Abstract: Dynamic error-quantizer tuning systems and methods prevent misconvergence to local minima by using a dynamic quantizer circuit that controls reference voltages of three or more comparators that are independently adjusted to modify the transfer function of the dynamic quantizer circuit. A weighted sum of the comparator outputs is subtracted from the input to form an error signal in a control loop. The ratio of the reference voltages is chosen to reduce or eliminate local minima during a convergence of the control loop and is set to values that minimize a mean squared error signal with respect to discrete modulation states of the input after the convergence of the control loop is complete.

Abstract: Real-time systems and methods prevent duplication of independent signal streams in a coherent receiver subject to source separation controlled by multiplicative coefficients under adaptive feedback control. In various embodiments, this is achieved by first obtaining a first set of coefficients associated with a first signal stream and a second set of coefficients associated with a second signal stream. In response to the sets of coefficients satisfying a condition, the first set modified into a set of coefficients that is mutually orthogonal with respect to and replaces the second set of coefficients. The resulting series of coefficient values may then be used to perform source separation of independent signal streams without duplicating independent signal streams.

Abstract: A method and apparatus for transmitting and receiving high-bandwidth OFDM signals, while limiting the complexity of the OFDM signal processing is described. Bandwidth expansion is achieved by repetition of whole OFDM symbols with the polarity of repetitions determined by a long PN code. This technique ensures a perfectly white spectrum. Use of zero-suffix OFDM symbols allows a large tolerance to multipath channels, even while maintaining a single, low-rate RAKE finger for despreading in the receiver.

Abstract: An Accelerated Storage Controller (ASC) in an electronic device allows both conventional (slower) application processor to memory interfaces to be employed transparently to existing software, while also allowing software configuration to realize an accelerated storage architecture on demand. Some use cases for the electronic device do not require accelerated storage, and a bypass mode does not require any modification to existing software. Other use cases (such as fast download of multiple gigabytes of media) benefit from an accelerated storage architecture offloading transfer from the electronic device application processor, but could also work with the traditional processor to memory interface, at the cost of slower downloads. Embodiments of the present invention provide for both these possibilities in a software-configurable architecture. Furthermore, a number of other connectivity options are provided under software control to optimize performance and connectivity for different use case scenarios.

Abstract: An apparatus and method for generating a shared secret between at least two wireless portable electronic devices. A shared secret is generated by holding together the at least two devices and shaking them. An acceleration of the at least two devices is measured at least during a time window beginning at a time corresponding to when a magnitude of the acceleration exceeds a predetermined threshold. The acceleration is sampled, resulting in a plurality of vectors, such that a first vector is an initial sample of the acceleration during the time window. In some embodiments, the acceleration is measured in three dimensions. Dot products are calculated between the first vector and each of a plurality of subsequent vectors, resulting in an array of scalars. At least a portion of this array is used to generate the shared secret between the at least two devices.

Abstract: A signal processing circuit comprises a frequency up-conversion circuit (14, 60) for performing up-conversion with a first local oscillator frequency and a frequency down-conversion circuit (16) for performing down-conversion with a second local oscillator frequency. A digital signal processor (10) controls supply first signals representing a first complex signal to the up-conversion circuit, and receives second signals representing a second complex signal. The digital signal processor controls a compensation of I/Q mismatch of results of up-conversion and/or down-conversion. The digital signal processor (10) switches to a calibration mode for selecting a parameter of said compensation. In the calibration mode the first and second local oscillator frequencies have a frequency offset with respect to each other.

Abstract: A UWB or other transmitter reduces interference to a narrow-band victim receiver on a periodic basis by means of a frequency swept notch. The notch may be created using active interference cancellation signal processing or simple deletion of sub-carriers. Details are given of both methods.

Abstract: By partially serializing the transmission of a sequence keyed UWB symbol (FIG. 2), the number of parallel receiver branches required to receive such a transmission is reduced. The reduced number of receiver paths are re-used during the reception of each of the partially serialized portions of a UWB symbol, and the local oscillator (312, 332, 334, 336) output frequencies are changed for reception of each of those portions. Reducing the number of parallel receiver paths advantageously reduces the amount of power consumed by such a receiver. Similarly, the amount of area required to implement such a receiver in an integrated circuit is advantageously reduced. In a further aspect of the present invention, a synchronization sequence uses less than the complete set of frequency bands (402-408) available for transmission of a UWB symbol.

Abstract: A current boost circuit acts as an “eye opener” for a digital bus line. A controlled current injects a fraction of the normal signaling current magnitude from a source driver onto the bus line, after a transition between the two logical states on the bus line is detected. The duration of the additional current injection is a fraction of the unit interval. In one embodiment, a linear system uses the summation of a proportional boost current and a delayed and negated proportional boost current. In another embodiment, a positive or negative edge detection circuit triggers a monostable pulse generator that controls the injection of short bursts of additional current into the bus lines. In some embodiments the boost current is suppressed when the bus line is driven from a driver other than the source driver.

Abstract: A system, device and method are described for suppressing certain sub-carrier frequencies within a multi-path transmission system and efficiently notifying a receiver (400) of the suppressed sub-carriers. In various embodiments of the invention, an OFDM system uses the preamble (210) of an OFDM burst for indicating which sub-carrier frequencies are being suppressed by a transmitter (300).

Abstract: The present invention provides a system (300-400), apparatus (300-400), and method for an energy-based antenna selection technique in which the antenna that observes the largest SNR averaged over all carriers per sub-band (405) is selected for space-time coded MB-OFDM systems. Due to the frequency-selective nature of the system, different sub-band may have different channel gaining effect from the multi-path channels. We can perform energy-based antenna selection per sub-band, and the simulation results show that the proposed technique works not only for MB-OFDM UWB channels with shadowing, but also for the same channel without shadowing.

