Questions and Answers on Communication Technology
1. Explain what is meant by the term wireless. Wireless is a term used to describe telecommunications in which electromagnetic waves (rather than some form of wire) carry the signal over part or all of the communication path.
2. What is a frequency-shift-keying system? Describe two methods of generating FSK. Frequency-shift keying (FSK) is a method of transmitting digital signals.
6. Explain a method used to generate BPSK using Figure 10-5 as a basis. Need for modulation 1) to reduce the antenna height 2) to multiplex the more number of signals 3) to reduce the noise & distortions 4) to narrow banding the signal
8. What is coherent carrier recovery? The received BPSK signal is fed into the mixer circuit. The other input to the mixer circuit is driven by a reference oscillator synchronized to sin(wct).
10. Provide a brief description of the QAM system. Explain why it is an efficient. Method of achieving high data rates in limited bandwidth channels, characterized by two data signals that are 90° out of phase with each other. Achieve high data rates in limited bandwidth channels
13. The input data to a DPSK transmitter is 1 1 0 1. Determine the DPSK digital data stream and the DPSK RF output. 00100000
19. Explain the concept of frequency hopping spread spectrum. Frequency hopping is one of two basic modulation techniques used in spread spectrum signal transmission.
22. Define code division multiple access. A channel access method used by various radio communication technologies. CDMA is an example of multiple access, which is where several transmitters can send information simultaneously over a single communication channel.
25. Draw the block diagram of a DSSS transmit-receive system.
27. Draw the block diagram of an OFDM transmission.
31. What is the digital data rate for AM digital and what is its comparable quality? The digital data rate for AM HD radio is 36 kbps, which produces an audio signal with comparable quality to the current analog FM.
2. What is a frequency-shift-keying system? Describe two methods of generating FSK. Frequency-shift keying (FSK) is a method of transmitting digital signals.
6. Explain a method used to generate BPSK using Figure 10-5 as a basis. Need for modulation 1) to reduce the antenna height 2) to multiplex the more number of signals 3) to reduce the noise & distortions 4) to narrow banding the signal
8. What is coherent carrier recovery? The received BPSK signal is fed into the mixer circuit. The other input to the mixer circuit is driven by a reference oscillator synchronized to sin(wct).
10. Provide a brief description of the QAM system. Explain why it is an efficient. Method of achieving high data rates in limited bandwidth channels, characterized by two data signals that are 90° out of phase with each other. Achieve high data rates in limited bandwidth channels
13. The input data to a DPSK transmitter is 1 1 0 1. Determine the DPSK digital data stream and the DPSK RF output. 00100000
19. Explain the concept of frequency hopping spread spectrum. Frequency hopping is one of two basic modulation techniques used in spread spectrum signal transmission.
22. Define code division multiple access. A channel access method used by various radio communication technologies. CDMA is an example of multiple access, which is where several transmitters can send information simultaneously over a single communication channel.
25. Draw the block diagram of a DSSS transmit-receive system.
27. Draw the block diagram of an OFDM transmission.
31. What is the digital data rate for AM digital and what is its comparable quality? The digital data rate for AM HD radio is 36 kbps, which produces an audio signal with comparable quality to the current analog FM.