Timing and time information extraction from a phase modulated signal in a radio controlled clock receiver
First Claim
1. A radio receiver, comprising:
- a receiver circuit operative to receive a phase modulated (PM), pulse width modulation (PWM)/amplitude shift keyed (ASK) broadcast signal encoded with timing information separate from time information, said timing information based on a known synchronization sequence spanning multiple seconds; and
a circuit operative to extract said timing and time information from the phase of said received signal;
wherein said phase modulation comprises pulse width modulation/amplitude shift keyed modulated data transmitted with and without a phase reversal; and
wherein information represented by said phase modulation is independent of the information represented by said pulse width modulation/amplitude shift keyed modulation.
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Accused Products
Abstract
A system and method for a radio controlled clock receiver adapted to extract timing and time information from a phase modulated signal. The official time signal is broadcast from a central location using a modulation scheme that adds phase modulation to legacy pulse width modulated/amplitude modulation that allows for greatly improved performance. The information modulated onto the phase contains a known synchronization sequence having good autocorrelation properties, error-correcting coding for the time information and notifications of daylight-saving-time (DST) transitions that are provided months in advance. The modulation scheme is based on a form of phase modulation, such as binary-phase-shift-keying (BPSK) or phase reversal keying (PRK). A superframe comprising multiple frames with repeated information allows for the accumulation of received energy over multiple frames to provide for a corresponding gain in the receiver.
40 Citations
30 Claims
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1. A radio receiver, comprising:
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a receiver circuit operative to receive a phase modulated (PM), pulse width modulation (PWM)/amplitude shift keyed (ASK) broadcast signal encoded with timing information separate from time information, said timing information based on a known synchronization sequence spanning multiple seconds; and a circuit operative to extract said timing and time information from the phase of said received signal; wherein said phase modulation comprises pulse width modulation/amplitude shift keyed modulated data transmitted with and without a phase reversal; and wherein information represented by said phase modulation is independent of the information represented by said pulse width modulation/amplitude shift keyed modulation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A radio receiver method, said method comprising:
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receiving a phase modulated (PM), pulse width modulated (PWM)/amplitude shift keyed (ASK) broadcast signal encoded with timing information separate from time information, said timing information based on a known synchronization sequence spanning multiple seconds; and extracting said timing and time information from the phase of said received signal; wherein said phase modulation comprises pulse width modulation/amplitude shift keyed modulated data transmitted with and without a phase reversal; and wherein information represented by said phase modulation is independent of the information represented by said pulse width modulation/amplitude shift keyed modulation. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
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18. A radio receiver method for use in a timekeeping device, said method comprising:
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receiving a phase modulated (PM), pulse width modulated (PWM)/amplitude shift keyed (ASK) broadcast signal encoded with timing information separate from time information, said timing information based on a known synchronization sequence spanning multiple seconds; extracting said timing and time information from the phase of said received signal; and correlating said timing information against a known synchronization sequence so as to establish frame and symbol timing; wherein said phase modulation comprises pulse width modulation/amplitude shift keyed modulated data transmitted with and without a phase reversal; and wherein information represented by said phase modulation is independent of the information represented by said pulse width modulation/amplitude shift keyed modulation. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26)
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27. A radio receiver method, said method comprising:
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receiving a phase modulated (PM) broadcast signal encoded with timing information separate from time information, said timing information based on a known synchronization sequence spanning multiple seconds, wherein said timing and time information, intended for synchronization and time reference purposes, is conveyed in the phase of the carrier portion of said broadcast signal; and extracting said timing and time information from the phase of said received signal; wherein said phase modulation comprises pulse width modulation/amplitude shift keyed modulated data transmitted with and without a phase reversal; and wherein information represented by said phase modulation is independent of the information represented by said pulse width modulation/amplitude shift keyed modulation. - View Dependent Claims (28, 29, 30)
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Specification