Analog Devices,inc.

Analog Devices Global

Guanghua Man

Lei Wang

Joseph Bradford Brannon

Yi Wang

John Oates

Gina G Colangelo

Joseph Brad Brannon

Apparatus and methods for dual loop power amplifier digital pre-distortion systems are disclosed. In certain implementations, a dual DPD system includes a first digital pre-distorter (DPD) and a second DPD. A digital IF upconverter electrically coupled between the first and second DPDs separates the DPD system into independently controlled fine and coarse sections. The adaptive adjustment processor can be used to modify or pre-distort input signals in order to compensate for the power amplifier nonlinearity. It also controls the fine DPD section to correct an RF output signal single-band adjacent channel leakage ratio (ACLR), while it controls the coarse DPD section to correct an RF output signal dual band intermodulation distortion (IMD).

Apparatus and methods for dual loop power amplifier digital pre-distortion systems

In an example, there is disclosed a multiple-input analog-to-digital converter configured to receive a plurality of analog inputs and to output one or more digital outputs. In one embodiment, two input analog signals are received. The two analog signals may be mixed in a combiner, which provides them to a pipeline ADC. In another embodiment, the combiner may time multiplex the two analog input signals and provide two separate outputs signals. Advantageously, the multiple-input ADC of the present Specification may be realized with a single ADC pipeline.

Multi-input analog-to-digital converter

Synthesizers are configured with first and second phase-locked loops (PLL's). The first PLL is arranged to include a digitally-controlled oscillator (DCO) and to respond to an input signal to provide a reference signal with a plurality of selectable reference frequencies. The second PLL is arranged to include a voltage-controlled oscillator (VCO) to thereby provide output signals in response to the reference signal. This synthesizer structure is particularly effective when responding to a noisy input signal as may be the case, for example, in wireless communication systems that provide a network clock to transceivers through lengthy optical links.

Frequency synthesizers for wireless communication systems

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Greensboro, NC, United States of America

Guanghua Man