Abstract: A bandwidth-adjustable filter includes an operational amplifier, a first resistor, a first capacitor and a first resistor ladder circuit. The operational amplifier has a negative input terminal and a positive input terminal. The first resistor is coupled to one of the input terminals of the operational amplifier. The first capacitor is coupled to the first resistor. The first resistor ladder circuit is coupled in parallel to the first resistor for changing the resistance of the first resistor so as to adjust the bandwidth of the filter.

Abstract: A slave device that complies with Bluetooth communication protocol includes a communication module, a memory and a RF output module. The communication module can be operated to generate a driving signal. The memory stores an access code that complies with Bluetooth communication protocol and is electrically connected to the communication module. The memory is configured to determine whether or not to output the access code according to the driving signal output by the communication module. The RF output module is electrically connected to the memory so as to receive and output the access code.

Abstract: A bandwidth-adjustable filter includes an operational amplifier, a first resistor, a first capacitor and a first resistor ladder circuit. The operational amplifier has a negative input terminal and a positive input terminal The first resistor is coupled to one of the input terminals of the operational amplifier. The first capacitor is coupled to the first resistor. The first resistor ladder circuit is coupled in parallel to the first resistor for changing the resistance of the first resistor so as to adjust the bandwidth of the filter.

Abstract: A center frequency adjustment device for a communications receiver includes an A/D converter coupled to an analog filter in the communications receiver for converting an output signal of the analog filter to a digital signal, a carrier frequency offset estimator coupled to the A/D converter for estimating a carrier frequency offset of the communications receiver according to the digital signal, and a control circuit coupled to the analog filter and the carrier frequency offset estimator for adjusting a center frequency of the analog filter according to the carrier frequency offset.

Abstract: The invention discloses a message playback apparatus. The message playback apparatus includes a receiving module, an analysis module, a storage module, and an output module. The receiving module is used for receiving a plurality of external messages. The analysis module is used for selecting at least one target message from the external messages. The storage module is used for storing the at least one target message. The output module is used for reading out the at least one target message and transforming the at least one target message to an output signal.

Abstract: The invention discloses a simulating apparatus of facial expression comprising a casing and a facial expression module, wherein the casing has a transparent surface, and the facial expression module is configured in the casing and behind the transparent surface. The facial expression module comprises a plurality of light guiding components, a plurality of light sources, and a control module. The lighting guiding devices is used for making up a plurality of facial patterns; the light sources are configured at one side of the light guiding components, and the light, emitted by the light sources, can be transmitted through the light guiding components to bring the facial patterns a lighting effect; the control module is electrically connected to the light sources for selectively controlling the light sources to emit light.

Abstract: A low drop-out (LDO) voltage regulator with efficient frequency compensation is disclosed. The LDO voltage regulator includes an error amplifier, a transmission element, a voltage divider and a pole control unit. The error amplifier generates a control signal according to a reference voltage and a feedback voltage. The transmission element is coupled to the error amplifier, and adjusts an input voltage to generate an output voltage according to the control signal. The voltage divider is coupled to the transmission element, and performs a voltage division operation on the output voltage to generate the feedback voltage. The pole control unit is coupled to the transmission element, and provides and adjusts an output capacitor of the LDO voltage regulator to fix a frequency of a pole according to variation of an output impedance of the transmission element, so as to maintain loop stability.

Abstract: A method and device for calibrating in-phase and quadrature-phase (IQ) mismatch. The device is used in a direct down-conversion circuit of a communication system. The device has a first mixer for mixing an RF signal with a first carrier signal, so as to generate an in-phase analog signal; a second mixer for mixing the RF signal with a second carrier signal, so as to generate a quadrature-phase analog signal; an operation unit for executing a Least Mean Square (LMS) algorithm and thereby generating a compensation signal according to the in-phase analog signal and the quadrature-phase analog signal; and a calibration unit for compensating the in-phase analog signal and the quadrature-phase analog signal according to the compensation signal, so as to calibrate the IQ mismatch between the in-phase analog signal and the quadrature-phase analog signal.

Abstract: The present invention provides an apparatus for enhancing Q factor of an inductor. The apparatus includes a negative resistance generator coupled to the inductor for providing a negative resistance, and a bias circuit coupled to the negative resistance generator for biasing the negative resistance generator.

Abstract: A low noise amplifier for operating in response to different gain modes is disclosed. The low noise amplifier includes a voltage adjusting circuit, which provides a first bias voltage at a first gain mode and provides a second bias voltage at a second gain mode, where the second bias voltage is different from the first bias voltage; and an amplifying circuit coupled to the voltage adjusting circuit, for providing a first transfer characteristic according to the first bias voltage during the first gain mode in order to amplify an input signal to generate an output signal, and for providing a second transfer characteristic according to the second bias voltage during the second gain mode in order to amplify the input signal to generate the output signal.

