查询词典 frequency modulation

It is a combination of the pulse amplitude modulation and frequency modulation types.

该仪器系统是由脉冲幅度调制和频率调制两种遥测系统复合组成的。

The two most common types of modulation used in radio are amplitude modulation and frequency modulation.

无线电所用最常见的两种调制方式是调幅和调频。

Frequency modulation minimizes noise and provides greater fidelity than amplitude modulation, which is the older method of broadcasting.

调频最大程度的减小噪音，并且比调幅的保真度高，调幅是一种较老的传播方法。

Simulation results show that our algorithm enforces the adaptability of differential space-frequency modulation to the time delay expansion.Finally, we give our work to reduce the complexity of multiple symbol differential sphere decoding in differential space-time modulation. Through the modification of the enumeration strategy of the search tree in sphere decoding, we significantly reduce the complexity of detection at the expense of little loss on performance.

理论分析和仿真结果都验证了这种检测算法对长信道时延的适应能力论文最后还对差分空时调制中的多符号检测算法进行了研究，提出了一种降低差分空时调制系统中多符号差分球形译码算法复杂度的方法，通过改进球形译码中搜索树的排序策略，使得系统在牺牲较少性能的基础上大大降低了算法实现的复杂度。

The transmit part adopts the phase-locked loop pattern of frequency synthesizing technology and uses the MC145152 and MC12022 chips to compose the phase-locked loop.It locks the frequency of the carrier-wave at 35MHz.The stabilization of the carrier-wave can be 4×10-5,the accuracy can be 3×10-5.The frequency modulation and the confection of the carrier-wave are realized by the capacity-changing diode V149 and the integration voltage-control oscillator MC1648 chip.The end power amplifier uses the audion 2SC1970 to make it work in the third magnifying state,it improves the efficiency of the magnifier and the power of the output reaches the design demand.

发射部分采用锁相环式频率合成器技术， MC145152和MC12022芯片组成锁相环，将载波频率精确锁定在35MHz，输出载波的稳定度达到4×10-5，准确度达到3×10-5，由变容二极管V149和集成压控振荡器芯片MC1648实现对载波的调频调制；末级功放选用三极管2SC1970，使其工作在丙类放大状态，提高了放大器的效率，输出功率达到设计要求。

The sending end when the use of pulse modulation approach will be a binary digital signal into a frequency modulation of the pulse sequence, and driver fired infrared tube to the form of light pulses sent receiver will receive the pulse of light conversion to electrical signals , and then, after amplification, filtering and other treatment to the demodulation circuit after demodulation, reduced to a binary digital signal after the output.

发送端采用脉时调制方式，将二进制数字信号调制成某一频率的脉冲序列，并驱动红外发射管以光脉冲的形式发送出去；接收端将接收到的光脉转换成电信号，再经过放大、滤波等处理后送给解调电路进行解调，还原为二进制数字信号后输出。

In this study, two-tone stimulus paradigm with inter-pulse interval of 50 ms was used and two kinds of maskers, static frequency masker and dynamic frequency masker (up-sweep frequency modulation sound), were delivered to the animal before the probe under free field stimulation conditions.

自由声场刺激条件下，采用一定间隔的双声刺激模式(前一个声音为掩蔽声，后一个声音为探测声)，记录昆明小鼠下丘(inferior colliculus， IC)神经元的声反应。

The realization monolithic integrated circuit system double audio frequency, this radio has used double audio frequency decoding chip MT8870, demodulates the tonic train signalling from the frequency-modulated signal, and separates the double tonic train signalling from the tonic train signalling to enter the double audio frequency decoding electric circuit implementation letter command to decode, thus carries on the low gear rate using the frequency modulation channel the control command transmission.

为实现单片机控制的双音频解码，本收音机采用了双音频译码芯片MT8870，从调频信号中解调出音频信号，并从音频信号中分离出双音频信号进入双音频解码电路实行信令解码，从而利用调频信道进行低速率的控制指令的传输。

On the basis of analyzing the oscillatory frequency of crystal oscillator , the general expression of the frequency deviation of crystal frequency modulation oscillator is de rived .

本文在分析晶体调频振荡器振荡频率的基础上，得出了晶体调频振荡器频偏的一般表示式，最佳负载条件下的频偏设计公式和调制级有电流串联负反馈时的频偏设计关系式。

D dissertation. Based on GPS C/A code signal structure and performance characteristics, traits of aiming interference and jammer are analyzed. The best interference way is that wideband interference of uniform spectrum is made from wideband saw tooth frequency modulation and narrowband frequency modulation.

根据GPS的易受干扰的C/A码信号的特点，分析了对GPS的C/A码的瞄准式干扰、阻塞式干扰及相关干扰的特性，分析得知对GPS的C/A码的最佳干扰是锯齿宽带调频和噪声窄带调频相结合的均匀频谱宽带干扰。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。