Abstract: A circuit used for indicating process corner and extreme temperature mainly comprises a proportional to absolute temperature (PTAT) current source, a negative to absolute temperature (NTAT) current source, a constant to absolute temperature (CTAT) current source, a corner detector, a poly detector, an extreme temperature detector. The circuit can improve more power consumption without trade-off. In debug phase, the circuit can read out a state of a suspect sample and can run simulation check quickly to identify the real problem. In production phase, the circuit can easily read out at a processing station. In the mean time, a large quantity of data can be easily collected and analyzed.

Abstract: The present invention provides a dual mode sigma delta analog to digital converter (ADC), which only in one hardware implementation, used for low IF and near zero IF receiver. The dual mode sigma delta ADC comprises a first switched-capacitor integrator; a second switched-capacitor integrator; a quantizer; a feedback circuit and a mode device. By switching the mode device on or off, one could easily change the configuration of the disclosed ADC to decide the receiving signal falling in low-IF or near zero IF.

Abstract: The present invention discloses a circuit with three-stage of power-on sequence used for suppressing the pop noise in audio system. It mainly comprises a first resistor (R1); a capacitor (Cout); a first switch (SW1); a second switch (SW2); a soft start device; a first feedback amplifier; and a second feedback amplifier. By using the three-stage of power-on sequence, the present invention can effectively suppress the pop noise when the audio driver is power on.

Abstract: A radio communication transceiver achieving impedance matching when the transceiver operates in an output state and an input state respectively in a manner of switching a switch includes a transformer, a switch, a power amplifier (PA), and a low noise amplifier (LNA). The transformer has a primary winding including a first endpoint and a second endpoint and a secondary winding including a first endpoint and a second endpoint. The switch has a gate, a drain, and a source, wherein the gate receives a control signal, the drain is connected to the second endpoint of the primary winding, and the source is connected to the second endpoint of the secondary winding. The PA has an output terminal connected to the first endpoint of the primary winding of the transformer. The LNA has an input terminal connected to the second endpoint of the primary winding of the transformer.

Abstract: A speech detection method is presented, which includes the following steps. A first voice captured device samples a first signal and a second voice captured device samples a second signal. The first voice captured device is closer to a speech signal source than the second voice captured device. A first energy corresponding to the first signal within an interval is calculated, a second energy corresponding to the second signal within the interval is calculated, and a first ratio is calculated according to the first energy and the second energy. The first ratio is transformed into a second ratio. A threshold value is set. It is determined whether the speech signal source is detected by comparing the second ratio and the threshold value.

Abstract: The present invention discloses a method and apparatus to provide, effectively and robustly, a phase reference in phase-domain for digital phase-modulated signals. Not only the first-order but also higher order PLLs are delineated for robust and fast tracking of frequency errors and time-varying frequency errors between the transmitter and the receiver. This invention can be applied to any phase-modulated signal such as PSK, DPSK, ?/4-DPSK, and CPM. The decoders with this invention can achieve close to the performance of coherent detection. Reference [1] D. Divsalar and M. K. Simon, “Multiple-symbols differential detection of MPSK,” IEEE Trans. Commun., vol. 38, pp. 300-308, March 1990. [2] Specification of the Bluetooth System, 2.0+EDR, 4 Nov. 2004.

Abstract: A receiver capable of decoding a symbol based on information on a previous symbol, the symbol and a next symbol in a Gaussian frequency shift keying (GFSK) communication system is provided.

Abstract: The present invention discloses an effective apparatus and method to measure the received signal quality for a GFSK modulated signal with (or without) an unknown modulation index. The signal quality measurements are based on the decoded (unknown or known) bits and the trellis of the frequency discriminator output. This trellis is pre-calibrated with a reference Rx. The transmitted modulation index is also accurately estimated in this invention.

Abstract: The present invention discloses a circuit with ESD protection and high voltage conversion for a switching regulator. It mainly comprises a non-overlap circuit, a power P-type MOS device, a parasitic diode, a digital logic AND gate, a pair of resistance and capacitance, a power N-type MOS device, an ESD N-type MOS device, a Lx pin and an ESD protection cell. The present invention can effectively decrease the on-resistance of MOS device and then improve the circuit efficiency.

Abstract: An adaptive receiver for receiving a radio frequency (RF) signal and converting the RF signal at an RF frequency FRF toward a low intermediate frequency FIF is disclosed. The adaptive receiver comprises a pair of band pass filters with a nominal center frequency Fc equal to FIF, a look-up table (LUT) configured to estimate a frequency offset ?f, representing the center frequency of the band pass filter due to an operating temperature change and/or process variation, a micro controller configured to estimate the operating center frequency of the band pass filter (=FIF+?f with the frequency offset included) and use this new center frequency as the adaptive intermediate frequency FIF,AD, and a local oscillator generates oscillating signals at a frequency FLO equal to FRF minus FIF,AD. A temperature sensing device may also be included in this adaptive receiver.

Abstract: The present invention discloses a generating method for short training field in IEEE 802.11n communication systems, mainly comprising the steps of: storing only a first set of time-domain HT-STF sequences in the memory; and deriving a second set of the time-domain HT-STF sequences from the first set of the time-domain HT-STF sequences. The first set of time-domain HT-STF sequences is the time-domain HT-STF sequences either for lower 20 MHz of 40 MHz BW or upper 20 MHz of 40 MHz BW. According to the invention, it is shown that only one set of time-domain HT-STF sequence needs to be stored in the memory. The other three sets of time-domain HT-STF sequence can be generated easily from simple calculation. Therefore, the saving in buffer size to implement all four configurations is significant.

Abstract: The present invention discloses a two-step VCO calibration method. The two-step VCO calibration method, comprising power-on calibration, used to provide a coarse VCO tuning; real-time calibration, used to provide a fine VCO tuning according to the loaded result of said power-on calibration. The two-step VCO calibration method according to the present invention can cover all the variation of process and temperature and gain the advantages of shorter calibration time, smaller gain of VCO, pretty smaller size of passive loop filter and less operating power consumption.

Abstract: System performance in wireless communication is improved by increasing diversity in time, space and frequency. Information to be transmitted is processed by a convolution encoder to produce encoded bits. The encoded bits are interleaved and mapped to subcarriers. Symbols are created from the subcarriers and the symbols are transmitted so as to increase diversity in time, space and frequency. Circulation transmission in addition to interleaving is used to increase diversity. For example, circulation transmission can be symbol based or subcarrier based.