Abstract: A multi-band receiver is disclosed. The multi-band receiver includes a low-noise amplifier (LNA) and a mixer. The LNA includes a switched receiving circuit, a loading circuit, and a switching circuit. The switched receiving circuit has a first receiving circuit for receiving a first signal corresponding to a first frequency, and a second receiving circuit for receiving a second signal corresponding to a second frequency. The loading circuit is utilized for providing a specific load to the switched receiving circuit. The switching circuit is used for controlling whether the first signal or the second signal is transferred to the loading circuit. The mixer is coupled to the low-noise amplifier for receiving an output signal generated from the LNA and for down-converting the output signal.

Abstract: The invention discloses a lens set adapted to a webcam. The webcam has a first focal length. The lens set according to the invention includes a first lens and a second lens. The first lens is used to refract a light to generate a refracted light substantially parallel to an optical axis of the first lens. The second lens is used to focus the refracted light and project it to the webcam. The combination of the lens set and the webcam has a second focal length smaller than the first focal length.

Abstract: A transistor resistor and an associated method are provided to improve the resistance linearity of the transistor resistor. The transistor resistor includes a transistor operating in the resistive region, where the drain and source of the transistor receive an input signal and an output signal respectively. The transistor resistor also includes a compensating circuit for generating a compensating signal according to the input signal. The compensating signal is provided to the gate of the transistor such that the voltage difference between the gate and source of the transistor approximates to a constant.

Abstract: A low noise amplifier for operating in response to different gain modes is disclosed. The low noise amplifier includes a voltage adjusting circuit, which provides a first bias voltage at a first gain mode and provides a second bias voltage at a second gain mode, where the second bias voltage is different from the first bias voltage; and an amplifying circuit coupled to the voltage adjusting circuit, for providing a first transfer characteristic according to the first bias voltage during the first gain mode in order to amplify an input signal to generate an output signal, and for providing a second transfer characteristic according to the second bias voltage during the second gain mode in order to amplify the input signal to generate the output signal.

Abstract: Disclosed is a mixer comprising: a switching circuit, having a first pair of differential signal nodes and a second pair of differential signal nodes, for switching according to a local oscillation signal; an amplifying stage circuit, for receiving an input signal and amplifying the input signal; a load circuit, for serving as the loading of the mixer and generating an output signal of the mixer; a common-mode feedback circuit, for receiving the output signal and generating a feedback signal according to the output signal; a first current source, for receiving the feedback signal and generating a first current according to the feedback signal; and a second current source, for receiving the feedback signal and generating a second current according to the feedback signal.

Abstract: A mixer for the elimination of harmonic mixing in signal transmission is presented. The mixer incorporates a mixing unit and a modulation output unit. The mixing unit receives an input signal and a modulated signal, and outputs an output signal after signal mixing. The modulation output unit is for the generation of modulated signals, which are usually pulse-width modulated. The modulation output unit includes a delta sigma modulator and a digital domain code generator. The delta sigma modulator outputs the modulated signal responding to the received oscillation signal and digital domain code, the digital domain code generator generates the digital domain code in order to provide digital domain sine wave code for the use of the delta sigma modulator. The oscillation signal may be a signal of constant hi-frequency, or a signal that has a frequency larger or equal to that of the input signal by an integer factor.

Abstract: An apparatus and a method for calibrating IQ mismatch to ensure that an in-phase oscillating signal and a quadrature-phase oscillating signal are orthogonal to each other. The apparatus includes a mixer for mixing the in-phase oscillating signal with the quadrature-phase oscillating signal to generate an output signal, a control module for determining a control signal according to a low-frequency component of the output signal, and a phase adjusting module for adjusting the phase of a specific oscillating signal to ensure that the in-phase oscillating signal and the quadrature-phase oscillating signal are orthogonal to each other. The specific oscillating signal may be the in-phase or the quadrature-phase oscillating signal. The apparatus does not require a digital signal-processing unit to perform complex calculations nor requires additional oscillating sources for calibration. Hence, the circuit design is much simplified, and the consumption of system resources is significantly reduced.

Abstract: The present invention provides an apparatus for enhancing Q factor of an inductor. The apparatus includes a negative resistance generator coupled to the inductor for providing a negative resistance, and a bias circuit coupled to the negative resistance generator for biasing the negative resistance generator.

Abstract: Disclosed herein is a method of fabricating a device having a microstructure. The method includes forming a connector on a semiconductor substrate, coating the connector with a polymer layer, and immersing the semiconductor substrate and the coated connector in an etchant solution to form the microstructure from the semiconductor substrate and to release the coated connector and the microstructure from the semiconductor substrate such that the microstructure remains coupled to a further element of the device via the coated connector. In some cases, the microstructure is defined by forming an etch stop in the semiconductor substrate, and the microstructure and the semiconductor substrate are coated with a polymer layer, which may then be selectively patterned. The microstructure may then be released from the semiconductor substrate in accordance with the etch stop.