Editing Pulse-width modulation (section)

===Telecommunications===
In [[telecommunications]], PWM  is a form of signal [[modulation#Pulse modulation methods|modulation]] where the widths of the pulses correspond to specific data values encoded at one end and decoded at the other.

Pulses of various lengths (the information itself) will be sent at regular intervals (the carrier frequency of the modulation).
           _      _      _      _      _      _      _      _     
          | |    | |    | |    | |    | |    | |    | |    | |    
 Clock    | |    | |    | |    | |    | |    | |    | |    | |    
        __| |____| |____| |____| |____| |____| |____| |____| |____
 
                  _      __     ____          ____   _
 PWM signal      | |    |  |   |    |        |    | | |
                 | |    |  |   |    |        |    | | |
        _________| |____|  |___|    |________|    |_| |___________
 
 Data       0     1       2      4      0      4     1      0

The inclusion of a [[clock signal]] is not necessary, as the leading edge of the data signal can be used as the clock if a small offset is added to each data value in order to avoid a data value with a zero length pulse.
                 _      __     ___    _____   _      _____   __     _   
                | |    |  |   |   |  |     | | |    |     | |  |   | | 
 PWM signal     | |    |  |   |   |  |     | | |    |     | |  |   | |  
              __| |____|  |___|   |__|     |_| |____|     |_|  |___| |_____
 
 Data            0       1      2       4     0        4      1     0