Chapter 2 / 2.6

2.6 REVISION QUESTIONS

1. Write an equation for the sinusoidal voltage waveform as a function of distance travelled.

1. Write an equation for the sinusoidal voltage waveform as a function of the time it has been travelling.

1. Write an equation for the relationship between wavelength and frequency.

1. Sketch a 2-V, 1-kHz sine wave and a 4-V, 10-kHz sine wave in the time domain and the frequency domain.

1. Write an equation for a sinusoidal waveform, including the three wave properties of amplitude, frequency, and phase.

1. List the frequency ranges of the HF, VHF, UHF and SHF frequency bands. Briefly describe the communications uses of each band.

1. List four advantages of digital signals over analog signals.

1. Describe the difference between baud rate, data rate, and information rate.

1. Describe the difference between synchronous and asynchronous data transmission.

1. Explain why a perfectly rectangular digital pulse requires infinite bandwidth, and describe the practical consequence of this requirement.

1. A binary polar NRZ signal is transmitted at 8 bps. (a) Where does the first spectral null occur? (b) How does this change if the bit rate is doubled?

1. Describe inter-symbol interference (ISI) using both the time-domain and frequency-domain viewpoints.

1. Why does increasing the order of an M-ary signaling scheme reduce symbol rate but increase sensitivity to noise?

1. Explain why regeneration is possible for digital signals but not for analog signals.

1. A communication channel has a bandwidth of 3 kHz.
   (a) What is the maximum symbol rate for a noiseless channel?
   (b) Why is this rate not achievable in practice?

1. Distinguish clearly between: transmission rate, information rate, and channel capacity.

1. Give two reasons why modern high-speed systems prefer serial transmission over parallel transmission.

1. Explain why most long-distance communication systems use bandpass transmission rather than baseband transmission.