scholarly journals 1. Action Plans of Public Relations of 4K/8K and Picture Quality Improvement of 110 East Longitude CS Digital Broadcasting to High Definition

2018 ◽  
Vol 72 (3) ◽  
pp. 163-168
Author(s):  
Satellite and Regional Broadcasting Division
Keyword(s):  
Quality Improvement ◽  
Public Relations ◽  
Action Plans ◽  
Picture Quality ◽  
High Definition ◽  
Digital Broadcasting

High Definition Metrology-Based Quality Improvement of Surface Texture in Face Milling of Workpieces with Discontinuous Surfaces

2021 ◽  
pp. 1-38
Author(s):  
Guilong Li ◽  
Shichang Du ◽  
Bo Wang ◽  
Jun Lv ◽  
Yafei Deng
Keyword(s):  
Quality Improvement ◽  
Surface Texture ◽  
Mechanical Performance ◽  
Processing Parameters ◽  
Milling Process ◽  
Face Milling ◽  
Measurement Instruments ◽  
High Definition ◽  
Tool Marks

Abstract In face milling process, the quality of surface texture is vital for mechanical performance of workpieces. The quality of surface texture, especially for waviness, is directly affected by tool marks, a commonly observed phenomenon in face milling. However, appropriate approaches for evaluation and modeling of tool marks are absent to date. Limited to the resolution as well as the efficiency of conventional measurement instruments, the height data of tool marks is hard to be entirely obtained, leading to valuable information omission. Besides, most existing models of tool marks are established for general workpieces with regular geometry and continuous surfaces. Since the cutter-workpiece engagement mode has a significant impact on the generation of tool marks, current models could be inaccurate or invalid when dealing with workpieces with discontinuous surfaces. To overcome this shortage, a novel approach is proposed in this paper, aimed at quality improvement of surface texture in face milling of workpieces with discontinuous surfaces. Firstly, the evaluation indexes for tool marks are defined based on the recently developed high definition metrology (HDM). Secondly, the physical modeling of tool marks is presented, taking the face milling mechanism into account. Thirdly, the physical-informed optimization model is developed to search for the optimal processing parameters for surface quality improvement. At last, the effectiveness of the proposed approach is verified by a face milling experiment on the engine blocks.

scholarly journals Baseband Transceiver Design of a High Definition Radio FM System Using Joint Theoretical Analysis and FPGA Implementation

2014 ◽  
Vol 2014 ◽  
pp. 1-9
Author(s):  
Chien-Sheng Chen ◽  
Chyuan-Der Lu ◽  
Ho-Nien Shou ◽  
Le-Wei Lin
Keyword(s):  
Carrier Frequency ◽  
Orthogonal Frequency Division Multiplexing ◽  
Carrier Frequency Offset ◽  
Timing Synchronization ◽  
High Definition ◽  
Digital Radio ◽  
Radio Broadcasting ◽  
Field Programmable ◽  
Broadcasting System ◽  
Digital Broadcasting

Advances in wireless communications have enabled various technologies for wireless digital communication. In the field of digital radio broadcasting, several specifications have been proposed, such as Eureka-147 and digital radio mondiale (DRM). These systems require a new spectrum assignment, which incurs heavy cost due to the depletion of the available spectrum. Therefore, the in-band on-channel (IBOC) system has been developed to work in the same band with the conventional analog radio and to provide digital broadcasting services. This paper discusses the function and algorithm of the high definition (HD) radio frequency modulation (FM) digital radio broadcasting system. Content includes data format allocation, constellation mapping, orthogonal frequency division multiplexing (OFDM) modulation of the transmitter, timing synchronization, OFDM demodulation, integer and fraction carrier frequency (integer carrier frequency offset (ICFO) and fractional CFO (FCFO)) estimation, and channel estimation of the receiver. When we implement this system to the field programmable gate array (FPGA) based on a hardware platform, both theoretical and practical aspects have been considered to accommodate the available hardware resources.

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