54results about "Analogue adaptive filters" patented technology

An exemplary embodiment of the present invention described and shown in the specification and drawings is a transceiver with a receiver, a transmitter, a local oscillator (LO) generator, a controller, and a self-testing unit. All of these components can be packaged for integration into a single IC including components such as filters and inductors. The controller for adaptive programming and calibration of the receiver, transmitter and LO generator. The self-testing unit generates is used to determine the gain, frequency characteristics, selectivity, noise floor, and distortion behavior of the receiver, transmitter and LO generator. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or the meaning of the claims.

An exemplary embodiment of the present invention described and shown in the specification and drawings is a transceiver with a receiver, a transmitter, a local oscillator (LO) generator, a controller, and a self-testing unit. All of these components can be packaged for integration into a single IC including components such as filters and inductors. The controller for adaptive programming and calibration of the receiver, transmitter and LO generator. The self-testing unit generates is used to determine the gain, frequency characteristics, selectivity, noise floor, and distortion behavior of the receiver, transmitter and LO generator. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or the meaning of the claims.

Disclosed is a programmable impedance control circuit, comprising a voltage divider, the voltage divider comprising an MOS array supplied with a first voltage and an external resistance having an external impedance equal to N times said external resistance. The voltage divider outputs a second voltage. A reference voltage generator is provided for generating a third voltage corresponding to N/(N+M) times said first voltage as a reference voltage for said second voltage, and wherein M times internal impedance is used for N times external impedance (N=M or N<> M).

According to the general concept disclosed herein, a circuit for adaptive matching of a load impedance to a predetermined load-line impedance of a load-line connected to a power amplifier output includes a fixed matching network between the power transistor and an adaptive matching network, whereby the fixed matching network acts as an impedance inverter which results in a relatively low insertion loss at high power. Results indicate that the impedance-inverting network can be used over more than a factor of 10 in impedance variation. Further, the usage of the fixed matching network, close to the power transistor, allows for the implementation of transmission zeros and/or for a well defined load impedance at a predetermined harmonic frequency, independent of the (variable) load impedance at the fundamental frequency.

An exemplary embodiment of the present invention described and shown in the specification and drawings is a transceiver with a receiver, a transmitter, a local oscillator (LO) generator, a controller, and a self-testing unit. All of these components can be packaged for integration into a single IC including components such as filters and inductors. The controller for adaptive programming and calibration of the receiver, transmitter and LO generator. The self-testing unit generates is used to determine the gain, frequency characteristics, selectivity, noise floor, and distortion behavior of the receiver, transmitter and LO generator. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or the meaning of the claims.

An exemplary embodiment of the present invention described and shown in the specification and drawings is a transceiver with a receiver, a transmitter, a local oscillator (LO) generator, a controller, and a self-testing unit. All of these components can be packaged for integration into a single IC including components such as filters and inductors. The controller for adaptive programming and calibration of the receiver, transmitter and LO generator. The self-testing unit generates is used to determine the gain, frequency characteristics, selectivity, noise floor, and distortion behavior of the receiver, transmitter and LO generator. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or the meaning of the claims.

Embodiments of the invention provide an adaptive notch filter that employs a power detector as a feedback control mechanism to steer the notch filter. One such embodiment of the invention provides adaptive control of the notch filter capacitor to tune the notch filter frequency based upon a diode power detector. One embodiment of the invention provides a system including multiple cascaded adaptive notch filters each having a feedback control method from a power detector to separately control each filter. For one embodiment of the invention a method is disclosed for tuning an adaptive notch filter using a dithering process to determine a minimum power output at the power detector. One embodiment includes an adaptive notch filter implementing a device with a tunable resonance frequency.

An exemplary embodiment of the present invention described and shown in the specification and drawings is a transceiver with a receiver, a transmitter, a local oscillator (LO) generator, a controller, and a self-testing unit. All of these components can be packaged for integration into a single IC including components such as filters and inductors. The controller for adaptive programming and calibration of the receiver, transmitter and LO generator. The self-testing unit generates is used to determine the gain, frequency characteristics, selectivity, noise floor, and distortion behavior of the receiver, transmitter and LO generator. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or the meaning of the claims.

Aspects of a method and system for dynamic filtering and data conversion adjustments in a receiver are provided. Exemplary aspects of the invention may include a receiver comprising a data converter and one or more filters, and a resolution of the data converter and/or a frequency response of the filters may be varied/configured (e.g., via one or more switching elements) based on one or more characteristics of a received signal. The received signals may be amplified and/or filtered prior to determining the characteristics. The resolution of the data converter and/or a quality factor of one or more of the filters may be reduced when measured interference is below a threshold and increased when measured interference is above a threshold. The resolution of the data converter and/or the frequency response of the filter may be determined based on an error rate associated with the received signals.

The invention discloses an active noise control system based on a variable step LMS algorithm. According to the system, a filter based on the variable step LMS algorithm is applied to identification of a secondary channel; a filter weight value is updated by adjusting a step value of the filter; in order to obtain a relatively fast convergence rate, the step value of self-adaptive filtering in an initial phase is relatively high; and when the self-adaptive filtering approaches a steady state, the step size is reduced, so a relatively low steady state error can be obtained. The variable step LMS algorithm is applied to the identification of the secondary channel of the active noise control system, and the contradiction among the convergence rate, the steady state error and a tracking capability of a time-varying system can be solved well.

