Why are received spread spectrum signals resistant to interference?

1. A Signals not using the spread spectrum algorithm are suppressed in the receiver
2. B The high power used by a spread spectrum transmitter keeps its signal from being easily overpowered
3. C Built-in error correction codes minimize interference
4. D If the receiver detects interference, it will signal the transmitter to change frequencies

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

1. A Frequency hopping
2. B Direct sequence
3. C Binary phase-shift keying
4. D Phase compandored spread spectrum

Which describes spread spectrum frequency hopping?

1. A If interference is detected by the receiver, it will signal the transmitter to change frequencies
2. B RF signals are clipped to generate a wide band of harmonics which provides redundancy to correct errors
3. C A binary bit stream is used to shift the phase of an RF carrier very rapidly in a pseudorandom sequence
4. D Rapidly varying the frequency of a transmitted signal according to a pseudorandom sequence

What is the primary effect of extremely short rise or fall time on a CW signal?

1. A More difficult to copy
2. B The generation of RF harmonics
3. C The generation of key clicks
4. D More difficult to tune

What is the most common method of reducing key clicks?

1. A Increase keying waveform rise and fall times
2. B Insert low-pass filters at the transmitter output
3. C Reduce keying waveform rise and fall times
4. D Insert high-pass filters at the transmitter output

What is the advantage of including parity bits in ASCII characters?

1. A Faster transmission rate
2. B Signal-to-noise ratio is improved
3. C A larger character set is available
4. D Some types of errors can be detected

What is a common cause of overmodulation of AFSK signals?

1. A Excessive numbers of retries
2. B Excessive frequency deviation
3. C Bit errors in the modem
4. D Excessive transmit audio levels

What parameter evaluates distortion of an AFSK signal caused by excessive input audio levels?

1. A Signal-to-noise ratio
2. B Baud error rate
3. C Repeat Request Rate (RRR)
4. D Intermodulation Distortion (IMD)

What is considered an acceptable maximum IMD level for an idling PSK signal?

1. A +5 dB
2. B +10 dB
3. C +15 dB
4. D -30 dB

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

1. A Baudot uses 4 data bits per character, ASCII uses 7 or 8; Baudot uses 1 character as a letters/figures shift code, ASCII has no letters/figures code
2. B Baudot uses 5 data bits per character, ASCII uses 7 or 8; Baudot uses 2 characters as letters/figures shift codes, ASCII has no letters/figures shift code
3. C Baudot uses 6 data bits per character, ASCII uses 7 or 8; Baudot has no letters/figures shift code, ASCII uses 2 letters/figures shift codes
4. D Baudot uses 7 data bits per character, ASCII uses 8; Baudot has no letters/figures shift code, ASCII uses 2 letters/figures shift codes

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

1. A It includes built-in error correction features
2. B It contains fewer information bits per character than any other code
3. C It is possible to transmit both uppercase and lowercase text
4. D It uses one character as a shift code to send numeric and special characters