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T8A08

SIGNALS AND EMISSIONS · Basic characteristics of FM and SSB; Bandwidth of various modulation modes: CW, SSB, FM, fast-scan TV; Choice of emission type: selection of USB vs LSB, use of SSB for weak signal work, use of FM for VHF packet and repeaters

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What is the approximate bandwidth of a typical single sideband (SSB) voice signal?

  1. A1 kHz
  2. B3 kHz
  3. C6 kHz
  4. D15 kHz
Why SSB transmits only one sideband with the carrier suppressed, so its bandwidth equals the audio range being sent. Communications-quality speech is filtered to roughly 300 Hz to 3000 Hz, which puts a typical SSB voice signal at about 3 kHz wide. That is half the width of an AM signal, which carries both sidebands.
Watch out The 6 kHz figure is the bandwidth of a double-sideband AM signal, and 15 kHz is about what an FM voice signal occupies; 1 kHz is closer to a CW signal's width.
Pool bandwidths: CW 150 Hz, SSB 3 kHz, AM 6 kHz, FM 15 kHz. SSB is half of AM because one sideband is gone.
HamSandwich explanation, first draft. The question and answers are the NCVEC text.
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The rest of T8A

  1. T8A01 Which of the following is a form of amplitude modulation?
  2. T8A02 What type of modulation is commonly used for VHF packet radio transmissions?
  3. T8A03 Which type of voice mode is often used for long-distance (weak signal) contacts on the VHF and UHF bands?
  4. T8A04 Which type of modulation is commonly used for VHF and UHF voice repeaters?
  5. T8A05 Which of the following signal types has the narrowest bandwidth?
  6. T8A06 Which sideband is normally used for 10-meter HF, VHF, and UHF single-sideband communications?
  7. T8A07 What is one characteristic of single sideband (SSB) compared to FM?
  8. T8A08 What is the approximate bandwidth of a typical single sideband (SSB) voice signal?
  9. T8A09 What is the approximate bandwidth of an FM voice signal on VHF repeaters?
  10. T8A10 What is the approximate bandwidth of AM fast-scan TV transmissions?
  11. T8A11 What is the approximate bandwidth required to transmit a CW signal?
  12. T8A12 Which of the following is a disadvantage of FM compared with single sideband?
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