Remote signal transmission control including compensation for variations in transmitter components
First Claim
1. A method of controlling signal transmission from a transmitter having an oscillator, a transmitter portion and a microprocessor that drives the transmitter portion, comprising the steps of:
- (A) generating a test signal having an expected timing characteristic;
(B) determining whether the actual timing characteristic of the test signal corresponds to the expected timing characteristic;
(C) determining a correction factor using a difference between the actual and expected timing characteristics; and
(D) causing the microprocessor to utilize the correction factor in subsequent signal transmissions.
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Accused Products
Abstract
A transmitter, particularly useful for a remote keyless entry system, includes a less expensive oscillator. A strategy for compensating for tolerance variations caused by the less expensive components includes sending out a test signal with an expected signal profile. The test signal is then received and analyzed to compare it to the expected signal profile. Variations in timing characteristics of the signal compared to the expected characteristics are utilized to determine correction factors that are then programmed into a microprocessor of the transmitter so that subsequent signal transmissions will track an expected signal profile.
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Citations
17 Claims
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1. A method of controlling signal transmission from a transmitter having an oscillator, a transmitter portion and a microprocessor that drives the transmitter portion, comprising the steps of:
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(A) generating a test signal having an expected timing characteristic;
(B) determining whether the actual timing characteristic of the test signal corresponds to the expected timing characteristic;
(C) determining a correction factor using a difference between the actual and expected timing characteristics; and
(D) causing the microprocessor to utilize the correction factor in subsequent signal transmissions. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A transmitter for use in a remote keyless entry system, comprising:
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a microprocessor;
an oscillator that is at least partially resident within the microprocessor; and
a transmitting portion that transmits a signal having a desired timing characteristic for receipt by a remotely located receiver, the transmitting portion being driven by a feed signal from the microprocessor and the microprocessor being programmed to alter a baud rate used to generate the feed signal to compensate for a difference between the desired timing characteristic and an actual timing characteristic of the transmitted signal. - View Dependent Claims (12, 13, 15, 16, 17)
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14. A method of controlling signal transmission in a remote keyless entry system that includes a transmitter having a microprocessor, a transmitter portion that is driven by the microprocessor and an oscillator that is at least partially within the microprocessor, comprising the steps of:
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(A) generating a test signal having an expected frequency;
(B) determining whether the actual frequency of the test signal matches the expected frequency;
(C) determining a correction factor using a difference between the actual and expected frequencies; and
(D) causing the microprocessor to utilize the correction factor in subsequent signal transmissions.
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Specification