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Where is SSB located in the time domain?

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SSB (Single Sideband) modulation is a technique used in communication systems to transmit information more efficiently than traditional AM (Amplitude Modulation). In SSB, one of the sidebands and the carrier signal are suppressed, transmitting only a single sideband along with the carrier.

In the time domain, SSB modulation appears as a signal with a narrower bandwidth compared to standard AM. It typically looks like a modulated signal where one of the sidebands and the carrier has been removed. Let's consider an example where we're transmitting an audio signal using SSB modulation:

  1. AM Signal Representation: An AM signal in the time domain would look like a carrier wave oscillating at a specific frequency, with the audio signal modulating the amplitude of this carrier. You'd see a waveform that varies in amplitude (according to the audio signal) with the same frequency as the original audio signal, plus two sidebands, each containing a copy of the audio information mirrored around the carrier frequency.
  2. SSB Signal Representation: In SSB modulation, one of the sidebands (either the upper or lower sideband) and the carrier are suppressed. This means that in the time domain, you would see a waveform that only contains the remaining sideband and potentially a small residual carrier. The waveform appears as a narrower-bandwidth signal compared to AM, with the original audio information encoded within it.

Technically speaking, the location of the SSB in the time domain would depend on whether it is an Upper Sideband (USB) or Lower Sideband (LSB) modulation:

  • Upper Sideband (USB): If the upper sideband is transmitted, the time-domain representation would show the signal starting from the carrier frequency and extending upwards in frequency. The carrier itself might be significantly reduced or completely suppressed.
  • Lower Sideband (LSB): If the lower sideband is transmitted, the time-domain representation would show the signal starting from the carrier frequency and extending downwards in frequency. Similar to USB, the carrier might be significantly reduced or removed.

In both cases, the actual time-domain representation would be a complex waveform, but the key point is that the SSB signal only contains one sideband and has a reduced bandwidth compared to AM, making it more efficient in terms of spectrum utilization.