Side 1 af 15
10Digital Control Systems
Sampling, Z-transform, transfer function
Reg1_slide4Chap. 13.1-3,4,(5)
J.NyboRev.:14.04.04
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From analog to digital system
Figure 13.1Conversion of antennaazimuth positioncontrol system from:a. analog control tob. digital control
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Block-diagram of digital system
Figure 13.2a. Placement of the digital computer within the loop;b. detailed blockdiagram showingplacement of A/D and D/A converters
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Steps in analog-to-digital conversion:
Figure 13.4Steps in analog-to-digital conversion:a. analog signal;b. analog signal after sample-and-hold;c. conversion ofsamples to digitalnumbers
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Two views of uniform-rate sampling:
Figure 13.5Two views of uniform-ratesampling:a. switch opening and closing;b. product of timewaveform andsampling waveform
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Zero Order Hold
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Side 10 af 15
Z-transform of a sampled signal
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Inverse z-transform
• Partial fraction expansion (partial brøker)• Power series (polynomiers division)• Tables
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Pulse Transfer Function
Figure 13.8
Sampled-datasystems:a. continuous;b. sampled input;c. sampled inputand output
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Side 15 af 15
Sampled-data systems and their z-transforms
Figure 13.9Sampled-data systems and their z-transforms