Method and apparatus for processing wideband data in a digital cellular communication system
First Claim
1. A digital receiver for receiving a frequency-modulated (FM) signal, said digital receiver comprising:
- a digital FM demodulator for providing a demodulated information signal in response to said FM signal;
wideband message processing means for recovering message information from said demodulated information signal, said wideband message processing means including a word register circuit for storing message words included within said demodulated information signal and;
means for setting said digital receiver for operation in a control channel mode and a voice channel mode, said wideband message processing means further including a dotting detector for detecting a first dotting sequence within said demodulated information signal during operation in said control channel mode and for detecting a second dotting sequence within said demodulated information signal during operation in said voice channel mode.
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Accused Products
Abstract
A system and method for processing wideband data within digital FM transceiver. A digital FM demodulator within the transceiver produces a demodulated information signal in response to the FM signal. The digital FM receiver also includes a wideband message processing section for recovering message information from the demodulated information signal. A word register circuit within the wideband message processing section stores one or more repetitions of a message word recovered from the demodulated information signal. During operation of the FM receiver in a control channel mode, a dotting detector within the wideband processing section is used for detecting a first dotting sequence within the demodulated information signal. Similarly, the dotting detector serves to detect a second dotting sequence within the demodulated information signal during operation in a voice channel mode. A word sync sequence is also identified within the demodulated information signal prior to storage of the one or more repetitions of the received message word within the word register circuit. A reconstructed message word is then generated by comparing corresponding bits within the one or more repetitions of the one message word. A message prefilter determines whether a processor interrupt should be generated by ascertaining whether the reconstructed message word is of a predefined type. A digital FM transmitter of the transceiver is controlled on the basis of busy-idle channel status information recovered from the demodulated information signal.
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Citations
18 Claims
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1. A digital receiver for receiving a frequency-modulated (FM) signal, said digital receiver comprising:
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a digital FM demodulator for providing a demodulated information signal in response to said FM signal; wideband message processing means for recovering message information from said demodulated information signal, said wideband message processing means including a word register circuit for storing message words included within said demodulated information signal and; means for setting said digital receiver for operation in a control channel mode and a voice channel mode, said wideband message processing means further including a dotting detector for detecting a first dotting sequence within said demodulated information signal during operation in said control channel mode and for detecting a second dotting sequence within said demodulated information signal during operation in said voice channel mode. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A digital FM communications unit comprising:
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a digital FM receiver for receiving a frequency-modulated (FM) signal, said digital receiver including; a digital FM demodulator for providing a demodulated information signal in response to said FM signal, and wideband message processing means for recovering message information from said demodulated information signal and for storing message words included within said demodulated information signal in a word register circuit, said wideband message processing means including means for extracting system status information from said message information; a digital FM transmitter, responsive to said system status information, for transmitting an FM communication signal; and a microprocessor coupled to said digital FM receiver and to said digital FM transmitter, said wideband message processing means including a message prefilter for enabling said microprocessor to be interrupted only upon receipt of ones of said message words of predefined type. - View Dependent Claims (10, 11, 12, 13, 14)
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15. A method for recovering message information from a frequency-modulated (FM) signal, said method comprising the steps of:
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receiving said FM signal; generating a demodulated information signal upon receiving said FM signal; storing, in a word register circuit, message words included within said demodulated information signal; decoding said message words in order to recover said message information; selectively enabling operation in control channel and voice channel modes; detecting a first dotting sequence within said demodulated information signal during operation in said control channel mode; and detecting a second dotting sequence within said demodulated information signal during operation in said voice channel mode. - View Dependent Claims (16, 17, 18)
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Specification