正調頻 的英文怎麼說
中文拼音 [zhēngdiàobīn]
正調頻
英文
positive frequency modulation- 正 : 正名詞(正月) the first month of the lunar year; the first moon
- 調 : Ⅰ動詞1 (配合得均勻合適) harmonize; suit well; fit in perfectly 2 (使配合得均勻合適) mix; adju...
- 頻 : Ⅰ形容詞(次數多) frequent Ⅱ副詞(屢次) frequently; repeatedly Ⅲ名詞1 [物理學] (物體每秒鐘振動...
- 調頻 : frequency modulation (fm); frequency adjustment調頻磁帶錄音機 f m magnetic tape recorder; 調頻...
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Presents the model proposed for analyzing the vibration characteristics of shrouded blades and their calculation method by employing a wave propagation theory and modal synthesis technology coupled with a finite element method from the view point it is possible not only to conduct frequency modulation of the shrouded blades of a gas turbine, but also to utilize the friction effects between them to dissipate energy, thereby attaining the aim of vibration alleviation, as shrouded blades have been widely used in the design of high - speed turbomachinery, such as modern gas turbines and steam turbines, and with the shrouded blades forming an integral whole in a centrifugal force field, the vibration characteristics of the whole ring of blades are different from those of a single isolated blade, and this makes it essential to take into account the integral effect of blade shrouds, concludes from the calculation examples and engineering application that the above approach is valid and correct along with the possibility of considerably reducing the scale of calculation and analysis, and points out it is necessary to take into consideration the coupled effect of the whole ring of blades while the dynamic characteristics of shrouded blades is being analysed
帶冠葉片不但能調頻,還可以利用葉冠之間的摩擦效應來耗散能量,達到減振的目的.帶冠葉片在離心力場中形成一整體,其整圈葉片振動特性不同於單個孤立葉片,需考慮葉冠的整體效應.利用帶冠葉片系統的循環對稱性,提出了採用波傳播理論和模態綜合技術,結合有限元方法研究燃氣輪機帶冠葉片振動特性的分析模型和計算方法.算例和工程應用證明了該方法是效性的、正確的,並可以大大降低計算分析規模.研究表明帶冠葉片動力特性分析時必須考慮整圈葉片的耦合效應However, the paralleling communication can meet the requirements of high speed and fidelity in underwater signal transmissions. ofdm is a kind of novel paralleling transmission technology. the principle of ofdm is that the whole bandwidth can be divided into some subchannels, the high - speed serial signal stream is modulated by some orthogonal subcarriers
正交頻分復用( ofdm )是近年來數字通信中流行的一種并行傳輸新技術,其核心思想是將整個可用頻帶分割成多個正交子通道,將待傳輸的高速串列碼流并行的調制在這些子通道載波上。And pays emphasis on analyzing the system structure and system flow, the core techniques, the channel characteristic and parameters of dvb - t system. the system adopts some core techniques such as cofdm, a lot of tps ( transmission parameter signalling ) insert and guard interval, and so on. so it can withstand high - level ( up to odb ), long delay static and dynamic multipath distortion
論文首先描述了數字電視地面廣播的需求條件,技術難點和目前存在的問題,並重點分析了dvb - t系統結構流程,核心技術及系統通道特性和參數,該系統採用了cofdm (編碼正交頻分多路復用) ,大量導頻信號插入和保護間隔技術等核心技術,使之能抵抗高電平( 0db ) ,長延時的靜態和動態多徑失真,有利於數字和模擬電視的混合傳輸,它的多載波調制模式功能和性能在移動和便攜接收、同頻網等方面具有獨特的優勢。The radar which is embedded on platform sidelooking, but the platform will be disturbed by airflow inevitably. so, the radar will have a small sloping angle, thereby, the doppler centroid that is not zero and doppler frequency rate need to be estimated from the raw echo data in order to focus in azimuth commendably
