Abstract: An electronic audio device with a digital audio output channel in which an amplifier output voltage is gradually ramped up and down to avoid causing a popping sound when the device is turned on and off. This is accomplished without employing any additional hardware, by incrementally changing a digital input word applied to a digital audio source, such as a DSP, so as to gradually change the amplifier output voltage between a minimum, such as zero volts, and a DC working voltage. On powering up, the amplifier is only turned on after the digital word is applied, but while it still results in a minimum amplifier output, and on powering down the amplifier is turned off after it's output has been ramped down, but before removing the digital input word. Sources and output channels can also be switched over by powering down, and then powering up, following the same method.

Abstract: An electronic audio device with a digital audio output channel in which an amplifier output voltage is gradually ramped up and down to avoid causing a popping sound when the device is turned on and off. This is accomplished without employing any additional hardware, by incrementally changing a digital input word applied to a digital audio source, such as a DSP, so as to gradually change the amplifier output voltage between a minimum, such as zero volts, and a DC working voltage. On powering up, the amplifier is only turned on after the digital word is applied, but while it still results in a minimum amplifier output, and on powering down the amplifier is turned off after it's output has been ramped down, but before removing the digital input word. Sources and output channels can also be switched over by powering down, and then powering up, following the same method.

Abstract: A temperature-based real time clock calibration system and method for performing the same. The system in one embodiment includes a real time clock calibrated against a reference frequency, a temperature sensor being operative to measure a instantaneous temperature T1, and control circuitry operative to receive and sense the temperature T1. Control logic, preferably implemented in the control circuitry in one embodiment, determines when to recalibrate the real time clock against the reference frequency based on the measured temperature T1. In one embodiment, the reference frequency is generated by a main system clock. The system may be used during sleep mode or another reduced power operating mode of an electronic device.

Abstract: An electronic audio device with a digital audio output channel in which an amplifier output voltage is gradually ramped up and down to avoid causing a popping sound when the device is turned on and off. This is accomplished without employing any additional hardware, by incrementally changing a digital input word applied to a digital audio source, such as a DSP, so as to gradually change the amplifier output voltage between a minimum, such as zero volts, and a DC working voltage. On powering up, the amplifier is only turned on after the digital word is applied, but while it still results in a minimum amplifier output, and on powering down the amplifier is turned off after it's output has been ramped down, but before removing the digital input word. Sources and output channels can also be switched over by powering down, and then powering up, following the same method.

Abstract: Speech recording is effected in a GSM phone handset (100) by storing in a memory (116) speech frames during the presence of speech, one or more SID frames during the absence of speech, and data representative of the duration of the absence of speech. In this way memory (116) does not store silent speech frames, and utilisation of memory space is therefore particularly efficient. In addition, items such as a voice activity detector and a comfort noise estimator, which are already provided in the handset as part of the GSM system, are “re-used” by the invention, thereby making efficient use of already-provided hardware/software.