is about . In addition, we proposed a new signal processing method for the sensors. In the method, we defined the quotient between the complex multiplex computation times and the output data num as a new figure of merit to evaluate that algorithm efficiency in signal detection, and name that quotient the computation times -to- output data num ratio (CTOR). Simulation results showed that the new method realized better parameters evaluation precision and higher efficiency than Modified Rife method, could be implemented easily in embedded systems.

COMPARISON OF 1/f NOISE IN JFETs AND MOSFETs WITH SEVERAL FIGURES OF MERIT

2011 ◽  
Vol 10 (04) ◽  
pp. 447-465 ◽  
Author(s):  
FELIX A. LEVINZON ◽  
L. K. J. VANDAMME
Keyword(s):  
Thermal Noise ◽  
Empirical Relation ◽  
Low Noise ◽  
Corner Frequency ◽  
Current Gain ◽  
Noise Parameter ◽  
Input Noise ◽  
High Area ◽  
Measurement Results ◽  
Equivalent Input Noise

Measurement results are presented from 0.1 Hz to 100 kHz of 1/f and thermal noise in different n-JFETs, and n- and p-MOSFETs. The comparison of the 1/f noise is based on Hooge's empirical relation with the 1/f noise parameter α as figure of merit, without suggesting a physical origin. We find that the empirical relation for 1/f noise in MOSFETs and JFETs can be used as a tool to pinpoint the dominant noise source (either ΔN number fluctuations or Δμ mobility fluctuations) and its location, either in the channel or in the parasitic series resistance. Similar relations hold in JFETs and MOSFETs for the 1/f noise corner frequency fc, where thermal and 1/f noise are equal and the ratio fc/fT with fT the unity current gain frequency. The geometry independent parameter α and ratio fc/fT are compared from MOSFETs and JFETs with different channel width (W) and length (L). The results show that very low-noise n-JFETs have a corner frequency fc ≈ 40 Hz, and very low 1/f and thermal noise in agreement with the high W/L ratio and high area WL of the device. Specifically, the equivalent input noise voltage of the investigated JFET IF9030 was about 3.7 nV/√ Hz at 1 Hz, 1.3 nV/√Hz at 10 Hz, and about 0.6 nV/√ Hz (3.6 ×10-19 V2/Hz or Req th noise = 23 Ω) for f ≥ 100 Hz. The 1/f noise parameter α for that JFET is as low as α = 2 × 10-8. This α-value is among the lowest values ever observed. MOSFETs often have α, fc and fc/fT values that are a few decades higher than for JFETs.

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