Frequency Modulation System Research Articles

Fitting and verification of frequency modulation systems on children with normal hearing.

Several recent investigations support the use of frequency modulation (FM) systems in children with normal hearing and auditory processing or listening disorders such as those diagnosed with auditory processing disorders, autism spectrum disorders, attention-deficit hyperactivity disorder, Friedreich ataxia, and dyslexia. The American Academy of Audiology (AAA) published suggested procedures, but these guidelines do not cite research evidence to support the validity of the recommended procedures for fitting and verifying nonoccluding open-ear FM systems on children with normal hearing. Documenting the validity of these fitting procedures is critical to maximize the potential FM-system benefit in the above-mentioned populations of children with normal hearing and those with auditory-listening problems. The primary goal of this investigation was to determine the validity of the AAA real-ear approach to fitting FM systems on children with normal hearing. The secondary goal of this study was to examine speech-recognition performance in noise and loudness ratings without and with FM systems in children with normal hearing sensitivity. A two-group, cross-sectional design was used in the present study. Twenty-six typically functioning children, ages 5-12 yr, with normal hearing sensitivity participated in the study. Participants used a nonoccluding open-ear FM receiver during laboratory-based testing. Participants completed three laboratory tests: (1) real-ear measures, (2) speech recognition performance in noise, and (3) loudness ratings. Four real-ear measures were conducted to (1) verify that measured output met prescribed-gain targets across the 1000-4000 Hz frequency range for speech stimuli, (2) confirm that the FM-receiver volume did not exceed predicted uncomfortable loudness levels, and (3 and 4) measure changes to the real-ear unaided response when placing the FM receiver in the child's ear. After completion of the fitting, speech recognition in noise at a -5 signal-to-noise ratio and loudness ratings at a +5 signal-to-noise ratio were measured in four conditions: (1) no FM system, (2) FM receiver on the right ear, (3) FM receiver on the left ear, and (4) bilateral FM system. The results of this study suggested that the slightly modified AAA real-ear measurement procedures resulted in a valid fitting of one FM system on children with normal hearing. On average, prescriptive targets were met for 1000, 2000, 3000, and 4000 Hz within 3 dB, and maximum output of the FM system never exceeded and was significantly lower than predicted uncomfortable loudness levels for the children. There was a minimal change in the real-ear unaided response when the open-ear FM receiver was placed into the ear. Use of the FM system on one or both ears resulted in significantly better speech recognition in noise relative to a no-FM condition, and the unilateral and bilateral FM receivers resulted in a comfortably loud signal when listening in background noise. Real-ear measures are critical for obtaining an appropriate fit of an FM system on children with normal hearing.

Analysis on Anti-Noise Performance of Frequency Modulation System Based on MATLAB Simulation

The popularity of internet technology has brought the change very big to the life and production of modern humans, the current Internet technology application has penetrated into people in every aspect of modern life, has become an indispensable part of people's life. Firstly, system model of the current network communication to dissect, analyzes the architecture of network communication system, modulation and demodulation principle is applied to design the FM communication signal modulation system network communication in the Internet technology, the non coherent demodulation method to build FM demodulation system, realize the demodulation process through differential device, the anti noise performance of the method of frequency modulation system of MATLAB simulation experiments, the experimental results show that the method of anti noise performance significantly, to a certain extent, provide theoretical basis and technical support for the research in this field.

