A set of samples x[n] from a signal is converted to a set of numbers X[k] by using the DFT.
(a) If {x[0] , x[1] , x[2] , x[3] , x[4] } = {2, 8, ?3, 1, 9} , find the numerical value of X[0] .
(b) If x[n] consists of 24 samples taken from exactly three periods of a sinusoid at a sampling rate which is exactly eight times the frequency of the sinusoid, two values of X[k] in the range 0 ? k < 24 are not zero. Which ones are they?
(c) If x[n] consists of seven samples, all of which are the same, ?5, in the range 0 ? k < 7, which X[k] values are zero?
(d) If {x[0] , x[1] , x[2] , x[3] } = {a, b, 0, b} and
{X[0] , X [1] , X[2] , X[3] } = {A, B, 0, B * }
how are a and b related to each other? Express B in terms of a and b.
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Automatic transmission fluid contains additives designed to ________.
A) Change the friction characteristics of the fluid B) Reduce the rate of oxidation C) Clean the transmission D) All of these
The best method for preventing sexual harassment in the workplace is _____.
a. increase the victim's compensation b. promote the victim to a new job c. establish a no-tolerance policy d. improve employee screening methods
A temporary diversion has been constructed on a highway of +4% grade due to major repairs that are being undertaken on a bridge. The maximum speed allowed on the diversion is 20 mi/h. Determine the minimum distance from the diversion that a road sign should be located informing drivers of the temporary change on the highway. Assume that a driver can read a road sign within his or her area of vision at a distance of 30 ft for each inch of letter height.
Speed limit on highway = 65 mi/h Letter height of road sign = 8 inches Perception-reaction time = 2.5 sec What will be an ideal response?
Why should a carbon monoxide detector be used in any room where gas-fired space heaters are being used?
A) Because CO is an integral component of natural gas, a CO detector will alarm if there are any small gas leaks in the gas line. B) High levels of CO can cause nuisance trips of the space heater's oxygen depletion sensor. C) The efficiency of gas-fired space heaters drops when the CO level in the room exceeds 500 ppm. D) Gas-fired space heaters can produce carbon monoxide if the space they are operating in does not have adequate combustion air.