Chapter 2: FM & PM

If the amplitude of the modulating signal decreases, the carrier deviation​ (a)   .

• decreases
• increase
• remain constant
• goes to zero
• increases

FM bandwidth can be approximated by:

• Carson's rule & Shannon's rule

• Shannon's rule & Bessel's rule

• Bessel's rule & Carson's rule

• None of these

FREQUENCY MODULATION

• Changing the frequency to increase energy of a electromagnetic wave

• A method of transmitting signals by changing the amplitude of the wave

• Changing the volume of a broadcast signal

• A method of transmitting signals by changing the frequency of the wave

FM signal has a max frequency deviation of 10 kHz. The max modulating freq is 2 kHz. What is the modulation index?

• 2.5

• 0.5

• 4

• 5

The amount of frequency shift in FM is directly proportional to the​ ​ (a)   ​ ​ of the modulating signal.

• amplitude
• frequency
• phase
• time

An FM signal produces more sidebands than an AM signal.

• True

• False

Carson's rule is used to calculate ​​ (a)  

• bandwidth of FM signal
• signal to noise ratio
• modulation index
• noise figure
• noise factor

Match the following:

• Amplitude Modulation

• 
• Frequency Modulation

• 
• Phase Modulation

• 

In the phase modulated signal, the deviation of the frequency is ___________.

• constant

• proportional to both amplitude and frequency

• proportional to frequency

• square of amplitude

Phase modulation is generally not used for transmission because

• Its need higher power

• Its need large antenna sizes

• It is complex for decoding

• It does not carry much information