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Hearing aids are commonly fit with ear canals partially or fully open-a condition that increases the risk of acoustic feedback. Feedback limits the audiometric fitting range of devices by limiting usable gain. To guide clinical decision making and device selection, we developed the Peak Height Insertion Gain (PHIG) method to detect feedback spikes in the short-term insertion gain derived from audio recordings. Using a manikin, 145 audio recordings of a speech signal were obtained from seven hearing aids. Each hearing aid was programmed for a moderate high-frequency hearing loss with systematic variations in frequency response, gain, and feedback suppression; this created audio recordings that varied the presence and strength of feedback. Using subjective ratings from 13 expert judges, the presence of feedback was determined and then classified according to its temporal and tonal qualities. These classifications were used to optimize parameters for two versions of the PHIG method based on global and local analyses. When specificity was fixed at 0.95, the sensitivity of the global analysis was 0.86 and increased to 0.95 when combined with the local analysis. Without compromising performance, a clinically expedient version of the PHIG method can be obtained using only a single measurement.

Purpose: To calculate the real-ear insertion gain (REIG) according to the types of hearing aids, we evaluated the preferred REIGs of Korean hearing-impaired listeners and psychoacoustic differences between open-canal fitting (OF) and closed-canal fitting (CF).Methods: The subjects with sensorineural hearing loss were divided into OF group (4 monaural fittings, 15 binaural fittings with 34 ears), and CF group (8 monaural fittings, 13 binaural fittings with 34 ears). There were no statistical differences in hearing threshold level (HTL) at each octave frequencies, word recognition score (WRS) and Korean Adaptation of the International Outcome Inventory for Hearing Aids (K-IOI-HA) between the two groups. When there was no need for further electroacoustic adjustment of the hearing aid, sharpness and occlusion of amplified sound, clarity of sentence, and loudness of noise were evaluated based on the everyday experience. And REIGs with international speech test signal and WRS in sound-treated room were measured.Results: Preferred REIG for HTL was low for OF compared to CF in 0.5 kHz and 0.75 kHz at input SPL of 55 dB, 0.5 kHz at 60 dB SPL, 0.25 kHz and 0.5 kHz at 80 dB SPL. However, there were no differences in aided WRS and psychoacoustics between the two groups.Conclusion: In this study, the preferred REIG of OF and CF groups showed a difference under 0.75 kHz although there were no psychoacoustic differences between the two groups. Therefore, the results of this study should be considered when formulating Korean-type hearing aid fitting formula.

Background Hearing aid fitting guidelines recommend real ear measures (REM) to verify hearing aid performance. Unfortunately, approximately 70 to 80% of clinicians do not use REM, but instead download manufacturer first-fit. Studies report differences in performance between first-fit and programmed-fit with greatest differences in the higher frequencies. Recently, hearing aid and real ear analyzer (REA) manufacturers allow REA communication with hearing aid software feature to automatically program hearing aids to target. Little research is available reporting the accuracy of this feature. Purpose The aim of the study is to examine whether differences exist at 50, 65, and 80 dB SPL between two ReSound first-fit formulae (Audiogram+ and NAL-NL2) using ReSound AutoREM and Aurical NAL-NL2 Research Design The study design is of repeated measure type. Study Sample The study sample includes 48 ears. Data Collection and Analysis For the two fitting formulae, AutoREM real ear insertion gain (REIG) was measured at 50, 65, and 80 dB SPL and compared with measures from Aurical NAL-NL2. Results Mean AutoREM REIG for ReSound NAL-NL2 was 3 to 8 dB below Aurical NAL-NL2 for 50 dB SPL, within 1 to 3 dB for 65 dB SPL and 1 to 5 dB above for 80 dB SPL. Mean AutoREM REIG for Audiogram + was 1 to 12 dB below Aurical NAL-NL2 for 50 dB SPL, within 2 to 5 dB for 65 dB SPL and 1 to 7 dB above NAL-NL2 for 80 dB SPL. Conclusion Relative to the Aurical NAL-NL2, AutoREM REIG50 for Audiogram + and ReSound NAL-NL2 was lower. Relative to the Aurical NAL-NL2, AutoREM REIG65 for Audiogram + was higher at 1,000 Hz and lower at 4,000 to 6,000 Hz and for ReSound NAL-NL2 it was lower at 500 Hz and 4,000 Hz and higher at 3,000 Hz. Relative to the Aurical NAL-NL2, AutoREM REIG80 for Audiogram + was higher at 500 to 3,000 Hz and 6,000 Hz and ReSound NAL-NL2 was higher at 500 to 6,000 Hz. Because of wide intersubject variability clinicians should continue to use REM as a “check and balance” when using AutoREM.

