<button id="aukwi"></button> 5G通信系統中massive-MIMO-FBMC技術的結合概述摘要為了應對第五代移動通信（5G）中更高數據率和更低時延的需求，大規模MIMO （massive multiple-input multiple-output）技術已經被提出并被廣泛研究。大規模 MIMO技術能大幅度地提升多用戶網絡的容量。而在5G中的帶寬研究方面，特別 是針對碎片頻譜和頻譜靈活性問題，現有的正交頻分多址（Orthogonal Frequency Division Multiplexing, OFDM）技術不可能應對未來的挑戰，新的波形方案需要 被設計出來。基于此，FBMC（filter bank multicarrier）技術由于具有比OFDM低 得多的帶外頻譜泄露而被受到重視，并已被標準推進組IMT-2020列為5G物理層 的主要備選方案之一。 本文首先回顧了5G中波形設計方案（主要是FBMC調制）和大規模多天線系 統（即massive MIMO）的現有工作和主要挑戰。然后，簡要介紹了基于Massive MIMO的FBMC系統中的自均衡性質，該性質可以用于減少系統所需的子載波數 目。同時，FBMC中的盲信道跟蹤性質可以用于消除massive MIMO系統中的導頻 污染問題。盡管如此，如何將FBMC技術應用于massive MIMO系統中的誤碼率、 計算復雜度、線性需求等方面仍然不明確，未來更多的研究工作需要在massive MIMO-FBMC方面展開來。 關鍵詞：大規模MIMO；FBMC；自均衡；導頻污染；盲均衡
上傳時間： 2022-02-25
上傳用戶：
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：
本系統基于STM32單片機設計的非接觸式電流檢測控制系統,通過OPA548片將所給任意信號放大,由100Ω電阻和INA128芯片進行電流電壓轉換放大后,利用STM32單片機對獲取的電壓信號以0.488μs頻率采樣,利用STM32單片機的FFT庫,獲得信號的諧波信息。測量電流信號精準,該設計可廣泛應用在以STM32單片機為核心控制器件的新型儀表中,性能精準且抗干擾能力強。This system is a non-contact current detection and control system based on STM32 single chip microcomputer. It amplifiesany signal through OPA548 chip, converts and amplifies the current and voltage by 100 Ω resistance and INA128 chip. The obtainedvoltage signal is sampled at the frequency of 0.488 μs by STM 32 single chip microcomputer, and the harmonic information of the signalis obtained by the FFT library of STM 32 single chip microcomputer. The measurement of current signal is accurate. This design can bewidely used in a new instrument with STM 32 single chip microcomputer as its core control device, with accurate performance and stronganti-interference capability.
上傳時間： 2022-03-27
上傳用戶：
數字示波器功能強大,使用方便,但是價格相對昂貴。本文以Ti的MSP430F5529為主控器,以Altera公司的EP2C5T144C8 FPGA器件為邏輯控制部件設計數字示波器。模擬信號經程控放大、整形電路后形成方波信號送至FPGA測頻,根據頻率值選擇采用片上及片外高速AD分段采樣。FPGA控制片外AD采樣并將數據輸入到FIFO模塊中緩存,由單片機進行頻譜分析。測試表明:簡易示波器可以實現自動選檔、多采樣率采樣、高精度測頻及頻譜分析等功能。Digital oscilloscope is powerful and easy to use, but also expensive. The research group designed a low-cost digital oscilloscope, the chip of MSP430F5529 of TI is chosen as the main controller and the device of EP2C5T144C8 of Altera company is used as the logic control unit. Analog signal enter the programmable amplifier circuit, shaping circuit and other pre-processing circuit. The shaped rectangular wave signal is sent to FPGA for measure the frequency. According to the frequency value to select AD on-chip or off-chip high-speed AD for sampling. FPGA controls the off-chip AD sampling and buffers AD data by FIFO module. The single chip microcomputer receives the data, and do FFT for spectrum analysis. The test shows that the simple oscilloscope can realize automatic gain selection, sampling at different sampling rates, high precision frequency measurement and spectrum analysis.