場景成像的合成孔徑雷達一般是正側視放置,但是載機不可避免的要受到各種擾動影響,雷達會有一定的斜視角,從而導致了多普勒中心頻率不為零,多普勒調頻斜率也隨著雷達斜視角改變。Continuous single tune jamming is an effective jamming to linear frequency - modulated radar. however it can not suppress signal output after being full of the sidelobe suppress filter of the jammed bi - phase coded radar, no matter how great the power of it may be
單頻正弦波干擾對線性調頻雷達是一種有效干擾,但對於二相編碼雷達無論具有多大的功率在充滿二相編碼雷達接收機的旁瓣抑制濾波器后也不能壓制信號主瓣,因此是一種無效干擾。In order to ensure the normal operation of airplane navigation and communication system, you are kindly requested not to use your callularphone / cd player / fm receiver
為確保飛行和通信系統的正常操作,請您不要使用手提電話/激光唱機/調頻收音機。The spwm algorithm using symmetrical sample in this controller, can alter its frequency and amplitude. the good performance of the bldc motor controller using dsp is verified by the experiment
本文在分析了幾種spwm調制方法的基礎上,將基於對稱采樣法的spwm調制演算法應用於本設計中,產生了可調頻調幅的正弦波脈寬調制信號。We modulate the amplitude of the continuous single tune jamming by noise and produce the continuous noise - modulated jamming. this kind of jamming is effective to pc radar including linear frequency - modulated radar and bi - phase coded radar
在對單頻正弦波進行噪聲調幅后形成的噪聲調幅干擾對線性調頻雷達和二相編碼雷達都是有效干擾,其干擾特性和射頻噪聲干擾類似。Orthogonal frequency division multiplexing ( ofdm ) is a multi - carrier modulation method
正交頻分多路復用是一種多載波調制技術。The general signal sources represented by arbitrary waveform generator ( awg ) have become the most popular instruments in modern testing domains. awg can not only generate conventional waves such as sine wave, triangle wave, square wave, etc, but also generate unconventional waves such as linear frequency modulation wave, phrase modulation wave, amplitude modulation wave etc, the most important, it can create arbitrary wave
由於它可產生包括各種理想及非理想的波形信號,不但可以產生純凈的正弦波、方波、三角波等常規波形,而且可以產生線性調頻、調相、調幅信號以及程式控制占空比的低占空比方波,更為重要的是,能夠根據用戶測試需求生成任意波形。For lfm signal, we demonstrate the method of employing hamming weighting, spectrum correcting and phase modulation distortion
對線性調頻信號的旁瓣抑制介紹了經典海明窗加權處理方法、頻譜修正以及相位預矯正幾種方法。Because frequency - shift signal is a kind of modulation signal, it ' s waveform is two ac sine signal of alternating i. e. upper frequency and lower frequency which was generated by low frequency modulating middle frequency
由於移頻信號是一種調頻信號,其波形為低頻信號調制中心載頻信號后產生的低端載頻(下邊頻)和高端載頻(上邊頻)兩個交替變化的正弦交流信號。At the same tune, the paper analyses and discusses the control projects of the above parts. as for the hardware of the control system, on principle of reliability and considering the badly working condition of the vibratory roller, the paper chooses the special controller sp ecializing in the realm of construction machinery ' s control system in order to insure the reliability of the control system and simplify it. about the control quality of the system, the paper establishes the mathematical modes of the frequency modulation system and the amplitude modulation system, analyses the irrationality of the amplitude modulation project, puts forward to apply proportional - integral - differential controller ( pid controller ) to the traveling system and frequency modulation system
作為控制系統的方案設計的基礎,本文首先對影響壓實效果的振動參數進行了分析;然後針對智能振動壓路機的功能要求,將控制系統分為壓實參數的自動和手動控制、行走控制、轉向和蟹行控制以及智能灑水控制等幾個部分,對各部分的控制方案進行了分析對比和論證;在控制系統硬體設計方面,以可靠性為原則,考慮到振動壓路機的惡劣工況,選擇了專用於工程機械控制領域的專用控制器,使系統的硬體設計得以可靠性保障和簡化;針對控制系統控製品質問題,建立了調頻和調幅系統的控制模型,對調幅系統的控制不合理性進行了分析,提出採用pid控制器對行走和調頻系統進行校正;在軟體設計方面,對各個控制部分進行了軟體編程流程圖設計。Firstly, the principle of high resolution sar and theoretical imaging model were concisely introduced. pulse compression for line frequency modulation pulse signal, resolution of range direction and azimuth direction, and doppler history were discussed subsequently. in accordance with sar signal processing, range immigration was also involved
