nominal adj. 1.名字的,列名的。 2.名义上的,空有其名的;有名无实的。 3.微不足道的,轻微的。 4.名称上的;票面上的。 5.【语法】名词性的。 6.按计划进行的;令人满意的。 nominal capital 名义资本。 a nominal par 票面价格。 a nominal price 虚价。 a nominal partner 名义合伙人。 nominal quotation 【商业】牌价。 nominal wages 名义工资。 nominal horse-power 【物理学】标称马力。 nominal value 票面价值。 a nominal list of officers 职员名册。 a nominal register 名册。 n. 名词性的词。 n. -ism 【哲学】唯名论 (opp. realism)。 n. -ist 【哲学】唯名论者。 adj. -listic 【哲学】唯名论的。
In this method , the phase difference between two compared signals that have same nominal frequency can be converted into voltage signal by phase detector . the voltage signal varies linearly with the phase difference and can be displayed or recorded by some instruments 此方法是将两个被比对的标称值相同的标准频率信号之间的相位关系,通过线性鉴相器转换成与它成线性关系的电压信号,并通过相应的设备进行显示纪录。
The system can generate sweep frequency signal with frequency range from 100khz to 150mhz and power range from - 40dbm to + 18dbm , and measure the gain and phase of the crystal . according to the gain and phase information and the iec - 444 standard , crystal parameters can be calculated , such as nominal frequency , series resistance , shunt capacitance , motion capacitance , motion inductance , q factor and so on 该系统能产生频率范围达100khz 150mhz ,功率范围为? 40dbm + 18dbm的扫频信号,并能对晶振的增益和相位差进行测量,其测量结果按照iec - 444晶振测量标准进行实时处理和计算,从而得到晶振的串联谐振频率、并联谐振频率、等效电阻、静态电容、动态电容、动态电感和品质因数等主要电参数。
Because the nonlinearity of phase detector exists near 0 and 360 , the measurement precision is limited . according to the feature of each nominal frequency , two new measurement methods are discussed in the second chapter of this paper . the two methods can reduce the phase noise , eliminate the effect of nonlinearity and promote the measurem ent precision by taking measure 由于在0和360附近存在的非线性,限制了仪器的测量精度,所以在本文的第二章中通过两种新的测量方法的讨论,并根据各频率标准相位噪声的特点,针对性的采取措施和如何克服在0和360附近的非线性的影响,以达到提高测量精度的目的。