ENTC 4350

HOMEWORK SET 1

Chapter 3, Problem 16.

 An amplifier has an output signal of 3.6 V rms when a sinewave input signal of 0.1 V rms is present. State its gain in decibels.

A v

(

db

)  

3

.

6 20

log

0

.

1 20



1

.

556

 

31 20

.

1

log(

dB

36

)

Chapter 3, Problem 17.

 An amplifier has a gain of 20 dB. This represents an output-to-input ratio of _________.

A v

(

db

) 

20

dB



20

log  

V out V in

 

20 20

 log  

V out V in

  

1 10 1



10



V out V in

Chapter 3, Problem 21.

 The data below were collected by measurement with a voltmeter. Calculate: (a) mean voltage, (b) variance, (c) standard deviation.

4.35 6.21 5.02 3.99 3.02 6.00 4.77 3.3

4.05 5.43 3.45 1.99 6.15 5.75 2.98 5.43

2.22 3.49 4.00 4.40 5.20 5.70 7.01 8.10

4.33 4.00 5.20 4.65 4.34 3.90 5.45 6.90

S x m 4.35 4.711875

-0.36188 0.130954

6.21 4.711875 1.498125 2.244379

5.02 4.711875 0.308125 0.094941

3.99 4.711875

-0.72188 0.521104

3.02 4.711875

-1.69188 2.862441

6 4.711875 1.288125 1.659266

4.77 4.711875 0.058125 0.003379

3.3 4.711875

-1.41188 1.993391

4.05 4.711875

-0.66188 0.438079

5.43 4.711875 0.718125 0.515704

3.45 4.711875

-1.26188 1.592329

1.99 4.711875

-2.72188 7.408604

6.15 4.711875 1.438125 2.068204

5.75 4.711875 1.038125 1.077704

2.98 4.711875

-1.73188 2.999391

5.43 4.711875 0.718125 0.515704

2.22 4.711875

-2.49188 6.209441

3.49 4.711875

4 4.711875

4.4 4.711875

-1.22188 1.492979

-0.71188 0.506766

-0.31188 0.097266

5.2 4.711875 0.488125 0.238266

5.7 4.711875 0.988125 0.976391

7.01 4.711875 2.298125 5.281379

8.1 4.711875 3.388125 11.47939

4.33 4.711875

-0.38188 0.145829

4 4.711875

-0.71188 0.506766

5.2 4.711875 0.488125 0.238266

4.65 4.711875

4.34 4.711875

-0.06187 0.003829

-0.37188 0.138291

3.9 4.711875

-0.81188 0.659141

5.45 4.711875 0.738125 0.544829

6.9 4.711875 2.188125 4.787891

4.711875

150.78

1.857259 1.362813

Variance Std. Dev.