Abstract: This invention describes a programmable, digital implementation to shift an arbitrary frequency, or various frequencies in various communication systems of the original signal in the frequency domain. The correspondent phase accumulation to perform the desired frequency shift per sampling instant is perfectly tracked by counting up or down a simple integer. Several arbitrary frequency shifters with different mathematical models are provided. The correspondent implementations with Look-Up-Tables (LUT) are derived for high-speed implementations without further calculations of the values of the sine and cosine functions every sampling instant. Furthermore, a simple shift-and-add phase rotation is described to replace the four required real multiplications. If the original complex signal contains only one-bit each from real part and imaginary part, a surprisingly simple implementation is derived and disclosed for the overall arbitrary frequency shift operation.

Abstract: A power on reset signal generating apparatus is provided. The power on reset signal generating apparatus includes a trigger capacitor, a reference current supplying circuit, and a current regulator. One end of the trigger capacitor is coupled to a ground voltage, and the other end of the trigger capacitor generates a power on reset signal. The reference current supplying circuit is coupled to a signal generating end. The current regulator is coupled to the signal generating end, and the signal generating end draws a splitting current to adjust the value of the current received by the trigger capacitor.

Abstract: The present invention discloses an effective apparatus and method to measure the received signal quality for digital communication systems by measuring error vector measurement (EVM) with embedded EVM measurement block in receivers. The distinction of the present invention is that the EVMSIG and the EVMDATA are measured in the receiver for the SIGNAL fields and DATA fields, respectively. EVMSIG is a good indicator for one spatial stream and EVMDATA is a good indicator for current multiple streams. The receiver determines the optimum number of spatial data streams for feedback to the transmitter based on the combinations of EVMSIG and EVMDATA with or without other algorithms such as analysis on periodically requested sounding packet. The receiver also determines the optimum modulation and coding schemes for feedback based on the EVM measurements.

Abstract: The invention of a method and an apparatus for reception of long transmission range Bluetooth signals impaired by multipath are disclosed. The new reception method and apparatus proposed allows to increase the transmission range for data transmission in Bluetooth. The invention proposes the use of a new FDE adapted to SC transmission without a GI or CP. The proposed FDE very successfully mitigates ISI while being very implementation-friendly.

Abstract: A hybrid structure circuit for the cancellation of both Type-I and Type-II DC offsets. It comprises a static compensator in conjunction with a servo-loop feedback amplifier to suppress the undesired DC components present along the path of the base band after the direct conversion mixer. Two mixers are used to down convert a received RF signal directly to a base band signal with two components: in-phase and quadrature-phase. Both in-phase and quadrature-phase branches employ the same circuitry for DC offset cancellation. Miller effect is also utilized in the structure in order to implement the circuit on-chip.

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: A power saving method of a bi-directional communication wireless peripheral device includes providing a wireless communication protocol between a host and the bi-directional communication wireless peripheral device; establishing a bi-directional communication wireless link between the host and the bi-directional communication wireless peripheral device through the wireless communication protocol; and enter a power off mode when the bi-directional communication wireless link does not exist.

Abstract: A method for enhancing the Bluetooth transmission speed and robustness of an emitting end and a receiving end is provided. The method is utilized in a system having an emitting end and a receiving end, wherein at least one of the emitting and receiving ends is provided with BlueSPEED-PSK or BlueSPEED-DELTA-PSK (adapted Gray coded D16PSK) modulation with optional FEC.

Abstract: A method and device for computing the multiplicative inverse of element x in Galois field GF(p2m) is proposed. In particular, when p is a prime number and m is an integer, the inverse may be constructed based on the observation that xpm+1 is en element in sub-field GF(pm) and the inverse of xpm+1 can be carried out in the sub-field. The inverse of X may be obtained by multiplying x?1=(xpm+1)?1 by xpm.

Abstract: System performance in wireless communication is improved by increasing diversity in time, space and frequency. In OFDM-based MIMO systems in which the number of antennas M is greater then the number of simultaneously transmitted OFDM symbols N, circulation transmissions according to the present invention improve signal diversity. In symbol-based circulation transmission, N antennas are chosen from the M available antennas to transmit the N OFDM symbols. In subcarrier-based circulation transmission, M output OFDM symbols are composed from the QAM-mappled samples of the N input OFDM symbols. These M output OFDM symbols are then transmitted from the M antennas simultaneously.

Abstract: The present invention discloses an effective apparatus and method to measure the received signal quality for digital communication systems by measuring error vector measurement (EVM) with embedded EVM measurement block in receivers. The distinction of the present invention is that the EVMSIG and the EVMDATA are measured in the receiver for the SIGNAL fields and DATA fields, respectively. EVMSIG is a good indicator for one spatial stream and EVMDATA is a good indicator for current multiple streams. The receiver determines the optimum number of spatial data streams for feedback to the transmitter based on the combinations of EVMSIG and EVMDATA with or without other algorithms such as analysis on periodically requested sounding packet. The receiver also determines the optimum modulation and coding schemes for feedback based on the EVM measurements.

