253. An input to a 6-level quantizer has the probability density functionf(x) as shown in the figure 11.12. Decision boundaries of the quantizer are chosen so as to maximize the entropy of the quantizer output. If is given that 3 consecutive decision boundaries are '-1', '0' and '1'. L The values of a and b are

A. a= 1/6 and b = 1/12

B. a= 1/5 and b = 3/40

C.a= 1/4 andb= 1/16

D. a = 1/3 and b = 1/24

254. Assuming that the reconstruction levels of the quantizer are the midpoints of the decision boundaries, the ratio of signal power to quantization noise power is

A.31.25

B.62.5uA

C. 125 IAA

D. 250 IAA

255. The voltage Vo is

A.-0.781 V

B.-1.562 V

C. -3.125 V

D.-6.250 V

256. If a zero-crossing detector used in this system indicates a time of 510 1.1s, the state received would be 1/0.

A. f (x) - 271r; c7-

B. f (x) = 27[7(7 E_(,__m)

C.(x?m)2/2 o-2

D.2/2 cr21?(x?m)2/2 cs2

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