Baseband Transceiver Design of a High Definition Radio FM System Using Joint Theoretical Analysis and FPGA Implementation

Advances in wireless communications have enabled various technologies for wireless digital communication. In the field of digital radio broadcasting, several specifications have been proposed, such as Eureka-147 and digital radio mondiale (DRM). These systems require a new spectrum assignment, which incurs heavy cost due to the depletion of the available spectrum. Therefore, the in-band on-channel (IBOC) system has been developed to work in the same band with the conventional analog radio and to provide digital broadcasting services. This paper discusses the function and algorithm of the high definition (HD) radio frequency modulation (FM) digital radio broadcasting system. Content includes data format allocation, constellation mapping, orthogonal frequency division multiplexing (OFDM) modulation of the transmitter, timing synchronization, OFDM demodulation, integer and fraction carrier frequency (integer carrier frequency offset (ICFO) and fractional CFO (FCFO)) estimation, and channel estimation of the receiver. When we implement this system to the field programmable gate array (FPGA) based on a hardware platform, both theoretical and practical aspects have been considered to accommodate the available hardware resources.

Electromagnetic versus Electrical Coupling of Personal Frequency Modulation (FM) Receivers to Cochlear Implant Sound Processors

Previous research has suggested that electrically coupled frequency modulation (FM) systems substantially improved speech-recognition performance in noise in individuals with cochlear implants (CIs). However, there is limited evidence to support the use of electromagnetically coupled (neck loop) FM receivers with contemporary CI sound processors containing telecoils. The primary goal of this study was to compare speech-recognition performance in noise and subjective ratings of adolescents and adults using one of three contemporary CI sound processors coupled to electromagnetically and electrically coupled FM receivers from Oticon. A repeated-measures design was used to compare speech-recognition performance in noise and subjective ratings without and with the FM systems across three test sessions (Experiment 1) and to compare performance at different FM-gain settings (Experiment 2). Descriptive statistics were used in Experiment 3 to describe output differences measured through a CI sound processor. Experiment 1 included nine adolescents or adults with unilateral or bilateral Advanced Bionics Harmony (n = 3), Cochlear Nucleus 5 (n = 3), and MED-EL OPUS 2 (n = 3) CI sound processors. In Experiment 2, seven of the original nine participants were tested. In Experiment 3, electroacoustic output was measured from a Nucleus 5 sound processor when coupled to the electromagnetically coupled Oticon Arc neck loop and electrically coupled Oticon R2. In Experiment 1, participants completed a field trial with each FM receiver and three test sessions that included speech-recognition performance in noise and a subjective rating scale. In Experiment 2, participants were tested in three receiver-gain conditions. Results in both experiments were analyzed using repeated-measures analysis of variance. Experiment 3 involved electroacoustic-test measures to determine the monitor-earphone output of the CI alone and CI coupled to the two FM receivers. The results in Experiment 1 suggested that both FM receivers provided significantly better speech-recognition performance in noise than the CI alone; however, the electromagnetically coupled receiver provided significantly better speech-recognition performance in noise and better ratings in some situations than the electrically coupled receiver when set to the same gain. In Experiment 2, the primary analysis suggested significantly better speech-recognition performance in noise for the neck-loop versus electrically coupled receiver, but a second analysis, using the best performance across gain settings for each device, revealed no significant differences between the two FM receivers. Experiment 3 revealed monitor-earphone output differences in the Nucleus 5 sound processor for the two FM receivers when set to the +8 setting used in Experiment 1 but equal output when the electrically coupled device was set to a +16 gain setting and the electromagnetically coupled device was set to the +8 gain setting. Individuals with contemporary sound processors may show more favorable speech-recognition performance in noise electromagnetically coupled FM systems (i.e., Oticon Arc), which is most likely related to the input processing and signal processing pathway within the CI sound processor for direct input versus telecoil input. Further research is warranted to replicate these findings with a larger sample size and to develop and validate a more objective approach to fitting FM systems to CI sound processors.

