Introduction: Cochlear dead zones are defined as areas where the inner hair cells have been destroyed.Thresholds on the audiograms show the integrity of those parts of the ear that are tested. Care must be taken in interpretating audiograms. Thanks to the advances in understanding of cochlear functions, it is now possible to spot false responses that come from dead zones of the cochlea. Recently, cochlear dead regions have been detected via TEN (Threshold Equalizing NOISE) test in which ipsilateral broadband NOISE and threshold shifting are used.Materials and Methods: A review of the literature on the subject of dead zones published from 1993 to 2003 was performed using Pubmed, Ebsco, Science Direct, Google Scholar Thieme ProQuest databases and library sources. key word: were "cochlear dead zone", "traveling wave", "ten (threshold equalizing NOISE) test", "ipsilateral NOISE" and "real-ear measurement for hearing aids prescription".Conclusion: Hearing aids fitting process for patients with severe and sloping sensory neural hearing loss must be noted specially by amplifying active zone and avoiding amplification for dead region i.e., offering amplification to the transition frequencies that have better hearing than others, those among the fine regions and the dead zones. Dead zone detection may help in hearing aids fitting and fine tuning.

In this paper, a new method for extending and relaxing the NOISE-coupling (NC) technique is proposed to enhance the NOISE-shaping order without adding the number of integrators. The NOISE-shaping order of the introduced ∑∆ modulator whit applying a second-order NOISE-coupling technique is enhanced and its performance with optimizing the NOISE transfer function (NTF) zeros is improved. Also, by removing the analog adder at feedforward path and transferring it to a new feedback branch before the last integrator and adding second-order NC path can be decreased the input voltage swing to the quantizer. Thus, by improving the modulator resolution, power consumption can be reduced. Mathematical analyses and behavioural simulation results confirm the effectiveness of the new NC method. To examine its performance, a 2nd-order single loop ΣΔ modulator was designed. The new NOISE-coupling method is used to achieve the three-order NOISE shaping to increase the resolution with low complexity and low-power. The results show an outstanding improvement in signal-to-NOISE and distortion ratio (SNDR) compared to the conventional structure.

BACKGROUND AND OBJECTIVE: NOISE-induced hearing loss remains as the most common problem in industrial societies. This research was conducted to study NOISE-induced hearing loss by distortion-product otoacoustic emissions (DPOAEs).METHODS: This study was carried out on 12 male New Zealand White rabbits including control (exposed to NOISE) and experimental (exposed to 95 dBA SPL white NOISE at 500-8000 Hz for 8 hours per day during 5 consecutive days). DPOAEs were measured and compared in days zero (before exposure as baseline), eighth (experimental: an hour after latest exposure to NOISE for Temporary Threshold Shifts: TTS), tenth (experimental: 48 hours after latest exposure to NOISE for Permanent Threshold Shifts: PTSs).FINDINGS: The most and the least values of TTSs, PTSs and DPOAEs amplitude in NOISE group were correspond to frequencies of 5888.50 Hz and 588.00 Hz, respectively (p<0.05). There was a significant difference between TTSs, PTSs and DPOAEs amplitude at different frequencies in right and left ear of NOISE group (p<0.05). This difference was related to frequency 5888.5 Hz in each of right and left ear of NOISE group compared to other frequencies in same ear (p<0.05). There were not any significant difference between TTSs, PTSs and DPOAEs amplitude of right and left ear of NOISE group at different frequencies (p>0.05).CONCLUSION: Excessive NOISE can cause TTSs and NOISE-induced PTSs and decreased DPOAEs amplitudes. Therefore, DPOAEs can be attributed as a useful tool for study of NOISE-induced hearing loss.

In this paper, a novel LNA design based on improved NOISE cancellation technique in the frequency range of 27 to 31 GHz.is presented The proposed LNA is suitable for millimeter wave 5G wireless communication. The first stage of this two-stage LNA is designed with NOISE cancelation approach to decrease the NOISE figure of the system. In order to improve the design method, we utilizes a negative feedback by implementing a couple inductor with a transformer connection. The negative feedback provides an acceptable input matching and control the gain to increase the band width. The cascode structure is used in the second stage for its higher gain and stability and better reverse isolation at millimeter wave frequency. Furthermore, an inductor is utilized to boost the gain with neutralizing the capacitance of node between two transistors in a cascode structure. The CMOS silicon on insulator (SOI) is utilized to provide a high level of integration and low power consumption with the minimum cost. The proposed LNA is designed with 130 nm CMOS technology and has 22.14 dB gain with 1.86 dB NOISE figure at 29 GHz. The 3-dB bandwidth of the designed LNA is 4 GHz (14%) and its DC power consumption is 33.4 mW. The IIP3 is -16dBm and input reflection coefficient is better than -10dBm in the frequency range of interest. The proposed LNA is simulated by ADS software.

