is the wavelength a of the radio signal for (a) a 100-MHz FM radio and (b) a 10-GHz microwave radio relay system? Problem 3.3 A voltage waveform of a signal follows the equation x(t) = 5 cos(1 . 10 t) V, where t= time. What are the frequency, amplitude, radian frequency, and periodic time (period) of this signal? Problem 3.4 Draw the signal v(t) =5 cos(1 10st + 12) V. The vertical scale should be in volts and the horizontal scale in milliseconds. Problem 3.5 Compare digital telecommunications technology with analog technology and list the most important advantages of digital technology. Problem 3.6 What are the main three phases of PCM encoding (A/D conversion)? Explain how they are performed. Signals Carried over the Network Problem 3.7 What is nonuniform quantizing and why is it used? Problem 3.8 What is the minimum sampling rate of speech when the frequency band is 300 to 3,400 Hz and what is the minimum sampling frequency for high- fidelity music of 20 Hz to 20 kHz? Problem 3.9 Draw the spectrum of an analog signal after sampling when the sampling fre- quency is 8 kHz and the signal that is sampled is a sine wave with a frequency of 1 kHz. Draw the spectrum for each case when the analog signal frequency is 2, 5, and 6 kHz. What happens in each case when we reconstruct the origi- nal signal from the sampled signal with a lowpass filter that has a bandwidth of 4 kHz? Problem 3.10 The digital compact disc (CD) player is designed for a sound bandwidth of 20 kHz. Linear encoding with 16 bits per sample is used. Define (a) the mini- mum sampling rate, (b) the minimum binary data rate per channel (left or right), (c) the maximum SQR, and (d) the average SQR if the average signal level is 30 dB below the maximum value. Problem 3.11 Estimate what bit rate would be needed for each voice channel in the digital telephone network if linear PCM coding is used. The same performance, with SQR at least 40 dB at signal levels higher than -40 dBm0 (sine wave), is required. (Hint: Estimate with the help of Figure 3.13 how much q