1) discrete frequency
离散频率
1.
The results show that the impinging tone dominates the discrete frequency noise with short impinging distances.
结果表明:对于凹、凸、平三种形状的冲击面,当冲击距离较小时,冲击单音主导了离散频率噪声;冲击单音最强音的频率随压比增大呈现频级阶越的现象;射流噪声总声压级随压比成类似对数增长的关系,当喷嘴压比大于2。
2.
A kind of induction motor soft start control method based on discrete frequency principle is introduced.
介绍了一种基于离散频率原理的电机软启动控制方法。
2) D iscrete fenquency control
离散频率法
3) discrete frequency control
离散频率控制
1.
A discrete frequency control method is proposed for thyristorized static switch.
介绍了用于感应电机起动的离散频率控制方法。
4) discrete frequency-coding waveform
离散频率编码波形
1.
Aimed at the designing issue of discrete frequency-coding waveforms in a MIMO radar system,a method to optimally combine the selection of frequency-coding sequence using the genetic algorithm was presented.
针对MIMO雷达体制的离散频率编码波形设计问题,给出了一种采用遗传算法对频率编码序列的选取进行优化组合的方法。
5) discrete spectrum
离散频谱
1.
A new method is put forward for automatically identifying and modifying the parameters of the two close frequency components in discrete spectrum based on ICM.
在理论概括比值法原理的基础上 ,提出一种新的自动识别和修正离散频谱中两邻近谱峰参数的方法。
2.
A new method to identify and correct the parameters of intensive frequency components automatically in the discrete spectrum was presented.
提出一种自动识别和校正离散频谱中邻近谱峰参数的方法·该方法不仅保留了比值法计算简单的特点 ,而且既能识别间距不到一个频率分辨率的密集频率成分 ,又能校正峰间距为 1～ 6个频率分辨率的邻近谱峰参数 ,从而与比值法相辅相成 ,形成一套完整的离散频率信号分析方法·数值仿真结果证明了方法的有效性
3.
At present, the single harmonic component and far spaced multi frequency components in discrete spectrum can be identified by using the methods of spectrum correction, and its frequency, phase and amplitude can be corrected automatica.
目前频谱校正理论已经能准确地自动识别出离散频谱中的单频成分和间隔较远的多频率成分 ,并自动校正其频率、幅值和相位 ;对多频成分谱线干涉中的单频成分能自动判定 ,且能用参数识别法对两个密集频谱进行校正 ;对于密集频率成分信号 ,可用频谱细化的方法 ,将发生谱线干涉的各谱峰分离开 ,再进行识别和校正。
6) discrete variable frequency
离散变频
1.
This paper studied some technical problems arising during the soft starting of three-phase asynchronous motors with heavy loads,which was achieved by means of discrete variable frequency.
针对采用离散变频方式实现三相异步电动机重载软起动过程的一些技术问题进行了分析和研究。
2.
Based on characteristics of discrete variable frequency soft starting, a novel speed measuring method using residual voltage after AC dump was proposed, and its counting formula, analysis of errors were presented.
针对离散变频技术调压调频的特点,提出了基于电动机失电残余电压的测速方法,推导出了转速计算公式,并进行了误差分析。
3.
To solve the key problem of soft starting based on discrete variable frequency,the influence of different trigger-ing modes on the phase of first-harmonic of generated voltage was investigated and the selection of frequency steps and the switching process were analyzed.
针对离散变频软起动方法中的关键问题,研究了不同触发方式对分频电压基波相位的影响,并分析了各离散频段的选取及切换过程。
补充资料：离散时间周期序列的离散傅里叶级数表示
(1)
式中χ((n))N为一离散时间周期序列，其周期为N点，即
式中r为任意整数。X((k))N为频域周期序列，其周期亦为N点，即X(k)=X(k+lN)，式中l为任意整数。
从式(1)可导出已知X((k))N求χ((n))N的关系
(2)
式(1)和式(2)称为离散傅里叶级数对。
当离散时间周期序列整体向左移位m时,移位后的序列为χ((n+m))N，如果χ((n))N的离散傅里叶级数(DFS)表示为,则χ((n+m))N的DFS表示为
式中χ((n))N为一离散时间周期序列，其周期为N点，即
式中r为任意整数。X((k))N为频域周期序列，其周期亦为N点，即X(k)=X(k+lN)，式中l为任意整数。
从式(1)可导出已知X((k))N求χ((n))N的关系
(2)
式(1)和式(2)称为离散傅里叶级数对。
当离散时间周期序列整体向左移位m时,移位后的序列为χ((n+m))N，如果χ((n))N的离散傅里叶级数(DFS)表示为,则χ((n+m))N的DFS表示为
说明：补充资料仅用于学习参考，请勿用于其它任何用途。
参考词条