频率

Each of the N sinusoids that make up the model has unknown amplitude and a frequency that equals one of the N frequencies in the list of frequencies.

构成该模型的N个正弦波中的每个均具有未知幅度，并具有一频率，该频率与频率列表中的N个频率中的一个相等。

In this paper, on the basis of the description of the pile-driving process and the dynamic analysis of the pile and the HSPD, the relationship between the frequency and the pile-driving force has been established under the conditions of the pile strength and the HSDP working requirements. The frequency character of the ZYB200B HSPD system has been analyzed quantitatively in the vibrancy pile-driving process, therefore the frequency range and the best available frequency have been obtained.

本文首先通过对压桩过程的描述和桩与液压静力沉桩机的力学分析，确立了液压振动压桩在桩的强度条件下和液压静力沉桩机工作要求下的压桩频率与压桩力幅值之间的关系；定量分析振动压桩时系统的频率特性，得出了ZYB200B型液压静力沉桩机振动压桩时压桩频率的取值范围和系统能得到的最佳频率值。

A novel quasi-constant frequency hysteresis PWM control approach is presented in this paper. Frequency feedback is introduced in hysteresis current control to stabilize switching frequency. Comparing with the common used constant frequency current mode control, the new approach has better stability, faster transient and higher precision, as well as elimination of sub-harmonic oscillation.

摘 要：本文提出了一种新的准固定频率滞环PWM电流控制方法，该方法在滞环电流控制的基础上，引入频率反馈控制，使开关频率基本固定，解决了目前广泛使用的固定频率电流控制方法具有的次谐波振荡的问题，并且具有稳定性好、相应速度快、控制精度高的优点。

It is analyzed the influence of electrical locomotive carbody canopy on the frequency of the carbody vertical bending vibration,the side wall transverse bending vibration and the carbody torsion vibration around the longitudinal axis.

分析了电力机车车体顶盖对车体垂向弯曲振动频率、侧墙横向弯曲振动频率、车体绕纵向轴扭转振动频率的影响，指出车体顶盖对车体垂向弯曲振动频率的影响是很小的，并且通过实例验证了这一点。

The end linking the timing gears cap, the side wall of cylinder and the skirt section of the engineblock are the sound radiation resources of the two engineblock sides. Except that, this thesis calculates sound power level of radiated noise from the engineblock with MATV method. It is found that the noise radiated from the engineblock is slightly loud.

此外本文还应用MATV法计算了气缸体辐射噪声的声功率级，通过声功率级的计算发现：气缸体的辐射噪声偏高，达到了108.84dBA，并且在850Hz时，由于气缸体的激励频率与其第八阶固有频率相等，气缸体发生了共振，因而在该频率时，气缸体的辐射噪声最大，所占气缸体表面辐射噪声总能量比重也最高，该频率应该是本文噪声控制关心的重点。

This paper introduced the parameter frequency response method,developed ship rolling frequency response function equipped with two U-tube anti-rolling tanks with different natural frequencies,analyzed the tank parameters relative to rolling frequency response amplitude,and researched the effect of tank parameters on the ship rolling amplitude.

本文给出了参数频率响应法，推导了装备两个具有不同固有频率的被动式U型减摇水舱的船舶横摇频率响应函数，分析了影响船舶横摇频率响应幅值的水舱参数，通过仿真详细研究了水舱参数对船舶横摇减摇的影响。

Based on these design guides, the analysis and design of a low phase noise and low power dissipation, with 0. 18μm CMOS process, integrated Colpitts crystal oscillator with automatic gain controlled feedback loop as the amplitude-limiting technique, low dropout voltage regulation with band gap reference voltage and frequency tuning monotonicity guaranteed by digitally controlled variable capacitor array is performed to revise influence caused by process, voltage and temperature conditions for. handset. The oscillation with very stable amplitude value and frequency value is achieved.

它利用对工作温度、电源电压和制造工艺不敏感的带隙基准源和在集成电路中元件特性之间匹配好的优点产生了一个不随温度、电源和工艺改变而且可以跟踪工艺变化的参考基准电压，同时通过自动频率控制环路利用数字电路控制可变电容阵列控制瞬态频率稳定度，校正温度、电源和工艺改变对频率的影响，从而可以在很宽的电源电压范围(2.7v—3.7v)和温度范围(-40℃—125℃)以及CMOS工艺参数变化(TT、FF、SS、SF、FS)的条件下提供幅度稳定、频率稳定的振荡输出信号。

A new method used single-chip microcomputer technology which can realize the real-time correcting and automatic tracing with self-exciting frequency of separate-exciting frequency were proposed and with it the safety working situation were assured.

分析了并联型固态感应加热电源它激频率与自激频率不匹配引起停机时电源故障的原因和后果，提出了通过单片机技术实现并联型逆变器它激频率实时修正、自动跟踪自激频率的方法，保证了完成加热后停机过程中逆变器处于安全工作状态，并通过样机试验证实了其正确性和有效性。

But there was no current modulate circuit for TDLAS system.The design of modulation circuit for tunable diode laser based on DDS has been introduced.The main idea of design is using MCU to control DDS and D/A chips,so we can get sine wave and saw tooth signals.

DDS器件采用高速数字电路和高速D/A转换技术，具备了频率转换时间短、频率分辨率高、频率稳定度高、输出信号频率和相位可快速程控切换等优点，可以实现对信号的全数字式调制。

Numerical simulations and analytical results show: in longitudinal and oblique seas, ship may be subjected to primary parametric resonance with large roll amplitude and even capsizing, when encounter frequency is near the twice of roll natural frequency, wave length and ship length are of the same order and the wave height is larger than a certain value; in oblique seas, ship roll motion is a forcedly-parametrically excited oscillation, primary resonance occur as the encounter frequency is near the roll natural frequency, which may lead to large rolling and capsizing too.

数值仿真和解析分析结果表明：在纵浪和斜浪中，当遭遇频率接近船舶横摇固有频率的两倍，波长和船长接近，波高超过某一阈值的时候，船舶会发生主参数共振，产生大幅横摇甚至倾覆；在斜浪中，船舶发生的是参强激励横摇运动，遭遇频率接近横摇固有频率时，还会激起横摇主共振，同样会产生大幅横摇甚至倾覆。

With Death guitarist Schuldiner adopting vocal duties, the band made a major impact on the scene.

随着死亡的吉他手Schuldiner接受主唱的职务，乐队在现实中树立了重要的影响。

But he could still end up breakfasting on Swiss-government issue muesli because all six are accused of nicking around 45 million pounds they should have paid to FIFA.

不过他最后仍有可能沦为瑞士政府&议事餐桌&上的一道早餐，因为这所有六个人都被指控把本应支付给国际足联的大约4500万英镑骗了个精光。