Inertial Navigation System (INS) is one of the navigation systems widely used in various land-based, aerial, and marine applications. Among all types of INS, Microelectromechanical System (MEMS)-based INS can be widely utilized, owing to their low cost, lightweight, and small size. However, due to the manufacturing technology, MEMS-based INS suffers from deterministic and stochastic errors, which increase positioning errors over time. In this paper, a new effective NOISE reduction method is proposed that can provide more accurate outputs of MEMS-based inertial sensors. The intelligent method in this paper is a combined denoising method that combines Wavelet Transform (WT), Permutation Entropy (PE), Support Vector Regression (SVR), and Genetic Algorithm (GA). Firstly, WT is employed to obtain a time-frequency representation of raw data. Secondly, a four-element feature vector is formed. These four features are (1) amplitude of frequency, (2) its ratio to mean of amplitudes of all frequencies, (3) location of frequency in time-frequency representation, and (4) judgment on behaviors of frequency that is obtained by utilizing PE. Thirdly, based on the feature vector, the GA-SVR algorithm predicts amplitudes of all frequencies in the time-frequency representation of the deNOISEd signal. Finally, by employing inverse WT the deNOISEd signal is obtained. In this work, the outputs of the Inertial Measurement Unit (IMU) in ADIS16407 sensor, as a low-cost and MEMS-based INS, have been utilized for data collection. The proposed method has been compared with other NOISE reduction methods and the achieved results verify superior improvement than other methods.

Many important speech enhancement methods operate in frequency domain. In these methods, a frequency gain filter is multiplied by the noisy spectrum. In this paper, frequency methods are investigated and the gain filters are shown as functions of the Signal to NOISE Ratio (SNR). Since gain filters are functions of SNR, SNR estimation methods are presented and consequently a new SNR estimation method is proposed. Moreover, we proposed a technique for controlling the level of residual NOISE and shaping it. In our proposed techniques, the frequency gain filters are tuned in order to have less NOISE reduction and as a result achieve less distortion. In addition to controlling the level of NOISE, in our proposed technique, the shape of residual NOISE is changed in order to have more pleasant residual NOISE. For evaluation of methods, listening tests are performed and the results are reported based of four aspects of speech signals: musical residual NOISE, level of background NOISE, echo and unnatural residual NOISE. Evaluation of methods shows that the proposed methods are successful from these aspects point of view.

Background and Aims: Despite the recent advances in digital processing of hearing aids, a large number of users are not happy with their hearing aids. One of the major reasons for this is the lack of good recognition of speech in noisy environments. Digital NOISE reduction and directionality are some of the technologies that are helpful in this issue. The present study was conducted to evaluate the effects of these two technologies on listening comfort and speech recognition of individuals with moderate sensory-neural hearing loss. Materials and Methods: In the current study, we applied Acceptable NOISE Level (ANL) and Farsi Auditory Recognition of Digit in NOISE (FARDIN), as measures of listening comfort and speech intelligibility, respectively, on 18 participants (8 male and 10 female) who had moderate sensory neural hearing loss. We evaluated both these measures under six different hearing aid conditions: 1) Omnidirectional-DNR/off (baseline), 2) Omnidirectional-Broadband DNR, 3) Omnidirectional-Multichannel DNR, 4) Directional, 5) Directional-Broadband DNA, and 6) Directional-Multicellular DNR. Results: Both the digital NOISE reduction technology and the directionality improved the ANL, but the effect of directionality was more than the other. None of the digital NOISE reduction or directionality could improve the score in FARDIN test, but it did not make the results even worse. Conclusion: According to the results, since these two technologies improve listening comfort and do not affect speech comprehension, it is recommended that these two options be activated for adjusting the hearing aid in clinics.

With regards to wireless receiver systems, the effects of NOISE from all the following phases can be reduced using the gain of the low-NOISE amplifier (LNA). Therefore, boosting the specified signal power without adding a lot of NOISE and distortion will be necessary for the signal to be retrievable in the later phases or stages of the system. The proposed method in this study for NOISE reduction is based on the combination of two techniques: reversed-phase NOISE signal and non-reversed phase signal. The theoretical model for NOISE cancellation is presented along with the equations for the overall NOISE value, which are derived based on a two-port model. The circuit design is implemented using the 𝑇 𝑆 𝑀 𝐶 0. 18 𝜇 𝑚 𝐶 𝑀 𝑂 𝑆 𝑅 𝐹 technology on a Cadence Spectre RF tool. The current study also implemented a CMOS UWB LNA configuration with inter-stage matching as well as shunt-series inductive peaking. This design uses inductive source degeneration cascode technology along with an inter-stage matching network. Moreover, to boost impedance matching and power gain, a Chebyshev band pass filter is placed at the input while a shunt-series inductive peaking is placed at the output.

This paper examines the effects of operating point and device size on the high frequency NOISE parameters in CMOS technology, to eliminate high power dissipation challenge in simultaneous NOISE and input matching (SNIM) technique. Modified technique is applied to improve power dissipation problem, NOISE performance, gain and input/output matching of the LNA at center frequency of 5.2 GHz. The LNA is implemented in TSMC 0.18-µm CMOS process. Post-layout simulation results demonstrate LNA has reached to power consumption of 2.1 mW under 1.4 V supply while having, 2.71 dB NOISE figure, 1GHz Band-width, 16.38 dB power gain, -40.42 dB reverse isolation factor, -21.5 dB and -23.59 dB input/output return loss respectively.