Aiming at the problem of music noise introduced by classical spectral subtraction,a shorttime modulation domain(STM)spectral subtraction method has been successfully applied for singlechannel speech enhancement.Howeve...Aiming at the problem of music noise introduced by classical spectral subtraction,a shorttime modulation domain(STM)spectral subtraction method has been successfully applied for singlechannel speech enhancement.However,due to the inaccurate voice activity detection(VAD),the residual music noise and enhanced performance still need to be further improved,especially in the low signal to noise ratio(SNR)scenarios.To address this issue,an improved frame iterative spectral subtraction in the STM domain(IMModSSub)is proposed.More specifically,with the inter-frame correlation,the noise subtraction is directly applied to handle the noisy signal for each frame in the STM domain.Then,the noisy signal is classified into speech or silence frames based on a predefined threshold of segmented SNR.With these classification results,a corresponding mask function is developed for noisy speech after noise subtraction.Finally,exploiting the increased sparsity of speech signal in the modulation domain,the orthogonal matching pursuit(OMP)technique is employed to the speech frames for improving the speech quality and intelligibility.The effectiveness of the proposed method is evaluated with three types of noise,including white noise,pink noise,and hfchannel noise.The obtained results show that the proposed method outperforms some established baselines at lower SNRs(-5 to +5 dB).展开更多
Modulation domain measurement can be u sed to analyze the frequency,phase,and time intervals which transiently change with time.During the implementation of modulation domain analyzer,meas urement errors can be introd...Modulation domain measurement can be u sed to analyze the frequency,phase,and time intervals which transiently change with time.During the implementation of modulation domain analyzer,meas urement errors can be introduced in multiple parts.Aiming at a typical implementation of modul ation domain analyzer,this paper analyzes the inherent error between channe l s,temperature drift error in time-to-digital converter(TDC),random err or,time-base error and their influence on the modulation domain measurement.It also gives a correction sche me and comparison of the measurement results.The frequency resolution can be im proved from 10 to 12 bit/s after correction.展开更多
Digital enzyme-linked immunoassays(dELISA)have been successfully applied to the ultrasensitive quantification of analytes,including nucleic acids,proteins,cells,and extracellular vesicles,achieving robust detection li...Digital enzyme-linked immunoassays(dELISA)have been successfully applied to the ultrasensitive quantification of analytes,including nucleic acids,proteins,cells,and extracellular vesicles,achieving robust detection limits in complex clinical specimens such as blood,and demonstrating utility across a broad range of clinical applications.The ultrasensitivity of dELISA comes from partitioning single analytes,captured onto a microbead,into millions of compartments so that they can be counted individually.There is particular interest in using dELISA for multiplexed measurements,but generating and detecting the billions of compartments necessary to perform multiplexed ultrasensitive dELISA remains a challenge.To address this,we have developed a high-throughput,optofluidic platform that performs quantitative fluorescence measurements on five populations of microbeads,each encoded with distinct ratios of two fluorescent dyes,for digital assays.The key innovation of our work is the parallelization of droplet generation and detection,combined with time-domain encoding of the excitation sources into distinct patterns that barcode the emission signal of both dyes within each bead,achieving high throughput(6×10^(6) droplets/min)and accurate readout.Additionally,we modulate the exposure settings of the digital camera,capturing images of multiplexed beads and the droplet fluorescent substrate in consecutive frames,a method inspired by high dynamic range(HDR)photography.Our platform accurately classifies five populations of dual-encoded beads(accuracy>99%)and detects bead-bound streptavidin-horseradish peroxidase molecules in a third fluorescence channel.This work establishes the technological foundation to combine high multiplexing and high throughput for droplet digital assays.展开更多
In order to obtain large broadband, a novel travelling-wave modulator with nonperiodic domain inversions and ridge structure is proposed. The composite structure is designed to achieve velocity matching between the op...In order to obtain large broadband, a novel travelling-wave modulator with nonperiodic domain inversions and ridge structure is proposed. The composite structure is designed to achieve velocity matching between the optical wave and the microwave, to get a 50 characteristic impedance and to reduce the loss of the microwave electrodes with finite element method (FEM). The calculation results show that the frequency response of the new device is flat up to 350 GHz with interaction length of 1 cm, characteristic impedance of 49 , and microwave refractive index of 2.5.展开更多
