Direct variable frequency modulation method and modulation device thereof
A signal, complex baseband technology, applied in the field of direct frequency conversion modulation method and modulation device, can solve problems such as quadrature modulation, amplitude deviation, and lack of consideration, and achieve the effects of avoiding performance deterioration, excellent performance and simple structure
Inactive Publication Date: 2010-08-04
上海全波通信技术有限公司
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But this prior art is only aimed at the I, Q amplitude deviation in the transmission system
This system is based on the assumption that the local oscillator components are completely orthogonal, and performs adaptive balancing on the I and Q amplitude deviations in the direct conversion system, and performs quadrature without considering or solving the quadrature imbalance at all. The Complexity of Modulation
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[0025] The embodiments of the present invention are described in detail below. This embodiment is implemented on the premise of the technical solution of the present invention, and detailed implementation methods and specific operating procedures are provided, but the protection scope of the present invention is not limited to the following implementation example.
[0026] Such as figure 2 As shown, this embodiment includes: I-channel DAC 1, Q-channel DAC 2, the first fixed low-pass filter 3, the second fixed low-pass filter 4, the first multiplier 5, the second Multiplier 6, adder 7 and local oscillator generator 8, wherein: the input end of I road digital-to-analog converter 1, Q road digital-to-analog converter 2 receives I road base band data and Q road base band data respectively and I road analog Signal and Q channel analog signal output to the first fixed low-pass filter 3, the second fixed low-pass filter 4, the local oscillator generator 8 outputs the required in-ph...
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The invention relates to a direct variable frequency modulation method and a modulation device thereof, belonging to the technical field of digital communication. The modulation device comprises a dual-port digital-to-analog converter, a fixed low-pass filter, a local oscillation generator, two multipliers and an adder, wherein the input end of the dual-port digital-to-analog converter respectively receives I path baseband data and Q path baseband data and output an I path analog signal and a Q path analog signal to the fixed low-pass filter, the local oscillation generator outputs a required in-phase component signal and a required orthogonal component signal, the I path signal output by the fixed low-pass filter are multiplied by the in-phase component signal of a local oscillation frequency signal, the Q path signal output by the fixed low-pass filter are multiplied by the orthogonal component signal of the local oscillation frequency signal, the outputs of the two multipliers are transmitted to the adder for superposition, and the superposition result is output to a transmitting end. The invention avoids the deterioration of the performance of the orthogonal modulation system and the orthogonal demodulation system caused by the non-orthogonal phase of the local oscillation signal.
Description
technical field [0001] The present invention relates to a method and a device in the technical field of digital communication, in particular to a direct frequency conversion modulation method and a modulation device thereof. Background technique [0002] In a digital signal transmission system, it is necessary to up-convert the baseband signal to a radio frequency. Taking a digital TV transmission system as an example, an 8MHz baseband signal needs to be up-converted to a corresponding radio frequency, such as 48MHz to 866MHz. Traditional up-conversion has the following three methods: three-time frequency conversion, two-time frequency conversion and direct frequency conversion, among which: direct frequency conversion, that is, one-time frequency conversion, is highly recommended. Such as figure 1 As shown, the method of direct frequency conversion is to convert the complex digital baseband signal into a complex analog baseband signal, that is, a complex zero-IF signal; p...
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IPC IPC(8): H04L27/00H04B1/00H04L25/00
Inventor 李文华夏劲松宋伯炜范莹莹王先勇
Owner 上海全波通信技术有限公司