THE MAGAZINE FOR COMPUTER APPLICATIONS
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and unique applications through complete projects, practical
tutorials, and useful design techniques.

WHAT'S YOUR ENGINEERING QUOTIENT?

Problem 1—You are out walking your dog at sunset. You notice that there is a light sensor at the top of the streetlight next to you. This sensor is used to activate the lights along the street. The street lamps are around 100m (100 yards) apart. You notice that as the lights come on, the nearest light comes on first and the farthest light just a fraction later. If you assume that you can distinguish between two different events about 1/60 second apart, how fast did the sensor signal propagate between the lights?

There is only one problem — yesterday you were walking the dog at the other end of the street when the lights turned on. Then the nearest light again came on first, and the light with the sensor on top — that turned on last!

ANSWER

Problem 2—

A 1GHz clock signal is distributed to other parts of the circuit as shown below, using a 1mm copper trace on a low loss substrate (microstrip line No 1). The trace is split into four 1mm traces so that the clock signal can be delivered to four subsystems. Is this a good design?

ANSWER

Problem 3—What is nanotechnology?

ANSWER

Problem 4—What is meant by the term "Universal Shift Register"?

ANSWER

Problem 5—What is the counting sequence of a three bit "twisted ring" counter?

ANSWER

Problem 6—Write the assembly code to set all the 8086 flags to '1' at one go without using any arithmetic or logical instructions.

ANSWER

Problem 7—One end of a microstrip line (effective permittivity at 1GHz = 4) is left open, the other is terminated in matched load. What would be the impedance measured 37.5mm from the open end at 1GHz?

ANSWER

Problem 8—What is DMA? What is its use in a computer?

ANSWER

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