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Modulation and demodulation method and device based on i/q modem

A modulation method and modulator technology, applied in the field of communication, can solve problems such as modulation or demodulation signal damage, achieve the effect of improving modulation and demodulation performance and avoiding cross interference

Active Publication Date: 2011-12-21
ZTE CORP
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0017] Aiming at the problem that the image frequency component produced by the amplitude or phase imbalance of the I / Q branch in the I / Q modem in the related art will cause further damage to the modulated or demodulated signal if it falls within the signal band, the main purpose of the present invention To provide a modulation and demodulation method and device based on an I / Q modem to solve at least one of the above problems

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  • Modulation and demodulation method and device based on i/q modem

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Embodiment Construction

[0047] Hereinafter, the present invention will be described in detail with reference to the drawings and examples. It should be noted that, in the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

[0048] Figure 4 is a flowchart of a modulation method based on an I / Q modulator according to an embodiment of the present invention. Such as Figure 4 As shown, the modulation method based on the I / Q modulator according to the embodiment of the present invention includes the following processing:

[0049] Step S402: Move the frequency spectrum of the signal to be modulated to an area greater than 0 or less than 0;

[0050] Step S404: Using an I / Q modulator to modulate the signal to be modulated after shifting the frequency spectrum.

[0051] In the related art, the I / Q modulator is used for conventional modulation, and the image frequency component generated by the amplitude or phase imbalance o...

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Abstract

The invention discloses a modulation and demodulation method and a device based on an in-phase / quadrature (I / Q) modem. The modulation method comprises the following steps of: moving the frequency spectrum of a signal to be modulated into an area larger than 0 or smaller than 0 and adopting an I / Q modulator to modulate the signal to be modulated, of which the frequency spectrum is moved. The demodulation method comprises the following steps of: moving the frequency spectrum of a signal to be demodulated to an area larger than the center frequency f0 thereof or smaller than the center frequency f0 thereof; and adopting an I / Q demodulator to demodulate the signal to be demodulated, of which the frequency spectrum is moved. According to the technical scheme provided by the invention, the cross interference of mirror products with unbalanced local oscillator amplitude and unbalanced phase on the signal can be avoided and then the performance of modulation and demodulation can be greatly improved.

Description

technical field [0001] The present invention relates to the communication field, in particular to a modulation and demodulation method and device based on an I / Q modem. Background technique [0002] In the field of wireless digital communication, I / Q modem has a wide range of applications, and its working principle block diagram is as follows figure 1 shown. [0003] Depend on figure 1 It can be seen that the performance of the I / Q modulated signal or the I / Q demodulated signal has a great relationship with the local oscillator amplitude balance and phase balance of the I / Q branch. The following takes modulation as an example to illustrate the characteristics of the modulation signal damage caused by the unbalanced amplitude and phase of the local oscillator. [0004] Assuming that the amplitude imbalance of the I / Q branch in the I / Q modulator is a, the local oscillator amplitude of the I branch is 1+a, and the local oscillator amplitude of the Q branch is 1-a, and the mo...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L27/36
CPCH04M11/066H04B1/28
Inventor 陈侃浩
Owner ZTE CORP
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