Modulation device and method for implementing modulation suitable to EDGE system

Abstract

The device includes digital modulation in base band, digital up-conversion quadraphase modulator, and D/A converter in high speed. The digital modulation part includes generation module of switching control signal, diverter switch of modulation output, two pieces of diverter switch of modulation input, GMSK and 8PSK modulation modules in base band. The generation module of switching control signal generates one route of output switching control signal and two routes of input switching control signal. The two routes are anti phase. There is only one time slot cycle between output switching control signal and one of input switching control signal. Two pieces of diverter switch of modulation input are connected to data to be modulated and fixed bit 1 respectively. Digital up-conversion quadraphase modulator includes CIC filter and low pass FIR filter. Advantages are: switching modulation modes smoothly, better wireless indexes including modulation spectrum and switch spectrum.

Description

technical field [0001] The present invention relates to the field of mobile communication, in particular to a modulation device and modulation implementation method suitable for EDGE (Enhanced Data Rates For GSM Evolution, enhanced data rate GSM evolution scheme) system. Background technique [0002] GSM (Global System for Mobile Communications), as a second-generation digital mobile cellular communication system mainly based on voice services, has been widely used all over the world. However, with the development of mobile communication technology and the diversification of services, people's demand for mobile data services continues to increase. In order to meet people's demand for mobile data, the GSM system that mainly supports voice services has proposed two high-speed data service models in its Phase2 and Phase2+ specifications (the second-stage specification), namely, based on high-speed data bit rate and circuit switching HSCSD (High Speed ​​Circuit Switched Data) a...

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Problems solved by technology

[0005] However, when the existing scheme was realized, the following problems could not be effectively solved: firstly, the integrated digital up-conversion quadrature modulator simply adopts cascaded CIC filters (integrating comb filters) 21 and 22 to Interpolation filtering is realized, so a better modulation spectrum cannot be obtained; secondly, in the EDGE system, regardless of GMSK modulation or 8PSK modulation, a BURST (burst pulse) time slot needs to be fixedly transmitted. 156.25Symbol (symbol), the usual processing method It is to discard the 0.25 Symbol or combine the data of 8 BURST time slots in one frame into 6 156Symbol time slots and 2 157Symbol time slots, but these two methods will cause the modulation phase between adjacent time slots to be discontinuous, thus affecting ...

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