Understanding the fundamental dynamics of piled foundations is important for practitioners, as ground-borne vibration can result in adverse disturbances, particularly in urban areas. Through the development of computationally efficient models, this dissertation examines the vibration of piles due to (1) inertial excitation at the pile heads and (2) incident waves from underground railways. The latter excitation mechanism also considers the building superstructure above the foundation. The numerical models account for the dynamic motion in three-dimensional space and are formulated in the frequency domain. A new iterative model is developed using the boundary-element method (BEM) to study the effects due to wave scattering in inertially excited pile-groups. When different inertial loads are applied, the converged solutions of the iterative BEM model strongly agree with the interaction factors predicted using a conventional BEM model. A comprehensive parametric study on the inertial response of piles provides new insight into the wave-scattering effect and how various material and geometric parameters influence it, particularly at high excitation frequencies. The iterative approach is then used to combine the BEM model of a piled foundation and the semi-analytical model of an underground railway tunnel. The result is an efficient coupled tunnel-foundation model, which fully accounts for the source-receiver interaction that has been neglected in existing models. It is discovered that this interaction is most significant when the separation distance between the tunnel and foundation is less than the shear wavelengths in the soil. For the first time, two counteracting mechanisms that govern the added-foundation effect, which is the modification of the ground (greenfield) response when a foundation is constructed near an underground railway, are also highlighted in a thorough parametric study. It is demonstrated that a simple dashpot model is representative of the essential dynamics of a modern tall building, with respect to its base impedance, over the frequencies associated with the perception of vibration. When the simplified building model is combined with the coupled tunnel-foundation model, the differences between the train-induced vibration of a building that is supported on deep piles and shallow footings are likely to be imperceptible by the occupants. Furthermore, the mean vibrational energy entering through the foundations of a tall building is found to be dominated by the added-foundation effect. The effectiveness of full and partial base isolation to mitigate the vibration disturbances in a building is also explored using power-flow techniques. Finally, a virtual case study concerning the construction of a building next to a pre-existing underground railway tunnel shows how the developed models can be used in practice to evaluate the performance of different designs. The conclusions are expected to establish new guidelines for designing foundations and buildings near underground railways.

We have proposed a vector-sum phase shifter (VSPS) with a low phase shift error using a tunable active $g_{m}{\text {-}}{C}$ polyphase filter (PPF). The proposed VSPS realizes high insertion gain and a low phase shift error because the tunable active ${g}_{m}{\text {-}}{C}$ PPF exhibits insertion gain and low I/Q imbalance by easily controlling the transconductance of transistors. This study provides a general formula and design method based on the design equations of the tunable active ${g}_{m}{\text {-}}{C}$ PPF for VSPS. The analysis shows the limitation of the tunable frequency range of I/Q balance and the condition of the maximum insertion gain. The results also clarify that the relative bandwidth of the tunable active ${g}_{m}{\text {-}}{C}$ PPF is equivalent to that of the single-stage or multistage RC -PPF. The ${S}$ -band VSPS with the two-stage active ${g}_{m}{\text {-}}{C}$ PPF fabricated by the design method demonstrates improvement in phase shift errors lower than 0.52° rms in the 500-MHz bandwidth and high insertion gain of 13.4 dB with a frequency range of 2.2–3.2 GHz.

Purpose: This study aimed to compare the preferred real-ear insertion gain for Korean (PREIG-K) wearing multi-channel hearing aid with the National Acoustics Laboratories-Non-Linear version 2 (NAL-NL2; National Acoustic Laboratories) gains in order to develop Korean hearing aid fitting formula.Methods: A total of thirty one (62 ears) Korean hearing aid users were included in this study. All subjects wore in-the-canal or custom hearing aids in both ears. Individual hearing aid fitting procedures involved to adjust the gains for 50, 65, and 80 dB sound pressure level of speech across low, high, and wideband frequency bands based on participant’s subjective responses. In addition, only the high frequency bands of 1 kHz or more of the PREIG-K were re-adjusted to be the same as NAL-NL2 gain and then the word recognition scores (WRSs) were compared before and after the adjusting gain. Results: The results showed that the PREIG-K increased up to 1.5 kHz with the maximum amount, then the PREIG-K decreased across the frequencies. For all half octave frequencies, the PREIG-Ks were substantially less than the NAL-NL2. When the PREIG-K of high frequencies were re-adjusted same as the NAL-NL2 gains, the WRSs of the PREIG-K were not significantly different before and after gain adjustment. The slopes up to 1.5 kHz frequencies of the PREIG-K were steeper than the slopes of NAL-NL2 gain, however similar to the slope of manufactures’ fitting formulae.Conclusion: The development of an effective hearing aid fitting formula for improving the communication abilities of hearing-impaired Korean will require further experiments considering the language, physical characteristics, and word recognition used by Koreans.

Purpose The initial-fit provided by the hearing aid manufacturer’s software is generally a display of measurement done in the ear simulators. The need for verification of hearing aid output and gain in the real ear using probe-microphone measurement to match the prescriptive target is highlighted. The objective of the study was to evaluate the difference in real-ear aided response (REAR), real-ear insertion gain (REIG), aided thresholds, articulation index (AI) and word recognition score (WRS) in quiet, with hearing aid programmed to NAL-NL1 first-fit and NAL-NL1 optimized-fit using the probe-microphone technique. Methods In a repeated measure experimental design, 11 participants with a mean age of 41.09 (SD=±9.95) years having moderate and moderately-severe sensorineural hearing loss were tested monaurally in two aided conditions, with a 16-channel hearing aid programmed for manufacturer’s NAL-NL1 first-fit and optimized-fit to NAL-NL1 using probe-microphone verification. The REAR, REIG, aided threshold, articulation index and word recognition scores in quiet were obtained for both aided conditions. Results The REAR, REIG, aided threshold, AI and WRS in quiet were significantly better with the NAL-NL1 optimized-fit compared to manufacturer’s NAL-NL1 first-fit. Conclusion The optimized-fit yields better audibility and improved word recognition in quiet. This supports best practice guidelines of many professional organizations regarding the use of probe-microphone measurement as the “Gold standard” for verification of hearing aid fitting, thereby providing better satisfaction and quality of life to hearing aid users.

