One, foreword
Array signal treats a when treat a field as digital signal main branch, wide application is mixed at exploration of radar, sonar, communication, earthquake medical into resemble waiting for numerous domain; Shortwave frequency Duan Zechang is used at shortwave to measure Xiang Hebo bundle synthetic technology.
In shortwave frequency paragraph, equipment of array signal processing includes shortwave antenna normally blast, processor of signal of array of receiver of shortwave much radio frequency channel, back end 3 main component. Among them, shortwave antenna blast receive dimensional shortwave signal, shortwave receiver makes the frequency conversion below imitate to HF signal, receiver of much to shortwave radio frequency channel outputs array signal processor the array signal with hand-in-hand corresponding travel handles sampling of word of signal be valid algorithmic, give out final operation result.
Shortwave antenna blast as a result of shortwave frequency paragraph limitation, the volume of aerial unit is normally larger, aerial blast bore diameter is bigger also, cover an area of often nearly 10 mus; And receive the result to achieve those who had compared, shortwave antenna blast quite tall also to the requirement of circumjacent electromagnetism environment. This develops a process to be debugged mediumly to processor of shortwave array signal brought huge inconvenience with the experiment, at the same time also very all sorts of DSP algorithm research that go against array signal processor to be aimed at signal of shortwave of diverse array flow pattern and test and verify.
Handle equipment development, debugged real case in the light of shortwave array signal, the author chooses chip of digital signal processor (DSP) with chip of the transducer on the number (DigitalUpConverter, DUC) designed antenna of an imitate shortwave blast the array signal generator that outputs signal, shortwave antenna can be replaced below lab environment blast, generate the shortwave array signal of correspondence of all sorts of photograph of diverse array flow pattern, offer DSP of array signal processor to be debugged algorithmicly with condition of test and verify.
2, design train of thought
According to design conception, this array signal generator should can produce form of corresponding and diverse array neatly (carry the extent difference that has correspondence of diverse array form and phasic difference) , the shortwave array signal that enclothes Duan Fan of frequency of 1 ～ 30MHz basically to surround.
If use circuit of the frequency conversion on traditional imitate to realize radio frequency output, satisfy design conception very hard, because this author introduces the idea of software radio, chose the transducer on the number (DUC) , make in digital region on frequency conversion, generate signal of imitate of frequency of short wave height through D/A commutation next. The extent difference that brings to realize place of diverse array form and phasic difference, the author chose DSP chip, distinct range and phasic difference are joined to many signal in digital region.
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