scholarly journals High Frequency Bandwidth Extension for Audio Codec in Mobile Surveillance Device

2017 ◽  
Vol 10 (7) ◽  
pp. 93-104
Author(s):  
Bo Hang ◽  
Yi Wang ◽  
Changqing Kang
Keyword(s):  
High Frequency ◽  
Frequency Bandwidth ◽  
Bandwidth Extension ◽  
Audio Codec ◽  
Mobile Surveillance

scholarly journals Superwideband Bandwidth Extension Using Normalized MDCT Coefficients for Scalable Speech and Audio Coding

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Young Han Lee ◽  
Seung Ho Choi
Keyword(s):  
Discrete Cosine Transform ◽  
Audio Coding ◽  
Bandwidth Extension ◽  
Spectral Parameters ◽  
Cosine Transform ◽  
Modified Discrete Cosine Transform ◽  
Audio Codec ◽  
Speech And Audio Coding

A bandwidth extension (BWE) algorithm from wideband to superwideband (SWB) is proposed for a scalable speech/audio codec that uses modified discrete cosine transform (MDCT) coefficients as spectral parameters. The superwideband is first split into several subbands that are represented as gain parameters and normalized MDCT coefficients in the proposed BWE algorithm. We then estimate normalized MDCT coefficients of the wideband to be fetched for the superwideband and quantize the fetch indices. After that, we quantize gain parameters by using relative ratios between adjacent subbands. The proposed BWE algorithm is embedded into a standard superwideband codec, the SWB extension of G.729.1 Annex E, and its bitrate and quality are compared with those of the BWE algorithm already employed in the standard superwideband codec. It is shown from the comparison that the proposed BWE algorithm relatively reduces the bitrate by around 19% with better quality, compared to the BWE algorithm in the SWB extension of G.729.1 Annex E.

High frequency band limits in spectral analysis of heart rate variability in preterm infants

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Hadas Israeli-Mendlovic ◽  
Joseph Mendlovic ◽  
Luba Zuk ◽  
Michal Katz-Leurer
Keyword(s):  
Preterm Infants ◽  
High Frequency ◽  
Neonatal Intensive Care ◽  
Breathing Rate ◽  
Frequency Bandwidth ◽  
High Frequency Band ◽  
Constant Frequency ◽  
Band Power ◽  
The Time Domain ◽  
Electrocardiogram Ecg

Abstract Objectives The current study aims to assess different high-frequency (HF) band power calculations based on different frequency bandwidth values, and compare them with the time domain the root mean square of successive RR differences (RMSSD) value in preterm infants. Methods At week 32, electrocardiogram (ECG) and breathing rate (BR) were recorded for 24 h on 30 preterm infants born between 28 and 32 weeks. The recording held in the neonatal intensive care unit without any interruption of routine. Results The median 24 h BR was 40–78 breaths per minute. The RMSSD was highly and positively correlated with frequency bands that were based on each preterms BR range, or on a constant frequency with band limits of 0.4–2 Hz. Conclusions At week 32, HF band Hz limits should be calculated based on each child’s breathing rate, generally between 0.4 and 2 Hz.

A U-matched printed antenna for dual-band WiFi applications

2014 ◽  
Vol 7 (5) ◽  
pp. 551-556 ◽  
Author(s):  
Churng-Jou Tsai ◽  
Bo-Yuan Tsai
Keyword(s):  
High Frequency ◽  
Microstrip Line ◽  
Access Point ◽  
Wireless Access ◽  
Dual Band ◽  
Frequency Bandwidth ◽  
Printed Antenna ◽  
Directional Radiation ◽  
5 Ghz ◽  
And Control

In this paper, a novel and compact center-fed dual-band WiFi printed antenna is presented. This antenna is designed using two different arms which correspond to the oscillation points of the dual band, and uses parasitic capacitance and U-shaped microstrip line to match and control the necessary bandwidth. The measured frequency bandwidth of this antenna is 2.3–2.61 GHz (310 MHz, 12.7%) at 2 GHz, and the high-frequency bandwidth is 4.82–5.84 GHz (1020 MHz, 19.1%) at 5 GHz, which meets the requirements for applications in global WiFi communication. This PCB antenna is double-sided, long, and narrow; its size is 7 × 45.9 × 1 mm3; it can be applied to wireless access point; and it has a near-omni-directional radiation pattern. The design, analysis, and measured results of this proposed antenna will be presented.

