scholarly journals Accurate Prediction of Transimpedances and Equivalent Input Noise Current Densities of Tuned Optical Receiver Front Ends

1991 ◽  
Author(s):  
Qing Zhong Liu
Keyword(s):  
Optical Receiver ◽  
Accurate Prediction ◽  
Noise Current ◽  
Input Noise ◽  
Current Densities ◽  
Equivalent Input Noise

A 40Gb/s Transimpedance Amplifier Using Modified Regulated Cascode for Optical Fiber Communication

2012 ◽  
Vol 236-237 ◽  
pp. 958-963
Author(s):  
Ying Mei Chen ◽  
Tao Wang ◽  
Jin Fei Wang ◽  
Jian Wei Gong ◽  
Lei Zhu
Keyword(s):  
Optical Fiber ◽  
Optical Fiber Communication ◽  
Cmos Technology ◽  
Transimpedance Amplifier ◽  
Fiber Communication ◽  
Noise Current ◽  
Input Noise ◽  
Dc Power ◽  
Active Feedback ◽  
Equivalent Input Noise

This paper describes the design of a 40 Gb/s transimpedance amplifier (TIA) for high-density optical fiber communication system. This TIA incorporates modified regulated cascode (RGC), three order intersecting active feedback and passive feedback. Consuming a DC power of 14.5 mW, the single-ended circuit provides a transimpedance gain of 49.5 dB and a -3dB bandwidth up to 40 GHz in IBM 90-nm CMOS technology with a 1.2 V supply. Simulation results show the equivalent input noise current integrated from 1 MHz to 30 GHz is about 6.6 Arms

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.

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