A Synchronization Circuit of Quadrature Modulator Output DAC Based on Dual-loop Frequency Synthesis

A technology of quadrature modulator and frequency synthesizer, which is applied in the direction of instruments, electrical components, signal transmission systems, etc., can solve problems such as spectrum spurious, and achieve the effects of strong anti-interference ability, good design consistency, and correct sampling

Active Publication Date: 2019-12-20
XIAN INSTITUE OF SPACE RADIO TECH
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Problems solved by technology

[0005] The technical problem solved by the present invention is: to overcome the spectral spurious problem caused by the asynchronous output data of the high-speed DAC in the implementation process of the existing space-borne high-reliability modulator, and to provide a quadrature modulator output DAC based on double-loop frequency synthesis synchronous circuit

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  • A Synchronization Circuit of Quadrature Modulator Output DAC Based on Dual-loop Frequency Synthesis
  • A Synchronization Circuit of Quadrature Modulator Output DAC Based on Dual-loop Frequency Synthesis
  • A Synchronization Circuit of Quadrature Modulator Output DAC Based on Dual-loop Frequency Synthesis

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Embodiment Construction

[0031] The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0032] Considering the long-term work of the satellite in orbit and its complex space radiation environment, such as figure 1 The space-borne modulator shown is selected from ACTEL company's anti-fuse device RTAX250-CQ352 which is not sensitive to single events to realize the baseband data GMSK modulator design and Gaussian filter processing to improve the reliability of data processing. The digital-to-analog conversion part uses two pieces of DAC5670SP from TI Company, and cooperates with FPGA to complete the baseband molding process. The digital Gaussian filter designed by the GMSK modulator is quadruple sampling, and the sampling clock rate is four times the baseband data rate. The DAC5670SP device supports up to 2.4GHz sampling, which can meet the requirements of most modulators.

[0033] In order to obtain completely orthogonal two-way ...

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Abstract

The invention discloses a quadrature modulator output DAC (Digital-to-Analog Converter) synchronization circuit based on double-loop frequency synthesis. The quadrature modulator output DAC synchronization circuit comprises an I-path frequency synthesizer, a Q-path frequency synthesizer, an I-path DAC, a Q-path DAC and a variable time delay module, wherein the I-path frequency synthesizer is used for generating a sampling clock needed by the I-path DAC; the I-path DAC is used for performing 1 / N frequency division processing on the I-path DAC sampling clock, transmitting one path to an I path and a Q path of a quadrature modulator in order to synchronously process and output I-path data and Q-path data of the quadrature modulator according to an I-path frequency division clock, and outputting the other path to the Q-path frequency synthesizer after phase delay; and the Q-path frequency synthesizer is used for performing phase discrimination, low-pass filtering and N-frequency multiplication on the I-path frequency division clock serving as a reference signal and a Q-path frequency division clock output by the Q-path DAC in order to generate a Q-path DAC sampling clock. Through adoption of the quadrature modulator output DAC synchronization circuit, the problem of non-synchronous data output of a satellite-borne high-reliability modulator I / Q-path high-speed DAC is solved.

Description

technical field [0001] The invention belongs to the technical field of satellite communication synchronous circuits, and in particular relates to a dual-loop frequency synthesis-based quadrature modulator output DAC synchronous circuit, which can be used for highly reliable space-borne GMSK modulators, and can also be used for other space-borne analog quadrature modulators I, Q channel DAC data synchronization. Background technique [0002] With the development of satellite technology, the modulation method of the spaceborne modulator must meet the requirements of small out-of-band radiation, high frequency band utilization and high reliability. GMSK modulation is a typical constant-envelope digital modulation technology, which has the characteristics of small out-of-band radiation, frequency band utilization and suitability for nonlinear channel transmission. Therefore, the space-borne modulator adopts GMSK modulation. The GMSK modulator is a quadrature modulator. For the...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H03M1/66H03M1/74
CPCH03M1/662H03M1/74
Inventor 宋宝相赵俊艺何兵哲张伟徐进邹少存贾宏丽
Owner XIAN INSTITUE OF SPACE RADIO TECH
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