# Frenzel Self-test in Frequency Modulation - Answers

Answers key for Frenzel Self-test in Frequency Modulation from the book COMMUNICATIONS ELECTRONICS by Louis E. Frenzel. Make sure to familiarize each and every questions.

Below are the answers key for Frenzel Self-test in Chapter 4: Frequency Modulation from the book COMMUNICATIONS ELECTRONICS by Louis E. Frenzel. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.

1. angle

2. true

3. deviation

4. amplitude

5. increases, decreases (the reverse could also be true)

6. phase shift

7. frequency shift or deviation

8. changing or varying

9. amplitude, frequency

10. a

11. b

12. indirect FM

13. true

14. modulation index

15.3 (m = 10/33 = 3)

16. 5

17. 995.5, 1004.5 [3(1.5) = 4.5 KHz; 1000 4.5 = 995.5 and 1004.5 kHz]

18. 0.28

19. Bessel functions

20. 60 [2(5)(6)= 60 kHz]

21. 75 [(3.75/5)100 = 75%]

22. phase inversion or 180° shift

23. false

24. BW = 40 kHz; BW = 28 kHz using Carson's rule; Carson's rule gives narrower bandwidths because sidebands of less than 2 percent amplitude are not considered

25. noise

26. a

27. limiter (or clipper)

28. capture effect

29. C

30. spectrum space

31. false

32. high

33. pre-emphasis

34. high-pass filter

35. de-emphasis

36. 75

37. 2122