Abstract: In a radio including analog and digital portions, with at least one A/D converter between the analog and digital portions, and the selectivity of the radio at least partly implemented in the digital domain, an AGC controller sets a first variable gain amplifier (VGA) (302) to low gain upon a determination that a wide-band power estimation exceeds a wide-band threshold. The wide-band threshold is selected to reduce the occurrence of A/D converter saturation. If the wide-band power estimation is less than the wide-band threshold, then for each VGA (302) in the analog portion, a determination is made whether a narrow-band power estimate exceeds a narrow-band threshold, corresponding to that VGA (302), plus a hysteresis value, in which case that VGA (302) is set to low gain; or whether the narrow-band energy estimate is less than the narrow-band threshold minus a hysteresis value, in which case that VGA (302) is set to high gain.

Abstract: A current boost circuit acts as an “eye opener” for a digital bus line. A controlled current injects a fraction of the normal signaling current magnitude from a source driver onto the bus line, after a transition between the two logical states on the bus line is detected. The duration of the additional current injection is a fraction of the unit interval. In one embodiment, a linear system uses the summation of a proportional boost current and a delayed and negated proportional boost current. In another embodiment, a positive or negative edge detection circuit triggers a monostable pulse generator that controls the injection of short bursts of additional current into the bus lines. In some embodiments the boost current is suppressed when the bus line is driven from a driver other than the source driver.

Abstract: Clear channel assessment (CCA) is a very important issue in Ultra-Wideband (UWB) systems. An effective CCA mechanism will have a large impact on the overall throughput of the communications system. It is disclosed methods and circuits to carry out CCA determinations exploiting the structure of the pulse signal either by using a moving average or by performing a cross-correlation with a locally generated signal.

Abstract: An Accelerated Storage Controller (ASC) in an electronic device allows both conventional (slower) application processor to memory interfaces to be employed transparently to existing software, while also allowing software configuration to realize an accelerated storage architecture on demand. Some use cases for the electronic device do not require accelerated storage, and a bypass mode does not require any modification to existing software. Other use cases (such as fast download of multiple gigabytes of media) benefit from an accelerated storage architecture offloading transfer from the electronic device application processor, but could also work with the traditional processor to memory interface, at the cost of slower downloads. Embodiments of the present invention provide for both these possibilities in a software-configurable architecture. Furthermore, a number of other connectivity options are provided under software control to optimize performance and connectivity for different use case scenarios.

Abstract: By partially serializing the transmission of a sequence keyed UWB symbol (FIG. 2), the number of parallel receiver branches required to receive such a transmission is reduced. The reduced number of receiver paths are re-used during the reception of each of the partially serialized portions of a UWB symbol, and the local oscillator (312, 332, 334, 336) output frequencies are changed for reception of each of those portions. Reducing the number of parallel receiver paths advantageously reduces the amount of power consumed by such a receiver. Similarly, the amount of area required to implement such a receiver in an integrated circuit is advantageously reduced. In a further aspect of the present invention, a synchronization sequence uses less than the complete set of frequency bands (402-408) available for transmission of a UWB symbol.

Abstract: A signal processing circuit comprises a frequency up-conversion circuit (14, 60) for performing up-conversion with a first local oscillator frequency and a frequency down-conversion circuit (16) for performing down-conversion with a second local oscillator frequency. A digital signal processor (10) controls supply first signals representing a first complex signal to the up-conversion circuit, and receives second signals representing a second complex signal. The digital signal processor controls a compensation of I/Q mismatch of results of up-conversion and/or down-conversion. The digital signal processor (10) switches to a calibration mode for selecting a parameter of said compensation. In the calibration mode the first and second local oscillator frequencies have a frequency offset with respect to each other.

Abstract: An apparatus and method for generating a shared secret between at least two wireless portable electronic devices. A shared secret is generated by holding together the at least two devices and shaking them. An acceleration of the at least two devices is measured at least during a time window beginning at a time corresponding to when a magnitude of the acceleration exceeds a predetermined threshold. The acceleration is sampled, resulting in a plurality of vectors, such that a first vector is an initial sample of the acceleration during the time window. In some embodiments, the acceleration is measured in three dimensions. Dot products are calculated between the first vector and each of a plurality of subsequent vectors, resulting in an array of scalars. At least a portion of this array is used to generate the shared secret between the at least two devices.

Abstract: Secure wireless communication links are established between proximately-located devices, each of which includes respective audio transmitters and audio receivers. The audio transmitter of the first device can be used to transmit a device-dependent authentication key, which is received by the audio receiver of the second device. The audio transmitter of the second device can be used to transmit an acknowledgement, which is received at the audio receiver of the first device. The round-trip time from transmitting the authentication key from the first device to receiving the acknowledgement at the first device can be determined, and the decision of whether to establish the secure wireless communication link can be based on the determined round-trip time. In certain embodiments, these steps can be repeated starting with the second device to establish a two-way trust between the devices.

Abstract: The present invention, generally speaking, provides for signaling methods in which multiple sub-hands of a transmission band are continuously occupied by an OFDM signal that would otherwise occupy only a single sub-hand. In accordance with one embodiment, steps include producing an OFDM symbol; transforming the OFDM symbol to produce an OFDM signal; upsampling the OFDM signal to produce an upsampled OFDM signal; applying a pseudo-random code to the upsampled OFDM signal to produce a coded OFDM signal; and upconverting the coded OFDM signal to produce a radio frequency signal. In accordance with another embodiment, steps include producing a sequence of N consecutive identical OFDM symbols; transforming the OFDM symbols to produce corresponding OFDM signals; and upconverting the coded OFDM signal to produce a radio frequency signal; wherein the radio frequency signal occupies N sub-hands of a transmission band.