Texas Instruments Corporation

Chandrasekhar Sriram

Jawaharlal Tangudu

Sarma Sundareswara Gunturi

Sashidharan Venkatraman

Sthanunathan Ramakrishnan

Raju Kharataram Chaudhari

Jaiganesh Balakrishnan

Jagannathan Venkataraman

Sriram Murali

Eeshan Miglani

Neeraj Shrivastava

Pankaj Gupta

Sreenath Narayanan Potty

Viswanathan Nagarajan

Rajendrakumar Joish

Himanshu Varshney

Ajai Paulose

Ram Narayan Krishna Nama Mony

Divyeshkumar Mahendrabhai Patel

Venkateshwara Reddy Pothapu

Jagdish Kumar Agrawal

Pankaj Gaur

Karthik Khanna S

Shabbar Abbasi Vejlani

Mahesh Ravi Varma

A TX-TX pre-compensation system that estimates unwanted coupling in a victim transmit chain caused by an aggressor transmit chain and injects a pre-compensation signal to cancel out the estimated coupling. In some embodiments, a signal measurement module estimates the amplitude, phase, and envelope delay of the coupling and an isolation pre-compensation module generates the pre-compensation signal based on the estimated amplitude, the estimated phase, the estimated envelope delay, and the difference between the carrier frequencies of the transmit chains. Since the phase of the coupling may be affected by the carrier frequency of the transmit chains, in some embodiments the phase of the pre-compensation signal is adjusted in response to a change in carrier frequency. Since the amplitude of the coupling may be affected by attenuator gain settings, in some embodiments the amplitude of the pre-compensation signal may be adjusted in response to a change in attenuator gain setting.

Enhancing TX-TX isolation through digital pre-compensation

A channel response generating module and method for generating a channel response based on a ratio of a channel response corresponding to an image signal frequency bin in relation to a channel response corresponding to a traffic signal frequency bin, or a channel response corresponding to a first frequency bin in relation to a channel response corresponding to a second frequency bin, and a zero-IF signal transmitter employing the channel response generating module and method to efficiently suppress image signals or compensate traffic signals during transmission of IQ RF signals.

Channel tracking method and module

A non-linearity correction circuit includes a non-linearity coefficient estimation circuit. The non-linearity coefficient estimation circuit includes a data capture circuit, a non-linearity term generation circuit, a time-to-frequency conversion circuit, a bin identification circuit, a residual non-linearity conversion circuit, and a non-linearity coefficient generation circuit. The non-linearity term generation circuit is coupled to the data capture circuit. The time-to-frequency conversion circuit is coupled to the data capture circuit and the non-linearity term generation circuit. The bin identification circuit is coupled to the time-to-frequency conversion circuit. The residual non-linearity conversion circuit is coupled to the bin identification circuit. The non-linearity coefficient generation circuit is coupled to the bin identification circuit and the residual non-linearity conversion circuit.

Non-linearity correction

A non-linearity correction module, an optional droop corrector, and a zero-IF receiver with the non-linearity correction module and an optional droop corrector, wherein the non-linearity correction module is configured to generate a non-linearity term scaled to mitigate an inter-modulation component term of a RF signal received by the zero-IF receiver based on a test signal to enhance linearity in the zero-IF receiver and the optional droop corrector is configured to compensate a droop within a signal band of interest, caused by an analog low pass filter filtering a RF signal received by the zero-IF receiver, before a down-converted RF signal is fed into the non-linearity module.

Baseband corrector for RF non-linearity in zero-IF receiver

An IQ estimation module comprising a powerup state IQ estimator configured to generate powerup state IQ estimates based on a powerup calibration of the IQ estimation module, a steady state IQ estimator configured to generate steady state IQ estimates during a steady state operation of the IQ estimation module, and an IQ estimate extender configured to determine differences between the powerup state IQ estimates and steady state IQ estimates at their respective frequency bins and adjust the powerup state IQ estimates to improve the accuracy of IQ estimates.

IQ mismatch correction module

A channel estimation method and system for IQ imbalance and local oscillator leakage correction, wherein an example of a channel estimation system comprising a calibrating signal generator configured to generate at least one pair of calibrating signals, a feedback IQ mismatch estimator configured to measure feedback IQ mismatch estimates based on the pair of calibrating signals, and a calibrating signal based channel estimator configured to generate a channel estimate based on the pair of calibrating signals and the feedback IQ mismatch estimates.

Channel estimation method and system for IQ imbalance and local oscillator leakage correction

An IQ mismatch correction function generator configured to generate an enhanced IQ mismatch correction function to improve the compensation for IQ mismatch, and an IQ signal receiver with the IQ mismatch correction function generator, wherein the enhanced IQ mismatch correction function is determined based on an initial IQ mismatch correction function derived from IQ mismatch estimates corresponding to frequency bins where signals are present and error of the initial IQ mismatch correction function by comparing the values of the initial IQ mismatch correction function with IQ mismatch estimates corresponding to a respective bin of the frequency bins.

Enhanced IQ mismatch correction function generator

Multi-Nyquist differentiator circuits and a radio frequency sampling receiver that applies a multi-Nyquist differentiator circuit. A multi-Nyquist differentiator includes a fixed coefficient filter, a scaling circuit, and a summation circuit. The fixed coefficient filter is configured to filter digital samples generated by an ADC. The scaling circuit is coupled to an output of the fixed coefficient filter, and is configured to scale output of the fixed coefficient filter based on a selected Nyquist band. The summation circuit is coupled to the scaling circuit, and is configured to generate a derivative of the digital samples based on output of the scaling circuit.

Analog-to-digital converter non-linearity correction using multi-nyquist differentiator

A circuit for digital filtering an analog signal converted to digital, including an analog circuit to generate an analog signal, the analog signal including phase and/or gain errors. An analog-to-digital converter (ADC) to convert the analog signal to a digital signal output to a digital signal path. A frequency-dependent corrector filter included in the digital signal path, and configured as a parameterized filter, the parameterized filter configurable based on the DSA control signal with at least one complex filter parameter for each DSA attenuation step, to correct frequency-dependent errors in phase and/or gain.

Digital filtering for analog gain/phase errors

An integrated circuit chip includes an interleaved analog-to-digital converter (ADC) and an interleaving calibration circuit. The interleaved ADC includes a plurality of ADCs that are each configured to sample an analog signal. The interleaved ADC is configured to convert the analog signal into an interleaved analog-to-digital signal (IADC signal) that includes a plurality of spurious signals formed from mismatches between the plurality of ADCs. The interleaving calibration circuit is configured to receive the IADC signal from the interleaved ADC, generate a mismatch profile estimate corresponding to the plurality of spurious signals to generate one or more mismatch profile estimates, determine whether a first mismatch profile estimate is in a frequency band of interest, and, in response to a determination that the first mismatch profile estimate is in the frequency band of interest, generate a set of model parameters based on the first mismatch profile estimate.

Band specific interleaving mismatch compensation in RF ADCs

Circuitry for correcting non-linearity of an analog-to-digital converter. A non-linearity correction system for an analog-to-digital converter (ADC) includes coefficient storage, coefficient transformation circuitry, and correction circuitry. The coefficient storage is encoded with a first set of coefficients for correcting non-linearity of the ADC at a first sampling rate. The coefficient transformation circuitry is coupled to the coefficient storage. The coefficient transformation circuitry is configured to generate a second set of coefficients for correcting non-linearity of the ADC at a different sampling rate. The correction circuitry is configured to apply the second set of coefficients to correct non-linearity in output of the ADC while the ADC is operating at the different sampling rate.

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Chennai, India

Chandrasekhar Sriram