Coherent phase shift keyed demodulator for power line communication systems
First Claim
1. A demodulator for data bit signals modulating rectangular pulse signals derived from a binary phase shift keyed carrier, comprising:
- means sampling said rectangular pulses and producing polarity sample bits having either of two binary logic states corresponding to first and second levels of said rectangular pulse signals with predetermined equal groups of said sample bits cyclically occurring during each data bit interval;
means responsive to said predetermined equal groups of the sample bits for producing first vector component signals having a relative phase angle representation at a fundamental frequency for each separate one of said predetermined equal groups of the sample bits;
means responsive to a plurality of said predetermined groups of the sample bits for producing reference vector component signals having a relative phase angle representation at said fundamental frequency;
phase detector means producing correlation signals in response to phase comparisons of each of said first vector component signals and said reference vector component signals; and
means selectively summing said correlation signals when produced in response to phase comparisons of said first vector component signals produced from said separate ones of said predetermined equal groups of the sample bits occurring during the same data bit intervals.
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Abstract
An apparatus and method for coherent phase demodulation of a binary phase shift keyed carrier includes sequentially processing plus and minus polarity samples of plural carrier segments occurring within each carrier data symbol. The samples for each segment provide a binary coded signal for producing corresponding first and second relative phase angle vector signals. The second vector signals are summed over several data symbols to generate reference phase angle signal vector signals. Correlation signals are produced from phase comparison of each of the first vectors with the reference vector signals. The correlation signals are summed in a synchronized relationship for the carrier segments included in each data symbol. The sums of the correlation signals represent either positive or negative correlations with the one and zero data bits of the carrier data symbols.
58 Citations
24 Claims
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1. A demodulator for data bit signals modulating rectangular pulse signals derived from a binary phase shift keyed carrier, comprising:
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means sampling said rectangular pulses and producing polarity sample bits having either of two binary logic states corresponding to first and second levels of said rectangular pulse signals with predetermined equal groups of said sample bits cyclically occurring during each data bit interval; means responsive to said predetermined equal groups of the sample bits for producing first vector component signals having a relative phase angle representation at a fundamental frequency for each separate one of said predetermined equal groups of the sample bits; means responsive to a plurality of said predetermined groups of the sample bits for producing reference vector component signals having a relative phase angle representation at said fundamental frequency; phase detector means producing correlation signals in response to phase comparisons of each of said first vector component signals and said reference vector component signals; and means selectively summing said correlation signals when produced in response to phase comparisons of said first vector component signals produced from said separate ones of said predetermined equal groups of the sample bits occurring during the same data bit intervals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. 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:
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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. - View Dependent Claims (19, 20, 21, 22)
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23. A coherent phase demodulator comprising:
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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. - View Dependent Claims (24)
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Specification