Carrier Frequency Research Articles

Anti-interrupted-sampling repeater jamming method based on frequency agility waveform and sparse recovery

Interrupted-sampling repeater jamming (ISRJ) is a type of intra-pulse coherent jamming that poses a significant threat to radar detection and tracking of targets. This paper proposes an ISRJ suppression method based on frequency agile waveform and sparse recovery, starting from the temporal discontinuity and modulation characteristics of ISRJ. This method is particularly suitable for scenarios with high jamming duty ratio (JDR) and high jammer sampling duty ratio (SDR). By dividing the transmitted waveform into sub-pulses with different carrier frequencies and applying a two-round block sparse algorithm, the method accurately recovers three parameters of ISRJ, achieving effective jamming identification, reconstruction, and cancellation. Additionally, a target detection technique based on robust sparse recovery is proposed, significantly improving the stability and accuracy of target detection. Comparative experimental results conducted in three scenarios confirm the effectiveness and superiority of this method under high JDR and SDR conditions.

A 0.73 mW low power 9.6 GHz LC voltage-controlled oscillator achieves constant KVCO and −189.2 FOM

This article introduces a novel approach of LC voltage-controlled oscillator (VCO) to overcome the challenges present in the Phase-locked loop (PLL) in high-frequency applications and proposes a 9.6 GHz VCO based on gm-boosted structure. By utilizing a transformer and gain variation calibration technique, the proposed VCO reduces the losses caused by MOSFET’s operation in triode region, thereby improving phase noise. And KVCO remains relatively constant, fluctuating up and down by approximately 5 MHz around 100 MHz/V, which is suitable to be used in phase-locked-loops (PLL). The oscillator is fabricated in 22 nm CMOS process occupying 0.25 mm × 0.55 mm area and consuming 0.73 mW from 0.5 V supply voltage. The measured phase noise achieves −114.3 dBc/Hz at 1 MHz offset with a carrier frequency of 4.75 GHz, and the figure of merit (FoM) is −189.2 dBc/Hz. The results clearly demonstrate that the proposed design could work under low power consumption and achieve constant KVCO, making it well suitable for high-frequency PLL applications.

Effect of dynamic binaural beats on sleep quality: a proof-of-concept study with questionnaire and biosignals

Abstract Binaural beat (BB) has been investigated as a potential modality to enhance sleep quality. In this study, we introduce a new form of BB, referred to as dynamic BB (DBB), which incorporates dynamically changing carrier frequency differences between the left and right ears. Specifically, the carrier frequency of the right ear varied between 100 and 103 Hz over a period, while the left ear remained fixed at 100 Hz, yielding a frequency difference range of 0 to 3 Hz. The objective of this study was to examine the effect of DBB on sleep quality. Ten healthy participants were included in a cross-over design, where they experienced both DBB and a SHAM (absence of sound) condition across two consecutive nights, with polysomnography evaluation. DBB was administrated during pre-sleep initiation, sleep onset, and transition from rapid eye movement (REM) to non-REM stage. DBB significantly reduced sleep latency compared to the SHAM condition. Electrocardiogram analysis revealed that exposure to DBB led to diminished heart rate variability during the pre-sleep initiation and sleep onset periods, accompanied by a decrease in low-frequency power of heart rate during the sleep onset period. DBB might be effective in improving sleep quality, suggesting its possible application in insomnia treatments.