An analog equalization filter is disclosed which permits higher speed and linearity than existing designs, allowing for filtering operation to the hundreds of gigahertz range. Possible applications include fixed and adaptive equalization filtering and radio frequency filtering. The filter can be entirely implemented on an integrated circuit chip. The filter is based on transmission line based delay elements and transconductance amplifiers.

An adaptive equalizer finite impulse response (FIR) filter for high-speed communication channels with modest complexity, where the filter is iteratively updated during a training sequence by a circuit performing the update: {overscore (h)}(t+1)={overscore (h)}(t)+μ[sgn{d(t)}−sgn{z(t)−Kd(t)}]sgn{{overscore (x)}(t)}, where {overscore (h)}(t) is the filter vector representing the filter taps of the FIR filter, {overscore (x)}(t) is the data vector representing present and past samples of the received data x(t), d(t) is the desired data used for training, z(t) is the output of the FIR filter, μ determines the memory or window size of the adaptation, and K is a scale factor taking into account practical limitations of the communication channel, receiver, and equalizer. Furthermore, a procedure and circuit structure is provided for calibrating the scale factor K.

The high frequency components of a SCSI signal are adaptively equalized using an adaptive filter having an adjustable gain. A comparator is used to compare an input signal with a predetermined threshold level. Based on the result of the comparison, the adjustable gain of the adaptive filter is modified.

The invention discloses an instant messaging system comprising a signal frequency collection circuit, a comparison compensation circuit and a filtering and voltage stabilization output circuit, wherein the signal frequency collection circuit collects signal frequency in a signal transmission channel in the instant messaging system, the comparison compensation circuit compares and adjusts the signal frequency, the signal frequency is proportionally amplified by an operational amplifier AR3 and then input into the filtering and voltage stabilization output circuit, meanwhile a compensator AR4 isdesigned for compensating the level of the operational amplifier AR3, the filtering and voltage stabilization output circuit outputs a signal after performing filtering and voltage stabilization on the signal, that is to say, the signal flows into the signal transmission channel of the instant messaging system. According to the system provided by the invention, the problem that the signal is instable and the signal transmission efficiency of the instant messaging system due to the fact that the signal frequency in the signal transmission channel in the instant messaging system has a time-varying characteristic and the frequency conversion is relatively fast is effectively solved.

An adaptive equalizer finite impulse response (FIR) filter for high-speed communication channels with modest complexity, where the filter is iteratively updated during a training sequence by a circuit performing the update: {overscore (h)}(t+1)={overscore (h)}(t)+μ[sgn{d(t)}−sgn{z(t)−Kd(t)}]sgn{{overscore (x)}(t)}, where {overscore (h)}(t) is the filter vector representing the filter taps of the FIR filter, {overscore (x)}(t) is the data vector representing present and past samples of the received data x(t), d(t) is the desired data used for training, z(t) is the output of the FIR filter, μ determines the memory or window size of the adaptation, and K is a scale factor taking into account practical limitations of the communication channel, receiver, and equalizer. Furthermore, a procedure and circuit structure is provided for calibrating the scale factor K.

Adjustable gain circuits (AGCs) within serial filter stages are initialized to maximum gain. The output of each AGC is then sampled and converted to digital representation for use by control logic in setting the gain for the respective AGC. The gain adjustment decision for each AGC is performed in one shot, sequentially backwards from the last AGC, such that gain may be adapted simply and quickly within a number of cycles equal to the number of AGCs. Performance is enhanced by a fast-adapting cell in which capacitances are switched into the input path and feedback loop of an amplifier to reduce direct current gain within the transfer function through charge sharing dividing down the output voltage.

Systems and methods that reduce phase noise are provided. In one embodiment, a method may include one or more of the following: generating a signal at a particular frequency in which the signal may be associated with a harmonic frequency signal disposed at a harmonic frequency; and selectively attenuating frequency content disposed in a region around the harmonic frequency. The signal may be associated with a second harmonic frequency signal disposed at a second harmonic frequency. Frequency content disposed in a second region around the second harmonic frequency may be selectively attenuated. One or more non-linear operations may be applied to the signal and the applied signal may be transmitted.

Methods and systems for processing a signal with a corresponding noise profile are disclosed. Aspects of the method may comprise analyzing spectral content of the noise profile. At least one noise harmonic within the signal may be filtered based on said analyzed spectral content. The filtered signal may be amplified. The noise profile may comprise a phase noise profile. The signal may comprise at least one of a sinusoidal signal and a noise signal. At least one filter coefficient that is used to filter the at least one noise harmonic may be determined. The filtering may comprise low pass filtering. The signal may be modulated prior to filtering. The amplifying may comprise buffering. A non-linearity characteristic of the signal may be determined and a noise harmonic may be low-pass filtered within the signal based on the determined non-linearity characteristic.