Demodulation and timing synchronization combined method for GFSK (Gauss Frequency Shift Key)

A timing synchronization and timing error technology, applied in the digital field, can solve the problems of high hardware overhead, unsuitable for hardware implementation, and low processing efficiency, achieving the effects of low hardware overhead, good timing detection performance, and simplification of complexity

Inactive Publication Date: 2011-08-31
浙江瑞讯微电子有限公司
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Problems solved by technology

But all in all, the processing efficiency of this method is not high, because the modular square operation and DFT operation will introduce a large delay in hardwa

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  • Demodulation and timing synchronization combined method for GFSK (Gauss Frequency Shift Key)
  • Demodulation and timing synchronization combined method for GFSK (Gauss Frequency Shift Key)
  • Demodulation and timing synchronization combined method for GFSK (Gauss Frequency Shift Key)

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Embodiment Construction

[0029] Such as image 3 As shown, our demodulation and timing synchronization loop consists of 6 sub-modules, which are interpolation filter, complex conjugate multiplier, phase module, timing error detector, loop filter and numerically controlled oscillator. The other summation module and decision device only participate in demodulation and do not involve timing synchronization function.

[0030] The demodulation and timing synchronization process involved in this scheme can be divided into the following 6 steps:

[0031] Step 1: Perform interpolation calculation on the sampled signal. First perform the matrix multiplication operation of 1x4 and 4x3, refer to the following formula:

[0032]

[0033] The 1x4 matrix in the formula represents 4 sampled signals input continuously , Indicates the nth sampled signal. The 4x3 matrix is ​​the parameter matrix of the filter, where α, β are the parameters of the interpolation filter. For the input sampling signal, calculate ...

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Abstract

The invention relates to a demodulation and timing synchronization combined method for a GFSK (Gauss Frequency Shift Key). In the invention, an oversampling signal is used as an input of a demodulation and synchronization loop; after a phase of the sampling signal is adjusted by an interpolation filter, conjugate multiplication is carried out on the sampling signal by every two continuous sampling values to obtain a phase difference; and the phase difference is used as an input of timing error detection. With a difference between front and back phase values as a direction of error adjustment,a middle phase value of every three continuously calculated phase values is used as a size of the error adjustment. A timing error is fed back to the interpolation filter after passing through a loopfilter, and a new sampling value is adjusted again and again. By using the invention, the realization complicatedness of hardware is simplified and the use of a square error detection algorithm is avoided under an oversampling situation; and the demodulation and timing synchronization combined method for the GFSK, provided by the invention, has the advantages of small hardware cost and good timing detection performance.

Description

technical field [0001] The invention belongs to the field of digital technology, and relates to a combined method of GFSK demodulation and timing synchronization. Background technique [0002] Gaussian Frequency Shift Keying (GFSK), a frequency-based modulation method. It uses a Gaussian low-pass filter to limit the spectrum width of the signal before modulation, so as to obtain a more compact spectrum and improve the utilization efficiency of the frequency band. [0003] Currently commonly used GFSK digital demodulation schemes include zero-crossing detection method, differential phase detection method and direct phase detection method. The basic principle of the zero-crossing detection method is that the zero-crossing point of the digital FM wave varies with the carrier frequency, so the difference information of the carrier frequency can be obtained by detecting the number of zero-crossing points. The basic principle of differential detection is to perform conjugate mul...

Claims

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Application Information

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IPC IPC(8): H04L27/14H04W56/00
Inventor 刘朝晖蒋辉
Owner 浙江瑞讯微电子有限公司
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