This paper analytically investigates the dynamic interaction of two neighboring tunnels in the saturated soil. The twin tunnels are simulated using the Flugge shell theory, and the surrounding soil is modelled by the Biot’s theory. The solution for cylindrical waves in saturated porous media is derived by applying the potential decomposition. The addition theorem is subsequently introduced to translate cylindrical waves, thereby satisfying the boundary conditions at the interfaces between the twin tunnels and saturated soil. Numerical examples are presented to analyze soil vibrations under different loading conditions calculated by different tunnel models. The neighboring tunnels have strong dynamic interaction, resulting in the insertion gain up to ± 20 dB. It is recommended to account for the interaction between neighboring tunnels when calculating the vibrations from underground railways.

The objective of this paper is to introduce a methodology to design an active differential mode (DM) filter at the input side of ac/dc converters to cancel DM electromagnetic interference noise within concerned frequency range. The boost power factor correction ac/dc converter was taken as an example for DM active filter design. The active filter is analyzed based on the developed DM noise model. The design of DM active filter to achieve desired insertion gain and stability is addressed in detail. Both simulations and experiments were conducted to validate the proposed methodology. It is found that the proposed design methodology can meet the design objective and the stability challenge for the DM active filter of ac/dc converters.

Smaller size and lower loss are always the target of EMI filter which suppresses EMI emitted by power electronics converter. Digital EMI filter (DEF) is the best solution to suppress the conducted EMI in size and loss, especially for high-power converters. However, for current DEF model, it is not enough to describe the filtering ability. The model which can describe DEF stability is absent. To cope with these, this paper proposes a modeling technique about filter and stable behavior of DEF system. In proposed technique, the insertion gain model can accurately describe the filtering behavior, and the loop gain model can predict the stability of DEF system. Experimental testbed based on a Boost converter as EMI interference is built. Experimental results validate that the proposed model can successfully predict the stability and performance of DEF system.

Ground-borne vibration in buildings is a growing problem in crowded cities due to the pressure to build ever closer to underground railway tunnels. Despite advances in numerical models for the prediction of ground-borne vibration, it is yet unclear how effective deep piled foundations are at mitigating the vibration transmitted into a building compared to shallow foundations, such as footings. The power-flow insertion gain is used as a measure of the building's overall vibration performance when piles, rather than footings, are included in the foundation. The tunnel-foundation system is based on the pipe-in-pipe model of a longitudinally invariant tunnel coupled to a boundary-element model of the foundation using an iterative wave-scattering approach. The initial theoretical study presented in this paper shows that piles generally attenuate the vibration levels in a benchmark building compared to footings. It is also shown how a simplified model for a tall building, based on a series of individual dashpots, can account for the modification of the foundation vibration field when the building is constructed.

This paper presents an analysis of a 8-12 GHz active 0.25 μm GaAs pHEMT MMIC circulator intended for integration into a phased array. The architecture is based on a closed-loop connection of three asymmetric -5.6-dB Lange couplers and resistive-feedback gain-matched amplifiers. The nominal simulated performance shows an isolation of 20 dB over a 40% bandwidth, with a return loss of better than 10 dB and an insertion gain of 2.4 dB across the band. The degradation in circuit performance is analyzed as a function of variations in port impedance. A loop-gain analysis demonstrates the circuit stability for port impedances in the VSWR = 2 circle, simulating coupling in a phased array. We show in simulation and measurements that the bandwidth, match on all ports and insertion gain are not sensitive and agree with simulations. However, the isolation degrades from 20 dB when the port impedances change within a VSWR=1.1 circle. Additionally, we show that the deviation of the coupler design from the nominal case affects the isolation. The statistical analysis gives insight into design criteria of this type of circulator for insertion into phased array.

This paper describes the design methodology and the On-Wafer (OW) measurement results of two broadband two stages MMIC High Power Amplifiers (HPAs) operating in the 8-12 GHz bandwidth. A Balanced HPA (BA-HPA) and a Single-Ended HPA (SE-HPA) are considered, they are fabricated on 150 nm HEMT Gallium Nitride on Silicon Carbide technology (AlGaN/GaN on SiC) called GH15 from UMS. The main aim of this realization was the achievement of a high Output Power associated with a very high Power Added Efficiency. To obtain a good compromise between output power and power added efficiency, a multi harmonic tuning approach of load and source impedances has been applied. In addition, particular attention was given to the way of drawing the matching network layouts to minimize the coupling effect between different elements.The On-Wafer measured power results under pulsed wave signal of the BA-HPA demonstrate a maximum output power (P OUT ) higher than 15 W (42 dBm) with 52% Power Added Efficiency (PAE) and 22 dB of insertion gain (G I ) in the 8-12 GHz bandwidth. Moreover, in the same previous bandwidth, the SE-HPA reaches a maximum P OUT equal to 43 dBm associated with54% PAE and 23 dB G I .To our knowledge, these results are one of the best in terms of PAE performances and frequency bandwidth trade-offs.

EMI filters are traditionally designed to attenuate the low-frequency harmonics as the filter exhibits an insertion gain of -20 dB/decade per added filter component which inherently attenuates the high-frequency noise. However, the self-parasitics of EMI filter components and mutual couplings between the components and traces decrease the attenuation capability of the filter at higher frequencies. This paper model the filter components and traces in ANSYS high-frequency structure simulator (HFSS) tool and attempts to relate the couplings to the filter and trace placements. A single-stage differential mode (DM) filter has been analyzed and optimum component placement has been identified. It has been shown that on average 17 dB higher insertion gain can be achieved with layout optimization in comparison to commonly used component placement.

