High-speed parallel OQPSK demodulation clock restoring system

Abstract

The invention provides a high-speed parallel OQPSK demodulation clock restoring system which comprises a parallel delay module, a parallel interpolation calculation module, a parallel clock error extraction module, a parallel threshold calculation module and a parallel interpolation coefficient generation module. New 4AR channel parallel Q' channel data are formed after the parallel delay module delays for T / 2 to 4AR channel parallel Q channel data in 4AR channel base-band data output by matched filtering. The new 4AR channel parallel Q' channel data and original 4AR channel parallel I channel data are taken into the parallel interpolation calculation module. The obtained 4AR channel data after interpolation are sent to the parallel clock error extraction module to obtain parallel clock errors epsilon T. Meanwhile, the threshold value is obtained by carrying out clock locking indication calculating and integral accumulating on the parallel data after the interpolation, the epsilon T is sent to the parallel interpolation coefficient generation module after parallel low-pass filtering is carried out, and the new generated 4AR channel interpolation coefficient is fed back to the parallel interpolation calculation module. After the threshold reaches a stable value and a clock loop is locked, the parallel interpolation calculation module outputs the maximum value of the data to restore a clock.

Description

technical field [0001] The invention belongs to the communication field and relates to a high-speed digital demodulator. Background technique [0002] The QPSK modulation method has been widely used in practical systems, but due to its 180° phase shift, after band-limiting processing, a zero-envelope phenomenon may appear. This phenomenon needs to be avoided especially in nonlinear band-limited channels. Although the fluctuation of the envelope can be weakened or eliminated by the nonlinear amplifier, it will expand the spectrum at the same time, and its side lobes will interfere with the signals of adjacent channels, and the band-limited filtering during transmission will be completely useless. Therefore, in actual work, certain processing is usually performed on the QPSK signal to avoid the above-mentioned problems. Offset quadrature phase shift keying OQPSK is one of the better schemes. During quadrature modulation, OQPSK delays the quadrature roadbase band signal rela...

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Problems solved by technology

[0010] The phase and clock joint estimation algorithm has good performance, but there is a contradiction between the estimation accuracy and the frequency deviation capture range. At the same time, due to the large number of parallel channels, its implementation structure is quite complicated, the calculation amount is extremely large, and it takes up a lot of resources. Especially complex when implementing high speed

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