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 Posted: Mon 11:07, 04 Apr 2011 Post subject: Chirp signal based on DDS technology generation sy |
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Chirp signal based on DDS technology generation system
Delay time. The frequency of the signal from the current plant can be set phase difference between the two signals △ a mTof × 360. . (2) signal analysis system ,[link widoczny dla zalogowanych], known in determining the environment, the difference only with the current scan frequency. In this, the difference between the different frequency values at the incremental PID algorithm implemented △ ( bogey ) First [2.45e (k) A 3.5e ( Chi a 1) +1.25 e ( Chi -2 ) ], ( 3 ) where k is coefficient. 24 of Foshan University ( Natural Science) Volume 22, sine wave signal generator 3.2 Program Design program flow shown in Figure 5 . First, reset the AD7008 , the register is zero; and then load the selected sine wave frequency, phase , amplitude ; determine the scanning center amplitude , decoupling limit and the scanning frequency ( up- , down-conversion ); initial frequency of the input parameters F, termination of the frequency F,, period T; to determine the number of Ⅳ and frequency conversion value af, scanning begins. Through appropriate regulation, by the former three -band difference between the value generated by the frequency to determine the value of time required under the PID control increment correction , and thus achieve better control effect , resulting in the desired different frequency , phase And the amplitude of the sine wave. 4 Results and Analysis of chirp signal source system design , using the flowchart in Figure 5 signal of the DDS technology, advanced electronic control system can achieve linear scanning , frequency scanning , coding, scanning and other technologies help to improve wavelet The frequency, high-resolution seismic exploration to create better conditions. Phase of the automatic control system accuracy ± 6. , The frequency accuracy of 0.1Hz, amplitude control precision of 0.01mm. The practical application , the amplitude stability of the sine wave is good enough , high resolution and accuracy to meet the imaging requirements.
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