Hearing Matters

Figure: Neural response consistency improves after one year of FM use in children with dyslexia, with the average r-value increasing from 0.606 to 0.743. (Adapted from Proc Natl Acad Sci U S A 2012;109[41]:16731-16736.)In our September columnhttp://journals.lww.com/thehearingjournal/Fulltext/2013/09000/Hearing_Matters___For_Reading_Development,.4.aspx, we discussed the impact of impaired auditory processing on reading development, which suggests that auditory training might be a viable management strategy for children who have dyslexia or are at risk of developing reading problems. But is there any evidence to support treatment efficacy for this kind of disorder? Let's first look at evidence supporting remediation efforts. Even a short, three-hour training session on phonological awareness can improve reading-related skills and neural discrimination of speech sounds (mismatch negativity; MMN) in preschool children (Brain Res 2012;1448:42-55http://www.sciencedirect.com/science/article/pii/S0006899312001941). Several studies have shown benefits over longer time periods typical of commercial training programs. For example, children with dyslexia who participated in 35 to 40 sessions of Earobics, a popular auditory training program, had better auditory processing following training, as demonstrated by better speech-evoked auditory brainstem responses (ABRs) in noise and better performance on reading-related tests of cognitive ability (Behav Brain Res 2005;-156[1]:95-103http://www.sciencedirect.com/science/article/pii/S0166432804001809).Figure: Nina Kraus, PhDIn these children, ABR latencies prior to training predicted improvement in syllable discrimination, suggesting that the speech-evoked ABR can be useful in determining who is most likely to benefit from training. One example of an environmental modification used to enhance access to the acoustic signal is a frequency modulation (FM) system.There is now evidence for the benefits of using FM systems for improving both reading performance and neural response consistency (Proc Natl Acad Sci U S A 2012;109[41]:16731-16736http://www.pnas.org/content/109/41/16731.abstract). In the FM study, children with dyslexia (age 8 to 14) wore Phonak EduLink systems during lecture-based classes, approximately four hours per day, for the nine-month academic year. Another group of children with dyslexia attending the same classes did not use the assistive listening devices and served as the matched control group. In the summers before and after the school year, both groups, along with a group of typically developing children, were tested with ABRs.Figure: Samira Anderson, AuD, PhDAfter one year, the children using FM systems had improved neural response consistency and greater gains in reading compared with the matched control or typically developing groups. Importantly, response consistency in the FM group increased to levels equivalent to those of typically developing children. Notably, the children with dyslexia with good phonological skills prior to using the FM systems did not show improvements in either phonological skills or response consistency, suggesting that it is important to identify which children are going to benefit from FM use based on pretest measures. Electrophysiologic measures have demonstrated that both auditory training programs and FM use can improve auditory processing and reading outcomes. Furthermore, it may be possible to identify the children who are most likely to benefit from one or both of these treatment strategies.

A Proposed Electroacoustic Test Protocol for Personal FM Receivers Coupled to Cochlear Implant Sound Processors

Current fitting guidelines from the American Academy of Audiology (Academy) support the use of objective electroacoustic measures and behavioral testing when fitting frequency modulation (FM) systems to hearing aids. However, only behavioral testing is recommended when fitting FM systems to individuals with cochlear implants (CIs) because a protocol for conducting electroacoustic measures has yet to be developed for this population. The purpose of this study was to propose and examine the validity of a newly developed, objective, electroacoustic test protocol for fitting electrically and electromagnetically coupled FM systems to CI sound processors. Electroacoustic measures were conducted and replicated in the laboratory with three contemporary CI sound processors and several FM system combinations. A repeated measures design was used with four participants to examine the validity of the proposed electroacoustic test protocol. Three contemporary CI sound processors were tested electroacoustically in the laboratory while coupled to combinations of five FM receivers and four FM transmitters. Two adolescents using Cochlear Nucleus 5 sound processors and two adult participants using MED-EL OPUS 2 sound processors completed behavioral and subjective measures. Using current hearing aid practice guidelines from the Academy, electroacoustic measurements were conducted in the laboratory with the CIs and FM systems to determine transparency, where equivalent inputs to the CI and FM microphones result in equivalent outputs. Using a hearing aid analyzer, acoustic output from the CI sound processor was measured via monitor earphones and specialized equipment from CI manufacturers with 65 dB SPL speech inputs (1) to the sound processor and (2) to the FM transmitter microphones. The FM gain or volume was adjusted to attempt to achieve transparency for outputs from the two input devices. The four participants completed some or all of the following measures: speech recognition in noise without and with two FM systems in a classroom, loudness ratings without and with two FM systems measures in a quiet condition in a classroom, and questionnaires. Transparency was achieved for most CI and FM combinations, but most systems required adjustments to FM gain or volume relative to the manufacturer default setting. Despite adjustments to the systems, transparency was not attainable for some FM receiver and transmitter combinations. Behavioral testing in four participants provided preliminary support to the proposed electroacoustic test protocol. Valid and reliable electroacoustic test measures may be feasible with CIs coupled to FM systems with specialized equipment from the CI manufacturer. Advances in equipment available for electroacoustic testing with these devices as well as additional research will lend further support to this objective approach to fitting FM systems to CIs.

