zero carrier 中文意思是什麼
zero carrier
解釋
零振幅載波-
In communications, an amplitude modulated signal in which the amplitude of the carrier is reduced to zero for some part of the cycle of the modulating waveform
通信技術中的一種調幅信號，其載波的振幅在調制波形周期的某些部分減少到零。 -
In digital holography, the off - axis setup ca n ' t make effective use of the pixels of a ccd camera because of the necessity for carrier fringe. and the size of the reconstructed image is also limited by the presence of zero - order and conjugate image in off - axis digital holography
數字全息中，由於記錄介質ccd的有限解析度，同軸數字全息較離軸數字全息有更多的優點，它可以有效利用ccd的像元個數，擴大再現像的視場，提高再現像的解析度，更適合記錄小尺度三維物體。 -
Ds signal is twice modulated with the rapid pseudorandom noise sequence and the carrier. so it appears cyclostationary. in the field of spectral correlation, ds signals appears its characteristic as fallows : for the amplitude of spectral correlation, the information of carrier frequency and pn code rate are contained on the spectrum frequency equal to zero sheet, and also the pn code rate is contained on the sheet of spectrum frequency equal to carrier frequency ; for the phase of spectral correlation, the information of carrier initial phase is contained on the sheet of cyclic frequency equal to double carrier frequency
Ds信號是經過高速偽隨機序列和正弦載波二次調制的寬帶信號，因此具有周期平穩特性，它在譜相關域表現為:幅頻特性在譜頻率等於零截面切片上包含了載頻和偽碼速率信息特徵，在譜頻率等於載頻截面切片上包含了偽碼速率信息特徵;相頻特性在循環頻率等於兩倍載頻截面切片上包含了載波初相信息特徵。 -
At present the manufacture of surface acoustic wave use the technology of the final submicron. a series of the devices of low insertion loss, high q saw rayleigh surface acoustic wave resonators or stws that insertion loss has less than 5db, load quality factor ( ql ) is more than 1000 on the quartz piezoelectric with zero of first temperature factor in the research. these difference frequencies are 60mhz, 280mhz, 739mhz and 1ghz of normal frequency and at also surface acoustic wave. using 1. 25db noise factor amplifier, careful design curcuit, good setting printed curcuit board, and using the 1ghz surface transverse wave resonator as frequency element, researching the low phase noise surface acoustic wave with sideband phase noise near ? 120dbc / hz deviating 1khz on carrier, spurious suppress with 80db
本研究採用一階溫度系數為零的壓電石英基片上製作出損耗小於5db 、有載品值因素（ ql值）超過1000的一系列低損耗、高q值聲表面波rayleigh波或stw諧振器，頻率分別為60mhz 、 280mhz 、 739mhz和1ghz等不同頻率的高性能聲表面波諧振器。並採用噪聲系數為1 . 25db的低噪聲系數放大器，精心設計電路，優化設計布置印製電路板，用標稱頻率為1ghz的聲表面波諧振器為頻率控制元件，製作出在偏離載頻1khz處的單邊帶相位噪聲近- 120dbc / hz 、雜波抑制達80db以上的低相位噪聲聲表面波振蕩器。
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