The document provides an overview of amplitude modulation (AM) and frequency modulation (FM) in radio electronics, detailing their definitions, frequency ranges, and the advantages of FM over AM. It includes a knowledge check with multiple-choice questions about radio stations and their characteristics, as well as activities for identifying local stations and creating a radio talk show script. Additionally, it explains the process of radio transmission and the technical differences between AM and FM, emphasizing the superior sound quality of FM due to its higher bandwidth.

1. AMPLITUDE
MODULATION/
FREQUENCY
MODULATION
ELECTRONICS 10

2. LET’S CHECK YOUR KNOWLEDGE
1. What does AM stand for?
a. Ante Meridian
b. After Meridian
c. Aptitude Modulation
d. Amplitude Modulation

3. 2. What is the frequency
range of AM radio?
a. 125 kHz -1,250 kHz
b. 535 kHz – 1,705 kHz
c. 675 kHz – 1,975 kHz
d. 875 kHz – 2,075 kHz

4. 3. Why does FM radio have
a better sound quality?
a. Higher bandwidth
b. Lower bandwidth
c. Stable bandwidth
d. Unstable bandwidth

5. 4. What does FM stand for?
a. Fair Modulation
b. Front Modulation
c. Frequency Modulation
d. Frequency Moderation

6. 5. What is the frequency range
of FM radio?
a. 88 mHz – 108 mHz
b. 98 mHz – 108 mHz
c. 108 mHz – 118 mHz
d. 118 mHz – 128 mHz

7. 6. Which type of radio station
is 90.7 MHz?
a. AM Radio
b. FM Radio
c. Both AM and FM Radio
d. None of the above

8. 7. Which of the following is an
example of an FM radio station
with its frequency?
a. 594 kHz Super Radyo DZBB
b. 666 kHz National DZRH
c. 882 kHz Todong Lakas DWIZ
d. 107.5 MHz WISH

9. 8. Which of the following is the
advantage of FM radio over AM
radio?
a. FM is cheaper than AM
b. FM is less prone to interference
than AM
c. FM has a lower bandwidth, so it
can have more stations than AM

10. 9. What is being varied or
modulated in FM radio?
a. Amplitude
b. Frequency
c. Wavelength

11. 10. What is being varied or
modulated in AM radio?
a. Amplitude
b. Frequency
c. Period
d. Wavelength

12. Activity: Know My Station
Let’s find out:
What are the frequencies and names of some radio
stations in the
Philippines and the locality?
Let’s use these materials:
ball pen, paper and an AM/FM radio
Let’s do it this way:
1. Turn the radio on.
2. Name and locate the amplitude or frequency of the
FIVE AM and FM radio stations that can be heard on

14. Guide Questions:
1. Did you find it easy to locate the AM and
FM radio stations?
2. Have you located a frequency of the
nearest radio station in your locality?
Give the name of the nearest radio station.
3. What challenges have you experienced in
doing this activity?

15. PROCESS OF RADIO TRANSMISSION

16. 1. By changing the amplitude or height of the
carrier wave (Amplitude Modulation).

17. 2. By changing the frequency or how fast the
carrier wave travels (Frequency Modulation).

18. PROCESS OF RADIO TRANSMISSION

19. Despite that radio waves continuously coming from
many stations surrounding us, the radio receiver does not
receive them simultaneously. It is because the stations
broadcast at different specific frequencies. The radio has to
be tuned in to a precise frequency to find the right signal.
The numbers on the radio dial represent frequencies
used by the local radio stations. If the FM dial is set at
107.5 (WISH 107.5), the radio signal is broadcasted at
107,500,000 MegaHertz (MHz), or 107,500,000 cycles per
second.

20. FM uses a higher frequency range and
bandwidth than AM. AM radio operates from
535 kHz (kiloHertz) to 1605 kHz. When turning
the dial on the radio, the number changes by 10
kHz each time. It means that each station has
10 kHz of bandwidth on which to broadcast. On
the other hand, FM radio operates between 88
MHz and 108 MHz and increments every 200
kHz.

21. FM station has an allocated 150 kHz of
bandwidth, which is 15 times that of an AM
station. It means that an FM station can transmit
15 times as much information as an AM station.
It explains why music sounds so much better on
FM. Since music has more electrical information
than a monophonic voice audio signal, FM
typically broadcasts music, and AM generally
sticks to news and talk show programs.

27. Activity:2
Let’s use these materials:
paper, and ball pen, CP
Let’s do it this way:
1.Make a script of a radio talk show on the topic
“Differences between AM and FM.”
2.Make an audio recorded presentation of a
radio talk show discussing the differences
between AM and FM.