Signal Sampling and Quantization - Digital Signal Processing: Fundamentals and Applications - page 53

• 40 dB rejection at the frequency of 18,000 Hz
• Butterworth filter.
Determine the cutoff frequency and order for the anti-image filter.

2.21. Given the 2-bit flash ADC unit with an analog sample-and-hold voltage of 2 volts shown in
Figure 2.39 , determine the output bits.
2.22. Given the R-2R DAC unit with a 2-bit value defined as b 1 b 0 ¼ 01 shown in Figure 2.40 ,
determine the converted voltage.

V R = 5 Vvolts

in

= 2

Encoding
logic

R

11

Comparators

+
−

3 V R

10

= 375 .

b1b0

4

R

V R
2

+
−

01

= 25 .

R

+
−

00

V R
4

= 125 .

R

FIGURE 2.39

2-bit flash ADC in Problem 2.21.

V R = 5

1
2

1
2

VV = b + b

0 R 1 0

1 2

V
R

I =

R

R

1

R

I /2

R

0

b 1 = 0

2 R

R

R

V 0

−

1

I / 4

−

0

b 0 = 1

2 R

Adder Phase shfter

I / 4

2 R

FIGURE 2.40
2-bit R-2R DAC in Problem 2.22.