Switched Capacitor Type DAC
The switching of the capacitor is done by two phase clock in the switched capacitor type DAC. When the phase Ø1 is at high state, all the capacitors are switched to ground and discharged. Similarly when the phase Ø2 is at high state, all the capacitors are switched to reference voltage.
Write
the general formula for the output voltage of the switched Capacitor type DAC.
The output voltage of the switched capacitor
type DAC
Vout
= ( Ceq / 2C ) × E
Where
Ceq = Equivalent capacitance when all the inputs
are high
C = Sum of the all capacitance in the circuit
E = Reference voltage
What
are the applications of the switched capacitor type DAC?
The switched capacitor type DAC is used to
construct filters and amplifiers.
Why
the counter type ADC is called as digital ramp ADC?
The counter type ADC is called as digital ramp
ADC because the output of the DAC is staircase or step by step.
Which
are the digital devices used for the construction of the counter type ADC?
AND gate, latches and Digital to Analog
converter
How
to calculate resolution of the analog to digital converter?
The resolution of the analog to digital
converter is given by the ratio of full scale reading to the number of bits in
the counter.
Resolution = Full scale reading / Number of
bits
What
are the disadvantages of the counter type A / D converter?
Disadvantages
The conversion time
depends upon the analog input therefore more conversion time for the larger
input.
What
is quantization error?
Quantization error
The resolution of the
counter type analog to digital converter has built in error, it is referred as quantization
error.
Why
the counter type A / D converter is very slow?
The counter type A / D converter is very slow
because it reset after each conversion.
Why
the tracking type A / D converter is faster than the counter type A / D
converter?
The count in the tracking type A / D converter
is not reset after each sample therefore it is faster than the counter type A /
D converter.
What
is disadvantage of tracking type A / D converter?
Disadvantage of tracking type A / D converter
When the analog input
remains constant, the output of the counter oscillates about the constant
analog input.
Define
: Conversion time
Conversion time
It is defined as the time
required for converting a single analog input to digital output.
What
are the advantages and disadvantages of the flash type A / D converter?
Advantage of flash
type A / D converter
Less conversion time
Disadvantage of
flash type A / D converter
More number of
comparators requires i.e. it requires 2N – 1 comparators for N bit
converter
How
many comparators do the flash type A / D converter requires?
The n bit flash type A / D converter requires
2n – 1 comparator.
Why
the flash type A / D converter do not require clock signal?
The flash type A / D converter don’t require clock signal because there is no timing period in this type of converter.
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