Radio frequency data communications device

Claim 3

A method in accordance with claim 1 wherein the radio frequency identification device further comprises a clock recovery circuit configured to recover a clock from the incoming radio frequency signals, the clock recovery circuit including a phase lock loop and wherein the tests further comprise: determining whether frequency lock is achieved on the incoming radio frequency signal within a predetermined amount of time; switching from the receiver-on mode to the microprocessor-on mode when the phase lock loop has achieved frequency lock within the predetermined time; and returning to the sleep mode when the phase lock loop has not achieved frequency lock within the predetermined time.

Claim 4

A radio frequency communications device comprising: a single integrated circuit including a transmitter and a receiver, the integrated circuit being configured to periodically check if a radio frequency signal is being received by the receiver, the integrated circuit further including a timer configured to set a time period for the checking, the timer having a frequency lock loop, the frequency lock loop including a current controlled oscillator, the integrated circuit being configured to recover a clock frequency from the received signal, the transmitter being configured to use the recovered clock frequency, the integrated circuit being configured to switch between a sleep mode, a receiver-on power mode in which more power is consumed than in the sleep mode and in which the checking takes place, and a microprocessor-on power mode in which more power is consumed than in the receiver-on power mode, the integrated circuit further including a variable value divider coupled to the output of the frequency lock loop, the value of the divider being programmable in response to a radio frequency command received by the receiver which contains data representing the desired value of the divider, so as to permit remote programming of the time period of the checking.

Claim 5

A radio frequency communications device comprising: a single integrated circuit including a transmitter and a receiver, the integrated circuit being configured to periodically check if a radio frequency signal is being received by the receiver, the integrated circuit further including a timer configured to set a time period for the checking, the timer having a frequency lock loop, the frequency lock loop including a current controlled oscillator, the integrated circuit being configured to recover a clock frequency from the received signal, the transmitter being configured to use the recovered clock frequency, the integrated circuit being configured to switch between a sleep mode, a receiver-on power mode in which more power is consumed than in the sleep mode and in which the checking takes place, and a microprocessor-on power mode in which more power is consumed than in the receiver-on power mode, the integrated circuit further including a variable value divider coupled to the output of the frequency lock loop, the value of the divider being programmable in response to a radio frequency command received by the receiver which contains data representing the desired value of the divider, so as to permit remote programming of the time period of the checking.

Claim 6

A radio frequency communications device in accordance with claim 3 and further comprising a selectively engageable countdown timer configured to prevent switching from the sleep mode to the receiver-on mode for a predetermined amount of time set by a radio frequency command, received by the receiver, containing data representing the desired amount of time.

Claim 7

A radio frequency communications device in accordance with claim 3 wherein the device is configured to receive and process commands from an interrogator transmitting a radio frequency signal and to enable the frequency lock loop only during processing of a command, to calibrate the timer to a clock frequency recovered from a received command.

Claim 12

A method as claimed in claim 7 wherein the radio frequency identification device includes a wake-up controller circuit, wherein the determining when a predetermined time interval has elapsed is performed by the wake-up controller circuit, and returning the radio receiver to the sleep mode comprises: turning off the master receiver bias; and restarting a timer in the wake-up controller.

Claim 13

A method as claimed in claim 8, further comprising: receiving by the receiver and decoding by the microprocessor a wake-up timer interval reset signal for setting a new wake-up interval in a wake-up interval timer in the wake-up controller; and resetting the wake-up interval in the wake-up timer in response to the wake-up timer interval reset signal.

Claim 14

A method as claimed in claim 7, wherein asserting a bias control signal comprises turning on a bias control signal to turn on a master receiver bias to provide electrical power to a clock and data recovery circuit and a voltage controlled oscillator, the method further comprising, prior to providing a microprocessor wake-up signal and after determining when a second number of spread spectrum transitions of the radio frequency signal occurs during the second predetermined interval: determining, during an interval of predetermined length, presence or absence of clock signal acquisition from the radio frequency signal by the clock and data recovery circuit, and, when absence of clock signal acquisition is determined, returning the radio receiver circuit to the sleep mode; and determining, during an interval of predetermined length, when the voltage controlled oscillator and clock and data recovery circuit have acquired frequency lock, and, when absence of frequency lock is determined, returning the radio receiver to the sleep mode.

Claim 17

The method of claim 11, further comprising, prior to providing a microprocessor wake-up signal, determining, during a frequency lock interval of predetermined length, when the voltage controlled oscillator and clock and data recovery circuit have acquired frequency lock, and, when absence of frequency lock is determined, returning the radio receiver to the sleep mode.

Claim 20

A method as claimed in claim 13 wherein changing the state to a fourth mode when a third criterion is met includes providing a microprocessor wake-up signal when a variable frequency oscillator achieves frequency lock with a received RF signal.