Abstract: The present invention discloses an antenna diversity switch, used for receiving and transmitting RF signals for dual-mode co-existence wireless communication system. The antenna diversity switch comprises a first transmitting port; a second transmitting port; a receiving port; a first control unit, electrically connected between the first transmitting port and a first antenna; a second control unit, electrically connected between the first transmitting port and a second antenna; a third control unit, electrically connected between the second transmitting port and the first antenna; a forth control unit, electrically connected between the second transmitting port and the second antenna; a fifth control unit, electrically connected between the receiving port and the first antenna; a sixth control unit, electrically connected between the receiving port and the second antenna. The antenna diversity switch according to the present invention meets the requirement of IEEE 802.

Abstract: A communication system may include an equalizing device for DC-offset mitigation. The system includes: an input analog-to-digital converter configured to receive an input signal and produce a digital signal from the input signal; and a DC-offset estimation device coupled with the input analog-to-digital converter. The DC-offset estimation device is configured to produce a quantized DC-offset estimate from the digital signal. And the input analog-to-digital converter is configured to receive the quantized DC-offset estimate and to adjust a DC offset of the digital signal.

Abstract: A charge control system for lithium battery using pulse width modulation is provided, and it detects the existing voltage of the charging lithium battery by a voltage detector and passes this voltage value to a microprocessor preset in the hand-held apparatus. Thus, the microprocessor can decide the applicable charge stage and confirm the status of the charging battery depending on the different Voltage values in real time. Next, the microprocessor controls a control unit by a pulse width modulation signal to modulate the power-source, which comes from an adaptor, as a constant current or a constant voltage to charge the battery. Accordingly, the charge process is completed by repeating the voltage detection and the duty cycle modulation of the control unit.

Abstract: The present invention discloses a dual-band RF transceiver. The transceiver comprises a first module, used as the RF front-end of the dual-band transceiver and used for receiving and transmitting a first RF signal and a second RF signal; a second module, electrically connected to the first module, used as the IF IQ modulator/demodulator of the dual-band RF transceiver; a third module, electrically connected to the first and the second modules, used as the tripe-band phase-locked frequency synthesizer of the dual-band RF transceiver and used for providing a first local oscillating signal and a second local oscillating signal to the first module, and a third local oscillating signal to the second module. The dual-band RF transceiver according to the present invention realizes the dual-band triple-mode operation of IEEE802.11 a/b/g by a single dual-band RF module, and therefore the circuit size, power dissipation, component count, and cost can be dramatically reduced.

Abstract: A communication network switch system, comprising: a first phone number database accessed by a cable telephony network service provider; a second phone number database accessed by an internet service provider; a plurality of communication network switch devices conducting audio and/or data communications therebetween through a cable telephony network or an internet, the communication network switch devices switching audio and/or data communications between the cable telephony network or an internet telephony system and a short-range wireless communication network; and a plurality of mobile communication devices each of which including a long-range wireless network system transceiver module, a short-range wireless network system transceiver module and a switch device module.

Abstract: A power saving method of a bi-directional communication wireless peripheral device includes providing a wireless communication protocol between a host and the bi-directional communication wireless peripheral device; establishing a bi-directional communication wireless link between the host and the bi-directional communication wireless peripheral device through the wireless communication protocol; and enter a power off mode when the bi-directional communication wireless link does not exist.

Abstract: An operation method of a wireless pointing input apparatus is provided. The operation method includes following steps. The displacement vector of the wireless pointing input apparatus is detected with a resolution. The displacement vector of the wireless pointing input apparatus is transmitted to a host in a wireless way every a time interval. The time interval is decreased correspondingly if the resolution is increased. Or, the time interval is increased correspondingly if the resolution is decreased.

Abstract: The present invention discloses a dual-band active filter having filtering response and positive pass-band gain. The dual-band active filter includes an input match unit for gain match of the dual-band active filter and for having a band-pass filtering response; a first gain stage electrically connected to the first input match unit for providing the flat gain of the dual-band active filter; an inter-stage unit electrically connected to the first gain stage for matching gain and for having a band-stop filter response; a second gain stage electrically connected to the inter stage unit for providing the flat gain of the dual-band active filter; and an output unit electrically connected to the second gain stage for matching the dual-band active filter and for having a low-pass filtering response.

Abstract: An apparatus of sequentially decoding CCK codes includes a series of received signal registers used to respectively temporarily save the received signals, a phase selector used to select one numeral from 1, ?1, j or ?j respectively for CCK code of each chip to multiple with the signal register, a series of adders used to sequentially complete adding operation, a series of sequential operation registers used to save values obtained from the sequential selecting operation of the phase selectors and the sequential adding operation of the adders, and a comparing device used to select a maximal value from those saved in the operation registers. The comparing device includes a comparator and a maximum register. According to the invention, the data processing speeds up while the hardware complexity is reduced.