With the development of the society and the economy, the problem of energy consumption and pollution of the environment has become increasingly prominent. So green, low-carbon and energy saving have attracted more and more attention from people. In recent years, communications industries have kept the concept of Green Communication and promoted energy conservation vigorously. Also,
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Today, as the electronic technology is developing fantastically fast, higher performance of frequency synthesizer is put forward, wide frequency range, high frequency resolution, low jump time, low phase noise, high spurious restraining and controlled by program .These requirements are too hard to reached by using normal analog circuit. Therefore, how to design a new frequency
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The open style mobile communication experiment system is one kind of mobile communication basic principle demonstration system. And the mobile communication terminal is divided into many modules to realize. Its circuit can be modified easily. This design’s goal is to let the general students can experience and test the principle and realization of mobile communication
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In recent decades, mobile communication has entered a period of rapid development, it is closely related to people’s daily lives and has become a necessity in people’s lives, the current mobile communication is in the second generation to third generation of the phase transition.The modulation is a key technology in mobile communication, and it is
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High spectral efficiency digital modulation technique was used to improve the spectrum efficiency, but it produced a non-constant envelope signal which required a higher linearity of the power amplifier. Typically, the method which improved the linearity of the power amplifier was reducing its output power, so that the power amplifier was operating at the linear
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SDR(Software Defined Radio) is the development direction of wireless communication system, which enables the implementation of new wireless communication systems through the software without any change on the hardware. At present, the evolution of 3G to LTE or a more advanced communication system uses the SDR.This paper describes the basic principles of wireless communication systems
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The rapid development of digital communications results in the coexistence of many different communication systems, which leads to a lot of disturbance for the communication among different communication systems. In order to handle variety of modulated signals on the same platform, the modulation recognition technology of communication signals has been widely studied. First, the background
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Besides the constant envelope modulation, wireless signals are always subjected to the nonlinear distortions from amplifiers or A/D and D/A converters which is mainly characterized by the peak clipping. The problem of clipping is more severe when the peak-to-average power ratio (PAPR) is large. Clipping will result in two adverse effects:the re-growth of the side-band
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As a basic source of electronic equipment, the waveform generator has been widely used in communication, measurement, research and teaching. The signal of traditional analog waveform generator is limited, and the output frequency and amplitude is unstable. As the development of direct digital synthesis(DDS), there are some waveform generators based on specific DDS chip with
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Modulation method is the fundamental part of a digital communication system. It plays a critical role in system’s performance. Nowadays, the communication technology develops very rapidly, while the development of modulation methods becomes relatively pale by comparison. This thesis focuses on the orthogonality restriction (OR) in traditional modulation methods. Based on the ideas of relaxing
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