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Video voice transmission method based on QPSK modulation and demodulation

A video voice, modulation and demodulation technology, applied in the transmission system, free space transmission, electromagnetic wave transmission system, etc., can solve the problem that the actual coherent optical communication system cannot be flexibly used, the versatility is not strong, and it is difficult to meet the real-time requirements of the wireless optical communication system. sexual demands

Pending Publication Date: 2020-08-25
XIAN UNIV OF TECH
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Problems solved by technology

[0004] At present, most of the research on QPSK modulation and demodulation is in the offline demodulation stage, which is not universal and cannot be flexibly used in actual coherent optical communication systems.
It is difficult to meet the occasion of wireless optical communication system, which requires high real-time performance, so most of them have been in the stage of laboratory research and test simulation

Method used

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  • Video voice transmission method based on QPSK modulation and demodulation
  • Video voice transmission method based on QPSK modulation and demodulation
  • Video voice transmission method based on QPSK modulation and demodulation

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Embodiment Construction

[0071] The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0072] A kind of video voice transmission method based on QPSK modulation and demodulation of the present invention, refer to figure 1 with figure 2 , including the following steps:

[0073] Step 1: Perform QPSK modulation on the acquired signal

[0074] Collect two signals from the signal generator, including electrical signals and optical signals, and perform FPGA preprocessing on the collected two signals. FPGA preprocessing mainly uses data reading storage module, frequency division module, serial-to-parallel conversion module and differential encoding module. Including inputting the signal output from the signal generator into the FPGA system, the FPGA system reads the data first, then stores the data, performs serial-to-parallel conversion on the stored data, outputs the serially input data in parallel, and finally performs different...

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Abstract

The invention discloses a video voice transmission method based on QPSK modulation and demodulation. The method comprises the following steps: carrying out QPSK modulation on acquired signals, performing modulating to output two paths of signals, carrying out 90-degree phase shift on one path of signals to obtain an I path of signals, directly outputting the other path of signals to obtain a Q path of signals, and processing the I path of signals and the Q path of signals by adopting a Schmidt orthogonalization algorithm to realize orthogonal imbalance compensation; estimating the frequency ofan output signal, carrying out loose tail ring carrier synchronization on the signal to generate an error signal only related to the phase, extracting the carrier through repeated operation of a loop, and transmitting the finally extracted carrier signal by adopting the Ethernet to finish the transmission of video voice. According to the video voice transmission method based on QPSK modulation and demodulation, DQPSK signals in coherent light communication can be demodulated in real time, and high speed and real-time performance of video transmission in a coherent light communication system are achieved.

Description

technical field [0001] The invention belongs to the technical field of wireless laser communication, and relates to a video and voice transmission method based on QPSK modulation and demodulation. Background technique [0002] With the rapid development of communication technology, the amount of data to be transmitted is increasing, and higher requirements are placed on traditional transmission bandwidth and speed. Coherent optical communication has attracted much attention because of its high detection sensitivity, transmission rate and spectrum utilization. In the coherent optical communication system, the high-order modulation format is used to further increase the system transmission capacity. Compared with other modulation methods (such as BPSK and OOK), QPSK (Quadrature Phase Shift Keying) modulation has high frequency band utilization and anti-interference The advantages of strong capability, good spectrum characteristics, and low bit error rate have been widely used...

Claims

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Application Information

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IPC IPC(8): H04B10/11H04B10/50H04B10/54H04B10/61
CPCH04B10/11H04B10/541H04B10/613H04B10/503
Inventor 柯熙政白佳俊吴加丽
Owner XIAN UNIV OF TECH
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