E7E01:

Which of the following can be used to generate FM phone emissions?

  1. A balanced modulator on the audio amplifier
  2. A reactance modulator on the oscillator
  3. A reactance modulator on the final amplifier
  4. A balanced modulator on the oscillator

E7E02:

What is the function of a reactance modulator?

  1. To produce PM signals by using an electrically variable resistance
  2. To produce AM signals by using an electrically variable inductance or capacitance
  3. To produce AM signals by using an electrically variable resistance
  4. To produce PM signals by using an electrically variable inductance or capacitance

E7E03:

How does an analog phase modulator function?

  1. By varying the tuning of a microphone preamplifier to produce PM signals
  2. By varying the tuning of an amplifier tank circuit to produce AM signals
  3. By varying the tuning of an amplifier tank circuit to produce PM signals
  4. By varying the tuning of a microphone preamplifier to produce AM signals

E7E04:

What is one way a single-sideband phone signal can be generated?

  1. By using a balanced modulator followed by a filter
  2. By using a reactance modulator followed by a mixer
  3. By using a loop modulator followed by a mixer
  4. By driving a product detector with a DSB signal

E7E05:

What circuit is added to an FM transmitter to boost the higher audio frequencies?

  1. A de-emphasis network
  2. A heterodyne suppressor
  3. An audio prescaler
  4. A pre-emphasis network

E7E06:

Why is de-emphasis commonly used in FM communications receivers?

  1. For compatibility with transmitters using phase modulation
  2. To reduce impulse noise reception
  3. For higher efficiency
  4. To remove third-order distortion products

E7E07:

What is meant by the term baseband in radio communications?

  1. The lowest frequency band that the transmitter or receiver covers
  2. The frequency components present in the modulating signal
  3. The unmodulated bandwidth of the transmitted signal
  4. The basic oscillator frequency in an FM transmitter that is multiplied to increase the deviation and carrier frequency

E7E08:

What are the principal frequencies that appear at the output of a mixer circuit?

  1. Two and four times the original frequency
  2. The sum, difference and square root of the input frequencies
  3. The two input frequencies along with their sum and difference frequencies
  4. 1.414 and 0.707 times the input frequency

E7E09:

What occurs when an excessive amount of signal energy reaches a mixer circuit?

  1. Spurious mixer products are generated
  2. Mixer blanking occurs
  3. Automatic limiting occurs
  4. A beat frequency is generated

E7E10:

How does a diode detector function?

  1. By rectification and filtering of RF signals
  2. By breakdown of the Zener voltage
  3. By mixing signals with noise in the transition region of the diode
  4. By sensing the change of reactance in the diode with respect to frequency

E7E11:

Which type of detector is used for demodulating SSB signals?

  1. Discriminator
  2. Phase detector
  3. Product detector
  4. Phase comparator

E7E12:

What is a frequency discriminator stage in a FM receiver?

  1. An FM generator circuit
  2. A circuit for filtering two closely adjacent signals
  3. An automatic band-switching circuit
  4. A circuit for detecting FM signals