Computer Officer/Bank IT Officer Exam Preparation Materials

Short Note on Data and Signals

  1. Data must be transformed into electromagnetic signals prior to transmission across a network.
  2. Data and signals can be either analog or digital.
  3. A signal is periodic if it consists of a continuously repeating pattern.
  4. Each sine wave can be characterized by its amplitude, frequency, and phase.
  5. Frequency and period are inverses of each other.
  6. A time-domain graph plots amplitude as a function of time.
  7. A frequency-domain graph plots each sine wave’s peak amplitude against its frequency.
  8. By using Fourier analysis, any composite signal can be represented as a combination of simple sine waves.
  9. The spectrum of a signal consists of the sine waves that make up the signal.
  10. The bandwidth of a signal is the range of frequencies the signal occupies. Bandwidth is determined by finding the difference between the highest and lowest frequency components.
  11. Bit rate (number of bits per second) and bit interval (duration of 1 bit) are terms used to describe digital signals.
  12. A digital signal is a composite signal with an infinite bandwidth.
  13. Bit rate and bandwidth are proportional to each other.
  14. The Nyquist formula determines the theoretical data rate for a noiseless channel.
  15. The Shannon capacity determines the theoretical maximum data rate for a noisy channel.
  16. Attenuation, distortion, and noise can impair a signal.
  17. Attenuation is the loss of a signal’s energy due to the resistance of the medium.
  18. The decibel measures the relative strength of two signals or a signal at two different points.
  19. Distortion is the alteration of a signal due to the differing propagation speeds of each of the frequencies that make up a signal.
  20. Noise is the external energy that corrupts a signal.
  21. We can evaluate transmission media by throughput, propagation speed, and propagation time.
  22. The wavelength of a frequency is defined as the propagation speed divided by the frequency.
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