Mitigation measures against railway vibration in buildings can include elastomeric mounts or springs inserted between building foundation and building upper structure. The method for predicting the performance is usually simplistic and based on the dynamic transmissibility of a single degree of freedom mass-spring oscillator on a rigid base. One method is to express the isolation performance as an insertion gain based on the building floor velocities. It is named the Building Insertion Gain Indicator (BIGI). Another method, called the Power Flow Insertion Gain (PFIG), has also been proposed in [1]. Then, the isolator performance is expressed as the difference of injected power to the building upper structure. In practice, both indicators need two identical buildings (with and without isolator) to be obtained automatically. A method to indirectly obtain the PFIG, using only an isolated building, has been developed and numerically validated for a 2D case in [2, 4]. It is based on the isolator transmissibility (ratio of velocities on both sides of the isolator) that is corrected with foundation and upper structure mobilities. In this paper, the theory is extended to a construction near railway tracks after being validated through comparisons between experiments and simulations. In this case, the isolator transmissibility and foundation mobility are measured. As the upper-structure mobility cannot be measured, it is obtained with a 2.5D simulation. Finally, it is compared to the other methods of evaluating isolator performance.

In the procurement of track support systems for railways planned in the vicinity of receptors sensitive to groundborne noise and vibration it can be necessary to specify parameters of components of the system in order to ensure that its in-service performance will deliver the required level of mitigation against the effects of groundborne noise and vibration. In previous comparable schemes in the UK it has been the practice to specify the performance of the track system in terms of Insertion Gain (IG) defined as the difference between the vibration spectrum at a reception point with the mitigating track in place, and with a hypothetically “very stiff” track support system. It is necessary to have a means of verifying that a proposed system is likely to satisfy the requirements and it is desirable to simplify the method of evaluation of predicted track performance based on the stated parameters. A simplified algorithm for rapidly calculating the insertion gain of a two-stage (or single-stage) resilient track support system has been developed using the finite-difference method. This provides a tool for evaluating the predicted performance of a variety of proposed track support systems in order to compare it against the required specification.

Objective. Speech perception in cocktail party scenarios has been the concern of a group of researchers who are involved with the design of hearing-aid devices.Approach. In this paper, a new unified ear-EEG-based binaural speech enhancement system is introduced for hearing-impaired (HI) listeners. The proposed model, which is based on auditory attention detection (AAD) and individual hearing threshold (HT) characteristics, has four main processing stages. In the binaural processing stage, a system based on the deep neural network is trained to estimate auditory ratio masks for each of the speakers in the mixture signal. In the EEG processing stage, AAD is employed to select one ratio mask corresponding to the attended speech. Here, the same EEG data is also used to predict the HTs of listeners who participated in the EEG recordings. The third stage, called insertion gain computation, concerns the calculation of a special amplification gain based on individual HTs. Finally, in the selection-resynthesis-amplification stage, the attended speech signals of the target are resynthesized based on the selected auditory mask and then are amplified using the computed insertion gain.Main results. The detection of the attended speech and the HTs are achieved by classifiers that are trained with features extracted from the scalp EEG or the ear EEG signals. The results of evaluating AAD and HT detection show high detection accuracies. The systematic evaluations of the proposed system yield substantial intelligibility and quality improvements for the HI and normal-hearingaudiograms.Significance. The AAD method determines the direction of attention from single-trial EEG signals without access to audio signals of the speakers. The amplification procedure could be adjusted for each subject based on the individual HTs. The present model has the potential to be considered as an important processing tool to personalize the neuro-steered hearing aids.

Objective We used real-ear insertion gain (REIG), with the international speech test signal (ISTS), to evaluate the amplifying characteristics of hearing aids, set for patients who have been wearing such aids for a long time in a stable manner. We further compared this to the target values of the DSLv5 and NAL-NL2 methods. Methods The subjects were adults with moderate sensorineural hearing loss. We examined 40 ears in 25 individuals (15 people wearing hearing aids in both ears and ten people wearing aid in only one ear). Fit assessments were performed based on the speech performance-intensity functions and tolerance of environmental noise, and the ears studied were categorized as either ears with sufficient benefit or ears with insufficient benefit. Additionally, we evaluated the REIG for international speech test signals at 65-dB and 80-dB sound pressure level (SPL). We compared the REIG and target values for voice input at 65-dB and 80-dB SPL, calculated from the DSLv5 and NAL-NL2 methods. Results Among the 40 ears, 34 received sufficient benefit and six received an insufficient benefit from hearing aids. The REIG for ISTS at 65-dB in the sufficient benefit ears, at frequencies of 1,000 Hz and 2,000 Hz, were similar to the target values of NAL-NL2 and DSLv5 but were significantly lower at 250 Hz, 500 Hz, and 4,000 Hz frequencies. The compression ratio of REIG for sufficient benefit ears was similar to that of DSLv5. The REIG for ISTS at 65-dB in the insufficient benefit ears was smaller than that in the sufficient benefit ears at frequencies of 2,000 Hz and 4,000 Hz. Conclusion This study suggested that the target values of NAL-NL2 and DSLv5 are appropriate, even for Japanese-speaking individuals, at mid-pitch sounds. Although it is necessary to investigate the necessity for low-pitch and high-pitch gains further in the future, this study provides meaningful data regarding the amplifying characteristics in Japanese-speaking individuals who have been wearing hearing aids in a stable manner.