Claim 21

A radio frequency identification device comprising: a radio receiver having an output; a wake-up timer circuit providing a receiver wake-up signal to the radio receiver at predetermined intervals to change a state of the radio frequency identification device from a sleep mode requiring a first power level to a second mode requiring a second power level greater than the first power level; a radio frequency signal detection circuit having an input coupled to the radio receiver output, the radio frequency detection circuit providing an output signal returning the radio frequency identification device to the sleep mode when no radio frequency signal is detected, the radio frequency signal detection circuit setting the radio frequency detection device to a third mode requiring more power than the second mode when a radio frequency circuit is detected; a wake-up controller circuit having an input coupled to the radio receiver output, the wake-up controller circuit first testing the radio frequency signal to determine when a first number of spread spectrum transitions of the radio frequency signal occurs during a first predetermined interval, the wake-up controller circuit providing an output signal returning the radio frequency identification device to the sleep mode when the wake-up controller circuit determines that the first number of transitions does not occur during the first predetermined interval, the wake-up controller circuit then testing the radio frequency signal to determine when a second number of spread spectrum transitions of the radio frequency signal occurs during a second predetermined interval and providing an output signal returning the radio frequency identification device to the sleep mode when the wake-up controller circuit determines that the second number of transitions does not occur during the second predetermined interval; a clock and data recovery circuit including a phase-locked loop, the clock and data recovery circuit having an input coupled to the radio receiver output, the clock and data recovery circuit determining, during an interval of predetermined length, presence or absence of voltage controlled oscillator signal acquisition from the radio frequency signal and returning the radio receiver to the sleep mode when absence of clock signal acquisition is determined; and a microprocessor having a data input coupled to the radio receiver output and a control input coupled to the wake-up controller circuit, the wake-up controller circuit providing a microprocessor wake-up signal to the microprocessor when the first number of transitions occurs during the first predetermined interval, the second number of transitions occurs during the second predetermined interval and the wake-up controller determines presence of voltage controlled oscillator signal acquisition from the radio frequency signal, the microprocessor wake-up signal setting the radio frequency identification device to a processor-on mode requiring a fourth power level that is greater than the third power level.

Claim 22

A radio frequency identification device comprising: a radio receiver having an output; a wake-up timer circuit providing a receiver wake-up signal to the radio receiver at predetermined intervals to change a state of the radio frequency identification device from a sleep mode requiring a first power level to a second mode requiring a second power level greater than the first power level; a radio frequency signal detection circuit having an input coupled to the radio receiver output, the radio frequency detection circuit providing an output signal returning the radio frequency identification device to the sleep mode when no radio frequency signal is detected, the radio frequency signal detection circuit setting the radio frequency detection device to a third mode requiring more power than the second mode when a radio frequency circuit is detected; a wake-up controller circuit having an input coupled to the radio receiver output, the wake-up controller circuit first testing the radio frequency signal to determine when a first number of spread spectrum transitions of the radio frequency signal occurs during a first predetermined interval, the wake-up controller circuit providing an output signal returning the radio frequency identification device to the sleep mode when the wake-up controller circuit determines that the first number of transitions does not occur during the first predetermined interval, the wake-up controller circuit then testing the radio frequency signal to determine when a second number of spread spectrum transitions of the radio frequency signal occurs during a second predetermined interval and providing an output signal returning the radio frequency identification device to the sleep mode when the wake-up controller circuit determines that the second number of transitions does not occur during the second predetermined interval; a clock and data recovery circuit including a phase-locked loop, the clock and data recovery circuit having an input coupled to the radio receiver output, the clock and data recovery circuit determining, during an interval of predetermined length, presence or absence of voltage controlled oscillator signal acquisition from the radio frequency signal and returning the radio receiver to the sleep mode when absence of clock signal acquisition is determined; and a microprocessor having a data input coupled to the radio receiver output and a control input coupled to the wake-up controller circuit, the wake-up controller circuit providing a microprocessor wake-up signal to the microprocessor when the first number of transitions occurs during the first predetermined interval, the second number of transitions occurs during the second predetermined interval and the wake-up controller determines presence of voltage controlled oscillator signal acquisition from the radio frequency signal, the microprocessor wake-up signal setting the radio frequency identification device to a processor-on mode requiring a fourth power level that is greater than the third power level.

Claim 23

A radio frequency identification device comprising: a radio receiver having an output and a control input; a microprocessor having a data input coupled to the radio receiver output and having a control input; a timer having an output coupled to the control input of the radio receiver, the timer providing an output signal to the radio receiver control input changing a state of the identification device from a sleep mode requiring a first power level to a second mode by turning the radio receiver in the identification device on in response to a first criterion, the radio receiver requiring a second power level greater than the first power level; and a wake-up controller circuit including an output coupled to the microprocessor control input, the wake-up controller circuit changing the state of the identification device from the second mode to a third mode when a second criterion is met, the third mode requiring a third power level greater than the second power level, and, when the second criterion is not met, changing the state from the second mode to the sleep mode, the wake up controller circuit providing an output signal to the microprocessor control input changing the state of the identification device from the third mode to a fourth mode when a third criterion is met, the fourth mode requiring a fourth power level greater than the third mode, and, when the third criterion is not met, changing the state from the third mode to the sleep mode.

Claim 24

A radio frequency identification device comprising: a radio receiver having an output and a control input; a microprocessor having a data input coupled to the radio receiver output and having a control input; a timer having an output coupled to the control input of the radio receiver, the timer providing an output signal to the radio receiver control input changing a state of the identification device from a sleep mode requiring a first power level to a second mode by turning the radio receiver in the identification device on in response to a first criterion, the radio receiver requiring a second power level greater than the first power level; and a wake-up controller circuit including an output coupled to the microprocessor control input, the wake-up controller circuit changing the state of the identification device from the second mode to a third mode when a second criterion is met, the third mode requiring a third power level greater than the second power level, and, when the second criterion is not met, changing the state from the second mode to the sleep mode, the wake up controller circuit providing an output signal to the microprocessor control input changing the state of the identification device from the third mode to a fourth mode when a third criterion is met, the fourth mode requiring a fourth power level greater than the third mode, and, when the third criterion is not met, changing the state from the third mode to the sleep mode.

Claim 25

The identification device as claimed in claim 16 wherein changing the state to a fourth mode when a third criterion is met includes providing a microprocessor wake-up signal when a variable frequency oscillator achieves frequency lock with a received RF signal.