Flexible Ultra-Wide Electro-Optic Frequency Combs for a High- Capacity Tunable 5G+ Millimeter-Wave Frequency Synthesizer

This paper presents a new scheme of a cost-effective tunable millimeter-wave (MMW) frequency synthesizer based on an ultra-wideband electro-optic frequency comb. The architecture for the quasi-tunable millimeter-wave frequency synthesizer mainly consists of a compact ultra-wide flat electro-optic frequency comb and a multi-tone frequency generator, which only includes a quantum dot mode-locked laser, a LiNbO3 dual-driving Mach–Zehnder modulator (DD-MZM) and Uni-traveling-carrier photodiode (UTC-PD). MMW signals generated with a quasi-tunable frequency are experimentally demonstrated. The difference in power is obtained for the different frequencies. The linewidth of the quasi-tunable frequency signals is less than 273 Hz. In addition, the single side band (SSB) phase noise of the 25, 37.5, 50 and 75 GHz is measured as −115, −106, −102 and −95 dBc/Hz at an offset of 1 kHz, respectively. The proposed frequency synthesizer has ultra-low phase noise, quasi-tunable frequency and simple structure. The research results of the frequency synthesizer are applied for 5G+ transmission with radio wave working at K-band and V-band. The flexible, compact and robust MMW frequency synthesizer is suitable for the future of ultra-high capacity 5G+ communication.

Pure tone discrimination with cochlear implants and filter-band spread

For many cochlear implant (CI) users, frequency discrimination is still challenging. We studied the effect of frequency differences relative to the electrode frequency bands on pure tone discrimination. A single-center, prospective, controlled, psychoacoustic exploratory study was conducted in a tertiary university referral center. Thirty-four patients with Cochlear Ltd. and MED-EL CIs and 19 age-matched normal-hearing control subjects were included. Two sinusoidal tones were presented with varying frequency differences. The reference tone frequency was chosen according to the center frequency of basal or apical electrodes. Discrimination abilities were psychophysically measured in a three-interval, two-alternative, forced-choice procedure (3I-2AFC) for various CI electrodes. Hit rates were measured, particularly with respect to discrimination abilities at the corner frequency of the electrode frequency-bands. The mean rate of correct decision concerning pitch difference was about 60% for CI users and about 90% for the normal-hearing control group. In CI users, the difference limen was two semitones, while normal-hearing participants detected the difference of one semitone. No influence of the corner frequency of the CI electrodes was found. In CI users, pure tone discrimination seems to be independent of tone positions relative to the corner frequency of the electrode frequency-band. Differences of 2 semitones can be distinguished within one electrode.

Performance analysis of DP-MZM radio over fiber links against fiber impairments

In this research article, the radio over fiber (RoF) Architecture using dual-parallel Mach–Zehnder modulator (DP-MZM) is analyzed and simulated. The nonlinearity is the main issues which degrade the performance of the RoF links. Using DP-MZM modulators, the nonlinearity can be reducing in the significant amount by controlling the bias voltages. The DP-MZM consists of two MZM modulators in parallel form with the variations of extinction ratio (ER). The proposed RoF link operated with single tone frequency signal at 10 GHz and the optical signal is transmitted further on Single mode optical fiber. The electrical spectrum at the output of photodetector confirms the quality of received signal while having desired and undesired terms. The proposed structure is designed using Optical Simulator simulation Software to confirm and validate the proposed results. The simulation output shows that the RF power of DP-MZM based RoF link has been found a decrement of 6.95 dB corresponding to undesired components with respect to desired RF signal for the increment in fiber length from 10 to 30 km. The digital transmission RoF link model is proposed and optimized for fiber impairments for 2–30 km, using 10 Gbps digital data string. electrical spectrum analyzer shows that very good eye openings for different fiber impairments, its shoes that proposed RoF model is optimized and having good SNR.

Emergence of Frequency-Dependent Motor Variability Within Supra-Second Auditory Cueing

Motor variability (MV) is an essential feature of the sensory motor system, and it plays an important role in sensory-motor learning. MV facilitates motor adaptation during auditory-motor synchronization (AMS). In AMS, individuals receive a series of similar auditory stimuli that come in a periodic manner at a fixed interval called an inter-stimulus interval (ISI). Peri-second ISI (1 second range) and supra-second ISI (>1 second) are differently processed, since these intervals involve different amount of cognitive resources. Supra-second ISI involves more top-down attention as compared to peri-second ISI. In this study we examined the effect of tone frequency (perceptual property of auditory stimuli) on predictive tapping and MV under peri-second and supra-second ranges. We examined the effect of tone frequency (a perceptual property of auditory stimuli) on predictive tapping and motor variability (MV) under short (peri-second) and long (supra-second) inter-stimulus intervals. Among 30 healthy participants (aged 18–35 years, M = 24.6 years), we randomly assigned equal numbers of these two inter-stimulus conditions to isochronous sound sequences. In their attempt to synchronize their motor responses with the tone, participants reproduced the ISI in their inter-tap intervals (ITIs). We analyzed their predictive tapping in terms of negative asynchrony (in which the tap occurs before the tone) and small positive asynchrony (0-100 ms), whereas we analyzed MV using the coefficient of variation (CV) of the ITI. We found that participants showed predictive tapping under short ISI, irrespective of the tone frequency. Moreover, their MV was unaffected by tone frequency. These findings imply that participants expressed MV in a predictive rather than reactive manner under short, but not long, ISI. Under long ISI, tone frequency had a significant effect on MV such that there was higher MV with the low-frequency than with the high-frequency tone. Thus, low-frequency tones are most suitable for auditory-motor learning in the supra-second range.

