查询词典 resonance frequency

The method comprises: 1 when GSM module needs to select a network, it firstly decides if there is a 900 MHz frequency range network capable of meeting the communication need; if yes, then selecting the 900 MHz frequency range network as the working network of the dual-mode mobile phone; otherwise, entering the step 2; 2 deciding if there is a 1800 frequency range network; if not, then returning the step 1 to reselect network; if yes, then selecting 1800 frequency range network as the working network of the dual-mode mobile phone.

本发明公开了一种PHS及GSM双模手机中GSM模块择网的方法，涉及无线通信领域，为解决PHS及GSM双模手机不同网络间信号干扰而提出，采用的技术方案为：(1)GSM模块需要择网时，首先判断是否存在满足通信要求的900MHz频段网络，若存在则选择该900MHz频段网络作为所述双模手机的工作网络，否则进入步骤(2)；(2)判断是否存在符合通信要求的1800MHz频段网络，若不存在则返回步骤(1)重新择网；若存在则选择1800MHz频段网络作为该双模手机的工作网络。

The frequency step-by-steps in the above frequency range is 250Hz; The phase noise is low; The output profile degree of distortion is small, and outputs the frequency after ring circuit locking the temperature stability and the time stability and the datum frequency is same.

在上述频率范围内频率步进是250Hz；相位噪声低；输出的波形的失真度小，并且在环路锁定后输出频率的温度稳定度和时间稳定度与基准频率相同。

The light frequency shift ,collision frequency shift and microwave power frequency shift on long term stability of influencing rubidium atom frequency standard are discussed in this paper.

对影响铷原子频标长期稳定度的光频移、碰撞频移和微波功率频移进行了分析。

ABSTRACT:The half-power bandwidth method is the commonly used method at home and abroad, the authors discover that factors, such as the sampling frequency, the frequency resolution, the ratio of the sampling frequency to the signal frequency, the analyzed width and the damping ratio, make the estimated damping ratio fluctuate vastly. Mostly the result is incredible except for some conditions, the error is sometime amazing, which is not acceptable.

半功率带宽法是国内外常用的测试阻尼的方法，笔者发现半功率带宽法由于受到信号处理中的①采样频率SF②频率分辨率△f③采样频率与信号频率之比K ④采样分析的长度T和⑤阻尼比D的大小等因素的影响使得测得的阻尼比值波动很大，除少数状态是可信的外，多数状态是不稳定的，有时误差惊人，得到的测试数据不能使用，易导致错误的结论。

YFL is based on rich technological capability,absorbed professional development and production ultra audio frequency,high frequency,high frequency,intermediate frequency respond to the heating device.

英福伦以雄厚的技术实力为基础，专业专注于研制生产超音频，高频，中频感应加热设备。

Nowadays the researches of frequency distribution of data are almost limited to normal distribution, while other distributions are seldom studied. Many frequency distributions of data are not normal. This kinds of frequency distribution of data widely exist. Unimodal frequency distribution of data often occurs.

现在绝大多数关于频数资料分布的研究都是基于正态分布的，而对其他类型的分布研究得比较少，实际上频数分布在许多情况下并非呈现正态分布，分布的形态丰富多彩，很多资料都是呈现单峰分布，本研究就是利用数学上常见的八种连续型变量的分布类型去拟合单峰频数资料。

Then the creative research work on ultra-low frequency and large amplitude elcectromagnetic vibrator based on moving magnet is done, improving exciting signal at ultra-low frequency, and, the theoretic analysis and experiment model are studied. Thus, the reference for establishing ultra-low frequency standard vibrator in future is provided. In chapter 5, two control strategies for ultra-low frequency standard vibrator test table waveform are studied.

首先采用机械振动隔振理论，研究设计了机械低通滤波器来滤除噪声信号，并运用等效的小振级信号进行了实验研究，得出了有益的结论；然后为提高超低频时激振信号，作者创造性地提出了动铁型大位移的电动振动台结构，进行了理论分析和实验模型研究，为将来建立大位移的超低频标准振动台提供了参考。

The curve obviously declined from the low frequency to the middle frequency section, and was reduced to zero in the high frequency section, which objectively showed the change in imaging characteristics of the eyes from the low to high frequency areas.

PSF分析系统可直接采用屈光系统MTF曲线表达人眼的成像特征，该曲线MTF值从低频至中频迅速下降，高频趋向缓和至零，定量并客观地表达了人眼成像质量从低频至高频的改变。

The study on the electrical property shows that its dielectric property decreases with the slowly increase of frequency in dry state; in hygrometric state (52.9%), the dielectric property grows obviously and declines swiftly with the increase of frequency; and it tends to be stable when the frequency is over 10^4Hz. The specific resistance decreases linearly with the increase of the frequency. The results indicate that the electric properties of the hot press moulded wheat gluten are subject to the compaction rate of the material structure.

对小麦麸质模压板的电性能研究表明，干态下其介电性能随电场频率增加而下降，但变化小；湿态下其介电性能明显提高，且随频率增加迅速下降，超过10^4Hz后区域变化趋于稳定；热压小麦麸质材料的电阻率随频率的增加呈直线下降；小麦麸质热压材料的电性能主要决定于材料结构的密实程度。

The digital frequency source this paper researched uses high integrated DDS chip AD9851 as frequency sources and signal mirac processors AT89C51 as system control center, it can output 10Hz-20MHz signal with high-precision and high stability frequency. The evenness of signal within the range of 10MHz is low to 0.1dB degree, and the smallest step is low to 10Hz frequency.

本课题研究的数字频率源采用高集成度DDS芯片AD9851作为频率源；以单片机AT89C51作为系统的控制中心，实现了10Hz～20MHz的高精度、高稳定度的频率输出。10MHz内信号幅度的平坦度为0.1dB、频率最小步进为10Hz。

The dissecting of samples in group2 were difficult. The root of pulmonary artery and ascending aorta failed to be unfolded because fibrous tissue was tough, right and left fibrous trigone were too firm to be solved by hand. Cardiac muscle fibers couldn't be stripped along myofibrillar trajectory since they were prone to break because of their friability.

组2的心脏解剖困难，表现为纤维组织坚韧，游离肺动脉非常困难；徒手无法松解左、右纤维三角，肺动脉和主动脉根部的游离非常困难；心肌纤维坚硬、质脆，解剖时容易断离成碎块，无法沿纤维走行方向剥离。

We have battled against the odds in a province that has become increasingly violent.

我们对在一个争夺日益激烈省的可能性。