Leap Second and Daylight Saving Time Correction in a Radio Controlled Clock Receiver
First Claim
1. A radio receiver method, said method comprising:
- receiving a phase modulated (PM), pulse width modulated (PWM)/amplitude shift keyed (ASK) broadcast signal encoded with phase-modulated time information frames;
extracting said time information frames from the phase of said received signal; and
wherein each said time information frame includes a synchronization sequence field, and one or more fields adapted to communicate a schedule for a next daylight-saving time transition, said schedule indicating the specific day for said transition.
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Accused Products
Abstract
A novel and useful system and method for leap second and daylight saving time (DST) correction for use in a radio controlled clock (RCC) receiver. The RCC receiver extracts schedule information from the frame, including the time for the DST transition and whether a leap second needs to be added at the end of this half-year. Linear error correcting coding is used for the leap second and the DST on/off indications, while non-linear error correcting coding (e.g., a look up table) is used for the DST schedule to enhance reception reliability in the presence of noise and interference. The one second/one hour corrections are scheduled to occur when they should take place and the correction is applied exactly when DST or leap second is to go into effect, without having to receive anything around the time of the correction.
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Citations
14 Claims
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1. 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 phase-modulated time information frames; extracting said time information frames from the phase of said received signal; and wherein each said time information frame includes a synchronization sequence field, and one or more fields adapted to communicate a schedule for a next daylight-saving time transition, said schedule indicating the specific day for said transition. - View Dependent Claims (2, 3, 4)
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5. 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 phase-modulated time information frames; extracting said time information frames from the phase of the carrier of said modulated received signal, wherein each said time information frame includes a synchronization sequence field, a daylight-saving time hour information field and a daylight-saving time day information field, said daylight-saving time hour information and said daylight-saving time day information comprising a multi-bit field encoded using a nonlinear error correction code; and utilizing a lookup table, constructed a priori and stored in said receiver, to decode said multi-bit field to yield decoded daylight-saving time hour information and daylight-saving time day information. - View Dependent Claims (6, 7, 8, 9, 10)
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11. 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 phase-modulated time information frames; a frame extractor operative to extract said time information frames from the phase of the carrier of said received signal, wherein each said time information frame includes a synchronization sequence field, daylight saving time (DST) hour information and DST day information, said DST hour information and said DST day information comprising a multi-bit field encoded using a nonlinear error correction code; and a lookup table constructed a priori and stored in said radio receiver, said lookup table used to extract and decode said multi-bit field to yield decoded DST hour and day information. - View Dependent Claims (12, 13, 14)
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Specification