초록 ▼

A radiotelephone (104) in a radiotelephone system (100) enters a low power sleep mode and times the duration of the sleep mode using a sleep clock generator (205) having a coarse resolution. The radiotelephone synchronizes timing of the radiotelephone to system timing using an oscillator (116) havin

A radiotelephone (104) in a radiotelephone system (100) enters a low power sleep mode and times the duration of the sleep mode using a sleep clock generator (205) having a coarse resolution. The radiotelephone synchronizes timing of the radiotelephone to system timing using an oscillator (116) having a fine resolution. The radiotelephone then exits the low power sleep mode synchronized with system timing.

대표청구항 ▼

[ What is claimed is:] [11.] A radiotelephone configured for operation in a code division multiple access (CDMA) radiotelephone system including a plurality of base stations, transmitting a short pseudorandom noise (PN) sequence including a system timing indicator comprising a PN roll boundary of th

[ What is claimed is:] [11.] A radiotelephone configured for operation in a code division multiple access (CDMA) radiotelephone system including a plurality of base stations, transmitting a short pseudorandom noise (PN) sequence including a system timing indicator comprising a PN roll boundary of the short PN sequence, the radiotelephone comprising:a PN code generator providing a short PN sequence to align with the system timing indicator;a reference oscillator for generating a reference clock signal synchronized to the system timing indicator using the short PN sequence from the PN code generator at a first rate;a sleep clock generator for generating a sleep clock signal;a reference timer for counting periods of the reference clock signal;a sleep timer for counting periods of the sleep clock signal;a controller for determining timing accuracy of the sleep clock generator by relating the periods of the sleep clock signal to the periods of the reference clock signal, the controller determining an offset between the reference clock signal and the sleep clock signal; anda sleep time controller for placing the radiotelephone in a low power sleep mode having a duration based on the timing accuracy of the sleep clock generator, the sleep time controller adjusting the duration by combining timing of the sleep clock signal and the offset.