App Up the Volume

You have accessThe ASHA LeaderApp-titude1 Oct 2013App Up the VolumeA growing number of mobile tools can help people with hearing loss better understand the world—and help the world better understand them. Carrie SpanglerAuD, CCC-A Carrie Spangler Google Scholar More articles by this author , AuD, CCC-A https://doi.org/10.1044/leader.APP.18102013.32 SectionsAboutPDF ToolsAdd to favorites ShareFacebookTwitterLinked In There’s an app for everything, right? But are there any out there to make the hearing world an easier place to live for those with hearing loss? As an audiologist with hearing loss, I sought answers to this question as part of my constant quest for hearing-related technology advances. And I found that, indeed, there are apps available to help expand people’s hearing and communication-related capabilities. Advocacy in preschool We want our kids with hearing loss to start advocating for their needs at a young age, and tablet apps can help. Why not have your preschooler “star” in his or her own book, using Book Creator for iPad by Red Jumper Studio (bit.ly/book_creator)? This app allows you to creatively work on goals related to ensuring that the child with hearing loss receives appropriate support. Take pictures of the child wearing hearing aids or using a frequency modulation system, and involve friends in the classroom. You can easily import the pictures, add sound and record the child’s voice. Save it in a book-browsing app such as iBooks (bit.ly/ibooks_app) or as a pdf. A tool for teens Music is a central theme in the lives of teens and their friends, and not understanding or hearing the lyrics correctly can be embarrassing for teens with hearing loss. Enter TuneWiki Lyrics, Inc. (downloadable at iTunes, bit.ly/tunewikiapp; Google Play, bit.ly/tunewikiappdroid), a free app that allows users to access song lyrics at the touch of their fingertips. No more embarrassing mondegreens or misheard and misunderstood lyrics! One example of a common mondegreen is mishearing the McCoys’ “Hang on, Sloopy” as “Hang on, stupid.” Knowing words to songs is a social networking opportunity for teens, and it can also serve as a protective tool for their parents with hearing loss. The app can help parents identify appropriate and inappropriate music immediately. Independence for adults As a professional with hearing impairment, I may miss many portions of a telephone conversation, especially if the conversation occurs in a compromised listening situation, such as at a roadside or airport. One free app that helps “fill in the blanks” is ClearCaptions by Purple Communications, Inc., available for Apple iOS products (bit.ly/clearcaptionsios) and Android products (bit.ly/clearcaptionsdroid). This app performs a similar service to closed captioning on your television, allowing you to read what is being said on your smartphone or tablet screen. You can also scroll up and read something you might have missed. Performance for professionals The Smart Voice Recorder app allows you to record and save sound clips and is available for free via iTunes (bit.ly/smartrecorderios) and Google Play (bit.ly/smartvoicedroid). It serves as a useful tool for educating school staff about the effects of classroom acoustics on children’s performance. For example, you can use a sound clip of a teacher giving an oral spelling test in a noisy classroom to show how this can be unfair to students with hearing difficulties. If you need to perform a functional listening evaluation, you can use the app to record a sound bite on the Web demonstrating classroom noise. You can also record clips of what hearing loss sounds like, so that you can easily demonstrate this when a teachable moment comes up. I recommend attaching a portable mini-speaker to your phone to ensure that your audience can clearly hear the clips you play. Author Notes Carrie Spangler, AuD, CCC-A, is an educational audiology clinician with the University of Akron in Ohio. She brings a personal perspective to her work, as she lives with bilateral hearing loss and hearing aids. [email protected] Advertising Disclaimer | Advertise With Us Advertising Disclaimer | Advertise With Us Additional Resources FiguresSourcesRelatedDetails Volume 18Issue 10October 2013 Get Permissions Add to your Mendeley library History Published in print: Oct 1, 2013 Metrics Downloaded 63 times Topicsasha-topicsleader_do_tagleader-topicsasha-article-typesCopyright & Permissions© 2013 American Speech-Language-Hearing AssociationPDF DownloadLoading ...

