Resynchronizing timing sync pulses in a synchronizing RF system

• US 7,522,685 B2
• Filed: 06/01/2004
• Issued: 04/21/2009
• Est. Priority Date: 06/01/2004
• Status: Active Grant

• Current Assignee: Ademco Inc. (Resideo Technologies, Inc.)
• Original Assignee: Honeywell International Inc.
• Inventors: Zakrewski, David S.
• Primary Examiner(s): Liu; Shuwang
• Assistant Examiner(s): TAYONG, HELENE E
• Application Number:
  US10/858,452
• Publication Number:
  US 20050265501A1
• Time in Patent Office: 1,785 Days
• Field of Search: 375/354, 455/574, 455/502, 455/572, 370/55, 370/311, 370/95.1, 340/870.02, 379/60, 379/63, 379/59
• US Class Current: 375/354
• CPC Class Codes: G08B 25/14 Central alarm receiver or annunciator arrangements
• CPC Class Codes: G08B 27/008 with transmission via TV or radio broadcast
• CPC Class Codes: H04L 7/10 Arrangements for initial synchronisation

Abstract

A synchronizing method and system between a Radio Frequency (RF) transmitter and a battery powered receiver wherein the transmitter transmits short duration first periodic sync signals which are used by the receiver to maintain proper synchronization of the receiver with the transmitter during second periodic wake-up windows for transmission of data. The receiver wakes for a short duration at the start of each periodic wake up window to receive a possible transmission of data, and if no transmission is received goes back to sleep, and if a transmission is received stays awake to receive the full transmission of data. The receiver accurately times a number of consecutive first periodic sync signals received from the transmitter in order to more accurately determine when the receiving device should come out of a sleep mode.

Claims

1. A synchronizing method between a Radio Frequency (RF) transmitter and a battery powered RF receiver wherein:

the transmitter transmits first periodic sync signals which are received and used by the receiver to maintain proper synchronization of the receiver with the transmitter during second periodic wake up windows for possible transmissions of data;

the transmitter transmits data during at least some of the second periodic wake up windows for the transmission of data;

the receiver wakes periodically from a sleep mode to receive the first periodic sync signals which are used by the receiver to maintain the receiver properly synchronized with the transmitter during the second periodic wake up windows for possible transmissions of data from the transmitter;

the receiver accurately times a number of consecutive first periodic sync signals received from the transmitter in order to accurately determine the second periodic wake up windows when the receiver comes out of the sleep mode;

the receiver wakes periodically for a short duration at the start of each second periodic wake up window to receive a possible transmission of data, and if no transmission is received goes back to the sleep mode, and if a transmission is received stays awake to receive the transmission of data, such that an average current consumed by the battery powered receiver to wake periodically to receive the first periodic sync signals to maintain synchronization and to wake periodically to listen for the possible second periodic transmissions of data is less than the average current required to maintain the receiver awake continuously.

2. The method of claim 1, wherein the receiver, upon power-up and after the receiver has received initial configuration data from the transmitter, remains awake and receiving until the receiver has received and timed a number of consecutive sync pulses.

3. The method of claim 2, wherein the receiver averages the timing of the consecutive sync pulses, and an average timing is used to determine the next wake up time period for the receiver.

4. The method of claim 1, wherein the receiver, upon power-up and after the receiver has received any new configuration data from the transmitter, remains awake and receiving until the receiver has received and timed a number of consecutive sync pulses.

5. The method of claim 4, wherein the receiver averages the timing of the consecutive sync pulses, and an average timing is used to determine the next wake up time period for the receiver.

6. The method of claim 1, wherein the receiver periodically several times a day awakes and remains awake and receiving until the receiver has received and timed a number of consecutive sync pulses

7. The method of claim 6, wherein the receiver averages the timing of the consecutive sync pulses, and an average timing is used to determine the next wake up time period for the receiver.

8. The method of claim 1, wherein the transmitter transmits the first periodic sync signals over short durations and with a periodicity such that a total of all of the first periodic sync signals over a period of one hour is equal to or less than a total of 2seconds on-air time per hour.

9. The method of claim 1, wherein the periodicity of the second periodic wake up windows is substantially 3 seconds, such that the average response time of the battery powered receiver to changes reflected by the transmissions of data is less than 1.5seconds on average and no greater than 3 seconds in a worst case.

10. The method of claim 1, operated in a security alarm system having an AC powered control panel with the transmitter which transmits periodic RF messages on the present status of the security alarm system to a plurality of battery powered reduced display monitors, each having a said battery powered receiver, to provide a display of the current status of the security alarm system.

11. A synchronizing system between a Radio Frequency (RF) transmitter and a battery powered RF receiver wherein:

the transmitter includes means for transmitting first periodic sync signals which are received and used by the receiver to maintain proper synchronization of the receiver with the transmitter during second periodic wake up windows for possible transmissions of data;

the transmitter includes means for transmitting data during at least some of the second periodic wake up windows for the transmission of data;

the receiver includes means for waking periodically to receive the first periodic sync signals which are used by the receiver to maintain the receiver properly synchronized with the transmitter during the second periodic wake up windows for possible transmissions of data from the transmitter;

the receiver includes means for accurately timing a number of consecutive first periodic sync signals from the transmitter in order to accurately determine the second periodic wake up windows when the receiver comes out of a sleep mode;

the receiver includes means for waking periodically for a short duration at the start of each second periodic wake up window to receive a possible transmission of data, and if no transmission is received goes back to sleep, and if a transmission is received stays awake to receive the transmission of data, such that an average current consumed by the battery powered receiver to wake periodically to receive the first periodic sync signals to maintain synchronization and to wake periodically to listen for the possible second periodic transmissions of data is less than the average current required to maintain the receiver awake continuously.

12. The system of claim 11, wherein the receiver, upon power-up and after the receiver has received initial configuration data from the transmitter, remains awake and receiving until the receiver has received and timed a number of consecutive sync pulses.

13. The system of claim 12, wherein the receiver averages the timing of the consecutive sync pulses, and an average timing is used to determine the next wake up time period for the receiver.

14. The system of claim 11, wherein the receiver, upon power-up and after the receiver has received any new configuration data from the transmitter, remains awake and receiving until the receiver has received and timed a number of consecutive sync pulses.

15. The system of claim 14, wherein the receiver averages the timing of the consecutive sync pulses, and an average timing is used to determine the next wake up time period for the receiver.

16. The system of claim 11, wherein the receiver periodically several times a day awakes and remains awake and receiving until the receiver has received and timed a number of consecutive sync pulses.

17. The system of claim 16, wherein the receiver averages the timing of the consecutive sync pulses, and an average timing is used to determine the next wake up time period for the receiver.

18. The system of claim 11, wherein the transmitter transmits the first periodic sync signals over short durations and with a periodicity such that a total of all of the first periodic sync signals over a period of one hour is equal to or less than a total of 2 seconds on-air time per hour.

19. The system of claim 11, wherein the periodicity of the second periodic wake up windows is substantially 3 seconds, such that the average response time of the battery powered receiver to changes reflected by the transmissions of data is less than 1.5 seconds on average and no greater than 3 seconds in a worst case.

20. The system of claim 11, operated in a security alarm system having an AC powered control panel with the transmitter which transmits periodic RF messages on the present status of the security alarm system to a plurality of battery powered reduced display monitors, each having a said battery powered receiver, to provide a display of the current status of the security alarm system.