Full/half-duplex unmanned aerial vehicles assisted wireless systems: Performance analysis and optimization

In this paper, we explore the utilization of both full-duplex (FD) and half-duplex (HD) transmission modes on unmanned aerial vehicles (UAVs) to enhance wireless system performance. We consider two practical scenarios: one without a direct transmitter-user link and the other with such a link. For both cases, we derive mathematical expressions of outage probabilities (OPs) and throughputs of FD-UAV and HD-UAV systems, employing a realistic channel model aligned with the fifth and beyond generations (5G-B5G) standards. In cases where imperfect self-interference cancellation (SIC) occurs in FD-UAV systems, we introduce an optimal power allocation approach to enhance system performance. Numerical results underscore the benefits of cooperative communications, particularly when combining the direct link with the UAV link at the user, leading to an overall enhancement in system performance. Furthermore, we conduct a comprehensive analysis of various system parameters, including predefined rates, residual self-interference (RSI) levels, high carrier frequencies of Wi-Fi networks, and high altitudes of UAVs. The impact of RSI is particularly notable, and the proposed optimal power allocation approach significantly improves system performance in such cases. Specifically, the introduced scheme helps avoid error floors in regions of high transmit power, enabling throughputs to reach desired targets in FD-UAV systems. Crucially, the optimal power value is considerably lower than the traditional value often used without optimal power allocation, extending the operational duration of FD-UAV. Finally, to validate the derived mathematical expressions and affirm the effectiveness of the proposed approaches, we conduct Monte-Carlo simulations.

Multiplex fluorescent amplification-refractory mutation system PCR method for the detection of 10 genetic defects in Holstein cattle and its comparison with the KASP genotyping assay.

The common deleterious genetic defects in Holstein cattle include haplotypes 1-6 (HH1-HH6), haplotypes for cholesterol deficiency (HCD), bovine leukocyte adhesion deficiency (BLAD), complex vertebral malformation (CVM) and brachyspina syndrome (BS). Recessive inheritance patterns of these genetic defects permit the carriers to function normally, but homozygous recessive genotypes cause embryo loss or neonatal death. Therefore, rapid detection of the carriers is essential to manage these genetic defects. This study was conducted to develop a single-tube multiplex fluorescent amplification-refractory mutation system (mf-ARMS) PCR method for efficient genotyping of these 10 genetic defects and to compare its efficiency with the kompetitive allele specific PCR (KASP) genotyping assay. The mf-ARMS PCR method introduced 10 sets of tri-primers optimized with additional mismatches in the 3' end of wild and mutant-specific primers, size differentiation between wild and mutant-specific primers, fluorescent labeling of universal primers, adjustment of annealing temperatures and optimization of primer concentrations. The genotyping of 484 Holstein cows resulted in 16.12% carriers with at least one genetic defect, while no homozygous recessive genotype was detected. This study found carrier frequencies ranging from 0.0% (HH6) to 3.72% (HH3) for individual defects. The mf-ARMS PCR method demonstrated improved detection, time and cost efficiency compared with the KASP method for these defects. Therefore, the application of mf-ARMS PCR for genotyping Holstein cattle is anticipated to decrease the frequency of lethal alleles and limit the transmission of these genetic defects.

Orthogonal-Frequency Simultaneous Wireless Power and Data Transfer for High-Power Wireless EV Charging

In a simultaneous wireless power and data transfer (SWPDT) system using common coils, achieving high-speed communication in high-power wireless charging systems is challenging due to power transfer interference on communication. Based on high-frequency data carrier-based SWPDT (HFDC-SWPDT) technology, this paper proposes an orthogonal-frequency simultaneous wireless power and data transfer (OF-SWPDT) method to minimize interference where the data carrier frequency is orthogonal to the power carrier frequency and its harmonics. In addition, a guard band is inserted between the spectra of power harmonics and data in order to further separate the power and data spectra. Thus, a high-power, high-speed SWPDT system is achieved. Finally, an 11 kW prototype with 64.125 kbps full-duplex communication is developed to validate the proposed method.

