In the thesis , i mainly discuss the digital if process theory of the sr . chapter 2 demonstrates the sampling and quantization theory of wideband if signal , and multiple rate signal processing theory - - - - including interpolation , decimation and oversampling . chapter 3 introduces the digital up ( down ) conversion between baseband - modulated and bandpass modulated signal through orthogonal modulating ( demodulating ) , at last , after discussing fir filter ' s properties and design methods , i give a design example 主要研究了基于软件无线电的数字中频处理技术理论:第二章介绍了中频信号的采样、量化理论；介绍多采样率信号处理中的抽取与内插相关理论；第三章介绍了基带调制信号与带通信号通过正交调制解调的数字上下变频技术；最后介绍fir滤波器的特点与设计方法，并列举一个实例说明。
The modulating signal is generated in the way of direct digital synthesizer technology . the signal has many characteristics such as ultra wide frequency bandwidth , ultra high frequency resolution and ultra good phasic continuity , etc . thus it can be achieved the high frequency and amplitude stability of the modulating signal 本文采用了数字频率合成技术( dds )来产生调制信号,它具有超宽的频率带宽、超高的频率分辨率和相位连续性等特点,可以实现声光调制信号的频率和振幅的高稳定性。
Abstract : a software method of frequency - modulated signal demodulating based on wavelet packet is proposed in this paper . a variety of frequency - modulated signals are analyzed in time - frequency domain and the spectrograms are presented . this method can detect instantaneous frequency effectively and get frequency - modulated information , can be widely applied to dynamic testing and software radio 文摘:提出了基于小波包的调频波解调方法，通过对各种调频信号进行时频分析，给出了信号的时间?频率谱图，能有效地检测到瞬时频率和获取调频信息，该方法可广泛应用于动态测试和软件无线电等领域。
A modulated signal of tria ( tt / pw ) added by a normal noise . is demonstrated for 2 - d dependence of the waveform on time and trials and 2 - d dependence of spectrum on frequency and trials to show different time domain and frequency domain properties of a random process including noise and signal 以三角波电压讯号加上准常态杂讯乘以无杂讯载波之调变讯号为例，图示含有杂讯电压讯号其波形随时间及试验之二维变动及频谱随频率及试验之二维变动，显示杂讯与讯号之随机过程在时域与频域之不同特性。
A modulated signal of eexp ( 2 * tt / pw ) added by a zero mean uniform noise . is demonstrated for 2 - d dependence of the waveform on time and trials and 2 - d dependence of spectrum on frequency and trials to show different time domain and frequency domain properties of a random process including noise and signal 以双边递减波电压讯号加上均匀杂讯乘以无杂讯载波之调变讯号为例，图示含有杂讯电压讯号其波形随时间及试验之二维变动及频谱随频率及试验之二维变动，显示杂讯与讯号之随机过程在时域与频域之不同特性。
Finally the modulated signal is embedded in the coefficients with relatively large absolute value on middle frequency range detail signal adaptively . the original digital audio signal is necessary when detecting the watermark . equally , spreading spectrum technology can improve the performance of watermark technology greatly , but it will increase the capacity of channel and the calculation of the algorithm as cost 在应用扩频技术的算法中，首先将视觉上可辨的二值水印图像降维为一维序列，再将一维水印序列伪随机排序并与m序列作扩频调制，最后对数字音频信号进行分段离散小波变换，把经过调制的水印信息自适应地嵌入到原音频信号小波分解中等尺度绝对值较大的分量上。
Based the research on the laser beam drift feedback control technique , analysing the beam drift and its frequency components , a laser beam directional stability method is studied in the thesis in detail , with its measurement and control circuit system that combines the laser beam intensity modulation and the beam drift feedback control technique . in this method , at first the laser beam intensity is modulated with the acoustooptic modulator , then the lock - in amplifier is applied to detect and demodulate the modulating signal , at last a feedback control signal is generated by the dsp control circuit at last , including : 1 本文在原有的激光光束漂移量反馈控制准直技术的基础上,对光束漂移量信号的数据和频谱进行了分析,重点研究了一种集声光调制光强与光束漂移量反馈控制准直技术于一体的激光光束方向稳定方法及其测控电路系统,该方法通过声光调制实现光强调制,接着通过锁相放大电路检测并解调调制信号,然后通过dsp控制电路进一步对光束的漂移量进行反馈控制。
In a tdma network , multiple users share the common medium ( or channel ) and bandwidth but different intervals of time . in case of the burst mode , the carrier of the modulated signal needs to be synchronized in a very short time . the common approaches such as a costas - loop and so on are no longer suitable any more 在一个时分多址( tdma )通信网络中，多个用户通过不同的时间段共享一个传输线路(或者信道)的带宽资源，每个用户只能在分配给自己的时间段内进行通信，这种突发方式信号的解调要求载波恢复要在很短的时间内完成，我们以往在连续信号解调器中采用的costas环等方法很难适应这种要求。
This article analyses the signal characteristics of several typical cw radars , and presents the principle and application of doppler radar . as one focal point , this article researches the generation and math characteristics of pseudorandom code modulated signal , analyses the spectrum of pseudorandom code phase modulation radar signal , and presents this kind of signal ' s application in distance and speed measurement . this article also researches the application of mono - pulse amplitude comparison radar in angle measurement finally , this article elaborates the working process of crs in uast 本文分析了几种典型的连续波雷达信号的特性，介绍了多普勒雷达的原理和应用；研究了伪随机编码信号的产生和数学特征，着重分析了伪码调相连续波雷达信号的频谱，及其在雷达测距、测速方面的应用；研究了单脉冲幅度比较体制在雷达测角中的应用；最后，阐述了超近反导系统中复合体制雷达的工作过程。
With the established rf front - end system simulation platform , adding the digital modulated baseband signal , this paper simulated the multifold digital modulated signal ’ s transmission , such as 2ask , qpsk , and 16qam . then researches of power compression and phase noise of local oscillation influence the bit error ratio for different modulated system . the designing is satisfied multifold functions request with the high - powered and integrated broadband rf front - end 随后在建立的宽带射频前端通用仿真平台上,加入基带数字调制信号,对多种数字调制格式的信号在该通用平台上的传输作了研究,模拟了2ask 、 qpsk和16qam等调制格式信号的发射与接收,研究了功率压缩和本振相位噪声对不同调制的误码率影响,实现了满足多种功能要求的宽带高性能综合射频前端的设计。
