Two 8-bit ADCs, one of single slope integrating type and

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Two 8-bit ADCs, one of single slope integrating type and other of successive approximation type, take T_A and T_B times to convert 5 V analog input signal to equivalent digital output. If the input analog signal is reduced to 2.5V, the approximate time taken by the two ADCs will respectively, be

1. T_A , T_B
2. T_A , T_B
  2
3. T_A , T_B
  2
4. T_A , T_B
  2 2

Correct Option: A

In Integrating type ADC , digital counter techniques is employed to measure time required for voltage ramp t o rise from zero to input voltage.
Therefore, it conversion time for 5V is T_A₁ then conversion time for 2.5V is T_A₂
In the case of successive type ADC, conversion time is independent of input voltage, therefore Conversion time for 2.5V input voltage is same to that of 5V input voltage. i.e. = T_B. time required to convert 2.5V input voltage to digital output.

	T_A	, T_B
	2

T_A ,	T_B
	2

	T_A	,	T_B
	2		2