Data vs Signal | Difference between Data and Signal
This page compares Data vs Signal and mentions difference between Data and Signal used in data communication with examples.
Introduction: Data and signals are like two building blocks of computer networks. All the data transmitted over channel can either be in analog form or digital form. Data are manipulated in the signal form suitable for the transmission channel. Like data elements, signal can also either in analog form or digital form.
Hence four possible combinations of data and signal are as follows.
• Analog data converted into analog signal form, for example Telephone.
• Digital data converted to analog signal form, for example modem.
• Analog data converted to digital signal form, for example codec.
• Digital data converted to digital signal form, for example digital transmitter.
As shown in the figure, 1 data element is represented by two signal elements. Hence ratio 'r' which defines number of data elements carried by each signal element is 1/2. The right side depicts two data elements are represented by one signal element, which gives 'r' equals 2/1 (i.e. 2). QPSK signal has 'r' equals 2, as it maps two bits by one signal waveform.
If four data elements are represented by three signal elements, 'r' equals 4/3. The data rate and signal rate are related by following equation or formula.
Data can be numbers, text, image, audio or video which are stored in computer system. The digital data stored are usually stored as binary ones or zeros.
Signals have three basic parameters viz. amplitude, frequency, bandwidth and phase. Noise and attenuation affect the signal over medium. Signals can either be in electric form or in electromagnetic (EM) form or optical form. There will be continuous signal or discrete signal.
Line coding techniques such as unipolar, polar, bipolar are used to convert data elements (i.e. digital data) to signal elements (i.e. digital signal).
Tabular difference between data and signal
Following table mentions difference between data and signal with respect to various parameters.
|• What is it ?||Data is the information we want to transmit.||Signal is the waveform format used to send data over channel.|
|• Function||Acts as payload of carrier||Acts as carrier which carries data or payload.|
|• Measurement quantity||Bit rate in bps or Kbps or Mbps or Gbps||Signal rate or baud rate in Baud, KBaud or Mbaud|
|• Affecting data communication parameter||Speed, Higher the bit rate higher is the speed||Bandwidth, lower the signal rate, lower is the bandwidth|
|• Format||Analog (Continuous) or digital form (Binary or discrete)||Analog (Electric, EM or Optical) or digital form (i.e. pulse such as NRZ or RZ )|
Line coding techniques
Difference between Unipolar Polar and Bipolar coding RZ vs NRZ vs Manchester coding RZ vs NRZ pulse shapes Advantages and disadvantages of NRZ encoding RZ encoding 2B1Q coding 8B6T coding 4D PAM5 coding MLT-3 coding 4B/5B encoding 8B/10B encoding R8ZS scrambling HDB3 scrambling
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