Systems and methods are disclosed for low power RF communications, comprising receiving an AM signal using a passive RF receiver circuit, converting the AM signal to a digital output signal using a comparator, receiving the digital output signal from the comparator, determining whether the digital output signal is valid or not using a digital signal processing circuit, and upon detection of a valid digital output signal, enabling an active RF receiver circuit for RF signal processing.

Telecommunication systems using multiple Nyquist zone operations are provided. In one aspect, a telecommunication system can include a first section and a second section. The first section can receive signals from at least one transmitting base station or transmitting terminal device. The received signals have frequencies in multiple frequency bands. The first section can also sample the received signals such that the received signals are aliased. The first section can also combine the aliased signals from the frequency bands into a combined frequency band in a common Nyquist zone. The second section can extract signals from the combined frequency band. The extracted signals are to be transmitted at frequencies in a frequency band from a Nyquist zone that is different than the common Nyquist zone. The second section can also transmit the extracted signals to at least one receiving base station or receiving terminal device. Other embodiments are disclosed.

Systems and methods are disclosed for low power RF communications, comprising receiving an AM signal using a passive RF receiver circuit, converting the AM signal to a digital output signal using a comparator, receiving the digital output signal from the comparator, determining whether the digital output signal is valid or not using a digital signal processing circuit, and upon detection of a valid digital output signal, enabling an active RF receiver circuit for RF signal processing.

A data transmission method for a data transmission system including a first device and a second device is disclosed. The method comprises the steps of transmitting a clock signal to synchronize the first device and the second device; transmitting a mode signal from the first device to the second device, wherein the mode signal indicates a transmission mode between the first device and the second device; and transmitting a serial data between the first device and the second device based on the clock signal, wherein the length of the serial data is determined based on the transmission mode.

Telecommunication systems using multiple Nyquist zone operations are provided. In one aspect, a telecommunication system can include a first section and a second section. The first section can receive signals from at least one transmitting base station or transmitting terminal device. The received signals have frequencies in multiple frequency bands. The first section can also sample the received signals such that the received signals are aliased. The first section can also combine the aliased signals from the frequency bands into a combined frequency band in a common Nyquist zone. The second section can extract signals from the combined frequency band. The extracted signals are to be transmitted at frequencies in a frequency band from a Nyquist zone that is different than the common Nyquist zone. The second section can also transmit the extracted signals to at least one receiving base station or receiving terminal device.

Systems and methods for improved coherent demodulation that account for variation of an effective channel estimation error with transmitted symbols are provided. In one embodiment, a wireless node includes a receiver front-end, a channel estimator, and a soft-value processor. The receiver front-end is adapted to output samples of a received signal. The channel estimator is adapted to estimate a channel between a transmitter of the received signal and the wireless node based on the samples of the received signal. The soft-value processor is adapted to process the samples of the received signal according to a soft-value generation scheme that accounts for variation of an effective channel estimation error with transmitted symbols to thereby provide corresponding soft values. By accounting for the variation of the effective channel estimation error with transmitted symbols, the soft-value processor provides improved performance, particularly in a low Signal-to-Noise Ratio (SNR) scenario.

A demodulation signal generator, coupled to an air-pulse generator comprising a flap pair, includes a resonance circuit. The resonance circuit produces a first demodulation signal and a second demodulation signal. The resonance circuit and the flap pair co-perform a resonance operation, such that the first demodulation signal and the second demodulation signal are generated via the co-performed resonance operation and have opposite polarity. The flap pair performs a differential movement to form an opening to perform a demodulation operation on a modulated air pressure variation.

A method and system for extracting values representative of modulation signal components from a modulated signal, the modulated signal containing a modulation signal, including developing a local clock signal which correlates in time to the modulated signal and includes a number of phase sectors per cycle and converting the modulated signal into a current that is representative of the signal and routing the current to the inverting input of an amplifier and charging one of a plurality of capacitive devices during each phase sector and sequentially connecting the capacitive devices between the output of the amplifier and the inverting input of the amplifier in non-overlapping sequences, the total of sequences being equal to one full cycle of the clock.

A method and system for extracting values representative of modulation signal components from a modulated signal, the modulated signal containing a modulation signal, including developing a local clock signal which correlates in time to the modulated signal and includes a number of phase sectors per cycle and converting the modulated signal into a current that is representative of the signal and routing the current to the inverting input of an amplifier and charging one of a plurality of capacitive devices during each phase sector and sequentially connecting the capacitive devices between the output of the amplifier and the inverting input of the amplifier in non-overlapping sequences, the total of sequences being equal to one full cycle of the clock.

A demodulator is mounted on a wireless power transmitter that conforms to the Qi standard, and demodulates an amplitude modulated signal superimposed on a coil current I.sub.COIL that flows through a primary coil of a transmission antenna, or otherwise on a coil voltage across both ends of the primary coil. Multiple demodulating units are each configured to have respectively different configurations, to operate in parallel, to extract a demodulated component from the coil current I.sub.COIL or otherwise from the coil voltage, and to generate baseband signals as demodulated signals. A signal processing unit employs a baseband signal that is correctly received, from among the multiple baseband signals generated by the multiple demodulating units, based on an error detection result obtained using a checksum.