Review WSN

1.The power we use at home has a frequency of 60 Hz. The fluorescent lights flickers at the twice the frequency of the power supply. How often does the light flicker? What is the period of the light flicker in seconds?

What is the frequency of a signal that does not change at all?

1.What is the frequency of a signal that changes instantaneously?

A sine wave is offset 1/4 cycle with respect to time 0. What is its phase in degrees and radians?

A sine wave is offset 1/6 cycle with respect to time 0. What is its phase in degrees and radians?

What is the wavelength of a red light (frequency = 4×10^14) in air? Assume propagation speed of light in air is 3×10^8.

If a periodic signal is decomposed into five sine waves with frequencies of 100, 300, 500, 700, and 900 Hz, what is its bandwidth?

A periodic signal has a bandwidth of 20 Hz. The highest frequency is 60 Hz. What is the lowest frequency?

A nonperiodic composite signal has a bandwidth of 200 kHz, with a middle frequency of 140 kHz and peak amplitude of 20 V. The two extreme frequencies have an amplitude of 0. Draw the frequency domain of the signal.

Assume we need to download text documents at the rate of 100 pages per minute. A page is an average of 24 lines with 80 characters in each line. Each character is 8 bit. What is the required bit rate of the channel?