Evaluation of Speech Recognition of Cochlear Implant Recipients Using a Personal Digital Adaptive Radio Frequency System

Previous research supports the use of frequency modulation (FM) systems for improving speech recognition in noise of individuals with cochlear implants (CIs). However, at this time, there is no published research on the potential speech recognition benefit of new digital adaptive wireless radio transmission systems. The goal of this study was to compare speech recognition in quiet and in noise of CI recipients while using traditional, fixed-gain analog FM systems, adaptive analog FM systems, and adaptive digital wireless radio frequency transmission systems. A three-way repeated-measures design was used to examine performance differences among devices, among speech recognition conditions in quiet and in increasing levels of background noise, and between users of Advanced Bionics and Cochlear CIs. Seventeen users of Advanced Bionics Harmony CI sound processors and 20 users of Cochlear Nucleus 5 sound processors were included in the study. Participants were tested in a total of 32 speech-recognition-in noise-test conditions, which included one no-FM and three device conditions (fixed-gain FM, adaptive FM, and adaptive digital) at the following signal levels: 64 dBA speech (at the location of the participant) in quiet and 64 dBA speech with competing noise at 50, 55, 60, 65, 70, 75, and 80 dBA noise levels. No significant differences were detected between the users of Advanced Bionics and Cochlear CIs. All of the radio frequency system conditions (i.e., fixed-gain FM, adaptive FM, and adaptive digital) outperformed the no-FM conditions in test situations with competing noise. Specifically, in conditions with 70, 75, and 80 dBA of competing noise, the adaptive digital system provided better performance than the fixed-gain and adaptive FM systems. The adaptive FM system did provide better performance than the fixed-gain FM system at 70 and 75 dBA of competing noise. At the lower noise levels of 50, 55, 60, and 65 dBA, no significant differences were detected across the three systems, and no significant differences were found across the quiet conditions. In all conditions, performance became poorer as the competing noise level increased. In high levels of noise, the adaptive digital system provides superior performance when compared to adaptive analog FM and fixed-gain FM systems.

Chemo-inspired genetic algorithm for function optimization

Finding global optimal solution for a non-linear optimization problem with high complexity became a challenge for the researchers. Evolutionary optimization process is being treated as an alternate paradigm to solve such problems. In this context, Bacterial Foraging Optimization (BFO) is a novel heuristic algorithm inspired from foraging behavior of Escherichia coli bacterium. At the same time, Genetic Algorithm (GA) has also achieved popularity from the academic and industrial communities to deal with such problems. To improve the solution quality further, the hybridization of GA with BFO (GA-BF) is proven to be much robust in recent past. It is found that while hybridizing GA with BFO, the behavior/mechanism of some of the operators seems to be repeated and it may lead to hamper the solution quality as well as increases the computational time. Hence, instead of taking the whole BFO to hybridize with GA (called GA-BF); only the chemotaxis step is picked from BFO mechanism and hybridized with GA. It is named as chemo-inspired Genetic Algorithm (CGA). The superiority of CGA over GA-BF algorithm is being realized through a set of four typical benchmark problems available in the literature. Later, the faster convergence of CGA is shown graphically. Hence, CGA outperforms GA-BF in terms of solution quality and the computational time. Moreover, two real life problems namely (a) solving system of linear equations and (b) frequency modulation sounds parameter identification problems have been solved, in order to justify the above conclusion.

