文中提出了基于直接中频采样的数字化GPS接收机码捕获电路。
A digital GPS PN code acquisition circuit based on direct IF sampling is presented.
提出用二分项采样法实现直接中频采样，而数字式检波器采用数字内插法。
It was suggested that direct intermediate frequency sampling was approached by two branch sampling, otherwise digital product detector was adopted to digital interpolation.
研究用一种中频采样和数字信号正交变换理论实现脉冲多普勒雷达信号正交采样的新技术。
The non-ideal characteristic of intermediate frequency signal is unfavorable for band-pass sampling and affects the performance of quadrature transform.
提出在传统的择大判决法的基础上，用多码元累加方法对中频采样信号直接进行同时解扩解调。
A new algorithm based on the traditional maximum-selection method is proposed. This method despreads and demodulates the IF sampled signal simultaneously by multi -symbol accumulation.
中频采样是数字正交鉴相系统中的一项关键技术，具有锐截止特性的中频采样滤波器可以改善鉴相系统的性能。
As a key technology in digital quadrature demodulation system, the direct IF sampling filter with sharp cutting-off transition band can improve the performance of demodulation system.
其次，介绍了中频采样在雷达信号处理中的应用和过采样技术及其噪声整形、FFT提高接收机动态范围的技术。
Then, it introduces the applications of the IF sampling in radar signal processing, and the over sampling and noise shaping techniques and FFT to improve the receiver dynamic range technology.
基于软件无线电的思想，论述了直接序列扩频接收机的数学模型，进而建立了一个宽带中频采样直扩系统接收机的实现框图。
On the basis of software radio, a mathematics model about DSSS receiver is described, and a realization diagram of wide_scope intermediate frequency sampling DSSS receiver is builded.
理想的软件无线电电台要求对天线接收的模拟信号经过放大后直接采样，但由于技术所限很难实现，而多采用中频采样的方法。
The ideal software radio requires the sampling system directly samples the amplified signal which was received by the antenna, but it can't be implemented due to the limit of technology.
在基于中频采样技术的数字中频接收机中，怎样在AD变换器位数受限的情况下实现较大的系统瞬时动态范围是系统设计中的一个重要问题。
In digital IF receiver based on IF sampling technology, one important issue of system design is how to realize wide instantaneous dynamic range, when the available digits of AD converter is limited.
接收机的每个通道都由高频放大器、中频放大、中频采样、数字正交器组成，另外还有DDS信号产生和频率激励源用来形成雷达发射机所需的S波段脉冲调制激励信号。
Each of them is composed of high frequency amplifier, intermediate frequency amplifier and sampling, digital phase uprightness intersector, DDS and the S band signal inspirator for the transmitter.
在此基础上，介绍了中频数字采样单元和基于FPGA的数字下变频单元的具体设计。
Based on these elements, the material design of if sample and digital down converter based on FPGA is specified.
以采样定理为基础，通过对三种跳频电台采样方案的比较得出结论，黑盒中频数字化方法是目前最合理的选择。
Based on sampling theorem, by the comparison of three sampling scheme, and the conclusion is drew that the black box of medium frequency digital is the most reasonable choice.
为满足高性能信号处理技术要求，需要直接对中频信号进行采样来得到正交双路信号。
To satisfy the requirement of high performance signal processing technique, it is demanded to use the direct sampling of IF signal to get quadrature signals.
然后介绍了数字化中频处理中的采样理论、正交混频解调、滤波抽取等基础理论。
The basic theory of IF signal processing, such as sample theory, quartered demodulating technology, filtering, draw-off and interpolating theory is discussed.
采用GPS中频信号采样器采集实际GPS数据，对搜索和跟踪算法进行了验证。
GPS digitized intermediate frequency signal sampler was used to validate the algorithm of acquisition and tracking of software receiver.
本文讨论了用直接对带限中频信号进行采样的方法来实现正交相干检波的基本原理，它们在工程实际中有很大的实用价值。
The principles of realizing quadrature coherent detector by direct sampling of bandlimited signal are discussed in this paper. They have great practical value in engineering.
提出了一个欠采样中频收发器的体系结构，它在中频数字化以前先通过欠采样将中频频率变到一个较低的频率。
A receiver architecture is presented that utilizes the subsampling concept to down-convert the IF signal to a lower IF before been digitized.
针对低信噪比的雷达回波信号数据采集，文中给出了中频带通采样方案，并选用PC I_9820高速采集卡实时采集和存储数据。
Aiming at data acquisition of radar echo signal with low SNR, IF band-pass sampling concept is proposed. High-speed acquisition card PCI_9820 is used to sample in real-time and store data.
该系统可以广泛地应庸于各种中频调制信号的采样与解调。
This system can be used to sample and demodulate many kinds of IF modulated waves, and its architecture design, some key techniques and software design are presented in detail.
根据中频带通采样雷达噪声频谱在线监测方法，实现环境噪声和外部干扰频谱在线监测。
According to method inspecting on-line of noises spectrum in the IF-sampling radar. Realised that inspecting noises and interference of environment on-line.
在较高中频上采样并进行后续处理，结果满足系统设计指标，且可以简化接收机的设计。
Sampling and subsequent processing in higher IF, the results satisfy the performance of the system designing, and thus simplify the structure of the receiver.
本文针对新型的卫星用接收机伪码捕获的性能指标要求 ，设计了一种基于中频直接采样数字化的伪码捕获算法。
The problem of PN code acquisition is the key technique in DSSS receiver when there are narrowband interferences in the received signal.
本文针对新型的卫星用接收机伪码捕获的性能指标要求 ，设计了一种基于中频直接采样数字化的伪码捕获算法。
The problem of PN code acquisition is the key technique in DSSS receiver when there are narrowband interferences in the received signal.
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