Radio frequency (RF) receiver with amplitude-shifted keying/frequency-shifted keying (ASK/FSK) duty cycle optimization algorithm
First Claim
1. A method of operating a radio frequency (RF) receiver for an automobile comprising the steps of:
- operating the RF receiver in a first mode for receiving Frequency Shift Keyed (FSK) modulated transmissions for a first period;
switching the RF receiver to a second mode for receiving an Amplitude Shift Keyed (ASK) modulated transmission for a second period, shorter than the first period;
switching the RF receiver back to the first mode responsive to the RF receiver determining that an ASK modulated transmissions is present;
switching the RF receiver back to the second mode after a first known time interval such that the RF receiver can receive a second ASK modulated transmission; and
maintaining the RF receiver in the second mode after the first known time interval to received the second ASK modulated transmission.
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Accused Products
Abstract
A radio frequency (RF) receiver for receiving transmissions of different modulations includes cycling between a first mode for receiving transmissions of a first modulation that occurs frequently and a second mode for receiving transmission of a second modulation that occurs infrequently. The example RF receiver is cycled between a first modulation for receiving a frequency shift keyed (FSK) transmission from a tire pressure monitoring (TPM) system and a second modulation for receiving an amplitude shift keyed (ASK) transmission from a remote keyless entry (RKE) system. The RF receiver cycles between different modulations to detect the most frequent FSK modulated transmissions while also detecting and receiving the relatively infrequent ASK modulated RKE transmissions without an undesirable delay.
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Citations
14 Claims
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1. A method of operating a radio frequency (RF) receiver for an automobile comprising the steps of:
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operating the RF receiver in a first mode for receiving Frequency Shift Keyed (FSK) modulated transmissions for a first period; switching the RF receiver to a second mode for receiving an Amplitude Shift Keyed (ASK) modulated transmission for a second period, shorter than the first period; switching the RF receiver back to the first mode responsive to the RF receiver determining that an ASK modulated transmissions is present; switching the RF receiver back to the second mode after a first known time interval such that the RF receiver can receive a second ASK modulated transmission; and maintaining the RF receiver in the second mode after the first known time interval to received the second ASK modulated transmission. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of operating an RF receiver for an automobile comprising the steps of:
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a) operating the RF receiver in a first mode for receiving Frequency Shift Keyed (FSK) modulated transmissions for a first period; b) switching the RF receiver to a second mode for receiving an Amplitude Shift Keyed (ASK) modulated transmission for a second period, shorter than the first period, wherein the second period is of a duration determined to detect the presence of the first ASK modulated transmission and shorter than a period required to receive the entire first ASK modulated transmission such that receipt of the first ASK modulated transmission in the second period provides a prompt for the RF receiver to operate in the second mode to receive a second ASK modulated transmission; c) switching the RF receiver back to the first mode responsive to the RF receiver determining that no ASK modulated transmissions is present; and d) maintaining the RF receiver in the second mode responsive to a first ASK modulated transmission being detected, wherein a first time interval between the first ASK modulated transmission and the second ASK modulated transmission is fixed and RF receiver switches back to operate in the first mode responsive to receiving the first ASK modulated signal until the first time interval expires where the RF receiver switches back to the second mode to receives the second ASK Modulated signal.
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10. A method of receiving transmissions from a tire pressure monitoring (TPM) system and a remote keyless entry (RKE) system with one RF receiver comprising the steps of:
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operating the RF receiver in a first mode for receiving a Frequency Shift Keyed (FSK) modulated transmission from the TPM system for a first period; switching the RF receiver to a second mode for receiving an Amplitude Shift Keyed (ASK) modulated transmission from the RKE system for a second period shorter than the first period and shorter than the ASK modulated transmission; searching for an ASK modulated transmission; and switching the RF receiver back to the first mode responsive to no ASK modulated transmission being detected, and prompting the RF receiver to switch into the second mode after a first known time interval for receiving a second ASK modulated signal responsive to receiving a first ASK modulated transmission during the second period. - View Dependent Claims (11, 12, 13, 14)
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Specification