While there have been many years of research on the acoustoelectric effect, there has not been a successful approach or demonstration to provide a manufacturable, continuous wave (CW) acoustoelectric amplifier (AEA) with insertion gain. This letter will present the results of a 169.5-MHz surface acoustic wave (SAW) delay line on 128YX lithium niobate with an embedded monolithic coupled AEA (CAEA) demonstrating a terminal gain of 1.2 dB. The impedance-matched delay line without the CAEA has an insertion loss of 4.6 dB, and with the operational CAEA, the measured gain is 1.2 dB, yielding a net insertion gain of 5.8 dB. The CAEA uses approximately 137 mW dc power at the current peak operational gain. This letter will present experimental results of device performance and discuss the new embodiment for achieving the net insertion gain.

The American Speech-Language-Hearing Association (ASHA) and American Academy of Audiology (AAA) have created Best Practice Guidelines for fitting hearing aids to adult patients. These guidelines recommend using real-ear measures (REM) to verify that measured output/gain of hearing aid(s) match a validated prescriptive target. Unfortunately, approximately 70–80% of audiologists do not routinely use REM when fitting hearing aids, instead relying on a manufacturer default “first-fit” setting. This is problematic because numerous studies report significant differences in REM between manufacturer first-fit and the same hearing aids using a REM or programmed-fit. These studies reported decreased prescribed gain/output in the higher frequencies for the first-fit compared with the programmed fit, which are important for recognizing speech. Currently, there is little research in peer-reviewed journals reporting if differences between hearing aids fitted using a manufacturer first-fit versus a programmed-fit result in significant differences in speech recognition in quiet, noise, and subjective outcomes.To examine if significant differences were present in monosyllabic word and phoneme recognition (consonant-nucleus-consonant; CNC) in quiet, sentence recognition in noise (Hearing in Noise Test; HINT), and subjective outcomes using the Abbreviated Profile of Hearing Aid Benefit (APHAB) and the Speech, Spatial and Qualities of Hearing (SSQ) questionnaires between hearing aids fit using one manufacturer’s first-fit and the same hearing aids with a programmed-fit using REM to National Acoustic Laboratories Nonlinear Version 2 (NAL-NL2) prescriptive target.A double-blind randomized crossover design was used. Throughout the study, one investigator performed all REM whereas a second investigator measured speech recognition in quiet, noise, and scored subjective outcome measures.Twenty-four adults with bilateral normal sloping to moderately severe sensorineural hearing loss with no prior experience with amplification.The hearing aids were fit using the proprietary manufacturer default first-fit and a programmed-fit to NAL-NL2 using real-ear insertion gain measures. The order of the two fittings was randomly assigned and counterbalanced. Participants acclimatized to each setting for four weeks and returned for assessment of performance via the revised CNC word lists, HINT, APHAB, and SSQ for the respective fitting.(1) A significant median advantage of 15% (p < 0.001; 95% CI: 9.7–24.3%) for words and 7.7% (p < 0.001; 95% CI: 5.9–10.9%) for phonemes for the programmed-fit compared with first-fit at 50 dB sound pressure level (SPL) and 4% (p < 0.01; 95% CI: 1.7–6.3%) for words at 65 dB SPL; (2) No significant differences for the HINT reception threshold for sentences (RTS); (3) A significant median advantage of 4.2% [p < 0.04; 95% confidence interval (CI): −0.6–13.2%] for the programmed-fit compared with the first-fit for the background noise subscale problem score for the APHAB; (4) No significant differences on the SSQ.Improved word and phoneme recognition for soft and words for average speech in quiet were reported for the programmed-fit. Seventy-nine percent of the participants preferred the programmed-fitting versus first-fit. Hearing aids, therefore, should be verified and programmed using REM to a prescriptive target versus no verification using a first-fit.

Objectives/Hypothesis The purpose of this study was to measure the degree of coupling between the floating mass transducer (FMT) and the round window membrane (RWM) in patients with conductive and mixed hearing loss implanted with the Vibrant Soundbridge (VSB) device. The efficiency of direct and indirect coupling of the FMT to the RWM was compared by measuring differences between the initial prescription targets and the final settings of the VSB audio processor after fine-tuning. Study Design Retrospective study. Methods Investigation of a group of subjects with either conductive or mixed hearing loss implanted with the VSB, a device that uses a FMT coupled to the RWM. There were two subgroups: subjects in which coupling was direct (no interposed material) or indirect (interposed material). The functional gain, insertion gain, and compression characteristics of the device were measured to assess the efficiency of coupling and to investigate the proximity of the fitting to prescriptive targets. Results Coupling for the subgroup with indirect coupling of the RWM was higher (better) than for the subgroup with direct coupling. The gain deviation from prescriptive targets was smaller for the subgroup with indirect coupling. Conclusions The coupling method can have an effect on the coupling efficiency and the final electroacoustic settings of the device. The prescription targets were not accurate for the majority of subjects from either subgroup. Indirect coupling appears to provide more effective stimulation of the cochlea. Level of Evidence 4. Laryngoscope, 127:2843–2849, 2017

Unilateral auditory deprivation or stimulation can induce changes in loudness and modify the sound level required to elicit the acoustic reflex. This has been explained in terms of a change in neural response, or gain, for a given sound level. However, it is unclear if these changes are driven by the asymmetry in auditory input or if they will also occur following bilateral changes in auditory input. The present study used a cross-over trial of unilateral and bilateral amplification to investigate changes in the acoustic reflex thresholds (ARTs) and the auditory brainstem response (ABR) in normal hearing listeners. Each treatment lasted 7 days and there was a 7-day washout period between the treatments. There was no significant change in the ART or ABR with either treatment. This null finding may have occurred because the amplification was insufficient to induce experience-related changes to the ABR and ART. Based on the null findings from the present study, and evidence of a change in ART in previous unilateral hearing aid use in normal hearing listeners, the threshold to trigger adaptive changes appears to be around 5 days of amplification with real ear insertion gain greater than 13-17 dB.