Detection of quadratic phase coupling by cross-bicoherence and spectral Granger causality in bifrequencies interactions

Quadratic Phase Coupling (QPC) serves as an essential statistical instrument for evaluating nonlinear synchronization within multivariate time series data, especially in signal processing and neuroscience fields. This study explores the precision of QPC detection using numerical estimates derived from cross-bicoherence and bivariate Granger causality within a straightforward, yet noisy, instantaneous multiplier model. It further assesses the impact of accidental statistically significant bifrequency interactions, introducing new metrics such as the ratio of bispectral quadratic phase coupling and the ratio of bivariate Granger causality quadratic phase coupling. Ratios nearing 1 signify a high degree of accuracy in detecting QPC. The coupling strength between interacting channels is identified as a key element that introduces nonlinearities, influencing the signal-to-noise ratio in the output channel. The model is tested across 59 experimental conditions of simulated recordings, with each condition evaluated against six coupling strength values, covering a wide range of carrier frequencies to examine a broad spectrum of scenarios. The findings demonstrate that the bispectral method outperforms bivariate Granger causality, particularly in identifying specific QPC under conditions of very weak couplings and in the presence of noise. The detection of specific QPC is crucial for neuroscience applications aimed at better understanding the temporal and spatial coordination between different brain regions.

Electromagnetic telemetry signal denoising: An interference elimination via parameter estimation

Electromagnetic telemetry has emerged as a promising technique for the real-time acquisition of downhole data. However, the transmission of electromagnetic waves through the formation encounters attenuation, leading to a weakened received signal at the surface, typically registering at the microvolt level. The growing presence of surface electrical equipment in well-site environments has engendered heightened electromagnetic interference, thus deteriorating the signal-to-noise ratio (SNR) of received signals. The conventional linear filtering method can effectively eliminate the electromagnetic interference at the wellsite, but it has no effect on the low frequency interference close to the carrier frequency, especially the common low-frequency pulse interference (LPI) and power line interference (PLI). To mitigate the adverse effects of surface noise, we propose a nonlinear processing method based on parameter estimation algorithms. Generally, the proposed method entails reconstructing the interference by accurate parameter estimation and subtracting it from the received signal, aiming to enhance the SNR of the received signal. Simulation data and real noise data collected in the field are processed to verify the effectiveness of the proposed method. The results demonstrate the superiority of this approach over traditional filtering techniques in effectively eradicating surface interference.

Millimeter-wave over fiber integrated sensing and communication system using self-coherent OFDM

Orthogonal frequency-division multiplexing (OFDM) waveform is highly preferred as a dual-function candidate for integrated sensing and communication (ISAC) systems. However, the sensitivity to both carrier frequency offset (CFO) and phase noise greatly impedes its applications in millimeter-wave ISAC systems. Here, we propose and experimentally demonstrate a photonic millimeter-wave ISAC system employing the virtual-carrier-aided self-coherent OFDM technique, wherein a digitally-generated local oscillator is transmitted along with the OFDM signal. Then, a compact CFO-immune and phase noise-immune envelope detection method is implemented for down-converting millimeter-wave communication and radar echo signals. In experiments, a V-band ISAC system is successfully implemented with a simplified remote radio unit, using the remote photonic millimeter-wave heterodyning up-conversion for downlink and the envelope detection-assisted down-conversion for uplink (or radar echoes). In the converged transmission link with a 5-km fiber link and 2-m space link, the Kramers–Kronig (KK) receiver supports a communication data rate up to 16-Gbit/s by mitigating signal-signal beat interference (SSBI). More significantly, the SSBI leads to negligible effects on the sensing performance when classic matched filtering is adopted for target identification. Consequently, a 4.8-cm range resolution and a 4-mm range accuracy are obtained for the radar sensing function.

