Interfacing to the Analog World Questions

• The amount of deviation of the measured step size from the ideal step size is a measure of linearity.
• In a digital storage scope, when memory is full, the next data point is lost.
• The current across the MSB "rung" of a 4-bit R/2R ladder DAC if the reference voltage is 5 v and R is 8 Ω is 625 µA.
• A sample-and-hold circuit is used in D/A conversion.
• When the inputs of a four-bit D/A converter are connected to a binary up-counter, the output looks like an upward sloping line.
• A data acquisition system may communicate via two common buses: the data bus and the control bus.
• The output of an analog-to-digital converter is a voltage level.
• When the analog input to a tracking A/D converter is at a constant level, the digital output will oscillate.
• A DAC is monotonic if its output increases as its binary input is incremented from one value to the next.
• To be useful, A/D or D/A converters must have meaningful representation of the analog quantity and a digital representation and the digital quantity as an analog representation.
• When a DAC output shows a deviation of the measured step size from the ideal step size, this error is called nonlinearity.
• An eight-bit D/A converter has a resolution of 0.125.
• If the least significant bit (LSB) of a four-bit binary-weighted resistor D/A converter connects to a 200 Ω resistor, then the resistor needed for the next bit is 100 Ω.
• It is possible to develop more than 16 different analog levels using 4-bit resolution.
• Generally speaking, DACs with a current output will have a shorter settling time than those with voltage outputs.
• D/A conversion is the process of taking a voltage or current and converting it to a digital code.
• Linearity error is the maximum deviation in step size from the ideal step size.
• The DAC0808 and the MC1408 are very popular and inexpensive 8-bit D/A converters.
• The primary disadvantage of the flash A/D converter is the large number of comparators required.
• A simultaneous, multiple comparator, or flash converter uses parallel encoding.