E8C01

Which one of the following digital codes consists of elements having unequal length?

Morse code

E8C02

What are some of the differences between the Baudot digital code and ASCII?

Baudot uses five data bits per character, ASCII uses seven; Baudot uses two characters as shift codes, ASCII has no shift code

E8C03

What is one advantage of using the ASCII code for data communications?

It is possible to transmit both upper and lower case text

E8C04

This question has been removed by the QPC

E8C05

What technique is used to minimize the bandwidth requirements of a PSK-31 signal?

Use of sinusoidal data pulses

E8C06

What is the necessary bandwidth of a 13-WPM international Morse code transmission?

Approximately 52 Hz

E8C07

What is the necessary bandwidth of a 170-hertz shift, 300-baud ASCII transmission?

0.5 kHz

E8C08

What is the necessary bandwidth of a 4800-Hz frequency shift, 9600-baud ASCII FM transmission?

15.36 kHz

E8C09

What term describes a wide-bandwidth communications system in which the transmitted carrier frequency varies according to some predetermined sequence?

Spread-spectrum communication

E8C10

Which of these techniques causes a digital signal to appear as wide-band noise to a conventional receiver?

Spread-spectrum

E8C11

What spread-spectrum communications technique alters the center frequency of a conventional carrier many times per second in accordance with a pseudo-random list of channels?

Frequency hopping

E8C12

What spread-spectrum communications technique uses a high speed binary bit stream to shift the phase of an RF carrier?

Direct sequence

E8C13

What makes spread-spectrum communications resistant to interference?

Only signals using the correct spreading sequence are received

E8C14

What is the advantage of including a parity bit with an ASCII character stream?

Some types of errors can be detected

E8C15

What is one advantage of using JT-65 coding?

Virtually perfect decoding of signals well below the noise

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