上傳時間： 2022-03-27
上傳用戶：
目的:自主研制一款超聲手術刀電源控制系統,以減少能量的消耗,維持手術刀的正常溫度。方法:對超聲換能器在諧振附近的等效電路建立模型,并設計基于數字信號處理(DSP)的超聲手術刀的硬件控制系統。結果:經對電源控制系統的電路和工作性能測試,生成的電流和電壓的有效值等參數,能夠及時調整電源的頻率,并達到預期的功能指標,使超聲手術刀工作在諧振狀態。結論:以DSP為核心設計的超聲手術刀電源控制系統,測試指標均能夠達到預期的要求,能夠使系統在諧振狀態下工作。Objective: To independently develop a power control system of ultrasonic scalpel so as to reduce the energy consumption and maintain the normal temperature of ultrasonic scalpel. Methods: In this paper, the model of equivalent circuit of ultrasonic transducer nearby syntony was built up, and the hardware control system of ultrasonic scalpel based on digital signal processing(DSP) was designed. Results: Through testing the circuit and work performance of power control system, the series of parameters such as effective value and so on which were produced by this system could adjust frequency of power source in time and attain anticipative functional indicator, and it took the ultrasonic scalpel to work in syntonic situation. Conclusion: The tested indicators of power control system of ultrasonic scalpel based on the kernel design of DSP can attain anticipative requirement, and can take this system to work in syntonic situation.
上傳時間： 2022-04-03
上傳用戶：bluedrops
走線狀態，+tab，改變線寬；2d 線狀態，+shift+tab ，切換倒角方式；crtl+左鍵 ：高亮選中網絡；左下角雙擊，層管理，顯示或隱藏某一層；旋轉：Space；X 軸鏡像：X；Y 軸鏡像：Y；板層管理：L；柵格設置：G；單位進制切換：Q；對齊-水平：A，D；對齊-垂直：A，I，I，Enter；對齊-頂部：A，T；對齊-底部：A，B；對齊-左側：A，L；對齊-右側：A，R；設計-類設置：D，C;設計-板層管理：D，K；
標簽： Altium Designer
上傳時間： 2022-04-17
上傳用戶：trh505
超聲波換能器作為一種實用的檢測手段，能實現聲波所攜帶的信息和電能之間轉換。它的性能優良，價格低廉，操作方便，易于調試，因此在工農業生產中發揮著重要的作用。但目前換能器驅動電路的發射頻率多為40 kHz，本文針對1 MHz的超聲波換能器電路進行了設計，主要介紹了它的發射驅動電路和接收驅動電路的設計方案，并對它們的功能進行了詳細地說明。最后搭建實驗平臺，并對電路的輸入、輸出模塊進行了測試。實驗結果表明，換能器電路運行良好，可以為超聲波高精度測量領域的應用提供參考。As a practical means of detection, ultrasonic transducer can realize the conversion between theinformation carried by sound wave and electric energy.It has the advantages of excellent performance,low cost, convenient operation and debugging, so plays an important role in industrial and agriculturalproduction.However, the transmitting frequency of the driving circuit for most transducer is 40 kHz.Thecircuit of 1 MHz ultrasonic transducer is designed In this paper. It mainly introduces the emissive drivingcircuit and the receiving circuit design and the detailed function of them. Finally, the experimentalplatform is built, and the circuit of input and output were tested. Experiments show that the transducer＇ s...
