Abstract: In a wireless power transfer system with multiple receivers, receiver management may be necessary to effectively provide power to the multiple receivers. In one implementation, receiver management includes sweeping or stepping the transmitter resonant and/or operating frequency. In another implementation, receiver management includes receiver self-management, in which the receiver load current duty cycle is controlled to maintain receiver voltage even in the presence of multiple receivers. In another implementation, receiver management includes receiver self-management, in which one or more receivers use a time-sharing heuristic to identify when other receivers are charging and wait to begin receiving a transfer of power until another receiver has stopped receiving a transfer of power.

Abstract: A wireless power transfer system includes: a non-resonant transmitter, or a transmitter with a resonant circuit; and a non-resonant receiver, or a receiver with a resonant circuit. In some implementations, a transmitter with a resonant circuit is operated away from its resonance frequency. In some implementations, a receiver with a resonant circuit is operated away from the transmitter resonance frequency and/or the transmitter operating frequency. In some implementations, the selection of receiver resonance frequency is based on receiver power requirements. Thus, wireless power transfer may be accomplished by operating away from resonance in a quasi-resonant or non-resonant mode, and further may be accomplished using a non-resonant transmitter and/or a non-resonant receiver. Effective power transfer may also be achieved between a transmitter and multiple receivers. A combination of resonant and non-resonant transmitter and receiver(s) may be used for power transfer.

Abstract: A wireless charging system includes a transmitter with tunable reactive components (such as capacitance or inductance). A metric related to power transfer from the transmitter through a coil is used to determine an amount to modify a Parameter. One metric is equal to |Vs|·|Is|·cos(?)·(Vcoil_ref/Vcoil), where |Vs| is magnitude of the power source voltage, |Is| is magnitude of the power source current, ? is phase difference between the power source voltage and power source current, Vcoil_ref is a normalization value, and Vcoil is voltage across the coil. The transmitter can further include a phase tracking and adjustment loop (such as a phase-locked loop).

Abstract: A transmitter includes an alternating current power source with tunable parameters. A tunable parameter may be capacitance, inductance, or frequency. A metric related to power transfer from the transmitter through a coil is used to determine an amount to modify a parameter. One metric is equal to |Vs|·|Is|·cos(?), where |Vs| is magnitude of the power source voltage, |Is| is magnitude of the power source current, and ? is phase difference between the power source voltage and power source current. Another metric is equal to |Vs|·|Is|·cos(?)·(Vcoil_ref/Vcoil), where |Vs| is magnitude of the power source voltage, |Is| is magnitude of the power source current, ? is phase difference between the power source voltage and power source current, Vcoil_ref is a normalization value, and Vcoil is voltage across the coil. The transmitter may further include a phase tracking and adjustment loop; for example, a phase-locked loop (PLL).

Abstract: In a wireless power transfer system with multiple receivers, receiver management may be necessary to effectively provide power to the multiple receivers. In one implementation, receiver management includes sweeping or stepping the transmitter resonant and/or operating frequency. In another implementation, receiver management includes receiver self-management, in which the receiver load current duty cycle is controlled to maintain receiver voltage even in the presence of multiple receivers. In another implementation, receiver management includes receiver self-management, in which one or more receivers use a time-sharing heuristic to identify when other receivers are charging and wait to begin receiving a transfer of power until another receiver has stopped receiving a transfer of power.

Abstract: A wireless power transfer system includes: a non-resonant transmitter, or a transmitter with a resonant circuit; and a non-resonant receiver, or a receiver with a resonant circuit. In some implementations, a transmitter with a resonant circuit is operated away from its resonance frequency. In some implementations, a receiver with a resonant circuit is operated away from the transmitter resonance frequency and/or the transmitter operating frequency. In some implementations, the selection of receiver resonance frequency is based on receiver power requirements. Thus, wireless power transfer may be accomplished by operating away from resonance in a quasi-resonant or non-resonant mode, and further may be accomplished using a non-resonant transmitter and/or a non-resonant receiver. Effective power transfer may also be achieved between a transmitter and multiple receivers. A combination of resonant and non-resonant transmitter and receiver(s) may be used for power transfer.

Abstract: A phase-frequency detection system and method for enhancing performance of the frequency detector in a phase-frequency detection system. Filtering of the frequency detector inputs makes operation of the frequency detector more robust in the presence of intersymbol interference within the incoming data signal and other non-ideal characteristics such as noise and crosstalk.

Abstract: A technique is disclosed for allowing a seamless handover between base stations in a TDMA controller as a telephone handset is transported from one base station's area to another. The disclosed circuitry enables the TDMA controller to assess the quality of the handover before switching to the new base station. When it is determined that a handover operation is to commence, transmissions are made in the original slot time and a handover slot time within the same frame. Also during the same frame, data is received at two separate slot times. Only when it is determined that the data received in the handover slot time contains no transmission errors is the handover completed by then only transmitting on the handover slot transmit time and receiving on the handover slot receive time. In the preferred embodiment, it is determined whether the received data contains no transmission errors by detecting the CRC codes, the signal strength, and the existence of any invalid words.

Abstract: An audio error mitigation technique for a TDMA communication system is disclosed. An audio error is assumed if any one of the following criteria is met: a detection of a CRC error in the control data or audio data within a slot; the received signal strength is below a certain threshold; or, the detection of an invalid code word, such as an all zero nibble. If either of the criteria is met, and the slot contains audio data, an error mitigation routine is performed. In one embodiment, the error mitigation routine replaces the faulty burst with the previous non-faulty burst. In another mitigation routine, any dv/dt spikes in the faulty burst are detected and smoothed by averaging nearby samples. In one embodiment, both mitigation routines are selectable in the TDMA system.

Abstract: The preferred embodiment improves the modulation accuracy of a communication system having a surface acoustic wave (SAW) device filtering a modulated signal. An equalizer filter is used to predistort the signal to be filtered so as to equalize the SAW filter response. In the preferred approach, the equalizer also provides baseband filtering. In this particular embodiment, the original baseband filter impulse response is convolved with the inverse of the actual SAW filter impulse response. The resulting values provide the coefficients for a digital filter (i.e., a modified baseband filter) forming part of a DQPSK modem. When the signal filtered by the modified baseband filter is then up-converted and filtered by the SAW filter, the predistortion caused by the modified baseband filter equalizes the SAW filter distortion, and only the modulation errors of the original baseband filter occur.

Abstract: A synchronization method for synchronizing a plurality of base stations in a TDMA communication system is disclosed. The synchronization topology may be via dedicated hardwire, via any DSL from the PSTN, or via an ad-hoc RF synchronization technique. Slots containing data are arranged in frames and these frames are transmitted to the base stations, and received from the base stations, by wireless telephone handsets. Each of the slots in a frame have a guard field comprising a plurality of guard bits. The base stations derive frame sync pulses via the received Unique Word correlation detect. These derived frame sync pulses are ultimately synchronized with frame sync signals received from the master base station.