Abstract:
An apparatus and method to control signal phase in a radio device includes a phase rotator configured to control a phase of a local oscillator. A phase error determination module is configured to determine phase error information based on received in-phase (I) and quadrature (Q) (IQ) signal values. A phase correction module is configured to derive from the received IQ signal values a correction signal and apply the correction signal to the phase rotator in a path of the local oscillator.
Abstract:
Systems and methods for adaptive clock and equalization control are provided for data receivers, which are based on a “closed loop” sampling clock framework that employs controllable and dynamically adapted time offsets on both local data and amplitude clocks. The controllable clock offsets are dynamically adapted using signal processing methods adapted to achieve optimum sampling of data and amplitude sampling clock signals to accurately detect data bits and optimize system equalization settings, including, decision-feedback equalizer and/or an optional linear equalizer preceding a decision-feedback equalizer.
Abstract:
A cordless modem comprises a radio pair interfaced to a standard data/fax modem which allows a user of a personal computer to wirelessly connect to a telephone line. One end of the radio pair is a remote unit interfaced to the modem contained within the PC while the other end is a base unit connected to a standard telephone wall jack. The base unit can selectively discriminate and adjust for signals received from a telephone voice handset or data signals received from the cordless modem remote unit. Upon receiving an off-hook signal or an incoming call signal, the base unit identifies the type of data (i.e., voice or computer modem data) and adapts accordingly by placing an FM modulator in either of a narrow band deviation or a wide band deviation covering the required range of the particular signal combined with local echo. That is, when voice data is present, a low deviation, narrow filter combination is selected. If, on the other hand, the computer data from the cordless modem is detected, a higher deviation, wider bandwidth filter is selected. In addition, the remote unit switches a pre-detection filter from one mode to another depending on whether it is connected to a computer modem or to a voice handset. Security from eavesdroppers as well as the mitigation of signal fading is provided by overlaying a pseudo-random number (PN) code on the FM modulated signal.
Abstract:
Systems and methods for adaptive clock and equalization control are provided for data receivers, which are based on a “closed loop” sampling clock framework that employs controllable and dynamically adapted time offsets on both local data and amplitude clocks. The controllable clock offsets are dynamically adapted using signal processing methods adapted to achieve optimum sampling of data and amplitude sampling clock signals to accurately detect data bits and optimize system equalization settings, including, decision-feedback equalizer and/or an optional linear equalizer preceding a decision-feedback equalizer.
Abstract:
Illustrative embodiments provide a computer implemented method and an apparatus for data decorrelation in a line equalizer adaptive system. The apparatus comprises an input and an output, forming a data path there between, wherein the input capable of receiving data to create received data and the output capable of sending data. The apparatus further comprises an adaptive equalizer capable of equalizing the received data, connected to the data path, and a synchronous decorrelator connected to the data path, in communication with the adaptive equalizer, wherein the synchronous decorrelator evaluates an adapt enable output for each received data input to the adaptive equalizer to determine whether the adaptive equalizer can update settings of the line equalizer adaptive system.
Abstract:
A quadrature modulation circuit includes a mixer circuit including an integrated sign modulation control circuit and a plurality of mixer ports. The mixer ports include a first input port, a second input port, an output port and a sign modulation control port. The modulation circuit generates a modulated signal by operation of the mixer circuit multiplying a modulating signal applied to the first input port with a carrier signal applied to the second input port to generate a mixed signal output from the output port, and by operation of the integrated sign modulation control circuit controlling polarity switching of a signal at one of the mixer ports in response to a sign modulation control signal input to the sign modulation control port.
Abstract:
A method for multipath resistant waveform coding is provided. The method adds a chip extension to an optimally designed waveform set to compensate for an expected time shift in the radio channel during the transmission and demodulation of the transmitted waveform. The chip extension can be added to the beginning and/or end of the input waveform. The number of chip extensions added is based on the expected multipath time delay in the radio channel. The chip extension method can be used in BPSK, QPSK, QBPSK, and a modified Quadrature-BPSK encoding scheme.
Abstract:
An apparatus and method to control signal phase in a radio device includes a phase rotator configured to control a phase of a local oscillator. A phase error determination module is configured to determine phase error information based on received in-phase (I) and quadrature (Q) (IQ) signal values. A phase correction module is configured to derive from the received IQ signal values a correction signal and apply the correction signal to the phase rotator in a path of the local oscillator.
Abstract:
Quadrature modulation systems, circuits and methods are provided to support various modulation modes including ASK (amplitude shift key), FSK (frequency shift key) and PSK (phase shift key) modulation at high data rates (e.g., gigabit data rates). For example, a modulation circuit includes a mixer circuit including an integrated sign modulation control circuit and a plurality of mixer ports. The mixer ports include a first input port, a second input port, an output port and a sign modulation control port. The modulation circuit generates a modulated signal by operation of the mixer circuit multiplying a modulating signal applied to the first input port with a carrier signal applied to the second input port to generate a mixed signal output from the output port, and by operation of the integrated sign modulation control circuit controlling polarity switching of a signal at one of the mixer ports in response to a sign modulation control signal input to the sign modulation control port. The sign modulation control signal can be a digital data signal having binary data encoded into the modulated signal.
Abstract:
Illustrative embodiments provide a computer implemented method and an apparatus for data decorrelation in a line equalizer adaptive system. The apparatus comprises an input and an output, forming a data path there between, wherein the input capable of receiving data to create received data and the output capable of sending data. The apparatus further comprises an adaptive equalizer capable of equalizing the received data, connected to the data path, and a synchronous decorrelator connected to the data path, in communication with the adaptive equalizer, wherein the synchronous decorrelator evaluates an adapt enable output for each received data input to the adaptive equalizer to determine whether the adaptive equalizer can update settings of the line equalizer adaptive system.