摘要:
Noise distribution shaping for signals, particularly for the application in receivers for CDMA signals. An embodiment provides a method for noise distribution shaping for signals comprising the acts of generating a blanking control signal by comparing a received signal comprising transitions with at least one blanking threshold, determining transitions of the received signal and zones around the determined transitions, and generating a transitions control signal comprising the determined transitions and zones, adapting the at least one blanking threshold or the received signal according to an offset value depending on the amplitude of the received signal and on the transitions control signal, and modifying the noise distribution of the received signal by applying blanking of the received signal under control of the blanking control signal.
摘要:
Control and feature systems for processing signals from a satellite positioning system include an expert system receiver manager; a joint detection, carrier centring and bit sync acquisition subsystem; peak detection; a multi-dimensional measurement interpolation subsystem; a system for mode switching between a navigational signal; and power control module for receiver.
摘要:
A receiver includes a plurality of de-spreading correlators that are programmed to only correlate a specific portion of the full spreading code according to an interleave factor. Each correlator may be associated with a different symbol. The received signal may be received at all correlators and is multiplied by a code generated by a code generator according to the symbol associated with the correlator. While each correlator may be despreading the received signal at all times, an enable signal is used to determine when information for an associated cell should be accumulated for each correlator.
摘要:
A receiver (100) is provided for signals of different signal strengths and modulated with respective pseudorandom noise (PN) codes. The receiver (100) includes a correlator circuit (120) operable to correlate the signals with a selectable locally-issued PN code having a Doppler and a code lag to produce a peak, the correlator circuit (120) being subject to cross correlation with a distinct PN code carried by least one of the signals that can produce cross correlation; and a cross correlation circuit (370, 400) operable to generate a variable comparison value related to the cross correlation as a function of values representing a Doppler difference and a code lag difference between the locally-issued PN code and the distinct PN code, and to use the variable comparison value to reject the peak as invalid from cross correlation or to pass the peak as a valid received peak.
摘要:
An integrated circuit for facilitating spread spectrum reception of data having a data bit period includes an hypothesis search circuit (120, 210, 220) operable to correlate a pseudorandom code with a signal input based on a received signal to produce correlation results, and a processor circuit (320) operable to coherently integrate the correlation results over plural sample windows (PreD1, PreD2) staggered relative to each other in the coherent integration interval and to non-coherently combine the coherently integrated results corresponding to the plural sample windows (PreD1, PreD2) to produce a received signal output, whereby enhancing performance. Other circuits, receivers and processes are also disclosed.
摘要:
Communication methods for receiving and demodulating in mobile devices signals from multiple locations and for providing baseband position finder signal. Providing in a first cross-correlator and filter cross-correlated in-phase and quadrature-phase filtered baseband signals from a digital input signal and in a second cross-correlator spread spectrum signals from a voice input signal. Providing Orthogonal Frequency Division Multiplex (OFDM) signal from a video input signal. Combining baseband position finder signal with one or more of cross-correlated in-phase and quadrature-phase filtered baseband signals, or cross-correlated in-phase and quadrature-phase spread spectrum baseband signals, or OFDM baseband signal, into a combined baseband signal and modulating and transmitting combined signal. Touch screen control signal for control of mobile devices.
摘要:
A spectral content of a baseband waveform is varied and a measure of the baseband waveform whose spectral content has been varied is used by a transmitter in order to convey information. According to embodiments of inventive concepts, a set of frequencies that is used to provide spectral content to the baseband waveform is varied. In some embodiments, the spectral content comprises non-contiguous first and second frequency intervals wherein a third frequency interval that is between the first and second frequency intervals remains substantially devoid of providing spectral content in order to reduce or avoid interference. In other embodiments, the spectral content that is varied comprises a bandwidth that is varied. The inventive concepts are relevant to 4G LTE carrier aggregation systems/methods and/or other aspects of 4G LTE. Various transmitter/receiver embodiments are disclosed including direct synthesis transmitter/receiver embodiments.
摘要:
A method for increasing accuracy of geolocation based on timing measurements of RF signals. The method includes: (a) receiving at a user one or more RF signals transmitted over time, (b) correlating the received signals with a plurality of replica waveforms, (c) creating a first set of estimates of the time or arrivals of the signals at the user, (d) using the first set of estimates to create a plurality of models, wherein each model assumes that some of the measurements are affected by multipath or interference, (e) testing the models to estimate the likelihood of timing measurements for each model, and (f) determining the set of LOS measurements as one associated with a model having the largest likelihood.
摘要:
A method for soft frame synchronization in a navigational receiver is provided. A distance between bits of a sync pattern received by the navigational receiver and a known sync pattern is computed. A probability of detection value for the received sync pattern based on the distance is assigned. A confidence level for the received sync pattern using the probability of detection value is computed. The confidence level is compared with a confidence threshold. If the confidence level is greater than or equal to the confidence threshold, the confidence level of the received sync pattern is updated to generate a credibility of the sync pattern. The credibility of the received sync pattern is compared with a predetermined credibility value and, if the credibility of the received sync pattern is greater than or equal to the predetermined credibility value, synchronization of the navigational receiver is performed using the received sync pattern.
摘要:
A method for detecting multi-path interference in a spread-spectrum signal. A variation of a first signal and a variation of a second signal is compared. The variation of the first signal corresponds to a correlation of the spread-spectrum signal and a spreading code having a first offset. The variation of the second signal corresponds to a correlation of the spread-spectrum signal and the spreading code having a second offset. Multi-path interference is detected in dependence on the comparison.