Multicarrier modulation and demodulation method for remote signal
A technology of multi-carrier modulation and demodulation method, which is applied in the field of multi-carrier modulation and demodulation of telecontrol signals, and can solve problems such as high noise, inability to meet the operating conditions of digital power line carrier machines, interference, etc.
Inactive Publication Date: 2011-09-07
XUJI GRP +1
View PDF0 Cites 0 Cited by
- Summary
- Abstract
- Description
- Claims
- Application Information
AI Technical Summary
Problems solved by technology
But the digital carrier machine is not omnipotent. Due to its high transmission capacity, it has certain requirements for the signal-to-noise ratio of the carrier channel. Therefore, some carrier channels in the field cannot meet the operating conditions of the digital power line carrier machine. When using a single sideband power line carrier machine, in order to make the transmission rate of the telecontrol signal not lower than 1200b / s, the frequency shift keying modulation (FSK) cannot be used, and the modulation technology with high frequency band utilization must be used to control the telecontrol signal. For processing, for example, single-carrier octal quadrature amplitude modulation (8QAM) can be used to complete single-sideband power line carrier multiplex transmission of one 2400bps or two 1200bps telecontrol, but due to the large noise and serious interference of the power line carrier channel, in order to Maximize the anti-pulse interference and narrow-band interference ability of telecontrol signal transmission, and effectively improve the utilization rate of the frequency band. Here, the principle of multi-carrier modulation (MCM) is used to realize the transmission of telecontrol signals
Method used
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View moreImage
Smart Image Click on the blue labels to locate them in the text.
Smart ImageViewing Examples
Examples
Experimental program
Comparison scheme
Effect test
Embodiment Construction
[0042] 1. The principle of single-carrier octal quadrature amplitude modulation (8QAM)
[0043] The block diagram of single carrier 8QAM modulation is as follows: figure 1 As shown, the data bit stream sent serially is first subjected to serial-to-parallel conversion, and the bit stream is converted into parallel symbols, and then signal mapping is performed every 3 bits (log28) to complete the mapping from data to signal constellation points, and the baseband spectrum is obtained:
[0044] X(k)=Ak+jBk (1)
[0045] Among them, Ak is the in-phase component, and Bk is the quadrature component. Since X(k) is a complex number, X(k) is also called a signal vector.
[0046] Perform complex modulation on the baseband signal, and move the baseband spectrum to fc,
[0047] y(k)=X(k)ej2πfck (2)
[0048] Since y(k) is a complex signal, take its real part to get a real digital signal yr(k):
[0049] yr(k)=Akcos(2πfck)-Bksin(2πfck) (3)
[0050] yr(k) is output by D / A to generate QAM ...
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More PUM
Login to View More Abstract
The invention relates to a multicarrier modulation and demodulation method for a remote signal. The method comprises the measures of the selection of reasonable frame period (sampling point number N), the selection of frame synchronization sequence, the encoding of data, the clock synchronization of the sending and the receiving of data and the like; at the same time, a subcarrier synchronizing signal is inserted in every four subcarriers in a transmitted data flow; a multicarrier signal is demodulated at a receiving end to obtain a signal sequence corresponding to a sending end to ensure theclock synchronization of the receiving end and the sending end; and a received signal can be demodulated correctly. Multicarrier modulation and demodulation are realized respectively by discrete Fourier inversion and Fourier transform. The invention improves the capacity against pulse interference and narrowband interference to the utmost extent, improves the utilization rate of frequency bandwidth effectively at the same time and ensures that the transmission speed of the remote signal of a single sideband power-line carrier is more than 1200b / s.
Description
technical field [0001] The invention relates to a multi-carrier modulation method and a demodulation method of telecontrol signals. Background technique [0002] (1) SSB power line carrier generally adopts frequency shift keying modulation (FSK) to realize the transmission of telecontrol signals. When voice and telecontrol are multiplexed, the transmission rate of telecontrol signals does not exceed 600b / s. The transmission rate of the telecontrol signal does not exceed 1200b / s when it is dedicated. In order to increase the transmission rate of the telecontrol signal, a modulation technique with high bandwidth efficiency must be adopted. [0003] (2) With the wide application of digital power line carrier in power line carrier communication, the problem that the telecontrol transmission rate of single sideband power line carrier does not exceed 1200b / s has been completely solved. But the digital carrier machine is not omnipotent. Due to its high transmission capacity, it h...
Claims
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More Application Information
Patent Timeline
Login to View More Patent Type & Authority Patents(China)
IPC IPC(8): H04L27/12H04B3/54
Inventor 王奎甫王宏淼苏陆军马仪成朱延章孟耀伟
Owner XUJI GRP