Abstract: A processor is configured to transition in and out of a low-power state at a first rate and to operate in a first mode or a second mode. In a particular method, the processor while coupled to a coder/decoder (CODEC) retrieves audio feature data from a buffer after transitioning out of the low-power state. The CODEC is configured to operate at a second rate in the first mode and at a third rate in the second mode, the second rate and the third rate each greater than the first rate. The audio feature data indicates features of audio data received during the low-power state of the processor. A ratio of CODEC activity to processor activity in the second mode is less than the ratio in the first mode.

Abstract: An interface unit of a mobile device coupled to an auxiliary device, the interface unit including: a first plurality of switches configured for power delivery to the auxiliary device; at least one isolation unit coupled to the first plurality of switches, the at least one isolation unit configured to isolate the multiple signals and to prevent disruption of data communication between the mobile device and the auxiliary device; and a second plurality of switches configured for the data communication between the mobile device and the auxiliary device, the second plurality of switches configured to bypass the at least one isolation unit.

Abstract: An interface unit of a mobile device coupled to an auxiliary device, the interface unit including: a first plurality of switches configured for power delivery to the auxiliary device; at least one isolation unit coupled to the first plurality of switches, the at least one isolation unit configured to isolate the multiple signals and to prevent disruption of data communication between the mobile device and the auxiliary device; and a second plurality of switches configured for the data communication between the mobile device and the auxiliary device, the second plurality of switches configured to bypass the at least one isolation unit.

Abstract: A particular apparatus includes a first buffer that is configured to store multiple audio data samples and a second buffer that is configured to store the multiple audio data samples. The first buffer is coupled to a first processor that is configured to analyze audio data samples to detect a keyword. The second buffer is coupled to a second processor that is configured to initialize a speech recognition engine (SRE) based on the multiple audio data samples. The first buffer has less storage capacity that the second buffer.

Abstract: A particular apparatus includes a coder/decoder (CODEC) including a first processor and a first buffer. The first processor is configured to analyze audio data samples to detect a keyword. The CODEC is configured to store a set of audio data samples at the first buffer. The apparatus also includes an application processor configured to receive the set of audio data samples from the CODEC via a bus and configured to initialize a speech recognition engine (SRE) based on the set of audio data samples. The application processor is configured to initialize the bus based on an indication from the CODEC that the keyword is detected.

Abstract: An apparatus includes an operational amplifier and a plurality of capacitors coupled to an input terminal of the operational amplifier and configured to be selectively coupled to receive one of an input voltage signal and an output voltage signal of the operational amplifier.

Abstract: A particular apparatus includes a coder/decoder (CODEC) including a first processor and a first buffer. The first processor is configured to analyze audio data samples to detect a keyword. The CODEC is configured to store a set of audio data samples at the first buffer. The apparatus also includes an application processor configured to receive the set of audio data samples from the CODEC via a bus and configured to initialize a speech recognition engine (SRE) based on the set of audio data samples. The application processor is configured to initialize the bus based on an indication from the CODEC that the keyword is detected.

Abstract: An apparatus includes an operational amplifier and a plurality of capacitors coupled to an input terminal of the operational amplifier and configured to be selectively coupled to receive one of an input voltage signal and an output voltage signal of the operational amplifier.

Abstract: A particular method includes transitioning out of a low-power state at a processor. The method also includes retrieving audio feature data from a buffer after transitioning out of the low-power state. The audio feature data indicates features of audio data received during the low-power state of the processor.

Abstract: A tuner uses a bank of tracking filters to preselect a channel to be received. Each tracking filter covers a range of frequencies. The tracking filters are tunable in frequency using switched capacitors and are tunable in gain by using switched resistors. The switched resistors can be controlled by an automatic gain control circuit that monitors the selected signal and adjust the tracking filter gain to achieve a desired signal level. A switch directs the received signal or signal from a test tone generator into the tracking filters. The test tone, generated by a frequency agile circuit, can be used to calibrate the filters, both in frequency and gain.

Abstract: A tunable duplexer using voltage-controlled varactors is presented. The center frequency, the pass band, and the stop band are each tunable to meet system requirements. A calibration circuit driving digital to analog converters produces the necessary voltages used in the resonant circuits. The tunable duplexer can be fabricated on a single silicon chip. On-chip transformers can be used to reduce the voltage level of signals in the filters to improve the linearity of the duplexer.

