Analog and Digital Transmission

Download 183.5 Kb.
Hajmi183.5 Kb.
1a DI Begimov Shaxrux

  • Analog and Digital Transmission
  • There are a number of differences between analog and digital transmission, and it is important to understand how conversions
  • between analog and digital occur. Let's look first at the older form of transmission, analog.
  • Analog Transmission
  • An analog wave form (or signal) is characterized by being continuously variable along amplitude and frequency. In the
  • case of telephony, for instance, when you speak into a handset, there are changes in the air pressure around your mouth.
  • Those changes in air pressure fall onto the handset, where they are amplified and then converted into current, or voltage
  • fluctuations. Those fluctuations in current are an analog of the actual voice pattern—hence the use of the term analog to describe these signals (see Figure
  • Digital Transmission
  • Digital transmission has several adv antages over analog transmission:
  • 1. Analog circuits require ampliers, and each amplier adds distortion and noise to the
  • signal.
  • 2. In contrast, digital ampliers regenerate an exact signal, eliminating cumulative
  • errors.An incoming (analog) signal is sampled, its v alue is determined, and the node
  • then generates a new signal from the bit v alue; the incoming signal is discarded.
  • With analog circuits, in termediate nodes amplify the incomiing signal, noise and all.
  • 3. V oice, data, video, etc. can all by carried by digital circuits. What about carrying
  • digital signals over analog circuit? The modem example shows the diculties in
  • carrying digital over analog.

Download 183.5 Kb.

Do'stlaringiz bilan baham:

Ma'lumotlar bazasi mualliflik huquqi bilan himoyalangan © 2024
ma'muriyatiga murojaat qiling