Better Speech Recognition with Digital RF System in Study of Cochlear Implants

Better Speech Recognition with Digital RF System in Study of Cochlear Implants

Bias and Variance in Frequency Estimation at the Leading Edge of a Peak in the Spectrum of a Windowed Signal Under Multipath Mitigation

Sinusoidal frequency estimation based on discrete Fourier transform provides accurate results for well-separated spectral tones. However, if a single sinusoid is disturbed by other tones, estimation accuracy may suffer significantly. In particular, the bias can increase considerably when the frequencies of the disturbances are close to that of the desired sinusoid. In addition to frequency estimation by maximization of the Schuster periodogram, examining a frequency located on the opposite side of the disturbance at the edge of the cost function may reduce its influence on the bias of the estimator. In this paper, we present an empirical appraisal of this bias reduction. Since our edge estimation procedure increases the variance of the estimated frequency, we also present an analytical method for assessing this increase. Possible applications are measurement or tracking tasks where frequency estimates with low bias are essential to the working of an overall measurement system. Further, we describe a method that combines the advantages of peak and edge estimation. All results were validated using simulations and data obtained from a frequency-modulated continuous-wave radar system.

Preschool Teachers' Perception and Use of Hearing Assistive Technology in Educational Settings

This study explored how often sound-field amplification and personal frequency-modulated (FM) systems are used in preschool classrooms, teacher perceptions of advantages and disadvantages of using hearing assistive technology, and teacher recommendations for hearing assistive technology use. The study used a cross-sectional survey design. Participants were professionals who provided services to preschool-age children who are deaf or hard of hearing in public or private schools. A total of 306 surveys were sent to 162 deaf education programs throughout the United States; 99 surveys were returned (32%). Simple statistics were used to describe the quantitative survey results; content analysis was completed on open-ended survey comments. Surveys were received from teachers working at listening and spoken language preschool programs (65%) and at bilingual-bicultural and total communication preschool programs (35%). Most respondents perceived that hearing assistive technology improved students' academic performance, speech and language development, behavior, and attention in the classroom. The majority of respondents also reported that they definitely would or probably would recommend a sound-field system (77%) or personal FM system (71%) to other educators. Hearing assistive technology is frequently used in preschool classrooms of children who are deaf or hard of hearing, with generally positive teacher perceptions of the benefits of using such technology.

Speech Recognition and Subjective Perceptions of Neck-Loop FM Receivers With Cochlear Implants

The goal of this investigation was to determine the potential benefit of using electromagnetically coupled frequency modulation (FM) neck-loop receivers to address common communication difficulties of adults and adolescents with cochlear implants (CIs). Fourteen participants with CIs used the neck-loop FM receiver for a trial period and participated in pre- and post trial sessions consisting of speech-recognition-in-noise measures with and without the FM system and a subjective rating scale. Most participants also recorded their experiences during the FM-system trial period in a journal. The results suggested significantly improved speech recognition in noise with the neck-loop FM system before and after the trial period, with no changes in performance between test sessions. On average, the rating scale and journals revealed improvements with the FM system, relative to the CI alone, in noisy environments or situations at a distance from the primary talker or sound source. The results of the study suggest that neck-loop FM receivers significantly improved speech recognition in noise and everyday listening challenges of people using the CIs in 2 separate test sessions. Additional research is warranted for other types of neck-loop receivers and CI sound processors.

