Abstract: A filter and a method of filtering a high frequency electrical signal using photonic components is disclosed. The filter has a serially fiber-coupled laser source, a modulator, a filter, and a photodetector. The electrical signal is applied to the modulator. The modulated light propagates through the filter which is constructed to pass not only a modulated sideband, but also at least a fraction of light at the carrier frequency of the laser. The photodetector detects a signal at the beat frequency between the carrier and sideband signals, after both signals have propagated through the filter. As a result, a separate optical branch for light at the carrier frequency is not required, which considerably simplifies the filter construction and makes it more stable and reliable.

Abstract: The invention relates to a method and circuit for linearizing amplifiers and other nonlinear circuits for multi-carrier signals. An output signal from the amplifier is sampled, and a correlation matrix of size N×N is computed from the sampled signal, wherein N exceeds the number of multiplexed carriers in the signal. A signal-to-distortion ratio (SDR) is then estimated based on a ratio of one or more largest to one or more smallest eigenvalues of the correlation matrix, and the signal into the amplifier is pre-distorted so as to maximize the SDR.

Abstract: The invention relates to a method and circuit for linearizing amplifiers and other nonlinear circuits for multi-carrier signals. An output signal from the amplifier is sampled, and a correlation matrix of size N×N is computed from the sampled signal, wherein N exceeds the number of multiplexed carriers in the signal. A signal-to-distortion ratio (SDR) is then estimated based on a ratio of one or more largest to one or more smallest eigenvalues of the correlation matrix, and the signal into the amplifier is pre-distorted so as to maximize the SDR.

Abstract: The invention provides a type-based method to compensate for distortions in circuits operating on a plurality of input modulated signals to form one or more output modulated signals. Steps of the method include low-rate sampling of the output signal to obtain a statistical characteristics thereof, and adjusting parameters of the circuit to introduce a controlled degree of cross-coupling between the signals until the statistical characteristics of the output signal approximates a reference characteristics defined by the used modulation formats. Another aspect of the invention provides a self-calibrating multi-port circuit implementing the method.

Abstract: The invention relates to methods and circuits for compensating linear in-band distortions such as those occurring in RF circuits of broad band communication systems. A low-rate sampling is used to collect statistical information about a modulated signal after it passed through the distorting circuits, which is then compared to reference statistical information for the modulated signal to iteratively adjust a frequency response of an equalizing linear filter inserted into the signal path so as to compensate for the distortions.

Abstract: A filter and a method of filtering a high frequency electrical signal using photonic components is disclosed. The filter has a serially fiber-coupled laser source, a modulator, a filter, and a photodetector. The electrical signal is applied to the modulator. The modulated light propagates through the filter which is constructed to pass not only a modulated sideband, but also at least a fraction of light at the carrier frequency of the laser. The photodetector detects a signal at the beat frequency between the carrier and sideband signals, after both signals have propagated through the filter. As a result, a separate optical branch for light at the carrier frequency is not required, which considerably simplifies the filter construction and makes it more stable and reliable.

Abstract: The invention relates to methods and circuits for compensating linear in-band distortions such as those occurring in RF circuits of broad band communication systems. A low-rate sampling is used to collect statistical information about a modulated signal after it passed through the distorting circuits, which is then compared to reference statistical information for the modulated signal to iteratively adjust a frequency response of an equalizing linear filter inserted into the signal path so as to compensate for the distortions.

Abstract: A bolt assembly for insertion into a rock wall including a hole having a diameter an a method thereof are provided. The assembly includes a resilient cylinder for insertion into the hole, a shaft for insertion into the cylinder, a grouting material for retaining the shaft within the cylinder and stiffening the assembly, and coupling means for coupling the extremity of the cylinder to the extremity of the shaft. The cylinder has a diameter which is greater than the diameter of the hole when the cylinder is uncompressed. In this manner, the cylinder is radially compressed when inserted into the hole and thereby frictionally engages the hole. The cylinder has an extremity extending outside the hole when it is inserted therein. The shaft includes an extremity which extends outside the hole when the shaft is inserted into the cylinder in an operating position.

Abstract: The invention provides a type-based method to compensate for distortions in circuits operating on a plurality of input modulated signals to form one or more output modulated signals. Steps of the method include low-rate sampling of the output signal to obtain a statistical characteristics thereof, and adjusting parameters of the circuit to introduce a controlled degree of cross-coupling between the signals until the statistical characteristics of the output signal approximates a reference characteristics defined by the used modulation formats. Another aspect of the invention provides a self-calibrating multi-port circuit implementing said method.

Abstract: This invention is about a novel estimation technique for generating a predistortion function to compensate for the AM-AM and AM-PM non-linear conversion distortions of non-linear power amplifiers or non-linear circuits. Based on the cumulative type of power amplifier output envelope, a non-parametric baseband predistortion function is derived. The non-parametric approach avoids any model mismatch. In addition, the technique does not need to demodulate the input signal.

Abstract: A method for self-calibrating a vector modulator is disclosed, including the step of pre-distortion coefficients in dependence upon an in-phase signal, a quadrature signal, and an output envelope of an RF signal, and further comprising the steps of transforming a value representative of an output envelope represented in a nonlinear domain into a value representative of the output envelope represented in a linear domain, determining a parameter vector x as a solution of a linear equation within the linear domain, and determining the pre-distortion coefficients from the parameter vector x.

Abstract: This invention is about a novel estimation technique for generating a predistortion function to compensate for the AM-AM and AM-PM non-linear conversion distortions of non-linear power amplifiers or non-linear circuits. Based on the cumulative type of power amplifier output envelope, a non-parametric baseband predistortion function is derived. The non-parametric approach avoids any model mismatch. In addition, the technique does not need to demodulate the input signal.

Abstract: A method for self-calibrating a vector modulator is disclosed, including the step of pre-distortion coefficients in dependence upon an in-phase signal, a quadrature signal, and an output envelope of an RF signal, and further comprising the steps of transforming a value representative of an output envelope represented in a nonlinear domain into a value representative of the output envelope represented in a linear domain, determining a parameter vector x as a solution of a linear equation within the linear domain, and determining the pre-distortion coefficients from the parameter vector x.

Abstract: The present invention relates to the regeneration of in-phase (I) and quadrature (Q) signals in electronic devices commonly used in communication, radar and instrumentation electronics. The original signal of interest comprises two orthogonal components that are mathematically modelled using complex values, which are then decomposed into a real (I) and an imaginary (Q) component. These two components are orthogonal to each other and represent fully the signal of interest. The present method adaptively compensates for the gain and phase imbalances and DC offsets in I and Q signal regeneration. First, 3 phase shifted versions of the received signal, either down-converted to some intermediate frequency (IF) or at baseband, are digitized. Although the optimum phase shift between each version is 360°/3, any phase shift different than 0° and 180° is acceptable and no a priori knowledge of the phase shifts is required.