This paper presents the implementation of a broadband quasi-circulator through a cascading distributed balun using a 90-nm CMOS process. The isolation, $\vert \text{S}31\vert $ , of the proposed three-port quasi-circulator can be acquired through the phase cancelation technique, by connecting an additional distributed amplifier in parallel between ports 1 and 3. The thorough analysis based on an eight-port chain matrix and scattering matrix is presented for refining the circuit parameters in the initial design. Measured results show that the proposed quasi-circulator attains a broad operation bandwidth ranging from 10 to 67 GHz. Moreover, the quasi-circulator also has good insertion gain of 0.5 to 4.8 dB, as well as isolation $\vert \text{S}31\vert $ , which is better than 23 dB. Consequently, the proposed quasi-circulator delivers wide bandwidth performance, good port-to-port isolations, good insertion gain, and high linearity based on the cascading distributed balun with phase cancelation technique.

Supplemental Digital Content is available in the text., Objectives: The objective of this study was to test the ability to achieve, maintain, and subjectively benefit from extended high-frequency amplification in a real-world use scenario, with a device that restores audibility for frequencies up to 10 kHz. Design: A total of 78 participants (149 ears) with mild to moderately-severe sensorineural hearing loss completed one of two studies conducted across eight clinical sites. Participants were fitted with a light-driven contact hearing aid (the Earlens system) that directly drives the tympanic membrane, allowing extended high-frequency output and amplification with minimal acoustic feedback. Cambridge Method for Loudness Equalization 2 - High Frequency (CAM2)-prescribed gains for experienced users were used for initial fitting, and adjustments were made when required according to participant preferences for loudness and comfort or when measures of functional gain (FG) indicated that more or less gain was needed. Participants wore the devices for an extended period. Prescribed versus adjusted output and gain, frequency-specific FG, and self-perceived benefit assessed with the Abbreviated Profile of Hearing Aid Benefit, and a custom questionnaire were documented. Self-perceived benefit results were compared with those for unaided listening and to ratings with participants’ own acoustic hearing aids. Results: The prescribed low-level insertion gain from 6 to 10 kHz averaged 53 dB across all ears, with a range from 26 to 86 dB. After adjustment, the gain from 6 to 10 kHz decreased to an average of 45 dB with a range from 16 to 86 dB. Measured FG averaged 39 dB from 6 to 10 kHz with a range from 11 to 62 dB. Abbreviated Profile of Hearing Aid Benefit results revealed a significant improvement in communication relative to unaided listening, averaging 28 to 32 percentage points for the background noise, reverberation, and ease of communication subscales. Relative to participants’ own hearing aids, the subscales ease of communication and aversiveness showed small but significant improvements for Earlens ranging from 6 to 7 percentage points. For the custom satisfaction questionnaire, most participants rated the Earlens system as better than their own hearing aids in most situations. Conclusions: Participants used and reported subjective benefit from the Earlens system. Most participants preferred slightly less gain at 6 to 10 kHz than prescribed for experienced users by CAM2, preferring similar gains to those prescribed for inexperienced users, but gains over the extended high frequencies were high relative to those that are currently available with acoustic hearing aids.

This paper presents the realization and characteristics of broadband plastic low cost packaged 5G High Power Frond-End (HPFE) operating in 24-31GHz bandwidth. This demonstrator includes a Transmit and Receive paths realized on mixed technologies: 150nm Gallium Nitride on Silicon Carbide (AlGaN/GaN on SiC) and 150nm Gallium Arsenide (GaAs). Continuous Wave (CW) measured power results of the Transmit path (Tx) demonstrates a maximum output power (P OUT, Tx ) higher than 2W (33.5dBm) with 24% power added efficiency (P AE), and 36dB of insertion gain (G I, Tx ) in the 24-31GHz bandwidth. The receiver path (Rx) presents an maximum output power (P OUT, Rx ) of 30mW (15.5dBm) and an average Noise Figure (NF) of 3.6dB with an associated Insertion Gain (G I, Rx ) of 20dB in the same bandwidth. The HPFE/Tx linearity has been investigated with several M-QAM modulation signals with 25/50 and 100MHz channel spacing and using Digital Pre-Distortion (DPD) leading to 48dBc Adjacent Channel Leakage Ratio (ACLR) and 40dB Mean Squared Error (MSE) for average output powers ranging from 17dBm to 25dBm. The linearity performances have been compared to the ones obtained with two other linear GaAs amplifiers (P A1 and P A2) dedicated to point to point telecommunications application: the HPFE presents similar linearity performances associated to a higher efficiency.

This paper presents the realization and characteristics of broadband plastic low cost packaged 5G High Power Frond-End (HPFE) operating in 24-31GHz bandwidth. This demonstrator includes a Transmit and Receive paths realized on mixed technologies: 150nm Gallium Nitride on Silicon Carbide (AlGaN/GaN on SiC) and 150nm Gallium Arsenide (GaAs).Continuous Wave (CW) measured power results of the Transmit path (Tx) demonstrates a maximum output power (P OUT,Tx ) higher than 2W (33.5dBm) with 25% drain efficiency (DE), 24% power added efficiency (PAE), and 36dB of insertion gain (G I,Tx ) in the 24-31GHz bandwidth. The receiver path (Rx) presents an maximum output power (P OUT,Rx ) of 30mW (15.5dBm) and an average Noise Figure (NF) of 3.6dB with an associated Insertion Gain (G I,Rx ) of 20dB in the same bandwidth.The HPFE/Tx linearity has been investigated with several M-QAM modulation signals with 25/50 and 100MHz channel spacing and using Digital Pre-Distortion (DPD) leading to 48dBc Adjacent Channel Leakage Ratio (ACLR) and 40dB Mean Squared Error (MSE) for average output powers ranging from 17dBm to 25dBm. The linearity performances have been compared to the ones obtained with two other linear GaAs amplifiers (PA1 and PA2) dedicated to point to point telecommunications application: the HPFE presents similar linearity performances associated to a higher efficiency.Thanks to the mixed technologies approach, an optimized trade-off in terms of integration, electrical performances and cost has been demonstrated.

