查询词典 frequency modulation

When the signal frequency is varied in response to the modulating signal we have FM frequency modulation.

当信号频率回应我们有 FM 的调整信号被改变的时候。

By utilizing the cross-gain modulation effect and the period-one oscillation harmonic frequency-locked in an optically injected semiconductor laser, we can extract the wavelength conversional individual channel optical clock from the optical-time-division-multiplexing signal. In a FP-LD, we numerically simulate the extraction of 20 GHz optical clock at 1550 nm from the 2×20 Gb/s OTDM signal at 1555 nm, and experimentally obtain the -105 dBc/Hz phase noise frequency division clock of 12.36 GHz to 6.18 GHz with simultaneous wavelength conversion from 1550.24 nm to 1545.91 nm.

采用一个FP半导体激光器作为全光分路时钟提取及波长转换器，数值模拟实现了从波长为1555 nm、速率为2×20 Gb/s的光时分复用信号中提取出波长转换为1550 nm、重复频率为20 GHz的分路光时钟，实验完成了从波长为1550.24 nm、重复频率为12.36 GHz光脉冲信号中提取出相位噪声为-105 dBc/Hz的波长为1545.91 nm、重复频率6.18 GHz的分频光时钟。

The key content of the whole essay is that it analyses frequency modulation, intermediate frequency,

本文的核心内容主要是系统分析了中频，调频波，数字模拟转换，模拟数字转换。

Their vocal quality is better than non-passerine, but still much less than oscine passerine. Compared with non-passerine, they appeared longer syllable length, higher basic frequency and more viable frequency ranges. Though the amplitude modulation properties enhanced their vocal production, the type of syllable is still stable and less of variety. So thephrase consisted of syllables are comparatively few and changes of the tone are relatively less.

且表现出很强的频率调制特性和特有的幅度调制特性，相对的音节时程比较长，基频较高且频率变化范围较大，所特有的幅度调制特性更增加了其控声的能力，但其音节的种类仍很单一，缺乏变化，由音节所组成的句型较少，音调变化幅度不大，因此，其叫声质量尽管较非鸣禽有所改善，但相对鸣禽而言却又远远不如。

Altera Corporation system to the Cyclone FPGA series of digital platform, microprocessor, bus, Digital Frequency Synthesizer, memory and I / O interface hardware concentrated in an FPGA, the use of direct digital frequency synthesis technology and digital modulation waveforms required to achieve the rise, Using FPGA ROM storage of the DDS waveform table, and make full use of on-chip resources, improve the system's accuracy, stability and robustness.

系统以 ALTERA公司的 Cyclone 系列 FPGA 为数字平台，将微处理器、总线、数字频率合成器、存储器和 I/O 接口等硬件设备集中在一片 FPGA 上，利用直接数字频率合成技术、数字调制技术实现所要求波形的产生，用 FPGA 中的 ROM 储存 DDS 所需的波形表，充分利用片上资源，提高了系统的精确度、稳定性和抗干扰性能。

Frequency modulation; frequency processing; echolocating; odontocete cetaceans; ultrasound; bioacoustics; sound localization; midbrain; binaural; mesencephalon; auditory cortex; clicks; auditory evoked potentials; inferior colliculus; superior colliculus

调频；频率处理；凭回声定位的方向；odontocete cetaceans；超声；生物声学；声源测定；中脑；两耳的；中脑；听觉皮层；棘爪；听觉诱发电位；下丘；上丘

Based on the theory of frequency modulation,the principle that frequency jittering spreads the spectrum energy of the voltage and current is analyzed.

针对传统的固定频率PWM控制方式引起的波形频谱能量集中、谐波幅值较大的缺点，文章基于频率调制的理论分析了开关频率抖动技术扩散电压频谱以及电流频谱能量的基本原理，结合传统的PWM控制器，采用三角波作为调制信号实现简单的频率抖动的方法。

Its, introduce one kind phase locking of adopting ring frequency synthesizer and 89C51 frequency modulation transmitter where one-chip computer control, have recommended the phase locking to surround performance of the integrated circuit (BU2618FV ) and typical application.

其之，介绍一种采用锁相环频率合成器(BU2618FV)和89C51单片机控制的调频发射机，并介绍介绍了锁相环集成电路（BU2618FV）的性能和典型应用。

At the first step, time-frequency distribution (spectrogram or pseudo Wigner-Ville distribution) of the time-varying signal is adopted and a peak-tracking scheme is designed to obtain a coarse ionosperic modulation estimation from the time-frequency distribution.

在第一步校正中，首先分析这种时变信号的时频分布，并设计了一种谱峰追踪方法从时频分布中获得粗糙的电离层频率调制估计。

Main Products: Network Analyzer, integrated tester, spectrum analyzer, noise figure testers, receiver, telephone tester, high, low-frequency signal source, audio, video signal source, high, low-frequency oscilloscope, modulation device, the video analyzer and so on.

主要产品：网络分析仪，综合测试仪，频谱分析仪，噪声系数测试仪，接收机，电话测试仪，高、低频信号源，音、视频信号源，高、低频示波器，调制仪，视频分析仪等。

Researches reveal that students who suffer from corporal punishment tend to resort to violence in their future life.

研究表明遭受过肉体惩罚的孩子倾向于在他们今后的人生中使用暴力。

Total sugar of sarcocarp and chlorophyll of pericarp increased firstly, and then decreased afterward along with altitude; Titratable acidity, ascorbicacid and anthocyanin of pericarp were increased along with altitude; The content of protein increased firstly and decreased afterward along with altitude; Carotenoid of pericarp were decreased along with altitude.

果肉总糖和果皮叶绿素含量随海拔高度升高先升高后降低；可滴定酸、维生素C和果皮花青苷含量均随海拔升高而升高；蛋白质在1720m处最大，1420m处最小；果皮类胡萝卜素随海拔升高而降低。