Abstract: A method and apparatus reduces current consumption of a mobile communication unit, such as a cellular or mobile telephone that communicates with a base station by disabling a temperature controlled crystal oscillator and a code generator while the mobile communication unit is in a sleep mode of operation, thereby reducing the sleep mode current consumed by the mobile communication unit. Prior to entering sleep mode, the mobile communications unit stores the state of the code generator and disables the temperature controlled crystal oscillator. Upon waking from sleep mode, the mobile communication unit calculates what the state of its code generator would have been if its temperature controlled crystal oscillator had not been disabled, and uses this calculated state to achieve synchronization with a code generator in the base station.

Abstract: An audio automatic gain control (AGC) circuit (301) employs a method (400, 500) and apparatus (300) for mitigating noise in an output signal (307) of the audio AGC circuit (301). The audio AGC circuit (301) or a circuit coupled to the audio AGC circuit, such as a speech encoder (302), determines (405) whether audio information is present in an input signal (137) to the audio AGC circuit (301). When audio information is not present, the audio AGC circuit (301) applies (411) a gain to the input signal (137) that is less than a current gain being applied, thereby mitigating noise in the audio AGC circuits output signal (220) when audio is not present.