The tranquil solution for the hearing impaired subjects to get rid of the impairment is to wear the appropriate hearing aid to increase the hearing level and clarity of the perceived speech. Though the present day hearing aids are inbuilt with a suitable noise removing algorithm to get a clear speech signal, the satisfaction among the users is low. The satisfaction of the hearing aid users will be enhanced only with the fixation of appropriate Real Ear Insertion Gain (REIG) values for different frequency bands of the perceived speech signal. Various prescriptive procedures were developed so far in prescribing these values. But, the strenuous task for the audiologists is in selecting the best procedure and to suggest required modifications. The present work focuses this problem faced by the audiologists by analyzing the various technical snags and arrived with suitable solutions. In the present work, an expert system was developed to predict gain values without the need of the prescriptive procedures and reduced the trial and error time of the audiologists. A gain suggestion database of the satisfied subjects was developed, and later it was used by the correlation algorithm in the gain prediction process. The successful gain suggestions of the most correlated subject for different frequencies in the database are recommended for the new subject. The developed expert system was validated by performing hearing aid trials with 256 hearing impaired subjects and 93.7% of them received satisfaction. The successful gain suggestions made by the expert system are stored continuously to strengthen the database, so as to recommend the most appropriate gain values for the new subject.

In this article, a compact W-band differential I---Q phase shifter is designed and implemented using 28-nm CMOS technology. The phase shifter is capable of achieving phase shifts ranging from 45° to 315° with a resolution of 90°. The design employs transmission-line baluns for creating a differential signal, Gilbert-cell-type active switches for generating 0° and 180° phase shifts and a 90° differential hybrid for obtaining differential I---Q signals. The hybrid is developed using capacitive-loaded slow-wave differential lines, thereby making it 75 % smaller than a conventional 90° hybrid. Furthermore, the modelling of a slow-wave differential line for odd-mode and even-mode propagation is explained. The phase shifter exhibits 12 dB of insertion loss, and the root-mean-square (RMS) gain and phase error are 0.55 dB and 16.6°, respectively, at 100 GHz. The total power consumption is 39 mW when using a 1-V supply. The chip size of the implemented design is 0.48 mm2 including the probing pads. The phase shifter design is further modified by replacing the baluns with single-stage differential buffer amplifiers to mitigate the signal loss. This modified version of the design shows +1 dB insertion gain with a total power consumption of 122.9 mW from a 1-V supply and realized at 0.565 mm2. A 13-dB gain improvement is obtained from the modified version and the measured RMS gain and phase error are 1.5 dB and 13°, respectively, at 100 GHz. After redesigning the layout, a minimum RMS phase error of 1.7° is expected in the simulations.

Purpose A model was developed to examine variables that influence signal-to-noise ratio (SNR) at the tympanic membrane (TM) when using a hearing aid (HA) and frequency modulated (FM) system. The model was used to explore how HA coupling influences SNR. Method To generate the model, HA output was measured in a coupler. Known coupler to real-ear transformations and known values for vent (gain) loss as a function of coupling were also used. The model was verified by measuring sound pressure level (SPL) at the TM in 6 ears. Results The model predicts similar overall SNRs at the TM regardless of coupling method when HA and FM microphones are active. The primary difference in SNR is in the low frequencies and depends on the amount of low frequency insertion gain and the noise levels at the HA and FM microphones. Conclusions A model was developed to explore how complex variables contribute to SNR at the TM. One variable, HA coupling, is predicted to have only a minimal effect on SNR at the TM when there is HA gain. Further studies will be needed to assess the real-world effectiveness of an FM system coupled to an open- versus closed-fit HA.

Measurements of ground vibration were taken in a rail tunnel and cross passage, before and after the installation of rail dampers. In addition to lower in-car noise, measurements indicated an immediate reduction in ground vibration, attributed to the rail dampers. While the most significant observed reduction in vibration was at frequencies above those of interest for ground-borne noise control (16–250 Hz), a reduction in average vibration of up to 9 dB was recorded at 150–200 Hz. This paper summarises the measurement results from two parallel rail tunnels. One of the tunnels includes results with and without rail dampers. Results from the opposite tunnel are used as a control data set. As a shuttle service was in operation at the time of the measurements, the same rolling stock was utilised for both tracks. The Pipe-in-Pipe (PiP) model has been used in an attempt to reproduce the measured change in vibration due to the addition of rail dampers. The initially selected model parameters reproduced the vibration reduction, but predicted it would occur at lower frequencies than indicated by the measurements, i.e. at 100–150 Hz. This simple model with the rail dampers represented as pure masses also suggested that vibration may increase above 160 Hz with the addition of rail dampers, but no increase was seen in the measurements at any frequency. Adjusting the model parameters improved the correlation of the modelled and measured insertion gains. Predictions were then made for the insertion gain on the surface immediately above the rail tunnel, to identify the potential for a change in ground-borne noise. A potential modest reduction in surface vibration in a small frequency range around 160 Hz has been predicted as a result of rail damper installation in a tunnel.

