2021-11-15 20:30:01 +00:00
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= ADC =
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An Analog to Digital Converter (ADC) is a type of circut that converts an
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analog voltage signal to a digital one, based upon some range of voltages.
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This is also known as sampling.
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== Overview ==
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2021-11-15 20:45:01 +00:00
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=== Parallel ===
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2021-11-15 20:30:01 +00:00
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1) Analog voltage is converted to a codeword, by running the voltage through a
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series of comparators, each tied to a different voltage
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2021-11-15 20:45:01 +00:00
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2) The series of codewords are put through a series of logic gates that convert
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the code words to a n-bit value, ranging from 0V to VREF
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- ie. VREF = 5V, 10-bit ADC, each step is 5/(2^10) = 4.9mV
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This is a very fast way to implement a ADC, however for a n-bit resolution it
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requires 2^n - 1 comparators, and 2N resistors (for voltage dividers) to
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convert the signal
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=== Counting ===
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1) Compare the analog input voltage to an output from a [[DAC]]
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2) Each time a comparison fails, increment a counter
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3) When the [[DAC]] voltage is larger than the analog voltage, we have found the
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correct value
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