Amateur Extra › E8
E8 Signals and Emissions
48 questions in the pool. Your exam will include 4, one from each group below.
E8A
Fourier analysis; RMS measurements; average RF power and peak envelope power (PEP); analog/digital conversion
- E8A01What technique shows that a square wave is made up of a sine wave and its odd harmonics?
- E8A02Which of the following is a type of analog-to-digital conversion?
- E8A03Which of the following describes a signal in the time domain?
- E8A04What is “dither” with respect to analog-to-digital converters?
- E8A05What is the benefit of making voltage measurements with a true-RMS calculating meter?
- E8A06What is the approximate ratio of PEP-to-average power in an unprocessed single-sideband phone signal?
- E8A07What determines the PEP-to-average power ratio of an unprocessed single-sideband phone signal?
- E8A08Why are direct or flash conversion analog-to-digital converters used for a software defined radio?
- E8A09How many different input levels can be encoded by an analog-to-digital converter with 8-bit resolution?
- E8A10What is the purpose of a low-pass filter used at the output of a digital-to-analog converter?
- E8A11Which of the following is a measure of the quality of an analog-to-digital converter?
E8B
Modulation and demodulation: modulation methods; modulation index and deviation ratio; frequency- and time-division multiplexing; orthogonal frequency-division multiplexing (OFDM)
- E8B01What is the modulation index of an FM signal?
- E8B02How does the modulation index of a phase-modulated emission vary with RF carrier frequency?
- E8B03What is the modulation index of an FM phone signal having a maximum frequency deviation of 3000 Hz either side of the carrier frequency if the highest modulating frequency is 1000 Hz?
- E8B04What is the modulation index of an FM phone signal having a maximum carrier deviation of plus or minus 6 kHz if the highest modulating frequency is 2 kHz?
- E8B05What is the deviation ratio of an FM phone signal having a maximum frequency swing of plus or minus 5 kHz if the highest modulation frequency is 3 kHz?
- E8B06What is the deviation ratio of an FM phone signal having a maximum frequency swing of plus or minus 7.5 kHz if the highest modulation frequency is 3.5 kHz?
- E8B07Orthogonal frequency-division multiplexing (OFDM) is a technique used for which types of amateur communication?
- E8B08What describes orthogonal frequency-division multiplexing (OFDM)?
- E8B09What is deviation ratio?
- E8B10What is frequency division multiplexing (FDM)?
- E8B11What is digital time division multiplexing?
E8C
Digital signals: digital communication modes; information rate vs. bandwidth; error correction; constellation diagrams
- E8C01What is Quadrature Amplitude Modulation or QAM?
- E8C02What is the definition of symbol rate in a digital transmission?
- E8C03Why should the phase of a PSK signal be changed at the zero crossing of the RF signal?
- E8C04What technique minimizes the bandwidth of a PSK31 signal?
- E8C05What is the approximate bandwidth of a 13-WPM International Morse Code transmission?
- E8C06What is the bandwidth of an FT8 signal?
- E8C07What is the bandwidth of a 4,800-Hz frequency shift, 9,600-baud ASCII FM transmission?
- E8C08How does ARQ accomplish error correction?
- E8C09Which digital code allows only one bit to change between sequential code values?
- E8C10How can data rate be increased without increasing bandwidth?
- E8C11What is the relationship between symbol rate and baud?
- E8C12What factors affect the bandwidth of a transmitted CW signal?
- E8C13What is described by the constellation diagram of a QAM or QPSK signal?
- E8C14What type of addresses do nodes have in a mesh network?
- E8C15What technique do individual nodes use to form a mesh network?
E8D
Keying defects and overmodulation of digital signals; digital codes; spread spectrum
- E8D01Why are received spread spectrum signals resistant to interference?
- E8D02What spread spectrum communications technique uses a high-speed binary bit stream to shift the phase of an RF carrier?
- E8D03Which describes spread spectrum frequency hopping?
- E8D04What is the primary effect of extremely short rise or fall time on a CW signal?
- E8D05What is the most common method of reducing key clicks?
- E8D06What is the advantage of including parity bits in ASCII characters?
- E8D07What is a common cause of overmodulation of AFSK signals?
- E8D08What parameter evaluates distortion of an AFSK signal caused by excessive input audio levels?
- E8D09What is considered an acceptable maximum IMD level for an idling PSK signal?
- E8D10What are some of the differences between the Baudot digital code and ASCII?
- E8D11What is one advantage of using ASCII code for data communications?