Coherent phase shift keyed demodulator for power line communication systems

A demodulator for coherent phase shift keyed carrier systems wherein binary data is phase reversal keyed in a carrier having equal data bit intervals, comprising:

• polarity sampling means for producing binary sample signals having opposite logic states in response to the positive and negative polarity states of said carrier during each of equal segments of said carrier occurring substantially wholly within each of said data bit intervals;
• means for producing first relative phase angle vector signals in response to said sample signals being derived from separate ones of said carrier segments;
• means for producing reference phase angle vector signals in response to a said sample signals being derived from a predetermined series of the carrier segments included substantially wholly within a predetermined number of said data bit intervals;
• a phase detector including multiplier means for producing correlation signals responsive to a product of said first vector signals and said reference vector signals occurring with each of the separate ones of the carrier segments;
• means sequentially summing said correlation signals in predetermined groups including a predetermined number of the correlation signals wherein said predetermined groups correspond to a like predetermined number of the equal carrier segments;
• and
• means responsive to the sums of each of the predetermined groups of said correlation signals for producing weighted positive and negative indications thereof wherein said positive and negative indications provide corresponding binary representations effective to produce data bit signals at the output of said demodulator designating the binary information of said carrier data bits.

A coherent phase demodulator comprising:

• sampling means for producing polarity sample signals responsive to the instantaneous polarities of a received carrier signal having phase reversal keyed binary data symbols, wherein the rate of said polarity sample signals produces recurring groups thereof during each data symbol;
• means for deriving first phase angle signals representing a relative phase angle value for each of consecutively occurring groups of said sample signals;
• means for deriving reference phase angle signals representing a reference phase angle value for each of consecutive occurring predetermined numbers of said groups of sample signals;
• phase detector means for producing correlation signals representing the degree of positive or negative correlation of each of said first phase angle signals with each of said reference phase angle signals;
• signal summing means responsive to said correlation signals for producing correlation sum signals representing the algebraic sums of said correlation signals occurring during separate ones of said data symbols so as to have plus and minus numerical representations responsive to the sum values of the positive and negative correlation indications of said correlation signals;
• and
• data signal output means responsive to the summed plus or minus numerical manifestation of either the positive or the negative correlations represented by each of said correlation sum signals for generating binary data signals corresponding to the binary logic representations of said binary data symbols modulating said received carrier.