An Improved Design of PIFA Antenna on Mobile Phone

2013 ◽  
Vol 718-720 ◽  
pp. 1634-1638 ◽  
Author(s):  
Li Yun Zhang ◽  
Zheng Ron Xiao ◽  
Jun Liao
Keyword(s):  
Mobile Phone ◽  
High Frequency ◽  
Return Loss ◽  
Antenna Design ◽  
Frequency Bandwidth ◽  
High Frequency Band ◽  
Simulation Results ◽  
Improved Design ◽  
High Band ◽  
Pifa Antenna

Firstly, the development and principle of PIFA antenna in mobile phone are introduced, and the typical PIFA antenna design is analyzed. The PIFA antenna simulation is based on HFSS software. It is found that the high frequency bandwidth of this kind of antenna is very narrow. Then related parameters are optimized, by increasing the parasitic branch in high frequency band. Simulation results show that the return loss of PIFA antenna in high band is improved and the antenna can be expanded in high band, and matched in low band simultaneously.

scholarly journals A Design of Dual Broadband Antenna in Mobile Communication System

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Jianming Zhou
Keyword(s):  
Mobile Communication ◽  
Communication System ◽  
High Frequency ◽  
Microstrip Line ◽  
Low Frequency ◽  
Dielectric Substrate ◽  
Frequency Bandwidth ◽  
Broadband Antenna ◽  
Feeding Method ◽  
Frequency Unit

A design of dual broadband antenna is proposed in this paper; it consists of one low frequency unit and two high frequency units. The low frequency unit consists of a pair of printing vibrators; the high frequency unit consists of a pair of printing oscillators, which is bent at its end, and high frequency unit and low frequency unit are set on the same dielectric substrate. Through adding a parasitic unit on antenna, it can enhance frequency bandwidth without affecting the bandwidth. In the high frequency unit, it adopts gap-coupled microstrip line feeding method in order to get enough bandwidth. Through the test of dual broadband antenna, it can be found that, in the low frequency part, the antenna covers 20% bandwidth of the total bandwidth, and it covers the frequency from 800 MHz to 980 MHz. In the high frequency, the antenna covers 60% of total bandwidth and its frequency is from 1540 MHz to 2860 MHz, so the designed antenna can satisfy the frequency requirements of 2G/3G/LTE (4G) communication system.

scholarly journals DESIGN AND SIMULATION OF DIELECTRIC RESONATOR ANTENNA (DRA) WITH CO-AXIAL PROBE FOR WIRELESS APPLICATION

2020 ◽  
Vol 5 (2) ◽  
pp. 75-83
Author(s):  
Devansh Sinha ◽  
Mohit Vyas ◽  
Sanjay Singh Kushwah
Keyword(s):  
High Frequency ◽  
Dielectric Resonator ◽  
Return Loss ◽  
Ground Plane ◽  
Impedance Bandwidth ◽  
Dielectric Resonator Antenna ◽  
Frequency Bandwidth ◽  
Rectangular Patch ◽  
Wireless Application ◽  
Potential Parameters

In this paper a Dielectric resonator antenna (DRA) consists of a rectangular geometry and a printed rectangular patch on top of it in order to achieve better performance and operation without significant increase in antenna size. DRA structure is proposed at a height of 2 mm from the ground plane and patch incorporated at the height of 3.638 mm. This work is mainly focused on increasing the potential parameters of DRA and analyze high frequency band. The proposed antenna is designed to resonate at 25 GHz and by varying the DRA size ‘a, then the simulated results shows variation in Return Loss. The impedance bandwidth of the DRA (23.417 GHz-26.961 GHz) and return loss is 26.543951dB.The proposed DRA is analyzed and design using CST-MSW (2010). The simulated result shows the Far field, smith chart. We have estimated the wavelength, frequency, bandwidth, Return loss and directivity.                                      

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