Receiver having a signal detector and bit synchronizer
First Claim
1. A receiver for receiving a signal having transitions between symbols occurring at a predetermined baud rate and having information within the symbols, comprising:
- demodulator means for demodulating the signal;
means coupled to the demodulator means for detecting the presence of the signal, the means comprising;
a multiplicity of counting registers;
means for establishing an integer number of sample windows per symbol, each sample window having a corresponding unique combination of a plurality of counting registers within said multiplicity of counting registers;
means for sensing the transitions of a received signal, the transitions occurring within each established sample window;
means for counting in the counting registers corresponding to each sample window in which a transition is sensed; and
means for generating a presence signal in response to a counting register having a predetermined number of counts;
means for determining the absence of the presence signal;
means for conserving power to the demodulator means in response to the absence of the presence signal; and
means coupled to the demodulating means for detecting the information in response to the presence signal.
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Abstract
An apparatus and method for processing a signal is capable of determining the presence of absence of a signal having a predetermined baud rate. By initializing counting registers to either first or second values, and receiving the signal, either the presence or absence of the baud rate may be more rapidly detected. Rapid detection provides for improved battery savings when the invention is used within a portable receiver such as a pager. The invention provides for positive detection of the predetermined baud rate while rejecting a baud rate being an integer divisor of the predetermined baud rate. Additionally, as a result of the determination of the presence of the predetermined baud rate, a sample clock may be established for receiving data at the baud rate.
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Citations
22 Claims
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1. A receiver for receiving a signal having transitions between symbols occurring at a predetermined baud rate and having information within the symbols, comprising:
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demodulator means for demodulating the signal; means coupled to the demodulator means for detecting the presence of the signal, the means comprising; a multiplicity of counting registers; means for establishing an integer number of sample windows per symbol, each sample window having a corresponding unique combination of a plurality of counting registers within said multiplicity of counting registers; means for sensing the transitions of a received signal, the transitions occurring within each established sample window; means for counting in the counting registers corresponding to each sample window in which a transition is sensed; and means for generating a presence signal in response to a counting register having a predetermined number of counts; means for determining the absence of the presence signal; means for conserving power to the demodulator means in response to the absence of the presence signal; and means coupled to the demodulating means for detecting the information in response to the presence signal.
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2. In a receiver, a method of detecting the presence of a first signal having transitions between symbols occurring at a predetermined baud rate, the method comprising the steps of:
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establishing an integer number of sample windows per symbol, each sample window having a corresponding unique combination of a plurality of counting registers within a multiplicity of counting registers; receiving the first signal and producing a received signal having transitions; sensing the transitions of the received signal occurring within each established sample window; counting in the counting registers corresponding to each sample window in which a transition is sensed; generating a presence signal in response to a counting register having a predetermined number of counts; and determining the absence of the presence signal; conserving power to the receiver in response to the absence of the presence signal. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10)
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11. In a receiver, a means for detecting the absence of a signal having transitions between symbols occurring at a predetermined baud rate, the means comprising:
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a multiplicity of counting registers; means for establishing an integer number of sample windows per symbol, each sample window having a corresponding unique combination of a plurality of counting registers within said multiplicity of counting registers; means for receiving a received signal having transitions; means for sensing the transitions of the received signal occurring within each established sample window; means for counting in the counting registers corresponding to each sample window in which a transition is sensed; means for generating an absence signal in response to all of the counting registers exceeding a predetermined number of counts; and conserving power to the receiver in response to the absence signal.
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12. In a receiver, a method of detecting the absence of a signal having transitions between symbols occurring at a predetermined baud rate, the method comprising the steps of:
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establishing an integer number of sample windows per symbol, each sample window having a corresponding unique combination of a plurality of counting registers within a multiplicity of counting registers; receiving a transmitted signal and producing a received signal having transitions; sensing the transitions of the received signal occurring within each established sample window; counting in the counting registers corresponding to each sample window in which a transition is sensed; generating an absence signal in response to all of the counting registers exceeding a predetermined number of counts; and conserving power to the receiver in response to the absence of the presence signal. - View Dependent Claims (13, 14, 15, 16, 17)
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18. A receiver for receiving a signal having transitions between symbols occurring at a predetermined baud rate and having information within the symbols, comprising:
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demodulator means for demodulating the signal; means for selectively detecting the presence or absence of the signal, the means comprising; a multiplicity of counting registers; means for establishing an integer number of sample windows per symbol, each sample window having a corresponding unique combination of a plurality of counting registers within said multiplicity of counting registers; means for selecting either presence detection or absence detection; means for receiving a transmitted signal and producing a received signal having transitions; means for sensing the transitions of the received signal occurring within each established sample window; means for counting in the counting registers corresponding to each sample window in which a transition is sensed; and means generating a presence signal in response to the selection of presence detection and a counting register having a first predetermined number of counts; and means for generating an absence signal in response to the selection of absence detection and all of the counting registers exceeding a second predetermined number of counts; means for conserving power to the demodulator means in response to the absence signal; and means for processing the information in response to the presence signal.
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19. In a receiver, a method of selectively detecting the presence or absence of a signal having transitions between symbols occurring at a predetermined baud rate, the method comprising the steps of:
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establishing an integer number of sample windows per symbol, each sample window having a corresponding unique combination of a plurality of counting registers within a multiplicity of counting registers; selecting either presence detection or absence detection; receiving a transmitted signal and producing a received signal having transitions; sensing the transitions of the received signal occurring within each established sample window; counting in the counting registers corresponding to each sample window in which a transition is sensed; and generating a presence signal in response to the selection of presence detection and a counting register having a first predetermined number of counts; and generating an absence signal in response to the selection of absence detection and all of the counting registers exceeding a second predetermined number of counts; conserving power to the receiver in response to the absence signal. - View Dependent Claims (20, 21, 22)
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Specification