hf high frequency 中文意思是什麼
hf high frequency
解釋
高頻，高音-
The ionosphere is a complex medium, which is aeolotropy, asymmetry, dispersive and changes randomly with time. in order to improve the communication quality of the shortwave that depends on the ionosphere, we should have aknowledge of the current condition of the ionosphere in real time. the backscatter sounding of high frequency can diagnose the real - time channel characters for shortwave communication or hf radar, which is great assistant to shortwave communication and hf radar
電離層是隨機時變，各向異性，非均勻、色散的復雜介質。為了保證依賴于電離層進行的短波通信質量，必須了解電離層的實時狀態信息。高頻返回散射探測可以實時監測與短波通信或高頻天波雷達相關的天波傳播通道的狀態，對短波通信和天波雷達工作起了重要的輔助作用。 -
The main results as follows results from sinoatrial node in vivo 1 、 under bilateral vagi intact condition the value of hf ( high frequency power ) component, lf ( low frequency power ) component and apen value of ibis was the highest, but the lf / hf ratio was the lowest ; unilateral vagotomy decreased apen value of ibis, right vagotomy increased lf / hf ratio but left vagotomy did not
05 ） 。在離體竇房結還記錄到自發輕度不規則放電，自發不規則放電使竇房結放電間期近似嫡從對照時的0二8土0 09 （ n 6 ）升高到不規則放電時的0 -
Abstract ： to obtain the high frequency ( hf ) array signals, an applied circuit called hf array signals generator is designed using dsp and duc ( digital up converter ). the generator simulates the generation of output signals of 9 - element arrays with different array format, different direction of arrival ( doa ) and existing cochannel signals respectively
為了在實驗室中獲得短波天線陣列信號，應用dsp晶元和duc晶元（數字上變頻器）設計了一個實用電路短波陣列信號發生器，模擬實現了短波九元天線陣的多種陣型、不同來波方向及存在同頻多信號時的陣列輸出信號。 -
Frequency - hopping ( fh ) is a novel spread spectrum communication technique, which develops very fast in military field due to its lpi / lpd ( low probability of intercept / detection ) properties and immunity against interferences, the extensive application of hf ( high frequency ) frequency - hopping radios in military has greatly enhanced the ability of military equipments against jamming and interception and brought up a new austere challenge for communication countermeasures
跳頻通信具有良好的抗干擾性，低截獲概率及組網能力，因此跳頻技術的一出現，便在軍事領域得到了極大的發展，採用跳頻技術的短波電臺在軍事通信中得到了廣泛應用，極大地提高了軍事裝備的抗截獲和抗干擾能力，向通信對抗提出了嚴峻的挑戰。 -
Othr ( over - the - horizon radar ) is a kind of hf ( high frequency ) radar with great expectation, which has arisen great concern worldwide because of its large coverage, anti - stealth character and so on
超視距雷達（ othr ）是一種具有較大發展前景的高頻雷達，以其覆蓋距離遠、覆蓋面積大和抗隱身等優良特點受到各國學者的廣泛關注。 -
Because of the limited cross - range resolution, high frequency ( hf ) over - the - horizon ( oth ) radar has the poor ability to determine the number of group targets and identify the large warship such as aircraft carrier in engineering applications
我國的高頻雷達已進入工程化應用階段，但由於受分辨能力的限制，在群組目標的個數分辨及大型船隻的識別等方面仍有不足之處。 -
Except with the advantages of long range early warning and anti - stealth, rending anti - radiation missiles useless, also for its inherent flexibility and mobility that enlarge warning region, high frequency ship - borne surface wave over - the - horizon radar ( hf sswothr ) has been widely used in military domain
高頻地波艦載超視距雷達具有遠距離預警、反隱身、抗反輻射導彈攻擊等方面的顯著特點。而且載艦本身的靈活性、機動性又提供了更廣闊的警戒空間，因此它在軍事上具有廣闊的應用前景。 -
The company talented people, give full play to their talents, continuous improvement, continuous innovation, in 1990s, improves the two series of hf including seven products to new energy - efficient products, and through the identification of new products at the provincial level, including : designed and developed by ourselves the new products gp - h - d 800kw electron tube - powered high frequency induction heating equipment filled the domestic gap
公司以其科學的質量管理雄厚的技術力量，連年被河北省科委命名為高新技術企業。並率先在同行業中通過了is09001 ： 20 .本公司生產的高頻焊管加熱設備為節能新型單迴路，整機電路成熟，可靠耐用。 -
Take integrity of object information into condition, a two - dimension signal processing method which can make a measurement of the target ’ s speed as well as the range is brought forward at the basis of waveform parameter design. and simulation in the background of hf multi - object with noise is taken. a comparison of signal properties, processing and antinoise detection performance is taken between mcpc and another two high range resolution radar signals : single carrier pulse coded signal and step frequency pulse coded signal
