Browsing by Author "Lee, Chia-Fone"

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A 0.6 V, 1.66mW Energy Harvester and Audio Driver for Tympanic Membrane Transducer with Wirelessly Optical Signal and Power Transfer
(2014-01-01)
Jian, Jhong-Ting
;
Song, Yu-Lin
;
Lee, Chia-Fone
;
Chou, Yuan-Fang
;
Cheni, Wei-Zen
An energy harvester and ultra-low-voltage audio driver to mechanically stimulate tympanic membrane (TM) transducer is presented. By wirelessly optical signal and power transfer, the audio driver is able to directly drive the actuator on the TM to improve sound quality while avoiding occlusion effects. The measured THD+N is 0.4% over the audio bandwidth with modulation index of 0.4, and maximum power conversion efficiency is 24.7%. The core circuits dissipate 1.66mW from 0.6 V through optical power transfer. Fabricated in TSMC 90 nm CMOS technology, the chip size is 0.88x0.84mm(2).
A Bone-Guided Cochlear Implant CMOS Microsystem Preserving Acoustic Hearing
(2017-01-01)
Qian, Xin-Hong
;
Wu, Yi-Chung
;
Yang, Tzu-Yi
;
Cheng, Cheng-Hsiang
;
Chu, Hsing-Chien
In this paper, a bone-guided cochlear implant (BGCI) SOC microsystem is proposed and designed. The BGCI microsystem uses four or more electrodes placed on the bone surface of the cochlea and one on the round window to preserve partially the acoustic hearing. The external SOC of the BGCI processes the acoustic signals and generates stimulation patterns and command that are transmitted to the implanted chip through the 13.56MHz wireless power and bidirectional data telemetry. The implanted chip with 4-channel high-voltage-tolerant stimulator generates biphasic stimulation currents up to 800 mu A and sends back the power indication and electrode impedance error signals to the external SOC. Electrical tests on the fabricated BGCI has been performed. The in-vivo animal tests on guinea pigs has shown the evoked Wave III of EABR waveforms. The proposed BGCI can be applied to patients with high-frequency hearing loss, tinnitus, and dizziness.
A HEARING MODEL TO ESTIMATE MANDARIN SPEECH INTELLIGIBILITY FOR THE HEARING IMPAIRED PATIENTS
(2015)
Tsai, Pei-Chun
;
Lin, Shih-Ting
;
Lee, Wen-Chung
;
Hsu, Chung-Chien
;
Chi, Tai-Shih
A hearing model, which is parameterized by hearing thresholds, degrees of loudness recruitment and reductions of frequency resolution of a hearing-impaired (HI) patient, is proposed in this paper. The model is developed in the filter-bank framework and is flexible for fitting hearing-loss conditions of HI patients. Psychoacoustic experiments were conducted under clean and noisy conditions to validate the model\'s capability in predicting Mandarin speech intelligibility for HI patients. Statistical analysis on the hearing-test results suggests that the proposed model can predict Mandarin speech intelligibility for HI patients to a certain degree.
A HEARING MODEL TO ESTIMATE MANDARIN SPEECH INTELLIGIBILITY FOR THE HEARING IMPAIRED PATIENTS
(2015-01-01)
Tsai, Pei-Chun
;
Lin, Shih-Ting
;
Lee, Wen-Chung
;
Hsu, Chung-Chien
;
Chi, Tai-Shih
A hearing model, which is parameterized by hearing thresholds, degrees of loudness recruitment and reductions of frequency resolution of a hearing-impaired (HI) patient, is proposed in this paper. The model is developed in the filter-bank framework and is flexible for fitting hearing-loss conditions of HI patients. Psychoacoustic experiments were conducted under clean and noisy conditions to validate the model's capability in predicting Mandarin speech intelligibility for HI patients. Statistical analysis on the hearing-test results suggests that the proposed model can predict Mandarin speech intelligibility for HI patients to a certain degree.