Impact of unilateral conductive hearing loss due to aural atresia on academic performance in children

This study evaluates the effect of unilateral conductive hearing loss secondary to aural atresia on elementary school children's academic performance. Case control survey and review of audiometric data. One hundred thirty-two surveys were mailed to families of children with aural atresia, and 48 surveys were sent to families of children with unilateral sensorineural hearing loss (SNHL) to identify rates of grade retention, use of any resource, and behavioral problems. Audiometric data of the cohort were tabulated. Of the 40 atresia patients, none repeated a grade, but 65% needed some resources: 12.5% currently use a hearing aid, 32.5% use(d) a frequency-modulated system in school, 47.5% had an Individualized Education Plan, and 45% utilized speech therapy. Compared to the unilateral SNHL group and a cohort of children with unilateral SNHL in an earlier study, children with unilateral atresia were less likely to repeat a grade. Children in both unilateral atresia and SNHL groups were more likely to utilize some resource in the academic setting compared to the unilateral SNHL children in the prior study. Unilateral conductive hearing loss due to aural atresia has an impact on academic performance in children, although not as profound when compared to children with unilateral SNHL. The majority of these children with unilateral atresia utilize resources in the school setting. Parents, educators, and health care professionals should be aware of the impact of unilateral conductive hearing loss and offer appropriate habilitative services.

Effects of Input Processing and Type of Personal Frequency Modulation System on Speech-Recognition Performance of Adults With Cochlear Implants

The objective of this study was to compare speech recognition in quiet and in noise for cochlear implant recipients using two different types of personal frequency modulation (FM) systems (directly coupled [direct auditory input] versus induction neckloop) with each of two sound processors (Cochlear Nucleus Freedom versus Cochlear Nucleus 5). Two different experiments were conducted within this study. In both these experiments, mixing of the FM signal within the Freedom processor was implemented via the same scheme used clinically for the Freedom sound processor. In Experiment 1, the aforementioned comparisons were conducted with the Nucleus 5 programmed so that the microphone and FM signals were mixed and then the mixed signals were subjected to autosensitivity control (ASC). In Experiment 2, comparisons between the two FM systems and processors were conducted again with the Nucleus 5 programmed to provide a more complex multistage implementation of ASC during the preprocessing stage. This study was a within-subject, repeated-measures design. Subjects were recruited from the patient population at the Hearts for Hearing Foundation in Oklahoma City, OK. Fifteen subjects participated in Experiment 1, and 16 subjects participated in Experiment 2. Subjects were adults who had used either unilateral or bilateral cochlear implants for at least 1 year. In this experiment, no differences were found in speech recognition in quiet obtained with the two different FM systems or the various sound-processor conditions. With each sound processor, speech recognition in noise was better with the directly coupled direct auditory input system relative to the neckloop system. The multistage ASC processing of the Nucleus 5 sound processor provided better performance than the single-stage approach for the Nucleus 5 and the Nucleus Freedom sound processor. Speech recognition in noise is substantially affected by the type of sound processor, FM system, and implementation of ASC used by a Cochlear implant recipient.

Design and Application of Amplitude-Locked Loop Separation System Based on SignalWAVe

In this paper, we adopt concepts from the SignalWAVe development platform for the multi-speech signal separation system of a frequency modulation system. The signal separation system is formed using a phase-locked loop in combination with an amplitude-locked loop (ALL) and is modeled using a digital finite-impulse response (FIR) filtering algorithm. Therein, the objective is to improve the signal distortion of co-channel interferences and additive white Gaussian noise (AWGN). In comparison to a traditional separation system, the ALL is achieved in the monitored system and in signal interception applications with a characteristic analysis based on the power spectrum density. The field programmable gate array (FPGA) design platform has the advantages of flow simplicity, easy reconfiguration, and high compatibility for verification. The design system is operated in real time and is implemented in the system model using various chip designs. The FPGA is implemented system as a system on a chip for high efficiency. According to the simulated performances under an applied AWGN channel, the ALL system in combination with a digital FIR filter achieves prefect performance. The SignalWAVe verification system was also implemented on the chip by building, verifying programs, and implemented communication functions for practical application in the industry.