本文首先分析了合成孔徑雷達高分辯力成像機理和sar成像理論模型,討論了線性調頻脈沖信號的匹配濾波(脈沖壓縮) 、 sar距離特性、方位特性和多普勒歷史,同時針對sar成像信號處理,分析了成像處理的基本原理和成像處理中的距離遷移校正等關鍵問題。In this dissertation, ofdm which has been the hottest spot in communication field recently will be considered as my direction. the dissertation will study some key techniques in mc - cdma system, such as modulation technique, peak - average power ratio, detection technique and synchronization problem of the whole system. what ' s more, the results of calculation and simulation will be given
本文以目前通信領域的熱點: ofdm (正交頻分復用)為研究方向,對于多載波cdma系統中的若干關鍵技術,即多載波cdma系統中的調制技術、峰平比性能、接收端檢測技術以及整個系統同步問題進行了研究,並給出相應的計算機模擬結果。Now cdma is very mature and becomes the key technique of the third - generation mobile communication systems. more and more attention is paid to the technique of multi - carrier. mc - cdma is combination of ofdm and cdma, thus advantages of both techniques are exploited
近年來移動通信技術發展迅猛,碼分多址技術到目前已經非常成熟,並成為了第三代移動通信系統的核心,人們將眼光聚集在正交頻分復用調制技術,將多載波調制技術應用於cdma中,從而兼具多載波技術和cdma技術的優點。In addition, research on esprit ( estimation of signal parameter via rotational invariance technique ) super - resolution imaging technology is made to improve image quality, especially in the case of small segment of viewing angle. afterward, a new multi - target isar imaging method for high - speed targets is presented
2 .在方位向的補償(相位校正)方面,利用多重的離散傅立葉變換( dcft ) ,對目標平動引起的相位線性調頻項的調頻斜率進行精確估計,並直接構造補償項對各個距離門進行補償。By the tuner, the dvb - t signal received has been converted to the if signal, and then demodulated by the cofdm demodulation chip. in the end, the usb controller sends the ts ( transport stream ) to the pc where it is decoded by the software
接收到的dvb - t信號經調諧器進行下變頻處理后輸出中頻信號,再進行cofdm (編碼正交頻分復用)解調,得到的ts碼流信號通過usb控制器送入pc機中進行軟體解碼播放。The arithmetic formulas for sine wave, linear frequency modulation signal, v - style frequency modulation signal, white noise signal, reverberation signal and echo signal are given by their definition
根據信號類型的定義,給出了正弦信號、線性調頻信號、 v型調頻信號、白噪聲、混響和回波信號的合成公式。On the other hand, recent advances in communication and modulation methodologice, as well as in adaptive digital signal processing and error detection and correction, have opened the way for the development of effective medium access control and physical layer protocols that support power line communications ( plc ) networks operating at speeds comparable to those obtained from specially wired and more recent wireless local area network in mid - 2001, an industrial standards organization called the homeplug powerline alliance, originally founded by 13 companies including cisco, motorola, intel, panasonic, and texas instruments, announced the completion of the homeplugl. o specification for a l. 0mb / s class in - home power line networking technology based on orthogonal frequency - division multiplexing ( ofdm )
但是,近年來通信和調制技術的發展,特別是自適應數字信號處理和錯誤檢測及糾正技術,使電力線通信技術出現新的mac層和物理層協議,其性能可以和一些專用有線網路以及最近十年流行的無線局域網技術想媲美。在2001年,一個由13個公司(包括cisco , motorola , intel , panasonic , andtexasinstruments )組成的組成的標準組織? ? homeplugpowerline聯盟,頒布了完整的homeplug1 . 0規范,改規范使基於正交頻分復用技術,主要針對10mb s室內電力線網路技術。分享友人