"Selective call receiver"

• US 5,252,963 A
• Filed: 03/16/1992
• Issued: 10/12/1993
• Est. Priority Date: 01/04/1990
• Status: Expired due to Term

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Moore, Morris A., DeLuca, Michael J., Snowden, Gregory O., Willard, David F., Schwendeman, Robert J.
• Primary Examiner(s): Yusko, Donald J.
• Assistant Examiner(s): Giust, John
• Application Number:
  US07/851,113
• Time in Patent Office: 575 Days
• Field of Search: 340/825.44, 340/825.47, 340/825.48, 340/825.57, 455/228, 455/343, 455/344, 455/127, 375/110, 375/116, 370/94.3, 370/100.1
• US Class Current: 340/7.38
• CPC Class Codes: H04B 1/1615 Switching on; Switching off, e.g. remotely battery saving circuits associated with selective call operation H04W52/00; details of power consumption reduction in a PLL, H03L7/0802, H03L7/14, H03L2207/08, H03L2207/18; muting amplifiers by gain control see H03G3/34
• CPC Class Codes: H04W 52/0283 with sequential power up or power down of successive circuit blocks, e.g. switching on the local oscillator before RF or mixer stages
• CPC Class Codes: H04W 88/022 Selective call receivers
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

In a battery powered selective call receiver receiving a synchronous signal, a battery saving method extends battery life by optimizing the amount of time the receiver circuit is activated when searching for the signal after previously acquiring synchronization. The battery saving method allows for turning the selective call receiver on without activating the receiver circuit. The receiver circuit is activated at a time later than the energization of the selective call receiver, where the time of activation of the receiver circuit is determined in response to the time passed since synchronization was last acquired and the system signal stability.

Claims

1. In a selective call receiver including a real time clock, a nonvolatile memory, and a receiver circuit for receiving a synchronous signal having a cycle time and a system signal stability, a method comprising the steps of:

acquiring synchronization at a first time with the synchronous signal;

storing said first time as a stored value in said nonvolatile memory;

de-energizing said selective call receiver;

energizing said selective call receiver at a second time without activating said receiver circuit; and

activating said receiver circuit to search for said synchronous signal at a third time later than said second time, said third time determined in response to said real time clock, said stored value, said cycle time and said system signal stability.

2. The method of claim 1, wherein said synchronous signal comprises bit synchronization signals, each bit synchronization signal having a predetermined time duration, the method further comprising after the step of energizing said selective call receiver the step of calculating said third time, said third time calculated from time elapsed since a time substantially equivalent to said stored value, said cycle time, said system signal stability, and said predetermined time duration.

3. The method of claim 1 further comprising after the step of de-energizing said selective call receiver and before the step of energizing said selective call receiver the steps of:

reacquiring synchronization at a fourth time;

storing said fourth time as said stored value in said nonvolatile memory, thereby overwriting said stored value previously stored therein; and

repeating said steps of reacquiring synchronization and storing said fourth time until said selective call receiver is energized.