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Mod 10- A to D conversion
ece331
16
Aerospace Engineering
Not Applicable
04/23/2016

Additional Aerospace Engineering Flashcards

Term
 A/D convertors function
Definition
 transform an analog signal into a digital signal for use(calculation, storage, decision making) in a digital system,why? Because the real world is analogic.
Term
 transducer
Definition
 A device that converts primary form of energy into corresponding signal with a different energy form(compass), take form of a sensor or actuator
Term
 Sensor
Definition
 A device that detects measures a signal(acquires info from the real world) ex a thermometer
Term
 Actuator
Definition
 A device that generates a signal (heater)
Term
 analog signal to digital sample features
Definition
 Max voltage<---> voltage reference high: VrhMin voltage<---> voltage ref low: Rrlvoltage sensitivity<---> AD resolutionfrequency components<---> sampling rate fs=1/Ts
Term
 Sampling ratenyquist criterionnumber of steps n=
Definition
 is the number of samples of audio carried per second- minimum sample freq should be twice the highest freq content of the sampled signalfs>= 2fhTs= 1/fsfcuttoff= fh2^b
Term
 aliasing
Definition
 frequency response incorrectly shows frequency
Term
 quantization
Definition
 number of discrete levels the analog signal is divided into between Vrh and Vrl#steps =2^b, more steps=better resp of sampled signals
Term
 resolution
Definition
 voltage per step =(Vrh- Vrl)/ n, =(Vrh- Vrl)/2^b
Term
 Analog value data rate
Definition
 Vanalog= Vdigital*resolution+ Vrl # of A/D result bits per second, d=fs*b     Vdig= (Vanalog-vrl)/Resolution
Term
 Analog valuedata rate
Definition
 Vanalog= Vdigital*resolution+ Vrl# of A/D result bits per second, d=fs*b
Term
 Integrating
Definition
 measures the time it takes to integrate a reference signal to match input value- common in digital voltmeters
Term
 flash
Definition
 bank of comparators sample input signal in parallel- very fast(Ghz+), size limit resolution: # of comparators needed. (2^n)-1
Term
 sigma delta
Definition
 oversamples signal by a large factor and filters the desired signal band, slow but high resolution
Term
 Successive- approximation register (SAR)
Definition
 Constantly compares input voltage to reference value; reference value moves closer to input value each cycle, #cycles=#bits resolution
Term
 pipelined
Definition
 combines successive approx and flashfast, high res, small chip size
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