Patent application number | Description | Published |
20140080412 | ADAPTIVE SLICER FOR A DISCRETE LEVEL AMPLITUDE MODULATION RECEIVER - In a wireless communication system, an initiator, such as a card reader, can communicate with a target, such as a smart card or other device emulating a smart card, by amplitude modulating a radio frequency signal. In a receiver, levels of samples of a digital baseband signal of the amplitude modulated signal can vary. Apparatus and methods associate a received sample with a hard or sliced output state (such as +1, 0, or −1) and update a value associated with the hard output state for accurate slicing of the samples. This permits the use of hard symbols in further processing rather than soft samples, which can dramatically reduce the complexity of circuitry. | 03-20-2014 |
20140086292 | SYSTEMS AND METHODS FOR DETECTING DATA COLLISIONS FOR A NEAR FIELD COMMUNICATION SYSTEM - In a wireless near field communication (NFC) system, a target, such as a smart card, can communicate with an initiator, such as a card reader, by load modulating a radio frequency (RF) signal generated by the initiator. When two or more targets load modulate the RF signal generated, “collisions” can occur with the load modulation. Apparatus and methods detect the presence or absence of collisions in a lower layer or physical layer and report the presence of detected collisions to an upper layer for further handling. | 03-27-2014 |
20140086347 | APPARATUS AND METHOD OF RECEIVER ARCHITECTURE AND LOW-COMPLEXITY DECODER FOR LINE-CODED AND AMPLITUDE-MODULATED SIGNAL - A receiver apparatus is disclosed. In one aspect, the apparatus includes a receiver | 03-27-2014 |
20140273828 | APPARATUS AND METHOD FOR REDUCING PHASE NOISE IN NEAR FIELD COMMUNICATION DEVICE SIGNALING - A method for communication between near field communication (NFC) devices includes generating a transmission signal, an in-phase local oscillator signal, and a quadrature local oscillator signal from edges of an input clock signal. The method further includes mixing a load modulated signal with the in-phase local oscillator signal to generate an in-phase baseband signal. The method further includes mixing the load modulated signal with the quadrature local oscillator signal to generate a quadrature baseband signal. The method further includes adjusting a phase delay of at least one of the in-phase local oscillator signal or the quadrature local oscillator signal in response to a first signal strength of the in-phase baseband signal and a second signal strength of the quadrature baseband signal. | 09-18-2014 |
20140321581 | METHODS AND SYSTEMS TO DETECT THE OCCURRENCE OF ERRONEOUS DEMODULATED BITS FOR DECISION FEEDBACK DEMODULATION - Systems and methods to detect the occurrence of erroneous demodulated bits for decision feedback demodulation are disclosed. In one implementation, an apparatus for detecting demodulation bit errors of a plurality of modulated bits includes a memory component configured to store a first threshold and a second threshold. The apparatus further includes a processor coupled to the memory component, the processor configured to retrieve the first threshold and second threshold from the memory component and to determine a demodulation metric value for each of the plurality of modulated bits, the processor further configured to count the number of demodulation metric values that cross the first threshold and compare the second threshold to the number of demodulation metric values that cross the first threshold. | 10-30-2014 |
20150133069 | FM RECEIVER WITH FREQUENCY DEVIATION-DEPENDENT ADAPTIVE CHANNEL FILTER - Methods, systems, and devices are described for wireless communications in a frequency modulation (FM) receiver with a frequency deviation-dependent adaptive channel filter. A maximum frequency deviation of an FM broadcast signal may be estimated. One or more coefficients of a channel filter may be adapted based at least in part on the maximum frequency deviation. The coefficient adaptation may include identifying a set of coefficients corresponding to the maximum frequency deviation and applying the set of coefficients to the channel filter. The set of coefficients may be identified by selecting one of multiple sets of coefficients stored in memory. In some instances, a signal quality metric (e.g., signal-to-noise ratio (SNR)) may be identified and may be used to modify a value of one or more of the set of coefficients applied to the channel filter. | 05-14-2015 |
20150137883 | ADAPTIVE FM DEMODULATOR SUPPORTING MULTIPLE MODES - Methods, systems, and devices are described for an adaptive demodulator that supports multiple modes. An FM signal may be received at a demodulator and parameters corresponding to the FM signal may be identified. Connections between multiple modules within the demodulator may be configured, based at least in part on the parameters, to select one of multiple demodulation modes supported by the demodulator to demodulate the FM signal. The modes may include a phase differencing mode, a phase-locked loop (PLL) mode, a frequency-compressive feedback (FCF) mode, and/or a quadrature detector mode. The parameters may include one or both of a signal strength of the FM signal and a maximum frequency deviation of the FM signal. Based on the parameters, one or more signals may be generated to configure the connections within the demodulator. A switch from one mode to another may occur when one of the parameters breaches a threshold value. | 05-21-2015 |
20150256324 | SYSTEMS AND METHODS FOR TIMING RECOVERY IN NEAR-FIELD COMMUNICATION - A method for inductively-coupled communications is described. The method includes receiving a signal. The method also includes analyzing the signal to estimate a symbol timing error. Estimating the symbol timing error may include comparing a location of a pause, a low-to-high or a high-to-low transition in the received signal with an ideal location of a pause or a transition. The method further includes adjusting symbol timing to correct for the symbol timing error. | 09-10-2015 |