Technique : PM - Phase Modulation (phase shift key)

  

    This example actually can send 2 bits at a time.

    Standard frequency used as a base.

    Shift in the phase represents a change from one bit type to the other.

    Requires a frequency at 2x the data rate for simple phase shift.

    OK to good for transmission but not for storage.

    Modems with simple phase shift key modulation delivered 1200 bits/s  
      or 2400 bits/s (2 bits per baud symbol).

    Often combined with frequency modulation to send more bits at same time.

    A variation called QAM form of PSK transmitted 4 bits per baud and
      increased throughput to 4800 or 9600 bits/s while using the same 
      carrier frequencies.

    Phase modulation combined with other encoding is used by wireless 
      networking, cable modems, digital cable and satellite TV.

    * Improved analog modems speeds were accomplished by advanced
      data encoding.

    Variations used in 802.11b-1999 (WiFi), some RFID implementations,
      Bluetooth, and satellite broadcasting.