Design and In Vivo Verification of a CMOS Bone-Guided Cochlear Implant Microsystem
(2019-11-01)
Qian, Xin-Hong
;
Wu, Yi-Chung
;
Yang, Tzu-Yi
;
Cheng, Cheng-Hsiang
;
Chu, Hsing-Chien
Objective: To develop and verify a CMOS bone-guided cochlear implant (BGCI) microsystem with electrodes placed on the bone surface of the cochlea and the outside of round window for treating high-frequency hearing loss. Methods: The BGCI microsystem consists of an external unit and an implanted unit. The external system-on-chip is designed to process acoustic signals through an acquisition circuit and an acoustic DSP processor to generate stimulation patterns and commands that are transmitted to the implanted unit through a 13.56 MHz wireless power and bidirectional data telemetry. In the wireless power telemetry, a voltage doubler/tripler (2X/3X) active rectifier is used to enhance the power conversion efficiency and generate 2 and 3 V output voltages. In the wireless data telemetry, phase-locked loop based binary phase-shift keying and load-shift keying modulators/demodulators are adopted for the downlink and uplink data through high-Q coils, respectively. The implanted chip with four-channel high-voltage-tolerant stimulator generates biphasic stimulation currents up to 800 mu A. Results: Electrical tests on the fabricated BGCI microsystem have been performed to verify the chip functions. The in vivo animal tests in guinea pigs have shown the evoked third wave of electrically evoked auditory brainstem response waveforms. It is verified that auditory nerves can be successfully stimulated and acoustic hearing can be partially preserved. Conclusion and Significance: Different from traditional cochlear implants, the proposed BGCI microsystem is less invasive, preserves partially acoustic hearing, and provides an effective alternative for treating high-frequency hearing loss.
Simulations of high-frequency vocoder on Mandarin speech recognition for acoustic hearing preserved cochlear implant
(2017-01-01)
Wu, Tsung-Chen
;
Chi, Tai-Shih
;
Lee, Chia-Fone
;
電機工程學系
;
Department of Electrical and Computer Engineering
Vocoder simulations are generally adopted to simulate the electrical hearing induced by the cochlear implant (CI). Our research group is developing a new four-electrode CI microsystem which induces high-frequency electrical hearing while preserving low-frequency acoustic hearing. To simulate the functionality of this CI, a previously developed hearing-impaired (HI) hearing model is combined with a 4-channel vocoder in this paper to respectively mimic the perceived acoustic hearing and electrical hearing. Psychoacoustic experiments are conducted on Mandarin speech recognition for determining parameters of electrodes for this CI. Simulation results show that initial consonants of Mandarin are more difficult to recognize than final vowels of Mandarin via acoustic hearing of HI patients. After electrical hearing being induced through logarithmic frequency distributed electrodes, speech intelligibility of HI patients is boosted for all Mandarin phonemes, especially for initial consonants. Similar results are consistently observed in clean and noisy test conditions.
The development of a non-surgical direct drive hearing device with a wireless actuator coupled to the tympanic membrane
(2013-12-01)
Song, Yu-Lin
;
Jian, Jhong-Ting
;
Chen, Wei-Zen
;
Shih, Chih-Hua
;
Chou, Yuan-Fang
A non-surgical, direct driving hearing device with an actuator placed on the tympanic membrane was designed, fabricated and tested. The actuator consisted of two photodiodes, an aluminum ring, two neodymium iron permanent magnets, two opposing wound coils, a latex membrane and a Provil Novo (TM) membrane. The transducer coupled to the ear drum-utilizing photodiodes and permanent magnets on the motive components could eliminate the need for electrical connections to the moving components. An optic probe was designed to allow sound and light signals to enter the ear canal. By using opto-electromagnetic coupling, the developed hearing device could transmit information over a distance without using cables. The wireless actuator was achieved by two configurations: in one, two light emitting diodes were used for carrying the input signals, and in the other, the corresponding photodiodes were used for receiving the light signals and generating the currents in the actuator. The wireless actuator was designed to use light to carry energy and transmit the signals; thus, the occlusion effect created by traditional ear molds could be avoided. Finally, the wireless actuator was fabricated and tested with a laser Doppler vibrometer. The actuator showed displacements of vibration between 30-0.2 nm and from 400 Hz to 7 kHz with reduced vibration at higher frequencies. The gain of the actuator with 120 mu A on the umbo displacement was approximately 3-13 dB from 400 to1500 Hz and decreased to 6 dB between 1500 Hz to 3 kHz and down to -1 to -6 dB above 3 kHz. Distortions of the umbo vibration amplitude were approximately -1 to -10 dB across frequencies. The results suggest that light can transmit the sound signal remotely and that adequate amplification can be achieved by this actuator. The reduced amplitude above 3 kHz was a consequence of the mass effect of the actuator, which should be miniaturized in the future. Crown Copyright (c) 2013 Published by Elsevier Ltd. All rights reserved.