midterm_F05_solution

midterm_F05_solution - Polytechnic University, Dept....

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Unformatted text preview: Polytechnic University, Dept. Electrical and Computer Engineering EE4414 Multimedia Communication System II, Fall 2005, Yao Wang ___________________________________________________________________________________ First Exam (10/20/2005 11-12:50) Closed-book, 1 sheet of notes (single or double sided) allowed, no peeking into neighbors! Please write your answers directly on the provided space. SOLUTION Your Name: ______________________________________________ Prob Score 1 2 3 4 5 Total 1. a. (25 pt) Consider the following two raster scan formats: progressive scan using 30 frames/second, 400 lines/frame, and interlaced scan using 60 fields/second, 200 lines/field. For each scan format, determine a. The overall line rate (lines/second) b. The maximum possible temporal frequency (number of cycles per second) of the signal c. The maximum possible vertical frequency (number of cycles per picture height) of the signal d. The maximum possible frequency (the number of cycles per second) in the 1D waveform of the raster signal, assuming the image aspect ratio is 1:1. e. Based on your results, explain the pros and cons of these two scan formats. Solution: For progressive scan: a, 30*400=12000 lines/s. b. the maximum temporal frequency is when successive frames alternate between black and white, with temporal frequency = frame rate/2 =15 cycles/s. c. the maximum vertical frequency is when successive lines alternate between black and white, with a frequency 400/2=200 cylces/picture-height d. the maximum frequency of the 1D waveform = sampling rate/2=400*200*30/2=1200000 cycles/s. For interlaced scan: a, 60*200=12000 lines/s. b. the maximum temporal frequency is when successive fields alternate between black and white, with temporal frequency = field rate/2 =30 cycles/s. c. the maximum vertical frequency is when successive lines alternate between black and white, with a frequency 200/2=100 cylces/picture-height d. the maximum frequency of the 1D waveform = sampling rate/2=200*200*60/2=1200000 cycles/s. From answer above, we see that the raster scan can support higher temporal resolution, but lower vertical resolution. Note for answers to the b-d, we dont need to use a Kell factor, as I am asking you about the possible maximum frequency of the signal, not the maximum frequency that can be supported by the system. 2. (25 pt) NTSC color TV system a. (10 pt) Figure 2(a) shows a simplified block diagram of an NTSC color TV transmitter. Briefly explain the function of each component. Draw a dashed box on this figure to include all components that comprises a QAM modulator that multiplexes I and Q signals together. Figure 2(a) The RGB to YIQ converter converts the original signal from RGB to YIQ coordinates. The three low pass filters (LPF1,LPF2, LPF3) bandlimit each signal according to its expected bandwidth and the allocated frequency band. The dashed box implements the QAM function, which multiplex the I and Q components into a single signal at a color sub-carrier frequency of fc. The BPF is a bandpass filter, which bandlimits the single signal at a color sub-carrier frequency of fc....
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This note was uploaded on 01/22/2012 for the course EE 4414 taught by Professor Wang during the Fall '07 term at NYU Poly.

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midterm_F05_solution - Polytechnic University, Dept....

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