Strong-field processes induced by an ultrashort linearly polarized pulse with two carrier frequencies

Strong-field processes induced by an ultrashort linearly polarized pulse with two carrier frequencies

Burden of Mendelian disorders in a large Middle Eastern biobank

BackgroundGenome sequencing of large biobanks from under-represented ancestries provides a valuable resource for the interrogation of Mendelian disease burden at world population level, complementing small-scale familial studies.MethodsHere, we interrogate 6045 whole genomes from Qatar—a Middle Eastern population with high consanguinity and understudied mutational burden—enrolled at the national Biobank and phenotyped for 58 clinically-relevant quantitative traits. We examine a curated set of 2648 Mendelian genes from 20 panels, annotating known and novel pathogenic variants and assessing their penetrance and impact on the measured traits.ResultsWe find that 62.5% of participants are carriers of at least 1 known pathogenic variant relating to recessive conditions, with homozygosity observed in 1 in 150 subjects (0.6%) for which Peninsular Arabs are particularly enriched versus other ancestries (5.8-fold). On average, 52.3 loss-of-function variants were found per genome, 6.5 of which affect a known Mendelian gene. Several variants annotated in ClinVar/HGMD as pathogenic appeared at intermediate frequencies in this cohort (1–3%), highlighting Arab founder effect, while others have exceedingly high frequencies (> 5%) prompting reconsideration as benign. Furthermore, cumulative gene burden analysis revealed 56 genes having gene carrier frequency > 1/50, including 5 ACMG Tier 3 panel genes which would be candidates for adding to newborn screening in the country. Additionally, leveraging 58 biobank traits, we systematically assess the impact of novel/rare variants on phenotypes and discover 39 candidate large-effect variants associating with extreme quantitative traits. Furthermore, through rare variant burden testing, we discover 13 genes with high mutational load, including 5 with impact on traits relevant to disease conditions, including metabolic disorder and type 2 diabetes, consistent with the high prevalence of these conditions in the region.ConclusionsThis study on the first phase of the growing Qatar Genome Program cohort provides a comprehensive resource from a Middle Eastern population to understand the global mutational burden in Mendelian genes and their impact on traits in seemingly healthy individuals in high consanguinity settings.

Two-way ranging with carrier frequency and phase offset compensation based on software defined radio

In the context of Two-Way Ranging (TWR)measurements, distinct transmitter and receiver devices lead to discrepancies in clock timing, resulting in a Carrier Frequency Offset (CFO) and Carrier Phase Offset (CPO) that diminish the accuracy of distance measurements. Furthermore, moving objects also exacerbate these issues, increasing measurement errors. The effect of the CFO leads to variations and bit value inversion in the code in one frame when measuring two-way ranging distances with N random number sequence. In order to resolve this issue, the Fast Fourier Transform (FFT) is used in this work to determine the CFO and peak cross-correlation for the searching CPO. In outdoor experiments using Software Defined Radio (SDR) conducted over a maximum distance of 80 m, it was found that the precision of measurements was accurate within 1.25 m, and the overall accuracy was within 0.82 m when the Signal-to-Noise Ratio (SNR) was greater than 5 dB.

ASIC design of power and area efficient programmable FIR filter using optimized Urdhva-Tiryagbhyam Multiplier for impedance cardiography

Impedance cardiography (ICG) is a rapidly growing non-invasive cardiac health monitoring approach. Synchronous detection of ICG requires an FIR filter to remove the high-frequency carrier signal. Low power consumption and compact area are critical considerations in the design of portable biomedical systems. This paper proposes a novel product quantization-based optimization strategy for the Urdhva Tiryagbhyam Sutra-based multiplier architecture. This paper presents an ASIC design of a low-power and low-area 64th-order programmable FIR filter architecture using the optimized Urdhva Tiryagbhyam Multiplier. The programmable architecture empowers medical practitioners to select the carrier frequency at which the ICG analysis will be performed. The elimination of redundant multipliers from the design based on the filter coefficients is demonstrated. The programmable Vedic FIR filter architecture (described in VHDL) is implemented on the Basys-3 FPGA board for rapid prototyping. The RTL-to-GDSII flow has been completed using Cadence digital design and sign-off tools for the SCL-180 nm technology. The results indicate that the proposed filter architecture occupies 41.33% less area and 42.16% lower power consumption than the contemporary designs described in the literature.

