16QAM (Quadrature Amplitude Modulation) carrier synchronization and loop synchronization locking detection method

A carrier synchronization and synchronous locking technology, which is applied in the direction of synchronization device, carrier adjustment, multi-carrier system, etc., can solve the problems of false lock or alarm, lock indication threshold and signal input amplitude, etc., and achieve low misjudgment rate and judgment Indicates the effect of stable and reliable, simple and effective method

Active Publication Date: 2018-05-18
10TH RES INST OF CETC
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Problems solved by technology

At the same time, it should be noted that one of the biggest shortcomings of this type of determination method is that the lock indication threshold is r

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  • 16QAM (Quadrature Amplitude Modulation) carrier synchronization and loop synchronization locking detection method
  • 16QAM (Quadrature Amplitude Modulation) carrier synchronization and loop synchronization locking detection method
  • 16QAM (Quadrature Amplitude Modulation) carrier synchronization and loop synchronization locking detection method

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Embodiment Construction

[0015] refer to figure 1 . According to the present invention, in the 16QAM demodulator, the received analog intermediate frequency modulation signal is converted into an intermediate frequency digital signal through a high-speed analog-to-digital converter ADC, and the intermediate frequency digital signal is sent to the back-end FPGA chip to perform corresponding carrier synchronization and bit synchronization. information processing; the intermediate frequency digital signal performs carrier synchronization to the carrier synchronization loop through the carrier synchronization module, and the data after carrier synchronization is divided into two channels of I and Q, and the synchronous data of the two channels of I and Q are respectively filtered through their respective low-pass filters After the high-frequency component is obtained, the useful signal is sent to the carrier synchronization lock detector for carrier synchronization lock detection. Compare to determine wh...

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Abstract

The invention provides a 16QAM (Quadrature Amplitude Modulation) carrier synchronization and loop synchronization locking detection method. Through utilization of the method, the influence of signal amplitude on 16QAM carrier synchronization and loop synchronization locking detection can be clearly eliminated. The technical scheme provided by the invention is realized through the following processthat carrier synchronized data is divided into I and Q ways; high frequency components in the data are filtered through lowpass filters; the filtered data is sent to a carrier synchronization lockingdetector for carrier synchronization locking detection; the carrier synchronization locking detector compares normalized high order moment calculation values of the I and Q ways with a detection threshold at each moment and judges whether a carrier synchronization loop is locked or unlocked; an indicator drives an FPGA reset signal to reset a phase-locked loop of the carrier synchronization loop;digital intermediate frequency signal carriers are demodulated to a zero intermediate frequency module through I and Q demodulators, so the carrier synchronization loop is locked on an accurate frequency again; zero intermediate frequency signals are sent to a rear-end clock recovery loop module for clock recovery; and judgment is carried out by a judgment module, thereby acquiring a receiving sequence.

Description

technical field [0001] The invention relates to digital demodulation of 16-order quadrature amplitude modulation (quadrature amplitude modulation), which is widely used in medium and large-capacity digital microwave communication systems, high data transmission of cable TV networks, satellite communications and other wireless communication fields, and is used to detect digital The method of whether the carrier demodulation loop in the demodulator is locked. More specifically, the present invention relates to a quadrature amplitude modulation 16QAM carrier synchronization loop synchronization lock detection method. technical background [0002] In a digital communication system, in order to transfer the signal to a frequency suitable for long-distance transmission, it is necessary to move the spectrum of the baseband signal to the radio frequency at the transmitter. Correspondingly, at the receiving end, the signal needs to be moved back from the radio frequency to the baseb...

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Application Information

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IPC IPC(8): H04L27/26H04L27/34H04L27/00H04L7/033
CPCH04L7/033H04L27/0014H04L27/2657H04L27/3483H04L2027/0071
Inventor 刘洋杜瑜唐婷
Owner 10TH RES INST OF CETC
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