In this paper we revisit hybrid analog-digital precoding systems with emphasis on their modelling and radio-frequency (RF) losses, to realistically evaluate their benefits in 5G system implementations. For this, we decompose the analog beamforming networks (ABFN) as a bank of commonly used RF components and formulate realistic model constraints based on their S-parameters. Specifically, we concentrate on fully-connected ABFN (FC-ABFN) and Butler networks for implementing the discrete Fourier transform (DFT) in the RF domain. The results presented in this paper reveal that the performance and energy efficiency of hybrid precoding systems are severely affected, once practical factors are considered in the overall design. In this context, we also show that Butler RF networks are capable of providing better performances than FC-ABFN for systems with a large number of RF chains.
標簽： Analog-Digital Precoding Hybrid
上傳時間： 2020-05-27
上傳用戶：shancjb
This book deals with a very important problem in power system planning for countries in which hydrogeneration accounts for the greatest part of the system power production. During the past thirty years many techniques have been developed to cope with the long-term operation of hydro reser- voirs. These techniques have been discussed in a number of publications, but they have not until now been documented in book form.
標簽： Long-Term Operation Optimal
上傳時間： 2020-06-07
上傳用戶：shancjb
本系統采用電動機電樞供電回路串接采樣電阻的方式來實現對小型直流有刷電動機的轉速測量。該系統主要由二階低通濾波電路,小信號放大電路、單片機測量顯示電路、開關穩壓電源電路等組成。同時自制電機測速裝置,用高頻磁環作為載體,用線圈繞制磁環,利用電磁感應原理檢測電機運行時的漏磁,將變化的磁場信號轉化為磁環上的感應電流。用信號處理單元電路將微弱電信號轉化為脈沖信號,送由單片機檢測,從而達到準確測量電機的速度的要求。In this system, the sampling resistance of armature power supply circuit is connected in series to measure the speed of small DC brush motor. The system is mainly composed of second-order low-pass filter circuit, small signal amplifier circuit, single-chip measurement and display circuit, switching regulated power supply circuit and so on. At the same time, the self-made motor speed measuring device uses high frequency magnetic ring as the carrier, coil winding magnetic ring, and electromagnetic induction principle to detect the leakage of magnetic field during the operation of the motor, which converts the changed magnetic field signal into the induced current on the magnetic ring. The weak electric signal is transformed into pulse signal by signal processing unit circuit, which is sent to single chip computer for detection, so as to meet the requirement of accurate measurement of motor speed.
標簽： 直流電動機
上傳時間： 2022-03-26
上傳用戶：
AR0231AT7C00XUEA0-DRBR（RGB濾光）安森美半導體推出采用突破性減少LED閃爍 (LFM)技術的新的230萬像素CMOS圖像傳感器樣品AR0231AT，為汽車先進駕駛輔助系統(ADAS)應用確立了一個新基準。新器件能捕獲1080p高動態范圍(HDR)視頻，還具備支持汽車安全完整性等級B(ASIL B)的特性。LFM技術(專利申請中)消除交通信號燈和汽車LED照明的高頻LED閃爍，令交通信號閱讀算法能于所有光照條件下工作。AR0231AT具有1/2.7英寸(6.82 mm)光學格式和1928(水平) x 1208(垂直)有源像素陣列。它采用最新的3.0微米背照式(BSI)像素及安森美半導體的DR-Pix?技術，提供雙轉換增益以在所有光照條件下提升性能。它以線性、HDR或LFM模式捕獲圖像，并提供模式間的幀到幀情境切換。 AR0231AT提供達4重曝光的HDR，以出色的噪聲性能捕獲超過120dB的動態范圍。AR0231AT能同步支持多個攝相機，以易于在汽車應用中實現多個傳感器節點，和通過一個簡單的雙線串行接口實現用戶可編程性。它還有多個數據接口，包括MIPI(移動產業處理器接口)、并行和HiSPi(高速串行像素接口)。其它關鍵特性還包括可選自動化或用戶控制的黑電平控制，支持擴頻時鐘輸入和提供多色濾波陣列選擇。封裝和現狀：AR0231AT采用11 mm x 10 mm iBGA-121封裝，現提供工程樣品。工作溫度范圍為-40℃至105℃(環境溫度)，將完全通過AEC-Q100認證。
標簽： 圖像傳感器
上傳時間： 2022-06-27
上傳用戶：XuVshu
This I develops based on the B/S structure student managementsystem management system, hoped brings a help to the novice
標簽： managementsystem management structure develops
上傳時間： 2014-01-07
上傳用戶：釣鰲牧馬
About: hamsterdb is a database engine written in ANSI C. It supports a B+Tree index structure, uses memory mapped I/O (if available), supports cursors, and can create in-memory databases. Release focus: Major feature enhancements Changes: This release comes with many changes and new features. It can manage multiple databases in one file. A new flag (HAM_LOCK_EXCLUSIVE) places an exclusive lock on the file. hamsterdb was ported to Windows CE, and the Solution file for Visual Studio 2005 now supports builds for x64. Several minor bugs were fixed, performance was improved, and small API changes occurred. Pre-built libraries for Windows (32-bit and 64-bit) are available for download. Author: cruppstahl
標簽： C. hamsterdb structure database
上傳時間： 2013-12-11
上傳用戶：LouieWu
2004China Undergraduate Mathematical Contest in Modeling (CUMCM)是2004年全國數學建模大賽的題目（B題）。現將題目，建模過程及利用“多元線性回歸和人工神經網絡”解題的源代碼上傳給大家一起分享。
標簽： 2004 Undergraduate Mathematical Modeling
上傳時間： 2014-01-08
上傳用戶：youth25
梯形公式計算面積近似值:In=Tn=h/2(f(a)+f(b)) 變長梯形面積:T2n=Tn/2+h/2∑f(Xk+h/2) 辛普生面積:I2n=(4T2n-Tn)/3
上傳時間： 2016-01-06
上傳用戶：qw12
b tree code for index in the database design
標簽： database design index tree
上傳時間： 2016-02-03
上傳用戶：z1191176801
I wrote this code early this year using ColdFire MCF5213 in codewarrior IDE. The LCD is STN B/W 320x240 dot matrix LCD. The code include 3 different fonts, and basic LCD driver. All original!
標簽： this codewarrior ColdFire wrote
上傳時間： 2013-12-20
上傳用戶：皇族傳媒
<button id="sekac"></button>
