Frequency Modulation

Question 0

What am I? The frequency occupied by the carrier when in an unmodulated state?

Answer 0

Centre frequency or carrier

Question 1

In the process of frequency modulation, the …………. of the modulating wave controls the resultant modulated wave

Answer 1

Amplitude

Question 2

What am I? The amount of change in frequency from centre frequency in the modulated wave that occurs with the maximum modulating wave amplitude?

Answer 2

Frequency deviation

Question 3

The higher the …………. of the modulating wave the greater the ………… of the carrier

Answer 3

Amplitude and deviation

Question 4

What am I? The difference between the very highest and lowest frequencies the modulated wave can attain?

Answer 4

Frequency swing

Question 5

What am I? The decimal number representing the ratio of the frequency deviation and the highest frequency of the modulating wave?

Answer 5

Modulation Index (MI)

Question 6

How many side frequencies are significant when the modulation index is 2?

Answer 6

3

Question 7

What is the equation for working out modulation index?

Answer 7

MI=fd/fm

Question 8

What do we use to calculate the significant transmission bandwidth?

Answer 8

Carsons rule

Question 9

What is the formula for working out transmission bandwidth?

Answer 9

Transmission BW=2(fd+fm)

Question 10

Can an FM carrier ever be over modulated?

Answer 10

No