Mechatronics_11_25_08_Dig2Analog

# Mechatronics_11_25_08_Dig2Analog - A/D and D/A details...

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A/D and D/A details Fundamentals of Mechatronics Engineering 11/25/08

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Recall the basics of A/D Samples an analog input (continuous voltage over 0-5 Volts)* The analog input gets converted to digital form, a certain number of bits. The Atmega 128 has a 10 bit A/D converter. 5 volt input=11 1111 1111=1023 0 volt input=00 0000 0000=0 Linear in between The Atmega 128 has a 10 bit A/D converter, but there are many sizes available : 8 bit, 12 bit, 16 bit, etc. You might imagine that if you take the same 0-5 volt input, and represent it as 0- 1023 (10 bit) versus 0-65,535 (16 bit), the 16 bit has much more resolution. It can represent smaller variations in the input that will be “rounded” off with the 10 bit A/D. So what is the resolution of a 10 bit A/D? 5 volts/1024=.0049 volts. This is called the quantization: Q=(Vmax-Vmin)/N, where N=2 , n=number of bits But, what does it mean as far as you accuracy? Let’s say that input was a temperature sensor with a range of 0 to 100 degC represented by 0-5 volts. 100 degC/ 5 volts

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## This note was uploaded on 09/08/2010 for the course ME 106 at San Jose State.

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Mechatronics_11_25_08_Dig2Analog - A/D and D/A details...

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