Abstract: Techniques are disclosed for compensating for second-order distortion in a wireless communication device. In a zero-intermediate frequency (IF) or low-IF architecture, IM2 distortion generated by the mixer (20) results in undesirable distortion levels in the baseband output signal. A compensation circuit (104) provides a measure of the IM2 distortion current independent of the radio frequency (RF) pathway to generate an IM2 calibration current. The IM2 calibration current is combined with the baseband output signal to thereby eliminate the IM2 currents generated within the RF pathway. In one embodiment, the calibration is provided at the factory during final testing. In alternative embodiment, additional circuitry (156, 158) may be added to the wireless communication device to provide a pathway between the transmitter (150) and the receiver (146). The transmitter signal is provided to the receiver to permit automatic calibration of the unit.

Abstract: A tunable duplexer using voltage-controlled varactors is presented. The center frequency, the pass band, and the stop band are each tunable to meet system requirements. A calibration circuit driving digital to analog converters produces the necessary voltages used in the resonant circuits. The tunable duplexer can be fabricated on a single silicon chip. On-chip transformers can be used to reduce the voltage level of signals in the filters to improve the linearity of the duplexer.

Abstract: A tunable duplexer using voltage-controlled varactors is presented. The center frequency, the pass band, and the stop band are each tunable to meet system requirements. A calibration circuit driving digital to analog converters produces the necessary voltages used in the resonant circuits. The tunable duplexer can be fabricated on a single silicon chip. On-chip transformers can be used to reduce the voltage level of signals in the filters to improve the linearity of the duplexer.

Abstract: Techniques are disclosed for compensating for second-order distortion in a wireless communication device. In a zero-intermediate frequency (IF) or low-IF architecture, IM2 distortion generated by the mixer (20) results in undesirable distortion levels in the baseband output signal. A compensation circuit (104) provides a measure of the IM2 distortion current independent of the radio frequency (RF) pathway to generate an IM2 calibration current. The IM2 calibration current is combined with the baseband output signal to thereby eliminate the IM2 currents generated within the RF pathway. In one embodiment, the calibration is provided at the factory during final testing. In alternative embodiment, additional circuitry (156, 158) may be added to the wireless communication device to provide a pathway between the transmitter (150) and the receiver (146). The transmitter signal is provided to the receiver to permit automatic calibration of the unit.

Abstract: In-phase (I) and quadrature-phase (Q) signals are corrected for both amplitude and phase imbalances by passing the I and Q signals successively through a first amplitude correction stage, a sum-difference stage, and a second amplitude correction stage. The first amplitude correction stage balances the signal levels of the I and Q signals. The sum-difference stage produce a sum of the input I and Q signals, and a difference of the input I and Q signals, resulting in ideal quadrature in the outputs produced. The second amplitude correction stage corrects the amplitude differences from the sum-difference stage. Circuit configurations are used that minimize errors produced by the signal processing stages.

Abstract: In-phase (I) and quadrature-phase (Q) signals are corrected for both amplitude and phase imbalances by passing the I and Q signals successively through a first amplitude correction stage, a sum-difference stage, and a second amplitude correction stage. The first amplitude correction stage balances the signal levels of the I and Q signals. The sum-difference stage produce a sum of the input I and Q signals, and a difference of the input I and Q signals, resulting in ideal quadrature in the outputs produced. The second amplitude correction stage corrects the amplitude differences from the sum-difference stage. Circuit configurations are used that minimize errors produced by the signal processing stages.

Abstract: The present invention reduces distortion in variable capacitance devices by connecting a circuit to the variable capacitance devices that has low impedance at predetermined frequencies to suppress those frequencies and also suppress harmonics and mixing products resulting from mixing of various frequencies.

Abstract: Tuners with high input impedance are connected to a common radio frequency (RF) signal source. A termination load external to the tuners provides matched impedance loading for the transmission line or cable driving the tuners. Alternatively, the termination load can be located inside one tuner with a switch to enable or disable the load. All tuners receive the same signal and no signal degradation is caused when connecting multiple tuners. The multiple tuner connection is useful in television signal receiving devices that receive more than one independent channel, such as digital video recorders or picture-in-picture television receivers.

Abstract: Techniques for processing incoming signals conforming to a plurality of standards or communication formats with a single baseband receive section are disclosed. In one aspect, a plurality of analog processing components are adjusted in response to a format select signal, set according to one of a plurality of supported formats or standards. In another aspect, the operating mode of an A/D converter is tuned in response to the format select signal. In yet another aspect, the response characteristics of a jammer filter are tuned in response to the format select signal. In yet another aspect, the adjustment of the plurality of analog processing components is carried out by varying the frequency of a sample clock in response to the format select signal. Various other aspects are also presented. These aspects have the benefit of allowing a single baseband receive section to be deployed to process analog signals conforming to a plurality of communications standards or formats, in a power and area efficient manner.