What is the modulation index of an FM signal?

1. A The ratio of frequency deviation to modulating signal frequency
2. B The ratio of modulating signal amplitude to frequency deviation
3. C The modulating signal frequency divided by the bandwidth of the transmitted signal
4. D The bandwidth of the transmitted signal divided by the modulating signal frequency

How does the modulation index of a phase-modulated emission vary with RF carrier frequency?

1. A It increases as the RF carrier frequency increases
2. B It decreases as the RF carrier frequency increases
3. C It varies with the square root of the RF carrier frequency
4. D It does not depend on the RF carrier frequency

What 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?

1. A 3
2. B 0.3
3. C 6
4. D 0.6

What 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?

1. A 0.3
2. B 3
3. C 0.6
4. D 6

What 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?

1. A 6
2. B 0.167
3. C 0.6
4. D 1.67

What 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?

1. A 2.14
2. B 0.214
3. C 0.47
4. D 47

Orthogonal frequency-division multiplexing (OFDM) is a technique used for which types of amateur communication?

1. A Digital modes
2. B Extremely low-power contacts
3. C EME
4. D OFDM signals are not allowed on amateur bands

What describes orthogonal frequency-division multiplexing (OFDM)?

1. A A frequency modulation technique that uses non-harmonically related frequencies
2. B A bandwidth compression technique using Fourier transforms
3. C A digital mode for narrow-band, slow-speed transmissions
4. D A digital modulation technique using subcarriers at frequencies chosen to avoid intersymbol interference

What is deviation ratio?

1. A The ratio of the audio modulating frequency to the center carrier frequency
2. B The ratio of the maximum carrier frequency deviation to the highest audio modulating frequency
3. C The ratio of the carrier center frequency to the audio modulating frequency
4. D The ratio of the highest audio modulating frequency to the average audio modulating frequency

What is frequency division multiplexing (FDM)?

1. A The transmitted signal jumps from band to band at a predetermined rate
2. B Dividing the transmitted signal into separate frequency bands that each carry a different data stream
3. C The transmitted signal is divided into packets of information
4. D Two or more information streams are merged into a digital combiner, which then pulse position modulates the transmitter

What is digital time division multiplexing?

1. A Two or more data streams are assigned to discrete sub-carriers on an FM transmitter
2. B Two or more signals are arranged to share discrete time slots of a data transmission
3. C Two or more data streams share the same channel by transmitting time of transmission as the sub-carrier
4. D Two or more signals are quadrature modulated to increase bandwidth efficiency