This paper presents a novel approach to improve aliasing rejection in comb-based decimation filters. The method is established on certain palindromic polynomials with all zeros on the unit circle and the sharpening te...This paper presents a novel approach to improve aliasing rejection in comb-based decimation filters. The method is established on certain palindromic polynomials with all zeros on the unit circle and the sharpening technique. As a result, aliasing rejection and the passband characteristic are improved. The method is illustrated with various examples and compared with the methods from the literature. .展开更多
We propose a new narrowband speech watermarking scheme by replacing part of the speech with a scaled and spectrally shaped hidden signal. Theoretically, it is proved that if a small amount of host speech is modified, ...We propose a new narrowband speech watermarking scheme by replacing part of the speech with a scaled and spectrally shaped hidden signal. Theoretically, it is proved that if a small amount of host speech is modified, then not only an ideal channel model for hidden communication can be established, but also high imperceptibility and good intelligibility can be achieved. Furthermore, a practical system implementation is proposed. At the embedder, the power normalization criterion is first imposed on a passband watermark signal by forcing its power level to be the same as the original passband excitation of the cover speech, and a synthesis filter is then used to spectrally shape the scaled watermark signal. At the extractor, a bandpass filter is first used to get rid of the out-of-band signal, and an analysis filter is then employed to compensate for the distortion introduced by the synthesis filter. Experimental results show that the data rate is as high as 400 bits/s with better bandwidth efficiency, and good imperceptibility is achieved. Moreover, this method is robust against various attacks existing in real applications.展开更多
A fifth order operational transconductance amplifier-C （OTA-C） Butterworth type low-pass filter with highly linear range and less passband attenuation is presented for wearable bio-telemetry monitoring applications ...A fifth order operational transconductance amplifier-C （OTA-C） Butterworth type low-pass filter with highly linear range and less passband attenuation is presented for wearable bio-telemetry monitoring applications in a UWB wireless body area network. The source degeneration structure applied in typical small transconduc- tance circuit is improved to provide a highly linear range for the OTA-C filter. Moreover, to reduce the passband attenuation of the filter, a cascode structure is employed as the output stage of the OTA. The OTA-based circuit is operated in weak inversion due to strict power limitation in the biomedical chip. The filter is fabricated in a SMIC 0.18-μm CMOS process. The measured results for the filter have shown a passband gain of -6.2 dB, while the -3-dB frequency is around 276 Hz. For the 0.8 Vpp sinusoidal input at 100 Hz, a total harmonic distortion （THD） of-56.8 dB is obtained. An electrocardiogram signal with noise interference is fed into this chip to validate the function of the designed filter.展开更多
In this paper, we investigate the optical transmission properties of perfect and defective two-segment-connected tri- angular waveguide networks （2SCTWNs） and find that after introducing defects in networks, many gr...In this paper, we investigate the optical transmission properties of perfect and defective two-segment-connected tri- angular waveguide networks （2SCTWNs） and find that after introducing defects in networks, many groups of transparent extreme narrow photonic passbands （ENPPs） will be created in the middle of the transmission spectra, the number for each group and the group number of ENPPs can he adjusted by the matching ratios of waveguide length （MRWLs）, the number of defects, and the number of unit cells of 2SCTWNs. The influences of MRWL, number of defects, and number of unit cells on the number, width, and position of these ENPPs are researched and a series of quantitative rules and prop- erties are obtained. It may be useful for the designing of high-sensitive optical switches, wavelength division multiplexers, extreme-narrowband filters, and other correlative waveguide network devices.展开更多
A structure-based microstrip passband filter with the center frequency of 2.6 GHz was put forward by using double-mode resonator based on defected ground structure （DGS） technology. A double-mode coupling resonator ...A structure-based microstrip passband filter with the center frequency of 2.6 GHz was put forward by using double-mode resonator based on defected ground structure （DGS） technology. A double-mode coupling resonator combined with DGS structure was used to achieve the resonance frequency and the filter size. CST microwave studio was used to optimize the attenuation performance to get the filter parameters. A structure-based passband filter was fabricated. Simulation is consistent with the measurement. Performance shows that the proposed filter could be suitable for the time division-long term devolution （TD-LTE） microwave systems at 2.6 GHz.展开更多
文摘This paper presents a novel approach to improve aliasing rejection in comb-based decimation filters. The method is established on certain palindromic polynomials with all zeros on the unit circle and the sharpening technique. As a result, aliasing rejection and the passband characteristic are improved. The method is illustrated with various examples and compared with the methods from the literature. .
