69 lines
3.2 KiB
Markdown
69 lines
3.2 KiB
Markdown
E8A Fourier analysis; RMS measurements; average RF power and peak envelope power (PEP); analog/digital conversion
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- [[E8A01]] (A)
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What technique shows that a square wave is made up of a sine wave and its odd harmonics? #card
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- [[A.]] Fourier analysis
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- [[B.]] Vector analysis
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- [[C.]] Numerical analysis
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- [[D.]] Differential analysis
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- [[E8A02]] (A)
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Which of the following is a type of analog-to-digital conversion? #card
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- [[A.]] Successive approximation
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- [[B.]] Harmonic regeneration
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- [[C.]] Level shifting
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- [[D.]] Phase reversal
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- [[E8A03]] (B)
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Which of the following describes a signal in the time domain? #card
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- [[A.]] Power at intervals of phase
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- [[B.]] Amplitude at different times
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- [[C.]] Frequency at different times
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- [[D.]] Discrete impulses in time order
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- [[E8A04]] (B)
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What is “dither” with respect to analog-to-digital converters? #card
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- [[A.]] An abnormal condition where the converter cannot settle on a value to represent the signal
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- [[B.]] A small amount of noise added to the input signal to reduce quantization noise
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- [[C.]] An error caused by irregular quantization step size
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- [[D.]] A method of decimation by randomly skipping samples
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- [[E8A05]] (D)
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What is the benefit of making voltage measurements with a true-RMS calculating meter? #card
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- [[A.]] An inverse Fourier transform can be used
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- [[B.]] The signal’s RMS noise factor is also calculated
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- [[C.]] The calculated RMS value can be converted directly into phasor form
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- [[D.]] RMS is measured for both sinusoidal and non-sinusoidal signals
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- [[E8A06]] (A)
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What is the approximate ratio of PEP-to-average power in an unprocessed single-sideband phone signal? #card
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- [[A.]] 2.5 to 1
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- [[B.]] 25 to 1
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- [[C.]] 1 to 1
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- [[D.]] 13 to 1
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- [[E8A07]] (B)
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What determines the PEP-to-average power ratio of an unprocessed single-sideband phone signal? #card
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- [[A.]] The frequency of the modulating signal
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- [[B.]] Speech characteristics
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- [[C.]] The degree of carrier suppression
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- [[D.]] Amplifier gain
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- [[E8A08]] (C)
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Why are direct or flash conversion analog-to-digital converters used for a software defined radio? #card
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- [[A.]] Very low power consumption decreases frequency drift
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- [[B.]] Immunity to out-of-sequence coding reduces spurious responses
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- [[C.]] Very high speed allows digitizing high frequencies
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- [[D.]] All these choices are correct
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- [[E8A09]] (D)
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How many different input levels can be encoded by an analog-to-digital converter with 8-bit resolution? #card
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- [[A.]] 8
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- [[B.]] 8 multiplied by the gain of the input amplifier
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- [[C.]] 256 divided by the gain of the input amplifier
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- [[D.]] 256
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- [[E8A10]] (C)
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What is the purpose of a low-pass filter used at the output of a digital-to-analog converter? #card
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- [[A.]] Lower the input bandwidth to increase the effective resolution
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- [[B.]] Improve accuracy by removing out-of-sequence codes from the input
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- [[C.]] Remove spurious sampling artifacts from the output signal
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- [[D.]] All these choices are correct
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- [[E8A11]] (A)
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Which of the following is a measure of the quality of an analog-to-digital converter? #card
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- [[A.]] Total harmonic distortion
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- [[B.]] Peak envelope power
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- [[C.]] Reciprocal mixing
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- [[D.]] Power factor
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