1 1 10 100 1000 analog usually use an op amp circuit

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Unformatted text preview: ! Usually use an op-amp circuit Often found as a pre-amplifier to ADC circuitry Simple circuit to computer natural logarithm Map binary values to analog outputs (voltages) Most devices have a digital interface – use time to encode value Time-varying digital signals – almost arbitrary resolution pulse-code modulation (data = number or width of pulses) pulse-width modulation (data = duty-cycle of pulses) frequency modulation (data = rate at which pulses occur) V VIN VOUT = loge ( VIN ) V V t t t 1 #$ %& $ ( Pulse a digital signal to get an average “analog” value The longer the pulse width, the higher the voltage Pulse-width ratio = tperiod tperiod $ & ) Most mechanical systems are low-pass filters Consider frequency components of pulse-width modulated signal Low frequency components affect components ton They pass through average value ton $ %& High frequency components are too fast to fight inertia They are “filtered out” Electrical RC-networks are low-pass filters t Time constant (τ = RC) sets “cutoff” frequency that separates low and high frequencies t t " % ' - )+ ) & . % )+ ) Re...
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This document was uploaded on 04/04/2014.

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