基金Project supported by the National Natural Science Foundation of China(No.61571110)
文摘We propose a new narrowband speech watermarking scheme by replacing part of the speech with a scaled and spectrally shaped hidden signal. Theoretically, it is proved that if a small amount of host speech is modified, then not only an ideal channel model for hidden communication can be established, but also high imperceptibility and good intelligibility can be achieved. Furthermore, a practical system implementation is proposed. At the embedder, the power normalization criterion is first imposed on a passband watermark signal by forcing its power level to be the same as the original passband excitation of the cover speech, and a synthesis filter is then used to spectrally shape the scaled watermark signal. At the extractor, a bandpass filter is first used to get rid of the out-of-band signal, and an analysis filter is then employed to compensate for the distortion introduced by the synthesis filter. Experimental results show that the data rate is as high as 400 bits/s with better bandwidth efficiency, and good imperceptibility is achieved. Moreover, this method is robust against various attacks existing in real applications.
基金Project supported by the National Natural Science Foundation of China(Nos.61161003,61264001,61166004)the Guangxi Natural Science Foundation(No.2013GXNSFAA019333)
文摘A fifth order operational transconductance amplifier-C （OTA-C） Butterworth type low-pass filter with highly linear range and less passband attenuation is presented for wearable bio-telemetry monitoring applications in a UWB wireless body area network. The source degeneration structure applied in typical small transconduc- tance circuit is improved to provide a highly linear range for the OTA-C filter. Moreover, to reduce the passband attenuation of the filter, a cascode structure is employed as the output stage of the OTA. The OTA-based circuit is operated in weak inversion due to strict power limitation in the biomedical chip. The filter is fabricated in a SMIC 0.18-μm CMOS process. The measured results for the filter have shown a passband gain of -6.2 dB, while the -3-dB frequency is around 276 Hz. For the 0.8 Vpp sinusoidal input at 100 Hz, a total harmonic distortion （THD） of-56.8 dB is obtained. An electrocardiogram signal with noise interference is fed into this chip to validate the function of the designed filter.
基金Project supported by the National Natural Science Foundations of China(Grant Nos.11374107 and 10974061)
文摘In this paper, we investigate the optical transmission properties of perfect and defective two-segment-connected tri- angular waveguide networks （2SCTWNs） and find that after introducing defects in networks, many groups of transparent extreme narrow photonic passbands （ENPPs） will be created in the middle of the transmission spectra, the number for each group and the group number of ENPPs can he adjusted by the matching ratios of waveguide length （MRWLs）, the number of defects, and the number of unit cells of 2SCTWNs. The influences of MRWL, number of defects, and number of unit cells on the number, width, and position of these ENPPs are researched and a series of quantitative rules and prop- erties are obtained. It may be useful for the designing of high-sensitive optical switches, wavelength division multiplexers, extreme-narrowband filters, and other correlative waveguide network devices.
基金supported by the National Natural Science Foundation of China (61202399)
文摘A structure-based microstrip passband filter with the center frequency of 2.6 GHz was put forward by using double-mode resonator based on defected ground structure （DGS） technology. A double-mode coupling resonator combined with DGS structure was used to achieve the resonance frequency and the filter size. CST microwave studio was used to optimize the attenuation performance to get the filter parameters. A structure-based passband filter was fabricated. Simulation is consistent with the measurement. Performance shows that the proposed filter could be suitable for the time division-long term devolution （TD-LTE） microwave systems at 2.6 GHz.