Groupitizing Improves Estimation of Numerosity of Auditory Sequences

Groupitizing is a recently described phenomenon of numerosity perception where clustering items of a set into smaller “subitizable” groups improves discrimination. Groupitizing is thought to be rooted on the subitizing system, with which it shares several properties: both phenomena accelerate counting and decrease estimation thresholds irrespective of stimulus format (for both simultaneous and sequential numerosity perception) and both rely on attention. As previous research on groupitizing has been almost completely limited to vision, the current study investigates whether it generalizes to other sensory modalities. Participants estimated the numerosity of a series of tones clustered either by proximity in time or by similarity in frequency. We found that compared with unstructured tone sequences, grouping lowered auditory estimation thresholds by up to 20%. The groupitizing advantage was similar across different grouping conditions, temporal proximity and tone frequency similarity. These results mirror the groupitizing effect for visual stimuli, suggesting that, like subitizing, groupitizing is an a-modal phenomenon.

Dynamic Auditory Remapping Across the Sleep-Wake Cycle

In a single day we transition from vigilant wakefulness to unconscious sleep and dreaming, undergoing diverse behavioural, physiological and neural changes. While during the awake state, exogenous stimuli and endogenous changes lead to sensory reorganisation, this remapping has not been charted throughout the sleep-wake cycle. We recorded neural activity in response to a range of tones using electroencephalography during a full night’s sleep, and examined whether auditory responses become more similar, dissimilar or remain unchanged between wakefulness, non-rapid (NREM) and rapid eye movement (REM) sleep. We found that neural similarities between pairs of auditory evoked potentials differed by conscious state in both early and late auditory processing stages. Furthermore, tone-pairs neural similarities were modulated by conscious state as a function of tone frequency, where some tone-pairs changed similarity between states and others continued unaffected. These findings demonstrate a state-, stimulus- and time-dependent functional reorganization of auditory processing across the sleep-wake cycle.

Speech-specific perceptual adaptation deficits in children and adults with dyslexia

According to several influential theoretical frameworks, phonological deficits in dyslexia result from reduced sensitivity to acoustic cues that are essential for the development of robust phonemic representations. Some accounts suggest that these deficits arise from impairments in rapid auditory adaptation processes that are either speech-specific or domain-general. Here, we examined the specificity of auditory adaptation deficits in dyslexia using a non-linguistic tone anchoring (adaptation) task and a linguistic selective adaptation task in children and adults with and without dyslexia. Children and adults with dyslexia had elevated tone-frequency discrimination thresholds, but both groups benefitted from anchoring to repeated stimuli to the same extent as typical readers. Additionally, although both dyslexia groups had overall reduced accuracy for speech sound identification, only the child group had reduced categorical perception for speech. Across both age groups, individuals with dyslexia had reduced perceptual adaptation to speech. These results highlight broad auditory perceptual deficits across development in individuals with dyslexia for both linguistic and non-linguistic domains, but speech-specific adaptation deficits. Finally, mediation models in children and adults revealed that the causal pathways from basic perception and adaptation to phonological awareness through speech categorization were not significant. Thus, rather than having causal effects, perceptual deficits may co-occur with the phonological deficits in dyslexia across development.

Intonation of the Altai language (simple one-component imperative utterances)

The paper presents the results of studying the Altai language intonation on the experimental material recorded from six speakers fluent in the Altai language from different regions of the Altai Republic. The recording program consisted of situational single-component imperative utterances. Twenty sentences were pronounced three times each in positive and negative versions, in singular and plural, having different degrees of imperativeness, but without any expressive emotional load. The single-compound motivational statements considered are expressed by imperative or desirable verb forms in the first-, second-, and third-person singular and plural in the affirmative and negative variants. The experimental phonetic study has revealed rising tone to be characteristic for positive and negative imperative one-component sentences, with fundamental tone frequency peaks at the last syllable and there being a possibility for intensity, presumably marking the stressed syllable, to shift within a word-form. The analysis showed the intonation marking of motivational statements to depend on their type: action stimulation, order or demand, are characterized by inclination, a request - by a combined ascending-descending tone, a ban - by a descending tone, advice - both by ascending-descending intonation and declination. In the negative version, in singular and plural, in three or more syllabic sentences on the negative particles -ba / -be, -pa / -pe, etc., there is an even tone or a decrease in the frequency of the fundamental tone. The peak of intensity in such sentences is realized on the last syllable of the verb. In addition, the vowel of the final syllable is usually prolonged.