2. A 1500 kHz carrier and a 2 kHz intelligence signal are combined in a non-linear device. List all the frequency components produced.
- 1498, 1500, and 1520KHz
3.If a carrier is amplitude modulated what causes the sideband frequencies?
- The non-linear mixing of the carrier and intelligence frequencies.
4.What determines the bandwidth of emission for an AM transmission?
- It is twice the frequency of the highest audio frequency transmitted.
The upper sideband is fc +FM where fc is the carrier frequency and FM is the modulation (audio) frequency .The lower sideband is fc – FM. The total bandwidth is 2*FM
5.Explain…show more content… - A high percentage of modulation is important so that the power is the sidebands.
20. During 100% modulation, what percentage of the average output power is in the sidebands? (33.33%)
- Pt = Pc (1+m2/2)
35. Draw a block diagram (or indicate which text book Figure # shows this) of an AM transmitter.
Chapter 3 (pp. 159-160)
- Figure 3-1 pg. 118
1. Draw a diagram (or indicate which text book Figure # shows this)of a tuned radio-frequency (TRF) radio receiver.
2. Explain the following: Sensitivity of a receiver, selectivity of a receiver. Why are these important characteristics? In what units are these usually expressed?
- Sensitivity: the minimum input RF signal to a receiver required to produce a specified audio signal at the output.
Selectivity: the extent to which a receiver can differentiate between the desire signal and
3.Explain why a receiver can be overly selective.
- A receiver that is overly selective can result in alack of fidelity because part of the intelligence is not included (filtered out)
6.Describe the advantages and disadvantages of a diode detector. * Advantages * Handle high power * Acceptable distortion levels * Efficient * Provide a usable dc voltage for the AGC circuits * Disadvantage * Reduce Q and selectivity * No amplification
10. Provide the advantages of a synchronous detector compared to a diode detector. Explain its