Voltage, in proportion to the information that we are trying to The pictures we saw above are examples of analog signals:Īn analog signal varies some physical property, such as There doesn't have to be much degradation for it to have a noticeable Lessening of strength and there is some noise added near the second The degradation may not be immediately obvious, but there is a general Property of the signal, such as electrical voltage, pressure of a sound "telephone." Or think about photocopies of photocopies ofĪnd this is the received signal (dashed) compared to the transmitted When we continue to transmit and transform signals, theĮffect is compounded. signals may get combined with interference from other.signals may fade with time and distance.Stored on videotape or DVD and played on your home VCR or DVD player.Īny time signals are transmitted, there will be some Converted to laser light, then electricity whenĪ similar kind of story can be told about visual images.Converted to spots on a CD when the CD is.
Frequency is measured in Hz orĬycles per second. Important characteristics are Frequency (aka pitch) andĪmplitude (aka loudness). Sound moves fast: in air, at 340 m/sec = 750 miles per hour. When sound is transmitted or stored it may need toĬhange form, hopefully without being destroyed.
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