Envelope Detector Control Path Enhancements for Low-Power Medical

Envelope Detector Control Path Enhancements for Low-Power Medical

Envelope Detector Control Path Enhancements for Low-Power Medical Applications J. Chan-Wai, B. Lawrence, V. Proulx ELG 4135 Electronics III Dr. Riadh Habash November 24th 2006 Team Members Jason Chan Wai

Brian Lawrence Valerie Proulx Conventional Envelope Detector Envelope detectors are used to obtain the envelope of an AM modulated signal.

Relevant Research Envelope Detector Proposed in Research Paper [1] Alegre, J.P., Celma, S., Sanz, M.T., and Garcia del Pozo. Low-ripple fast-settling envelope detector, Electronics Letters, 2006, 42, (18), pp. 1-2. Application: Hearing Aids and Cochlear Devices

We are interested in engineering for medical applications Hearing aids are designed for frequencies ranging from 250 to 4,000 Hz

Application: Hearing Aids and Cochlear Devices Original Control Path Control path proposed in referenced research paper Problems

Cannot receive low voltage signals High-pass filter No amplification Hearing aids require low voltage and low frequency signals

Noise amplified due to three stage MOSFET inverters Two separate control paths (180 out of phase) required to minimize the effect of noise Simulation

Simulation was performed on researched control path using PSpice Simulation Results 1 Output when input signal is 3V (large) Circuit functions as intended Simulation Results 2

At small voltages (300mV) the proposed control path does not function properly! Simulation Results Input signal not strong enough to drive MOSFET inverters Therefore, control path is unable to

properly switch the peak hold circuits at a peak in the input signal Problematic with low frequency signals (due to high-pass filter) Primary Goal Enhance the circuits response to weak, low frequency signals to ensure that they can switch the CMOS inverters and

therefore properly detect signal peaks Secondary Goals Minimize output noise Eliminate the need for a second control path Optimized Control Path

Proposed design utilizes active components in the input network! Simulation Results 1 Output of proposed control path with 300mV, 2kHz input signal

Simulation Results 2 Output of proposed control path with 300mV 500Hz input signal Simulation Results Capable

of receiving low voltage input signals within the desired frequency band Number of CMOS stages reduced (lower output noise) Single control path now capable of driving two control signals, eliminating the need for a second control circuit! Analysis Comparison: Passive Circuit PROS

Energy efficient Passive input network requires no power Speed

CONS Inability to receive low frequency, low voltage signals Requires two control paths Analysis Comparison: Active Circuit PROS Ability to receive low frequency, low voltage

signals Single control path required Lower output noise CONS Active stage requires more power usage than passive equivalent

Conclusion Researched envelope detector employing passive control path proves to be inadequate when utilized in hearing aids and cochlear devices Control path implementing active stage demonstrates acceptable performance for low voltage, low

frequency signal reception as required in Audio Sensory Medical (ASM) devices Recommended future work define an alternative implementation to the op-amp that provides equivalent performance at lower power consumption Followed Schedule

References [1] Alegre, J.P., Celma, S., Sanz, M.T., and Garcia del Pozo.: Low-ripple fastsettling envelope detector, Electronics Letters, 2006, 42, (18), pp. 1-2 [2] Communication Systems Tutorial: Envelope Detection, Utah State University: http://images.google.ca/imgres?imgurl=http://www.engineering.usu.edu/classes/ ece/5660/lab2/envdetpic.jpg&imgrefurl=http://www.engineering.usu.edu/classes/ ece/5660/lab2/

lab2.html&h=144&w=324&sz=7&hl=en&start=11&tbnid=Z7GdbY9TXA0qoM:&tb nh=50&tbnw=114&prev=/images%3Fq%3Denvelope%2Bdetector%2Bcircuit %26svnum%3D10%26hl%3Den%26lr%3D [3] Advanced frequency division bat detector: http://images.google.ca/imgres? imgurl=http://bertrik.sikken.nl/bat/pix/envlop1.gif&imgrefurl=http:// bertrik.sikken.nl/bat/ advdiv.htm&h=108&w=269&sz=2&hl=en&start=6&tbnid=tGVJMzfqre9kUM:&tbn h=45&tbnw=113&prev=/images%3Fq%3Denvelope%2Bdetector%2Bcircuit

%26svnum%3D10%26hl%3Den%26lr%3D [4] RAMALINGAM, RAVI RAMALINGAM Choice of hearing aids. The HINDO Newspaper: http://www.hinduonnet.com/2001/08/12/stories/1312048d.htm

Recently Viewed Presentations

  • Refresher 112/6

    Refresher 112/6

    Software per se. Common Types of Software-Related Claim Issues. We will now address several common types of software-related claim issues. It should be noted the use of the word "computer" in this presentation is intended to be a generic reference...
  • lowelibrary.weebly.com

    lowelibrary.weebly.com

    Roz the robot discovers that she is alone on a remote, wild island with no memory of where she is from or why she is there, and her only hope of survival is to try to learn about her new...
  • Read the OpenCDISC report - Pharmasug

    Read the OpenCDISC report - Pharmasug

    A message may caused by different reasons, we must check the detail to prevent hidden type II issue. Visit name of unplaned visits are not included in TV, already Explained in SDRG. Visitnum not given for some planed visit, data...
  • Electromagnetic Compatibility

    Electromagnetic Compatibility

    FM Modulation Index. Same deviation (volume), increasing the frequency. This slide shows the effect of a varying audio frequency with constant volume. Carson's Rule Needed bandwidth = 2x(max audio frequency + max deviation) is OK with a high mod index,...
  • Bild 1 - Karlstad University

    Bild 1 - Karlstad University

    For meeting 3 Yule (2006) Semantics (ch.10) The study of meaning. Pragmatics (ch.11) How the transmission of meaning depends not only on the linguistic knowledge of the speaker and listener, but also on the context of the utterance, knowledge about...
  • 2015-16 District 5950 Leadership

    2015-16 District 5950 Leadership

    District Leadership FY2019-20 Page 3. RI's Strategic Areas of Focus. Support & Strengthen Clubs. Focus & Increase Humanitarian Service. Enhance Public Image & Awareness
  • Achieving Food Security in Oic Member States in Post Crisis World

    Achieving Food Security in Oic Member States in Post Crisis World

    Deputy Director General, IOFS at the Press Conference in Nur Sultan, Kazakhstan on 09 September 2019 Introduction Food Security: OIC initiatives dated from establishment of OIC in 1969. Subsequent efforts intensified during the global food crisis in 2008. 1st Kazakh...
  • The Leadership Excellence Series Resolving Conflict 321 Definitions

    The Leadership Excellence Series Resolving Conflict 321 Definitions

    The Leadership Excellence Series Resolving Conflict 321 Conflict is what you get when two or more people have differences, real or perceived, that are not resolved. 1 Definitions Conflict resolution is what we do to identify and address conflict in...