Mark and space refer respectively to Ans Binary 1 and binary 0 2008 Created by

Mark and space refer respectively to ans binary 1 and

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5.Mark and space refer respectively to ©2008 Created by Kai Raimi – BHC COMMUNICATION ELECTRONIC 2 ND EDITION - FRENZEL 11
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6.The number of amplitude, frequency, or phase changes thattake place per second is known ad the 7. Data transmission of one character at a time with start and stop bits is known as what type of transmission? Ans: Asynchronous 8. The most widely used data communications code is Ans: ASCII 9. The ASCII code has Ans: 7 bits 10. Digital signals may be transmitted over the telephone network if Ans: they are converted to analog first. 11. Start and stop bits, respectively, are Ans: Space and mark 12. Which of the following is correct? Ans: The bit rate may be greater than the baud rate 13. A modem converts Ans: both analog signals to digital and digital signals to analog signals 14. Slow-speed modems use Ans: FSK 15. A carrier recovery circuit is not needed with Ans: DPSK 16. The basic modulator and demodulator circuits in PSK are Ans: Balanced modulators 17. The carrier used with a BPSK demodulator is Ans: The BPSK signal itself 18. A 9600 baud rate signal can pass over the voice-grade telephone line if which kind of modulation is used? Ans: QAM 19. Quadrature amplitude modulation is Ans: AM plus QPSK 20. A QAM modulator does not use a(n) Ans: XNOR 21. A rule or procedure that defines how data is to be transmitted is called a(n) Ans: Protocol 22. A popular PC protocol is Ans: Xmodem 23. A synchronous transmission usually begins with which character? Ans: SYN 24. The characters making up the message in a synchronous transmission are collectively referred to as a data Ans: Block 25. Bit errors in data transmission are usually cause by Ans: Noise 26. Which of the following is not a commonly used method of error detection? Ans: Redundancy 27.Which of the following words has the correct parity bit?Assume odd parity. The last bit is the parity bit 28. Another name for parity is Ans: Vertical redundancy check 29. Ten bit errors occur in two million transmitted. The bit error rate is Ans: 5 x 10 -6 Solution: 6 6 10 5 10 2 10 e 30. The building block of a parity or BCC generator is a(n) Ans: XOR 31. A longitudinal redundancy check produces a(n) Ans: Block check character 32. Dividing the data block by a constant produces a remainder that is used for error detection. It is called the Ans: CRC 33. A CRC generator uses which components? Ans: Shift register 34. Which of the following is not a LAN? Ans: Cable TV system 35. The fastest LAN topology is the Ans: Bus 36. Which is not a common LAN medium? Ans: Twin Lead 37. A mainframe computer connected to multiple terminals and PCs usually uses which configuration? Ans: Star 38. A small telephone switching system that can be used as a LAN is called a Ans: PBX 39. Which medium is the least susceptible to noise? Ans: Fiber-optic cable 40. Which medium is the most widely used in LANs? Ans: Twisted pair 41. Transmitting the data signal directly over the medium is referred to as Ans: Baseband 42. The techniques of using modulation and FDM to transmit multiple data channels of a common medium is known as Ans: Broadband 43. What is the minimum bandwidth required to transmit a 56 kbits/s binary signal with no noise?
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