A wireless stimulator system-on-chip with an optically writable ID for addressable cortical microimplants

For a profound understanding of brain function and connectivity, there is an escalating need to cover expansive cortical areas. While external recording methods such as electroencephalography (EEG) are prevalent, direct bidirectional interaction with the neural network mandates implanted electrodes. Integrating all microimplant functionalities into a single integrated circuit (IC) increases design complexities. Thus, challenges in the intricacies of distributed system networking have frustrated the drive toward implant miniaturization. In this context, we introduce addressable microimplants equipped with gate oxide-based anti-fuse (AF) Chip-IDs activated by a photodiode (PD) array. This mechanism generates a binary ID code by selectively degrading the anti-fuse gate oxide, eliminating the need for I/O PADs. These ID-equipped wireless micro-implants are distributed over vast regions, enabling bidirectional neural interfacing through recording and stimulation. We successfully fabricated an 8-channel wireless microstimulator and a spike-sensor in 180 nm CMOS, demonstrating the efficacy of the 5-bit Chip-ID in real-time networking scenarios. The system draws power from RF electromagnetic waves, receiving 1.2 V and 1 mW, and employs amplitude modulation at a 900 MHz carrier frequency for data communication. The minimum amplitude detected for demodulation was 350 mV, regenerating a 1 MHz clock and 34-bit command data. When tested, the array of eight microstimulators responded distinctly based on sequential command parameters. This IC realized in TSMC 180 nm CMOS technology, occupies only a 1 mm2 area.

Spectral holographic trapping: Creating dynamic force landscapes with polyphonic waves.

Acoustic trapping uses forces exerted by sound waves to transport small objects along specified trajectories in three dimensions. The structure of the time-averaged acoustic force landscape acting on an object is determined by the amplitude and phase profiles of the sound's pressure wave. These profiles typically are sculpted by deliberately selecting the amplitude and relative phase of the sound projected by each transducer in large arrays of transducers, all operating at the same carrier frequency. This approach leverages a powerful analogy with holographic optical trapping at the cost of considerable technical complexity. Acoustic force fields also can be shaped by the spectral content of the component sound waves in a manner that is not feasible with light. The same theoretical framework that predicts the time-averaged structure of monotone acoustic force landscapes can be applied to spectrally rich sound fields in the quasistatic approximation, creating opportunities for dexterous control using comparatively simple hardware. We demonstrate this approach to spectral holographic acoustic trapping by projecting acoustic conveyor beams that move millimeter-scale objects along prescribed paths. Spectral control of reflections provides yet another opportunity for controlling the structure and dynamics of an acoustic force landscape. We use this approach to realize two variations on the theme of a wave-driven oscillator, a deceptively simple dynamical system with surprisingly complex phenomenology.

Impact of specific electromagnetic radiation on wakefulness in mice

Electromagnetic radiation (EMR) in the environment, particularly in the microwave range, may constitute a public health concern. Exposure to 2.4 GHz EMR modulated by 100 Hz square pulses was recently reported to markedly increase wakefulness in mice. Here, we demonstrate that a similar wakefulness increase can be induced by the modulation frequency of 1,000 Hz, but not 10 Hz. In contrast to the carrier frequency of 2.4 GHz, 935 MHz EMR of the same power density has little impact on wakefulness irrespective of modulation frequency. Notably, the replacement of the 100 Hz square-pulsed modulation by sinusoidal-pulsed modulation of 2.4 GHz EMR still allows a marked increase of wakefulness. In contrast, continuous sinusoidal amplitude modulation of 100 Hz with the same time-averaged power output fails to trigger any detectable change of wakefulness. Therefore, alteration of sleep behavior by EMR depends upon not just carrier frequency but also frequency and mode of the modulation. These results implicate biological sensing mechanisms for specific EMR in animals.

