QPSK is a modulation technique for digital communications. It provides a way to send more information ( or information bits) in the channel then many other techniques. It uses a form of phase modulation to send “symbols” consistng of di-bits ( two bits for each symbol). A recent short paper released by Signal Processing Group Inc., describes the basis of the QPSK techniques using very little mathermatics and more graphics to clearly illustrate the operation. The paper may be accessed from the SPG website located at http://www.signalpro.biz using the “Free reports …” menu item. .