考慮到目標信息提取的相對完整性，以高頻雷達為背景，在對多載波相位編碼脈沖串信號參數設計的基礎上，推導了三種多載頻相位編碼脈沖串信號的距離速度二維處理過程並相應的對多目標噪聲環境進行了模擬;將多載波相位編碼信號與另外兩種距離高分辨信號:單載頻相位編碼信號和相位編碼階梯跳頻信號，在信號特性、處理過程和抗噪聲特性方面進行了對比;本文從理論上為多載波相位編碼信號的波形設計和分析、信號的處理打下基礎。 -
One components of the equipment : sf - ggp - 1solid state hf high frequency welder machine is composed by four parts : sor dc power supply vibratory output. touch screen plc control and wind - water exchange water cooling system
一， sf - ggp全固態高頻焊機主要由scr dc電源部分振蕩輸出部分觸摸屏plc控制部分三部分組成。 -
The ionosphere contamination imposing on the high - frequency ( hf ) radar echoes has to be suppressed since it severely degrades the detection performance of hf radar
摘要高頻雷達回波信號受到電離層污染從而影響了雷達的探測性能，因此需要進行去污染處理。 -
In this paper, consulting the idea of software radio and using the three important theories of maximum mean power estimate ( mmpe ) for symbol synchronization algorithm, the kalman decision - feedback equalization ( dfe ) algorithm and the decision - feedback phase lock loop ( dfpll ) algorithm, a kind of low frequency digital demodulate scheme over high - frequency ( hf ) radio channels for 8psk signial is realized
本文利用軟體無線電的思想，提出了一種hf通道8psk信號低頻采樣數字化解調方案。討論了實現該方案的三個核心演算法：最大平均功率定時同步演算法、判決反饋式鎖相環和卡爾曼均衡器，分析它們的基本理論，並進行了性能測試。 -
Upstream channels cover in 5 65mhz, which is a part of the bandwidth of high frequency （ hf ） and very high frequency （ vhf ）. it is liable to incur noises ingress onto the band. since hfc system has the tree - and - branch topology between the fiber - node and subscriber units, subscriber units belonging to one fiber - node share the same upstream channel, forming the " noise funneling " effect
上行頻帶位於5 - 65mhz之間，這一頻帶為高頻（ hf ）和甚高頻（ vhf ）的一部分，此頻帶易受噪聲干擾；此外，由於從光節點到用戶端為樹型分支結構，同一光節點的多個用戶共享同一通道，形成了漏斗效應。 -
Analyzing real hrv, proving the every segment power ( high frequency > low frequency ) of projection in frequency axis is times with the every segment power by using fft, the lf / hf by using 2 method is primarily sameness. 3d figure is a trenchancy tool for doctor to look over the relation between time and frequency
對實際的心率變異信號進行了維重慶大學碩士學位論文格納分析，證實通過計算三維時頻分佈對頻率軸的投影得到的各頻段（高頻段、低頻段等）功率，與直接用fft所得各頻段功率，二者只相差一個比例系數，並且二者lf hf的值基本相同。 -
Frequency - hopping ( fh ) is a novel spread spectrum communication technique, which develops very fast in military field due to its lpi / lpd ( low probability of intercept / detection ) properties and immunity against interferences, the extensive application of hf / vhf ( high frequency / very high frequency ) frequency - hopping radios in military has greatly enhanced the ability of military equipments against jamming and interception and ensure the safety and validity of chain of military command
跳頻技術是擴頻技術的一種，是80年代以來出現的一種新的通信方式。跳頻通信具有良好的抗干擾性，低截獲概率及組網能力，因此跳頻技術的一出現，便在軍事領域得到了極大的發展。採用跳頻技術的短波超短波電臺在軍事通信中得到了廣泛應用，極大地提高了軍事裝備的抗截獲和抗干擾能力，保證了軍事指揮系統的安全和有效性。 -
The technology of very low bit rate for hf ( high frequency ) communication means that, one technology of ecm ( electronic counter measures ) resistant communication is developed for low bit data message exchange in the time of battle which data communication is destroyed by electronic disturber. it is regarded by armies in the battle of information, because that it can overcome the very low snr ( signal noise ratio ), very high narrow - band interference and multipath with maxium delay of fifty millisecond
短波最低限度通信技術是在戰時強電磁干擾情況下能實現保證最低限度的數據報通信的一種抗干擾通信技術。由於其能有效的克服極低信噪比、較強的窄帶干擾和幾十毫秒的多徑，在信息戰中受到各軍高度重視。 -
By its super long life, hf ( high frequency ) electrodeless light establishes a separate sect in family of lights
高頻無極燈以其6萬小時的超長壽命在照明家族獨樹一幟。 -
In hf ( high frequency ) radar, the targets detected based on the spectrum processed by the two - dimension fft are peak - like, which makes the operator distinguish them from the clutter and background noise easiler in the 3d ( three - dimension ) display than the 2d
特別對于距離分辨力低的高頻雷達系統，其探測的目標通常近似為點目標，在經二維傅立葉變換得到的頻譜數據上呈現峰狀結構。
分享友人