Circuit for discriminating received signal modulation type
First Claim
1. A circuit for discriminating the modulation type of a received signal, comprising:
- a clock recovery circuit for recovering a data clock from received data;
a phase difference detector for detecting a phase difference between the data clock recovered by said clock recovery circuit and the received data;
a deviation calculation circuit for calculating a deviation between the phase difference detected by said phase difference detector and a deviation reference value preset in accordance with a modulation type;
a squaring circuit for squaring the deviation calculated by said deviation calculation circuit;
an average value calculation circuit for calculating an average value of a predetermined plurality number of consecutive ones of the square output calculated by said squaring circuit; and
a comparator for comparing the average value calculated by said average value calculation circuit with a predetermined decision reference value and outputting a discrimination signal in accordance with the comparison results.
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Accused Products
Abstract
A circuit for discriminating the modulation type of a received signal capable of discriminating the modulation type at high speed. This circuit includes: a clock recovery circuit for recovering a data clock from received data; a phase difference detector for detecting a phase difference between the data clock recovered by the clock recovery circuit and the received data; a deviation calculation circuit for calculating a deviation between the phase difference detected by the phase difference detector and a deviation reference value preset in accordance with a modulation type; a squaring circuit for squaring the deviation calculated by the deviation calculation circuit; an average value calculation circuit for calculating an average value of a predetermined plurality number of consecutive ones of the square output calculated by the squaring circuit; and a comparator for comparing the average value calculated by the average value calculation circuit with a predetermined decision reference value and outputting a discrimination signal in accordance with the comparison results.
19 Citations
2 Claims
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1. A circuit for discriminating the modulation type of a received signal, comprising:
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a clock recovery circuit for recovering a data clock from received data; a phase difference detector for detecting a phase difference between the data clock recovered by said clock recovery circuit and the received data; a deviation calculation circuit for calculating a deviation between the phase difference detected by said phase difference detector and a deviation reference value preset in accordance with a modulation type; a squaring circuit for squaring the deviation calculated by said deviation calculation circuit; an average value calculation circuit for calculating an average value of a predetermined plurality number of consecutive ones of the square output calculated by said squaring circuit; and a comparator for comparing the average value calculated by said average value calculation circuit with a predetermined decision reference value and outputting a discrimination signal in accordance with the comparison results.
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2. A circuit for discriminating the modulation type of a received signal, comprising:
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a clock recovery circuit for recovering a data clock from received data; a phase difference detector for detecting a phase difference between the data clock recovered by said clock recovery circuit and the received data; a deviation calculation circuit for calculating a deviation between the phase difference detected by said phase difference detector and a deviation reference value preset in accordance with a modulation type; an absolute deviation calculating circuit for calculating an absolute deviation of the deviation calculated by said deviation calculation circuit; an absolute deviation average calculation circuit for calculating an average value of a predetermined plurality number of consecutive ones of the absolute deviation calculated by said absolute deviation calculating circuit; and a comparator for comparing the absolute deviation average value calculated by said absolute deviation average calculation circuit with a predetermined decision reference value and outputting a discrimination signal in accordance with the comparison results.
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Specification