Communication receiving apparatus

Receiving apparatus for processing received differential phase shift keyed signals comprising

• detecting means for producing quadrature components of each received signal;
• analog-to-digital converting means coupled to said detecting means for deriving digital representations of the resultant of the quadrature components of each signal a number of times during the period of a received signal;
• the period of a received signal being the duration of the time period during which a received signal is being received;
• first storage means coupled to the analog-to-digital converting means for storing a digital representation of a resultant for a period equal to the period of a received signal;
• subtraction means coupled to said analog-to-digital converting means and to said first storage means for producing a digital representation of the difference between the digital representation of the resultant stored in the first storage means and each subsequently derived digital representation of a resultant during the period the digital representation of the resultant is stored in the first storage means;
• second storage means coupled to said subtraction means for storing one of the digital representations of a difference produced during the period the digital representation of a resultant is stored in the first storage means;
• data readout means coupled to said second storage means for reading out the digital representation of a difference stored in said second storage means;
• said first storage means being operable to store a digital representation therein in response to an actuating signal;
• said second storage means being operable to store a digital representation therein in response to an actuating signal;
• said data readout means being operable to read out the digital representation stored in said second storage means in response to an actuating signal;
• control means coupled to said first storage means, said second storage means, and said data readout means for producing said actuating signals to the first storage means, second storage means, and data readout means during each period of a received signal;
• and
• timing adjusting means coupled to said subtraction means and said control means for adjusting the times during the period of a received signal that the control means produces the actuating signals to the first and second storage means and to the data readout means;
• the timing adjusting means adjusting said times in response to the digital representations of differences produced by the subtraction means during a number of periods, each period being equal to the period of a received signal.