UNIT-1 1. _______ data have discrete statesand take discrete values. A) Analog B) Digital C) (a) or (b) D) None of the above 2. Signals can be ________. A) Analog B) Digital C) Either (a) or (b) D) Neither (a) nor (b) 3. _____ signals can have an infinite number of values in a range. A) Analog B) Digital C) (a) or (b) D) None of the above 4. _______ signals can have only a limited number of values. A) Analog B) Digital C) (a) or (b) D) None of the above 5. Frequency and period are ______. A) inverse of each other B) Proportional to each other C) The same D) None of the above 6. ________is the rate of change with respect to time. A) Amplitude B) Time C) Frequency D) Voltage 7. _______ describes the position ofthe waveform relative to time . A) Frequency B) Phase C) Amplitude D) Voltage 8. A sine wave in the ______ domain can be represented by one single spike in the _____ domain. A) Time; frequency B) Frequency; time C) Time; phase D) Phase; time 9. A _________ sine wave is not useful in data communications; we need to send a _______ signal. A) Composite; single-frequency B) single-frequency; composite C) single-frequency; double-frequency D) None of the above 10. The _____ of a composite signalis the difference between the highest and the lowest frequencies contained in that signal. A) Frequency B) Period C) Bandwidth D) Amplitude 11. A (n)_________ signal is a composite analog signal with an infinite bandwidth. A) digital B) analog C) Either (a) or (b) D) Neither (a) nor (b) 12. Baseband transmission of a digital signal is possible only if wehave a ____ channel. A) low-pass B) Band pass C) Low rate D) High rate 13. If the available channel is a ____ channel, we cannot send a digital signal directly to the channel. A) low-pass B) Band pass C) Low rate D) High rate 14. For a ______ channel, the Nyquist bit rate formula defines the theoretical maximum bit rate. A) Noisy B) Noiseless C) Band pass D) low-pass 15. For a ______ channel, we need to use the Shannon capacity to find the maximum bit rate. A) Noisy B) Noiseless C) Band pass D) low-pass 16. _________ can impair a signal. A) Attenuation B) Distortion C) Noise D) All of the above 17. The _________ product defines the number of bits that can fill thelink. A) bandwidth-period B) frequency-amplitude C) bandwidth-delay D) delay-amplitude 18. Before data can be transmitted, they must be transformed to ________. A) Periodic signals B) Electromagnetic signals C) aperiodic signals D) low-frequency sine waves 19. A periodic signal completes one cycle in 0.001 s. What is the frequency? A) 1 Hz B) 100 Hz C) 1 KHz D) 1 MHz 20. In a frequency-domain plot, the horizontal axis measures the ________. A) Peak amplitude B) Frequency C) Phase D) Slope 21. In a time-domain plot, the horizontal axis is a measure of ________. A) Signal amplitude B) Frequency C) Phase D) Time 22. If the bandwidth of a signal is5 KHz and the lowest frequency is52 KHz, what is the highest frequency? A) 5 KHz B) 10 KHz C) 47 KHz D) 57 KHz 23. What is the bandwidth of a signal that ranges from 1 MHz to 4 MHz? A) 4 MHz B) 1 KHz C) 3 MHz D) None of the above 24. As frequency increases, the period ________. A) Decreases B) Increases C) Remains the same D) Doubles 25. Given two sine waves A and B, if the frequency of A is twice that of B, then the period of B is ________ that of A. A) One-half B) Twice C) The same as D) Indeterminate from 26. A sine wave is ________. A) Periodic and continuous B) aperiodic and continuous C) Periodic and discrete D) Periodic and discrete 27. If the maximum amplitude of a sine wave is 2 V, the minimum amplitude is ________ V. A) 2 B) 1 C) -2 D) Between -2 and 2 28. A signal is measured at two different points. The power is P1 at the first point and P2 at the second point. The dB is 0. This means ________. A) P2 is zero B) P2 equals P1 C) P2 is much larger than P1 D) P2 is much smaller than P1 29. ________ is a type of transmission impairment in whichthe signal loses strength due to the resistance of the transmissionmedium. A) Attenuation B) Distortion C) Noise D) Decibel 30. ________ is a type of transmission impairment in whichthe signal loses strength due to the different propagation speeds of each frequency that makes up the signal. A) Attenuation B) Distortion C) Noise D) Decibel
Posted on: Fri, 07 Jun 2013 17:05:21 +0000