【正文】 相對于總時間間隔的 百分率。Envelope amplitude distribution (EAD): A cumulative distribution of the impulseresponse positive crossing rates of a bandpass filter at different spectrum amplitudes. 包絡(luò)幅值分布〔EAD〕：帶通濾波器在頻譜幅值不同時的脈沖響應(yīng)正交擾率的 累積分布。Noise amplitude distribution (NAD): A distribution showing the pulse amplitude thatis equaled or exceeded as a function of pulse repetition rate. 噪聲幅值分布〔NAD〕：隨脈沖重復(fù)率變化的一種表征到達或超過脈沖幅值的分布函數(shù)。Average crossing rate: The average rate at which a specified level (zero if not specified) is crossed in the positivegoing direction. 平均交擾率：規(guī)定的電平〔假設(shè)不規(guī)定那么為0〕被正向被交擾的平均比率。Power density: Emitted power per unit crosssectional area normal to the directionof propagation. 功率密度：垂直于傳播方向的每單位橫截面積上輻射通過的功率。FREQUENCY SPECTRUM MANAGEMENT 頻譜管理Radio waves or Hertzian waves: Electromagnetic waves of frequencies arbitrarily lower than 3000 GHz, propagated in space without artificial guide. 無線電波或赫茲波：無人工導(dǎo)引情況下在空間傳播的任何頻率低于3 000 GHz的電磁波。Radiation: The outward flow of energy from any source in the form of radio waves. 輻射：從源發(fā)出的能量以無線電波的形式向外傳播。 Emission: Radiation produced, or the production of radiation, by a radio transmitting station. (For example, the energy radiated by the local oscillator or a radio receiver would not be an emission but a radiation.) Note: However, in the field of EMI/ EMC, the term emission is used to describe the electromagnetic interference (both radiated and conducted) generated by an apparatus or an appliance. 發(fā)射：由無線電發(fā)射電臺產(chǎn)生的輻射或輻射產(chǎn)物。[例如，由本地振蕩器或無線電接收機產(chǎn)生的能量輻射不是發(fā)射，而是輻射。]注意：然而在EMI/EMC領(lǐng)域，術(shù)語發(fā)射用來描述由儀器或設(shè)備產(chǎn)生的電磁干擾〔含輻射的與傳導(dǎo)的兩種〕。Outofband emission: Emission on a frequency or frequencies immediately outside the necessary bandwidth which results from the modulation process, but excluding spurious emissions. 帶外發(fā)射：緊挨在必需的由調(diào)制過程造成的帶寬之外的一個或多個頻率的輻射，但不包括雜散輻射。Spurious emission: Emission on a frequency or frequencies which are outside the necessary bandwidth, the level of which may be reduced without affecting the corresponding transmission of information. Spurious emissions include harmonic emissions, parasitic emissions, intermodulation products, and frequencyconversion products, but exclude outofband emissions. 雜散發(fā)射：必要帶寬外的單個或多個頻率點上的發(fā)射。可以減小其電平而不影響相應(yīng)的信息傳輸。雜散輻射包括諧波發(fā)射、寄生發(fā)射、交調(diào)產(chǎn)物及變頻產(chǎn)物。帶外發(fā)射除外。Unwanted emissions: Consist of spurious emissions and outofband emissions. 無用發(fā)射：包括雜散發(fā)射和帶外發(fā)射。Allocation (of a frequency band): Entry in the Table of Frequency Allocations of a given frequency band for the purpose of its use by one or more terrestrial or space radio munication services or by the radio astronomy service under specified conditions. This term shall also be applied to the frequency band concerned. 〔頻帶〕分配：為了在規(guī)定條件下實現(xiàn)地球或太空范圍內(nèi)的一項或多項無線通信或射電天文學(xué)效勞，將一給定的頻帶登記到頻率分配表中。Allotment (of a radio frequency or radio frequency channel): Entry of a designated frequency channel in an agreed plan, adopted by a petent conference, for use by one or more administrations for a terrestrial or space radio munication service in one or more identified countries or geographic areas and under specified conditions. 