数字电路英文版.pptVIP

Control Tape drive Digital signal processing Y X Audio in Audio out 15. Which of the equations below expresses the voltage gain relationship for an operational amplifier? a. Vout = Vin/Av b. Vout/Vin = Rout/ Rin c. Vin/ Vout = Rout/ Rin d. Vout / Vin = - Rf / Rin 16. What is the inverting input on an op-amp referred to as, and why? a. Virtual ground; because it is connected to common. b. The (- ) input; to distinguish it from the other input. c. Virtual ground; because it has approximately zero volts on it with respect to the non-inverting terminal. d. Common input; because it is connected to the negative terminal of the power supply, which is in turn connected to circuit common. * * Accuracy. Accuracy is a comparison of the actual output of a DAC with the expected output. It is expressed as a percentage of a full-scale, or maximum, output voltage. For example, if a convert has a full-scale output of 10 V and the accuracy is + 0.1%, then the maximum error for any output voltage is (10V)(0.001) = 10 mV. Ideally, the accuracy should be no worse than + ? of a least significant bit. For an 8-bit converter, the least significant bit is 0.39% of full scale. The accuracy should be approximately + 0.2%. Linearity. A linear error is a deviation from the ideal straight-line output of a DAC. A special case is an offset error, which is the amount of output voltage when the input bits are all zeros. Monotonicity. A DAC is monotonic if it does not take any reverse steps when it is sequenced over its entire range of input bits. Settling time. Settling time is normally defined as the it takes a DAC to settle within + ? LSB of its final value when a change occurs in the input code. ( The settling time of a DAC is the time it takes for the DAC’s analog output settle to 99.95% of its new value after a digital input has been applied.) 18 EXAMPLE 13-2 Determine the resolution, expressed as a percentage, of the following: An 8-bit DAC (b) a 12-bit DAC Solution :