High carrier frequency for abetalipoproteinemia and evidence of a founder variant in a French-Canadian population

Abetalipoproteinemia (ABL) is a rare recessive genetic disease caused by bi-allelic pathogenic variants in the microsomal triglyceride transfer protein (MTTP) gene. This disease is characterized by a deficiency in the secretion of apolipoprotein B-containing lipoproteins. Patients with ABL present with neurological, hematological, and gastrointestinal symptoms due to fat malabsorption and a deficiency in liposoluble vitamins. In this report, we present a total of four ABL cases, including three new cases, all originating from the same French-Canadian founder population in Saguenay-Lac-Saint-Jean, Québec, Canada. These individuals are homozygous for the same pathogenic variant in the MTTP gene (c.419dup, p.Asn140Lysfs*2). We found that this variant is more common than anticipated in this population, with an estimated carrier frequency of 1:203. Early diagnosis is essential to initiate treatment known to prevent complications associated with ABL. Population carrier screening or newborn screening for ABL should be considered in this French-Canadian founder population.

A Model-Driven Deep Learning-Based Receiver for OFDM System With Carrier Frequency Offset

A Model-Driven Deep Learning-Based Receiver for OFDM System With Carrier Frequency Offset

Extremely Low Frequency PS-PWM Based Technique for Cascaded H-Bridge Converters With Grid Voltage Compensation Capability

Cascaded H-Bridge Converters (CHB) are good candidates for many industrial applications. Among the modulation techniques that can be applied to CHB converters, the Phase-shifted PWM method (PS-PWM) provides very good harmonic quality being the most popular modulation technique at the expense of presenting high switching losses. On the contrary Block Switching technique as well as Selective Harmonic elimination/mitigation (SHE/SHM) techniques provides lower switching frequency and losses with a lower harmonic quality. Additionally with these techniques the converter operation becomes stiff. In this work a modification of PS-PWM based on an extremely low frequency carrier is proposed with the objective of achieving both low switching losses and an acceptable harmonic quality, simultaneously. The main advantage of the proposed solution is the capability of adjusting the phase-shift angle among the carriers to compensate for harmonic grid voltage disturbance. Several experimental results have been reported to demonstrate the good performance of the proposed modulation technique.

Prevalence of common autosomal recessive mutation carriers in women in the Southern Vietnam following the application of expanded carrier screening

The common autosomal recessive (AR) mutation carrier is still unknown in Vietnam. This study aims to identify the most common AR gene mutation carriers in women of reproductive age to build a Vietnamese-specific carrier screening panel for AR and X-linked disorders in the preconception and prenatal healthcare program. A cross-sectional study was conducted at University Medical Center–Branch 2 in Ho Chi Minh City from December 1st, 2020, to June 30th, 2023. 338 women have consented to take a 5 mL blood test to identify 540 recessive genes. The carrier screening panel was designed based on the American College of Medical Genetics and Genomics (ACMG)-recommended genes and suggestions from 104 clinical experts in Vietnam. Obstetricians and genetic experts counseled all positive testing results to discuss the possibility of recessive diseases in their offspring. The most common recessive disorders were defined at a prevalence of 1 in 60 or greater, and those were added to a Vietnamese-specific carrier screening panel. 338 non-pregnant and pregnant women underwent the expanded carrier screening (ECS). The carrier frequency was 63.6%, in which 215 women carried at least one AR gene mutation. GJB2 hearing impairment was identified as the most common chronic condition (1 in 5). The second most common AR disorder was beta-thalassemia (1 in 16), followed by cystic fibrosis (1 in 23), G6PD deficiency (1 in 28), Wilson’s disease (1 in 31), Usher’s syndrome (1 in 31), and glycogen storage disease (1 in 56). Seven common recessive genes were added in ethnic-based carrier screening. Women in the South of Vietnam have been carried for many recessive conditions at high frequency, such as hearing impairment, genetic anemia, and cystic fibrosis. It is necessary to implement a preconception and prenatal screening program by using seven widely popular AR genes in a Vietnamese-specific carrier screening panel to reduce the burden related to AR and X-linked disorders.