Nuts & Bolts

Nuts & Bolts

Efficient Spectrum Sharing in the Presence of Multiple Narrowband Interference

In this paper, we study the spectrum usage efficiency by applying wideband methods and systems to the existing analog systems and applications. The essential motivation of this work is to define the prospective coexistence between analog FM and digital Spread Spectrum systems in an efficient way sharing the same frequency band. The potential overlaid Spread Spectrum (SS) system can spectrally coincide within the existing narrowband Frequency Modulated (FM) broadcasting system upon several limitations, originating a key motivation for the use of the FM radio frequency band in many applications, encompassing wireless personal and sensors networks. The performance of the SS system due to the overlaying analog FM system, consisting of multiple narrowband FM stations, is investigated in order to derive the relevant bit error probability and maximum achievable data rates. The SS system uses direct sequence (DS) spreading, through maximal length pseudorandom sequences with long spreading codes. The SS signal is evaluated throughout theoretical and simulation-based performance analysis, for various types of spreading scenarios, for different carrier frequency offset ({\Delta}f) and signal-to-interference ratios, in order to derive valuable results for future developing and planning of an overlay scenario.

Personal FM systems for children with autism spectrum disorders (ASD) and/or attention-deficit hyperactivity disorder (ADHD): An initial investigation

The goal of this initial investigation was to examine the potential benefit of a frequency modulation (FM) system for 11 children diagnosed with autism spectrum disorders (ASD), attention-deficit hyperactivity disorder (ADHD), or both disorders through measures of speech recognition performance in noise, observed classroom behavior, and teacher-rated educational risk and listening behaviors. Use of the FM system resulted in significant average improvements in speech recognition in noise for the children with ASD and ADHD as well as large effect sizes. When compared to typically functioning peers, children with ASD and ADHD had significantly poorer average speech recognition performance in noise without the FM system but comparable average performance when the FM system was used. Similarly, classroom observations yielded a significant increase in on-task behaviors and large effect sizes when the FM system was in use during two separate trial periods. Although teacher ratings on questionnaires showed no significant improvement in the average level of educational risk of participants, they did indicate significant improvement in average listening behaviors during two trial periods with the FM system. Given the significantly better speech recognition in noise, increased on-task behaviors, and improved teacher ratings of listening behaviors with the FM system, these devices may be a viable option for children who have ASD and ADHD in the classroom. However, an individual evaluation including audiological testing and a functional evaluation in the child's primary learning environment will be necessary to determine the benefit of an FM system for a particular student.Learning Outcomes: 1. The reader will be able to describe the potential benefit of FM systems for children with ASD and/or ADHD. 2. The reader will be able to identify on-task versus off-task listening behaviors in children with ASD and/or ADHD. 3. The reader will be able to explain the components of a successful pre-fit education program that may be necessary prior to fitting an FM system in children with ASD.

Interference coordination for LTE-Advanced and FM broadcasting interoperability

The surest way to guarantee that multiple wireless systems can concurrently exist harmlessly, when operating in the same or adjacent channel, is by analyzing spectrum overlapping. This paper proposes a more accurate model to evaluate the interference power from co-channel and adjacent channel of orthogonal frequency division multiplexing-based long term evolution-advanced (LTE-Advanced) towards broadcasting frequency modulation systems at 800 MHz. Power spectral density overlapping factor is employed, and closed form of the interference power loss is derived. Numerical results demonstrate that the proposed method evaluates more exact interference power than the advanced minimum coupling loss (A-MCL) method, where the co-channel and adjacent channel interference powers are reduced by 1.3 and 3 dB, correspondingly, compared to that obtained using the A-MCL method. This decreases the minimum separation distance between the two systems, which can eventually lead to efficient radio spectrum resources utilization.