FCCライセンス General 7月 5 2024 SUBELEMENT G8A SUBELEMENT G8A G8A – Carriers and modulation: AM, FM, and single sideband; modulation envelope; digital modulation; overmodulation; link budgets and link margins 1 / 14 G8A14What is link margin? A. The opposite of fade margin B. The difference between received power level and minimum required signal level at the input to the receiver C. Transmit power minus receiver sensitivity D. Receiver sensitivity plus 3 dB 2 / 14 G8A13What is a link budget? A. The financial costs associated with operating a radio link B. The sum of antenna gains minus system losses C. The sum of transmit power and antenna gains minus system losses as seen at the receiver 3 / 14 G8A12What is QPSK modulation? A. Modulation using quasi-parallel to serial conversion to reduce bandwidth B. Modulation using quadra-pole sideband keying to generate spread spectrum signals C. Modulation using Fast Fourier Transforms to generate frequencies at the first, second, third, and fourth harmonics of the carrier frequency to improve noise immunity D. Modulation in which digital data is transmitted using 0-, 90-, 180- and 270-degrees phase shift to represent pairs of bits 4 / 14 G8A11What is the modulation envelope of an AM signal? A. The waveform created by connecting the peak values of the modulated signal B. The carrier frequency that contains the signal C. Spurious signals that envelop nearby frequencies D. The bandwidth of the modulated signal 5 / 14 G8A10What is meant by the term “flat-topping,” when referring to an amplitude-modulated phone signal? A. Signal distortion caused by insufficient collector current B. The transmitter’s automatic level control (ALC) is properly adjusted C. Signal distortion caused by excessive drive or speech levels D. The transmitter’s carrier is properly suppressed 6 / 14 G8A09What type of modulation is used by FT8? A. 8-tone frequency shift keying B. Vestigial sideband C. Amplitude compressed AM D. 8-bit direct sequence spread spectrum 7 / 14 G8A08Which of the following is an effect of overmodulation? A. Insufficient audio B. Insufficient bandwidth C. Frequency drift D. Excessive bandwidth 8 / 14 G8A07Which of the following phone emissions uses the narrowest bandwidth? A. Single sideband B. Vestigial sideband C. Phase modulation D. Frequency modulation 9 / 14 G8A06Which of the following is characteristic of QPSK31? A. It is sideband sensitive B. Its encoding provides error correction C. Its bandwidth is approximately the same as BPSK31 D. All these choices are correct 10 / 14 G8A05What type of modulation varies the instantaneous power level of the RF signal? A. Power modulation B. Phase modulation C. Frequency modulation D. Amplitude modulation 11 / 14 G8A04What emission is produced by a reactance modulator connected to a transmitter RF amplifier stage? A. Multiplex modulation B. Phase modulation C. Amplitude modulation D. Pulse modulation 12 / 14 G8A03What is the name of the process that changes the instantaneous frequency of an RF wave to convey information? A. Frequency convolution B. Frequency transformation C. Frequency conversion D. Frequency modulation 13 / 14 G8A02What is the name of the process that changes the phase angle of an RF signal to convey information? A. Phase convolution B. Phase modulation C. Phase transformation D. Phase inversion 14 / 14 G8A01How is direct binary FSK modulation generated? A. By keying an FM transmitter with a sub-audible tone B. By changing an oscillator’s frequency directly with a digital control signal C. By using a transceiver’s computer data interface protocol to change frequencies D. By reconfiguring the CW keying input to act as a tone generator あなたのスコアは平均スコアは 0% 0% クイズを再開する Ed 0 コメント