基金National Natural Science Foundation of China(NSFC)(No.61671075)Major Program of National Natural Science Foundation of China(No.61631003)。
文摘Aiming at the problem of music noise introduced by classical spectral subtraction,a shorttime modulation domain(STM)spectral subtraction method has been successfully applied for singlechannel speech enhancement.However,due to the inaccurate voice activity detection(VAD),the residual music noise and enhanced performance still need to be further improved,especially in the low signal to noise ratio(SNR)scenarios.To address this issue,an improved frame iterative spectral subtraction in the STM domain(IMModSSub)is proposed.More specifically,with the inter-frame correlation,the noise subtraction is directly applied to handle the noisy signal for each frame in the STM domain.Then,the noisy signal is classified into speech or silence frames based on a predefined threshold of segmented SNR.With these classification results,a corresponding mask function is developed for noisy speech after noise subtraction.Finally,exploiting the increased sparsity of speech signal in the modulation domain,the orthogonal matching pursuit(OMP)technique is employed to the speech frames for improving the speech quality and intelligibility.The effectiveness of the proposed method is evaluated with three types of noise,including white noise,pink noise,and hfchannel noise.The obtained results show that the proposed method outperforms some established baselines at lower SNRs(-5 to +5 dB).
文摘Modulation domain measurement can be u sed to analyze the frequency,phase,and time intervals which transiently change with time.During the implementation of modulation domain analyzer,meas urement errors can be introduced in multiple parts.Aiming at a typical implementation of modul ation domain analyzer,this paper analyzes the inherent error between channe l s,temperature drift error in time-to-digital converter(TDC),random err or,time-base error and their influence on the modulation domain measurement.It also gives a correction sche me and comparison of the measurement results.The frequency resolution can be im proved from 10 to 12 bit/s after correction.
基金funding from the following sources:National Human Genome Research Institute(RM1-HG-010023)National Cancer Institute(R21CA236653,R33CA278551)+2 种基金National Institute of Mental Health(R33-NIMH-118170)National Institute of Allergy and Infectious Diseases(R33-AI-147406)National Defense Science and Engineering Graduate Fellowship.
文摘Digital enzyme-linked immunoassays(dELISA)have been successfully applied to the ultrasensitive quantification of analytes,including nucleic acids,proteins,cells,and extracellular vesicles,achieving robust detection limits in complex clinical specimens such as blood,and demonstrating utility across a broad range of clinical applications.The ultrasensitivity of dELISA comes from partitioning single analytes,captured onto a microbead,into millions of compartments so that they can be counted individually.There is particular interest in using dELISA for multiplexed measurements,but generating and detecting the billions of compartments necessary to perform multiplexed ultrasensitive dELISA remains a challenge.To address this,we have developed a high-throughput,optofluidic platform that performs quantitative fluorescence measurements on five populations of microbeads,each encoded with distinct ratios of two fluorescent dyes,for digital assays.The key innovation of our work is the parallelization of droplet generation and detection,combined with time-domain encoding of the excitation sources into distinct patterns that barcode the emission signal of both dyes within each bead,achieving high throughput(6×10^(6) droplets/min)and accurate readout.Additionally,we modulate the exposure settings of the digital camera,capturing images of multiplexed beads and the droplet fluorescent substrate in consecutive frames,a method inspired by high dynamic range(HDR)photography.Our platform accurately classifies five populations of dual-encoded beads(accuracy>99%)and detects bead-bound streptavidin-horseradish peroxidase molecules in a third fluorescence channel.This work establishes the technological foundation to combine high multiplexing and high throughput for droplet digital assays.
基金This work was supported by the National Natural Science Foundation of China(No.60077030)
文摘In order to obtain large broadband, a novel travelling-wave modulator with nonperiodic domain inversions and ridge structure is proposed. The composite structure is designed to achieve velocity matching between the optical wave and the microwave, to get a 50 characteristic impedance and to reduce the loss of the microwave electrodes with finite element method (FEM). The calculation results show that the frequency response of the new device is flat up to 350 GHz with interaction length of 1 cm, characteristic impedance of 49 , and microwave refractive index of 2.5.
