HOMEWORK SET 5 - Due: Tuesday, March. 16
Design a trans-Atlantic cable (5000 km) to carry voice signals (~500 Hz). Assume that low-noise amplifiers can be used to amplify the signal at the input by 103, and at the receiving end by 103. Use copper and teflon. A thin cable is desired. You may neglect shunt losses, dielectric losses, and internal inductance; consider only resistive losses. Also minimize frequency dependent amplitude variations. Helpful questions:
(a) What is the skin depth of copper at 500 Hz?
be?
(c) Target Zo = 50 W. What is 
?
(d) Calculate the needed internal and external conductor radii.
(e) How does the answer change if we consider internal inductance?
Design a video cable to distribute ~200 MHz signals in a local region (max length of ~10 km). Assume that the receiver can amplify the signals by 105. Use the same assumptions and answer the same set of questions as above.
Calculate the dielectric loss (assume) for:
Consider a computer screen that was designed to have no reflection for 500 nm light (green) by placing a quarter-wave coating (e = 2) on glass (e = 4). How much reflection is seen at other wavelengths (400 nm to 650 nm)? Plot your results.