58 results about "Amplifier nonlinearity" patented technology

A method and system provide the ability to measure a transmission performance characteristic. A signal is received and equalized. The equalized signal is demodulated and an ideal signal is generated from the demodulated equalized signal. A performance characteristic is the estimated from a difference between the ideal signal and the equalized signal.

A 5G base station transmitter at least partially precodes data for beam forming, and generates digital precoded baseband signals. Cross product circuitry coupled to the digital precoder, generates digital cross products of the digital precoded baseband signals. Both the baseband signals and the cross products are put through digital-to-analog converters (DACs), then provided to an analog non-linear precoder. The analog non-linear precoder combines the analog baseband signals, the cross products, with pre-distortion and precoder coefficients to generate a signal that is pre-compensated for power amplifier non-linearity. The pre-compensated signal is amplified by the power amplifier and transmitted via a phased antenna array. The number of extra DACs required for inserting pre-distortion when a hybrid digital / analog precoder is used can be limited to approximatelyNRF⁡(NRF-1)2,where NRF is the number of outputs of the digital precoder. This is significantly fewer than the number of extra DACs used by other methods.

The invention provides methods and devices for estimating power amplifier nonlinearity using simple correlation techniques. Methods and devices of the invention can monitor a power amplifier that has digitally modulated inputs and an output containing more than one signal stream. A preferred method of the invention creates a test signal by forming the products of several pseudorandom noise sequences from the digitally modulated inputs to the power amplifier. Nonlinear contributions of the power amplifier output are determined by cross-correlating the test signal and the total output signal of the power amplifier. In preferred embodiments, the determined nonlinear contributions of the power amplifier are used to introduce corrective predistortion in the power amplifier.

A 5G base station transmitter at least partially precodes data for beam forming, and generates digital precoded baseband signals. Cross product circuitry coupled to the digital precoder, generates digital cross products of the digital precoded baseband signals. Both the baseband signals and the cross products are put through digital-to-analog converters (DACs), then provided to an analog non-linear precoder. The analog non-linear precoder combines the analog baseband signals, the cross products, with pre-distortion and precoder coefficients to generate a signal that is pre-compensated for power amplifier non-linearity. The pre-compensated signal is amplified by the power amplifier and transmitted via a phased antenna array. The number of extra DACs required for inserting pre-distortion when a hybrid digital / analog precoder is used can be limited to approximatelyNRF(NRF-1)2,where NRF is the number of outputs of the digital precoder. This is significantly fewer than the number of extra DACs used by other methods.

A method is disclosed for obtaining high throughput linearity using a pre-distorter in front of a RF power amplifier, for instance a multi-carrier power amplifier (MCPA) for a communications system. The method can be carried out off-line to thereby save costs and components otherwise needed for a common on-line feed back. In a first step calibration is performed by measuring by an off-line spectrum analysis an output spectrum of the power amplifier and simultaneously applying a known input signal. As a next step digitized parameters characterizing the power amplifier are calculated in the frequency domain by comparing spectrum points between input spectrum and output spectrum. Thereafter calculated and weighted digitized parameters are transferred to a pre-distorting device. In a third step the known signal spectrum is transferred to the pre-distorting device feeding its output signal together with the original known signal spectrum to the power amplifier input thereby compensating for power amplifier non-linearity and minimizing inter-modulation products. Finally in a fourth step an uncompensated known input spectrum is compared with a corresponding compensated output spectrum of the power amplifier and the steps of calibration calculation are repeated until a best optimization input signal to the power amplifier regarding the inter-modulation products of the output signal has been achieved.

Nonlinearity correction circuit. This device has an amplitude converter which outputs the amplitude of the inputted complex baseband signals, a memory which outputs the inverse gain of the amplitude inputted as the address from the amplitude converter, an inverse number converter which outputs the inverse number of the inputted memory output, an FIR filter which filters the output signal of the inverse number converter, an inverse number converter which outputs the inverse number of the inputted FIR output, and a complex multiplier which performs a complex multiplication of the complex baseband signals and the output of the inverse number converter. To provide a device and a method of reducing the distortions caused by memory effects for nonlinearity corrections by multiplying the reverse characteristics of the nonlinear characteristics of the amplifier and the input signals in the base band.

A method and system provide the ability to measure a transmission performance characteristic. A signal is received and equalized. The equalized signal is demodulated and an ideal signal is generated from the demodulated equalized signal. A performance characteristic is the estimated from a difference between the ideal signal and the equalized signal.

A method and system provide the ability to measure a transmission performance characteristic. A signal is received and demodulated. An ideal signal is generated from the demodulated signal. The received signal is coherently averaged to reduce noise. The performance characteristic is the estimated TWTA nonlinearity from a difference between the coherently averaged ideal signal and received signal.

An electronic endoscope system is provided that includes an RGB transformer, an R-signal amplifier, and a GB-signal amplifier. The RGB transformer transforms image signals to RGB signals. The R-signal amplifier changes the amplitude of the R signals of the RGB signals to a predetermined gain value. The GB-signal amplifier nonlinearly changes the amplitude of the G signals and B signals of the RGB signals.

The invention discloses a self-adaptive digital pre-distortion linear system of a radio frequency power amplifier, comprising a base band processing module, a digital pre-distortion compensation module and a radio frequency power amplifier; the digital pre-distortion compensation module is connected to the middle of the base band processing module and the radio frequency power amplifier and used for bettering the distortion caused by the nonlinearly amplification of the radio frequency power amplifier. The invention provides the complete and optimized self-adaptive digital pre-distortion linear system structure of the radio frequency power amplifier capable of supporting various pre-distortion models; the invention has the advantages of being wide in applicable range, simple in structure and lower in implement cost at the fixed point.

A method of dynamically calculating and updating the Volterra kernels used by the Digital Pre Distortion engine based on output power, input signal bandwidth, multicarrier configuration, frequency response and power amplifier temperature. A dominant Volterra kernels searching DSP engine based on innovation bases with minimum RMS error selection is implemented to continuously update the Volterra kernels set used in DPD to model the power amplifier non linear behaviors.