上傳時間： 2022-04-28
上傳用戶：
基于TMS320F28035芯片為控制核心的空間矢量異步電機變頻器 我們設計的異步電機變頻調速器以TMS320F28035芯片為控制核心，通過輸出三相PWM波控制智能功率模塊IPM驅動三相異步電機。我們使用空間矢量SVPWM算法，并對其進行了優化。采用檢測反電勢的方法省去了昂貴的光電編碼器，大大節省了成本。同時開創性的研發了自動根據運行環境調節的自適應變頻算法，使我們的變頻調速器可以在電網條件惡劣的鄉村山區工作，由此該變頻器已被一家民用水泵生產企業預訂。關鍵字 變頻器 TMS320f28035 IPM SVPWM In our design, the asynchronous machine inverter based on the chip of TMS320F28035 drives the three-Phase asynchronous machine by sending three-phase PWM waves to the IPM, which is short for the Intelligent-Power-Module. The SVPWM (space vector pulse width modulation) strategy is applied to our control algorithm and we optimize it mainly in two aspects. Firstly the inverter detects the speed by measuring the Back EMF instead of installing an expensive photoelectric encoder for costs reduction.
標簽： tms320f28035 芯片
上傳時間： 2022-05-08
上傳用戶：zhanglei193
數字頻率計是電工電子中常用的測量儀器,數字頻率計通過用輸入待測信號對一特定長度的信號進行計數,從而得出頻率并通過數碼管直觀的顯示出來。本文提出了一種與輸入同步的數字頻率計的設計,提高了頻率計的精度,設計采用Multisim軟件進行設計和仿真的過程,介紹了其工作原理,硬件電路設計和仿真的過程。設計采用了Multisim軟件進行設計和仿真,設計結果得到的驗證。Digital frequency counter is used to measure the frequency of a signal.It is common to use a multivibrator to generate a standard 1 second time base signal and count input signal gated by this signal.However,the asynchronous of this time base signal with input signal will bring errors.In this paper,a high precision frequency counter which use synchronized time base signal generator is proposed.This frequency counter is designed and simulated by Multisim tools and result is verified.
標簽： multisim
上傳時間： 2022-05-08
上傳用戶：
射頻識別（即RFID，Radio Frequency Identification）技術是一種利用無線射頻信號進行自動識別并進行信息傳輸的技術。隨著社會的進步和科技的發展，它已經廣泛應用于公安、金融、交通、醫療等社會生活的各個方面。伴隨著各種射頻卡應用的越來越普及，與之相關的射頻卡讀卡器也取得了飛速的發展，越來越多的公司、科研機構紛紛投入到智能射頻卡讀卡器以及相關應用系統的研究和開發當中。 目前我國流行最廣泛的非接IC卡基本都是基于ISO/IEC14443協議的Mifare卡、TYPEA CPU卡、TYPEB CPU卡等，伴隨著這些卡的應用，相應讀卡器也有很多種，這些讀卡器所采用的核心設計都是利用微處理器控制相應射頻處理芯片來實現。目前國際上射頻處理芯片設計基本被恩智浦（NXP，Philips前身）、德州儀器(TI)等幾大半導體公司所控制，其高昂的費用不但影響了RFID技術在諸多領域的大面積推廣，也造成了大量外匯流失。 為響應國家關于半導體產業國產化的號召，加快國產射頻芯片在RFID領域的推廣應用，本文結合RFID技術以及嵌入式系統設計要求，采用上海復旦徼電子集團股份有限公司設計的FM17550射頻芯片結合意法半導體公司的CortexM0核的單片機設計了一款支持Mifare卡、TYPEA CPU卡、TYPEB CPU卡以及NFC功能的通用讀卡器。本設計最大的特點在于支持多類型射頻卡片且成本低廉。 本文首先闡述了射頻識別技術的研究應用現狀及相關的智能射頻卡應用的相關標準，接著從硬件方面介紹該射頻讀卡器所包含的主要模塊的相關設計，然后講述了射頻讀卡器在天線調試過程中的一些方法，軟件方面主要講述該讀卡器各種射頻卡片的功能實現以及在不同行業應用當中帶來的積極的社會和經濟價值。
上傳時間： 2022-06-09
上傳用戶：XuVshu