〔無線電頻率或無線電頻率信道的〕分配：供一個或多個管理機關(guān)按規(guī)定條件用于一個或多個參與國或地區(qū)進行地球或太空范圍內(nèi)的無線通信效勞，被授權(quán)會議接受登記一個約定方案中指定的頻率信道。Assignment (of a radio frequency or radio frequency channel): Authorization given by an administration for a radio station to use a radio frequency or radio frequency channel under specified conditions. 〔無線電頻率或無線電頻率信道的〕分配：由無線電臺站管理部門核準(zhǔn)，按規(guī)定條件使用無線電頻率或無線電頻率信道。Assigned frequency band: The frequency band within which the emission of a station is authorized。 the width of the band equals the necessary bandwidth plus twice the absolute value of the frequency tolerance. Where space stations are concerned, the assigned frequency band includes twice the maximum Doppler shift that may occur in relation to any point of the earth39。s surface. 分配的頻帶：臺站在批準(zhǔn)的頻帶內(nèi)發(fā)射；該頻帶的寬度等于必要帶寬加上頻率容限絕對值的2倍。對于空間站，指定的頻帶包括可以發(fā)生在有關(guān)的地球外表上任何地點的最大多卜勒頻移的2倍。Assigned frequency: The center of the frequency band assigned to a station. 分配的頻率：分配給臺站的頻帶的中心頻率。Frequency tolerance: The maximum permissible departure by the center frequency of the frequency band occupied by an emission from the assigned frequency, or by the characteristic frequency of an emission from the reference frequency. The frequency tolerance is expressed in parts in million per Hertz. 頻率容限：發(fā)射占有的帶寬中心頻率相對于指定頻率的，或發(fā)射的特征頻率相對于參考頻率的最大允許偏差。頻率容限以每赫茲百萬分之幾來表示。Interference: The effect of unwanted energy caused by one or a bination of emissions, radiations, or inductions upon reception in a radio munication system, manifested by any performance degradation, misinterpretation, or loss of information which could be extracted in the absence of such unwanted energy. 干擾：在無線電通信系統(tǒng)接收時，由一種發(fā)射、輻射、感應(yīng)或它們的組合產(chǎn)生的無用能量的效應(yīng)，表現(xiàn)為性能下降、誤判或使得原本沒有這種無用能量時能提取到的信息喪失。Protection ratio: The minimum value of the wantedtounwanted signal ratio, usually expressed in decibels, at the receiver, input determined under specified conditions such that a specified reception quality of the wanted signal is achieved at the receiver output. 防護率：在規(guī)定條件下，例如接收機輸出的有用信號到達規(guī)定的接收質(zhì)量，所確定的接收機輸入的有用信號與無用信號之比的最小值，通常以分貝表示。SIGNAL INTEGRITY 信號完整性Fall time: Time for a signal to change from a logic high state to a logic low state. 下降時間：信號從邏輯高狀態(tài)變化到邏輯低狀態(tài)所經(jīng)歷的時間。Flight time: Time difference between the signal at the driver reaching Vref with a reference/test load and the signal at the receiver reaching Vref. Flight time is also known as bus loss, since it historically was used to derate the spec Tco timing to account for the difference between the spec load and the actual system load impact on circuit timing. 飛行時間：在鼓勵器接參考/試驗負(fù)載情況下信號到達Vref與接收機信號到達Vref之間的時間差。飛行時間又稱總線損耗，因為歷史上曾用于減小額外時間Tco，觀測Tco是為了考慮專用負(fù)載與實際系統(tǒng)負(fù)載在影響環(huán)路時間方面的差異。ISI (Inter Symbol Interference): ISI refers to the interactions between the logic value/ symbol from the previous switching cycle and the symbol traveling on the same channel of the current cycle. ISI occurs as a result of energy stored in the channel summing with a latter unrelated signal. It is