In the following questions, pick the answer which seems most correct.

1. A Comm. Net. student, hanging out with some friends said, "Hey%20man,%20my%20Prof." told me that I can reduce the noise floor in my stereo by sticking it in LIQUID NITROGEN (Boiling point 77 degrees Kelvin) "!!%20" Cool dude! "%20was%20the%20reply.%20

" Assume that the bandwidth of a stereo is 20 kHz and that it will be able to operate in the liquid nitrogen. What will the total thermal-noise power be? Compute your answer in decibel watts and show work.

a) -157.8 dBw

b) -161.2 dBw

c) -166.7 dBw

2. In general, a digital waveform has infinite bandwidth.

a) True

b) False

3. The 787 AT&T/Zenith HDTV system has 1920 pixels by 787 lines and is not interlaced. The frame rate is 60 hz. What is the horizontal scanning frequency? Show work.

a) 15,750 Hz

b) 23,610 Hz

c) 47,220 Hz