A 36–40 GHz full 360° ultra-low phase error passive phase shifter with a novel phase compensation technique is presented in this paper. The proposed phase shifter consists of a four-way quadrature power divider as a vector generator, vector selector and two digital controlled artificial dielectric (DiCAD) phase shifter cells to achieve 4-bit (22.5° phase resolution) and full 360° synthesizing. DiCAD phase shifter cells not only provide 22.5° and 45° phase shifts but can also compensate the phase error due to its tuning mechanism. The measured RMS phase and gain error are under 2.6° and 2.6 dB over 36–40 GHz, respectively. The average insertion gain is about −20.2 dB with no dc consumption. Implemented in 90-nm CMOS, the chip size is 0.75 × 0.4 mm2 without pads. To the authors' knowledge, this phase shifter demonstrates the lowest RMS phase error among other reported millimeter-wave phase shifters.

This paper presents a 2-input and 3-output 0.35–1.5GHz switch cell with active balun. The proposed differential switch cell is composed of 8 differential series-shunt-series switches which improve the transmit efficiency of switch cell. Two wideband active baluns are used to compensate for the loss of passive switch cell which almost consumes no DC power. Fabricated by 0.18μm SiGe BiCMOS technology, the switch cell shows highest insertion gain of 9 dB and more than 40 dB isolation in working frequency band.

This paper presents a 6-bit active phase shifter in 0.13-μm SiGe BiCMOS technology for Ku-band phased arrays based on a phase interpolation technique. An input Marchand balun and a RC poly phase filter are used for high I/Q accuracy wideband quadrature generation with high linearity and an integrated current-mode DAC is used for controlling the amplitude of I/Q path signal to achieve 6-bit phase resolution. The phase shifter operates in the 12–18 GHz range. The simulation results show an rms phase error less than 2.61°. The average insertion gain ranges from −11.16 dB to −20.39 dB with an rms gain error less than 0.4 dB for 64 phase states. The phase shifter achieves an input P1dB of 9.98 dBm at 16 GHz for 0°-phase state. The core area of the phase shifter is 1.1×0.9 mm2, with a total current consumption of 13.4 mA from a 3.3 V supply voltage.

In this paper, a novel balanced amplifier antenna has been proposed for X-band. The antenna module consists of a microstrip fed ground slot excited cylindrical dielectric resonator (CDR). The unbalanced antenna output is converted into balanced outputs by a 180 degree rat-race hybrid which feed a differential low noise amplifier (LNA) consisting of two cascade stages. A marchand balun type biasing arrangement is employed for the differential LNA to increase common mode rejection ratio (CMRR). The differential LNA provides peak differential gain of 30 dB, CMRR of 16.8 dB and 12.6% 3 dB FBW. The insertion gain of the hybrid fed LNA is about 21 dB, 3 dB FBW is 8.4% and overall noise figure of the system is about 4 dB. The CDRA has peak gain of 5.47 dBi. The proposed design is suitable for modern receiver front-end applications requiring balanced outputs.

International audience; This paper presents the design, the realization and the power characteristics of plastic low cost packaged symmetric Doherty Power Amplifiers (DPA) operating in the 5.5-6.5GHz bandwidth. A single input (SI-DPA) and a dual input (DI-DPA) DPAs are proposed based on two power bars composed of two GaN HEMT cells (8 fingers of 275μm unit gate width). Input and output matching networks are designed on passive GaAs MMIC technology. To our knowledge, it is the first published SI and DI-DPAs working in C band, designed using Quasi-MMIC technology and assembled in plastic package. The measured power results under Continuous Wave (CW) signal of the SI-DPA demonstrate a maximum output power (Pout) upper than 20W (43.5dBm) with 50% drain efficiency (dE), 42% power added efficiency (PAE), 11dB of insertion gain (GI) in the 5.5-6.5GHz bandwidth. At 6dB output power Back-off (oBo), the drain efficiency is greater than 35% (32% PAE). The DPA linearity has been investigated with a 256QAM modulation signal of 30MHz bandwidth and using Digital Pre-Distortion (DPD) leading to a 50dBc Adjacent Channel Leakage Ratio (ACLR) at a 34 dBm average output power. The designed DI-DPA is identical to the SI-DPA without input power splitter. It demonstrates that the adjustment of power ratio between the main and the peak amplifiers associated with adequate bias points, improves all the power performances: linearity, PAE, oBo and GI. The DI-DPA reaches a 12.5 dB GI, a maximum Pout equal to 44dBm (3.5dB gain compression) with 45% PAE. Moreover, in the same previous bandwidth, 40% PAE with 4° of AM/PM variation are obtained at 6dBoBo and 36% PAE (AM/PM=3°) at 8dBoBo.

Planar electromagnetic interference (EMI) filters are widely used to restrain the conducted EMI of switching power supplies. Such filters are characterized by small size, low parasitic parameters, and better high-frequency performance than the passive discrete EMI filter. However, EMI filter performance cannot be exactly predicted by using existing methods. Therefore, this paper proposes a method to use scattering parameters (S-parameters) for the measurement of EMI filter performance. A planar EMI filter sample is established. From this sample, the relationship between S-parameters and insertion gain (IG) of EMI filter is derived. To determine the IG under different impedances, the EMI filter is theoretically calculated and practically measured. The differential structure of the near-field coupling model is also deduced, and the IG is calculated under standard impedance conditions. The calculated results and actual measurements are compared to verify the feasibility of the theory.