Method in a selective call receiver for synchronizing to a multi-level radio signal
First Claim
1. In a selective call receiver having an internal reference, a method for synchronizing the internal reference to at least one symbol edge of a plurality of symbols included in a multi-level radio signal received from a radio communication system, the method comprising the steps of:
- converting the multi-level radio signal to a sequence of state transitions representative of the plurality of symbols;
detecting at least one same state transition from the sequence of state transitions; and
synchronizing the internal reference to the at least one symbol edge of the plurality of symbols based on the at least one same state transition.
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Accused Products
Abstract
A selective call receiver (800), including a receiver circuit (101) and a processor (810), is used for synchronizing an internal reference to symbol edges of a plurality of symbols in a multi-level radio signal transmitted by a radio communication system. To perform this function the processor (810) is adapted to cause the receiver circuit (101) to demodulate the multilevel radio signal to in-phase and quadrature signals (108, 106), convert the in-phase and quadrature signals (108, 106) to a sequence of state transitions representative of the plurality of symbols, detect at least one same state transition from the sequence of state transitions, and synchronize the internal reference to the at least one symbol edge of the plurality of symbols based on the at least one same state transition.
19 Citations
24 Claims
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1. In a selective call receiver having an internal reference, a method for synchronizing the internal reference to at least one symbol edge of a plurality of symbols included in a multi-level radio signal received from a radio communication system, the method comprising the steps of:
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converting the multi-level radio signal to a sequence of state transitions representative of the plurality of symbols; detecting at least one same state transition from the sequence of state transitions; and synchronizing the internal reference to the at least one symbol edge of the plurality of symbols based on the at least one same state transition. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. In a selective call receiver having an internal reference, a method for synchronizing the internal reference to at least one symbol edge of a plurality of symbols included in a multi-level radio signal received from a radio communication system, the method comprising the steps of:
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converting the multi-level radio signal to a sequence of state transitions representative of the plurality of symbols; detecting a first plurality of same state transitions from the sequence of state transitions; using a mask-out window for generating a second plurality of same state transitions, wherein the mask-out window is applied to each of the plurality of symbols for eliminating same state transitions in the first plurality of same state transitions caused by noise in the multi-level radio signal; using a mask-in window for generating a third plurality of same state transitions, wherein the mask-in window is applied to each of the plurality of symbols for selecting a desirable same state transition from the second plurality of same state transitions effected by a desirable sequence of frequency deviations in the multi-level radio signal; and synchronizing the internal reference to the at least one symbol edge of the plurality of symbols based on the third plurality of same state transitions.
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10. In a selective call receiver having an internal reference, a method for synchronizing the internal reference to at least one symbol edge of a plurality of symbols included in a multi-level radio signal received from a radio communication system, the method comprising the steps of:
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converting the multi-level radio signal to a sequence of state transitions representative of the plurality of symbols; detecting a first plurality of same state transitions from the sequence of state transitions; using a mask-out window for generating a second plurality of same state transitions, wherein the mask-out window is applied to each of the plurality of symbols for eliminating same state transitions in the first plurality of same state transitions caused by noise in the multi-level radio signal, and wherein the mask-out window selects a first same state transition occurring during a symbol period, and eliminates subsequent same state transitions occurring during the symbol period; using a mask-in window for generating a third plurality of same state transitions, wherein the mask-in window is applied to each of the plurality of symbols for selecting a desirable same state transition from the second plurality of same state transitions effected by a desirable sequence of frequency deviations in the multi-level radio signal, wherein frequency deviations have polarities with respect to a frequency reference, and wherein the desirable sequence of frequency deviations comprises a first frequency deviation transitioning to a second frequency deviation having an opposite polarity to the first frequency deviation and having a magnitude of deviation greater than a predetermined value, and wherein the mask-in window is applied when the sequence of state transitions counted within a predetermined time indicates a presence of a desirable frequency deviation in the multi-level radio signal; delaying the third plurality of same state transitions one symbol period less a predetermined offset; and synchronizing the internal reference to the at least one symbol edge of the plurality of symbols based on the delayed third plurality of same state transitions.
