Communication data format
First Claim
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1. A system comprising:
- a device containing digital data arranged to include a plurality of variable data bits and synchronization bits, the number of said variable data bits being more than the number of said synchronization bits; and
a modulation circuit coupled to said device for generating modulated signals by modulating said digital data in accordance with a binary phase shift keying technique;
a demodulation circuit for generating demodulated signals from said modulated signals;
a decoder for correctly recovering said variable data bits from said demodulated signals, said decoder includes;
means for verifying that said demodulated signals contain said synchronization bits;
means for forming a complement of said demodulated signals; and
means for extracting said variable data bits.
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Abstract
A new data format used in a communication system employing binary phase shift keying modulation and demodulation is described. The data format provides for a frame comprising a plurality of variable data bits and synchronization bits. The number of variable data bits in the data format of the present invention is more than the number of synchronization bits. The data format preferably includes a CRC field for error detection. In order to uniquely decode the information contained in the frame, the inverse of frame should not be a valid frame. A method for detecting invalid frames is also disclosed.
24 Citations
12 Claims
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1. A system comprising:
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a device containing digital data arranged to include a plurality of variable data bits and synchronization bits, the number of said variable data bits being more than the number of said synchronization bits; and a modulation circuit coupled to said device for generating modulated signals by modulating said digital data in accordance with a binary phase shift keying technique; a demodulation circuit for generating demodulated signals from said modulated signals; a decoder for correctly recovering said variable data bits from said demodulated signals, said decoder includes; means for verifying that said demodulated signals contain said synchronization bits; means for forming a complement of said demodulated signals; and means for extracting said variable data bits. - View Dependent Claims (2, 3, 4)
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5. A method for determining whether a data frame is a valid frame, said valid frame having synchronization bits at a first set of predetermined positions and variable data bits at a second set of predetermined positions, comprising the steps of:
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scanning said first set of predetermined positions of said data frame; if said first set of predetermined positions contains said synchronization bits, extracting said variable data bits located at said second set of predetermined positions; if said first set of predetermined positions does not contain said synchronization bits; forming a complementary frame by inverting all bits in said data frame; scanning said first set of predetermined positions of said complementary frame; if said first set of predetermined positions of said complementary frame contains said synchronization bits, extracting said variable data bits located at said second set of predetermined positions of said complementary frame; and if said first set of predetermined positions of said complementary frame does not contain said synchronization bits, discarding said data frame. - View Dependent Claims (6, 7, 8, 9)
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10. A method for generating a valid frame having synchronization bits at a first set of predetermined positions and variable data bits at a second set of predetermined positions, comprising the steps of:
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assembling a test frame by placing synchronization bits at said first set of predetermined positions and variable data bits at said second set of predetermined positions; forming a complementary frame by inverting bits in said test frame; and discarding said test frame if the bits in said first set of predetermined positions of said complementary frame are the same as said synchronization bits. - View Dependent Claims (11, 12)
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Specification