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11. A radio receiver, comprising:
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a receiver circuit for receiving a multi-level radio signal having a plurality of symbols transmitted by a radio communication system; and a symbol synchronizer circuit having an internal reference, the symbol synchronizer circuit coupled to the receiver circuit, and adapted to; cause the receiver circuit to convert the multi-level radio signal to a sequence of state transitions representative of the plurality of symbols; detect at least one same state transition from the sequence of state transitions; and synchronize the internal reference to at least one symbol edge of the plurality of symbols based on the at least one same state transition. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
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20. A radio receiver, comprising:
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a receiver circuit for receiving a multi-level radio signal having a plurality of symbols transmitted by a radio communication system; and a symbol synchronizer circuit having an internal reference, the symbol synchronizer circuit coupled to the receiver circuit, and adapted to; cause the receiver circuit to convert the multi-level radio signal to a sequence of state transitions representative of the plurality of symbols; detect a first plurality of same state transitions from the sequence of state transitions; use a mask-out window for generating a second plurality of same state transitions, wherein the mask-out window is applied to each of the plurality of symbols for eliminating same state transitions in the first plurality of same state transitions caused by noise in the multi-level radio signal; use a mask-in window for generating a third plurality of same state transitions, wherein the mask-in window is applied to each of the plurality of symbols for selecting a desirable same state transition from the second plurality of same state transitions effected by a desirable sequence of frequency deviations in the multi-level radio signal; and synchronize the internal reference to at least one symbol edge of the plurality of symbols based on the third plurality of same state transitions. - View Dependent Claims (21)
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22. A radio receiver, comprising:
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a receiver circuit for receiving a multi-level radio signal having a plurality of symbols transmitted by a radio communication system; a symbol synchronizer circuit having an internal reference, the symbol synchronizer circuit coupled to the receiver circuit, and adapted to; cause the receiver circuit to convert the multi-level radio signal to a sequence of state transitions representative of the plurality of symbols; detect a first plurality of same state transitions from the sequence of state transitions; use a mask-out window for generating a second plurality of same state transitions, wherein the mask-out window is applied to each of the plurality of symbols for eliminating same state transitions in the first plurality of same state transitions caused by noise in the multi-level radio signal, and wherein the mask-out window selects a first same state transition occurring during a symbol period, and eliminates subsequent same state transitions occurring during the symbol period; using a mask-in window for generating a third plurality of same state transitions, wherein the mask-in window is applied to each of the plurality of symbols for selecting a desirable same state transition from the second plurality of same state transitions effected by a desirable sequence of frequency deviations in the multi-level radio signal, wherein frequency deviations have polarities with respect to a frequency reference, and wherein the desirable sequence of frequency deviations comprises a first frequency deviation transitioning to a second frequency deviation having an opposite polarity to the first frequency deviation and having a magnitude of deviation greater than a predetermined value, and wherein the mask-in window is applied when the sequence of state transitions counted within a predetermined time indicates a presence of a desirable frequency deviation in the multi-level radio signal; delay the third plurality of same state transitions one symbol period less a predetermined offset; and synchronize the internal reference to at least one symbol edge of the plurality of symbols based on the delayed third plurality of same state transitions. - View Dependent Claims (23)
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24. A selective call receiver, comprising:
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a receiver circuit for receiving a multi-level radio signal having a plurality of symbols transmitted by a radio communication system; and a processor having an internal reference, the processor coupled to the receiver circuit, and adapted to; cause the receiver circuit to demodulate the multi-level radio signal to in-phase and quadrature signals; convert the in-phase and quadrature signals to a sequence of state transitions representative of the plurality of symbols; detect at least one same state transition from the sequence of state transitions; and synchronize the internal reference to at least one symbol edge of the plurality of symbols based on the at least one same state transition.
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Specification