公开(公告)号：US10735038B2

公开(公告)日：2020-08-04

申请号：US15907544

申请日：2018-02-28

Applicant: NXP B.V.

Inventor： Radha Srinivasan ,  Ulrich Andreas Muehlmann ,  Frederic Benoist ,  Stefan Mendel ,  Steve Charpentier

IPC: H04B1/12 ,  H04B17/318 ,  H04B5/00 ,  H03M1/06 ,  H03M1/12

Abstract: Embodiments are provided for a method of operating a receiver system, the receiver system comprising one or more channels, the method comprising: monitoring a residual DC (direct current) offset in a present channel by sampling an output of an analog-to-digital converter (ADC) of the present channel; adjusting a DCO (direct current offset) correction signal that corresponds to the residual DC offset in response to an absolute value of the residual DC offset exceeding a programmable DCO threshold; and subtracting the DCO correction signal from an analog signal provided to the ADC to reduce the residual DC offset below the programmable DCO threshold.

公开(公告)号：US11588509B2

公开(公告)日：2023-02-21

申请号：US17446496

申请日：2021-08-31

Applicant: NXP B.V.

Inventor： Frederic Benoist

IPC: H04B1/16 ,  H04B5/00 ,  H04B1/08

Abstract: A near-field communication (NFC) receiver includes first and second input terminals for receiving first and second input signals having a modulated signal portion and a carrier signal portion. The receiver includes a digital-to-analog converter (DAC), a mixer, a track-and-hold (T&H) circuit, an amplifier, and an analog-to-digital converter. The mixer has a first input coupled to receive the first and second input signals and a second input coupled to receive a low frequency current from the DAC. The mixer subtracts the carrier portion from the first and second input signals using the DAC current at a level determined using a DSP in a feedback loop to approximate the carrier. The T&H circuit has an input coupled to receive the combined current and an output to provide a series of output samples. The ADC is coupled to receive the amplified output signal and to provide a digital representation of the amplified output signal.

公开(公告)号：US20220103195A1

公开(公告)日：2022-03-31

申请号：US17446496

申请日：2021-08-31

Applicant: NXP B.V.

Inventor： Frederic Benoist

IPC: H04B1/08 ,  H04B5/00

Abstract: A near-field communication (NFC) receiver includes first and second input terminals for receiving first and second input signals having a modulated signal portion and a carrier signal portion. The receiver includes a digital-to-analog converter (DAC), a mixer, a track-and-hold (T&H) circuit, an amplifier, and an analog-to-digital converter. The mixer has a first input coupled to receive the first and second input signals and a second input coupled to receive a low frequency current from the DAC. The mixer subtracts the carrier portion from the first and second input signals using the DAC current at a level determined using a DSP in a feedback loop to approximate the carrier. The T&H circuit has an input coupled to receive the combined current and an output to provide a series of output samples. The ADC is coupled to receive the amplified output signal and to provide a digital representation of the amplified output signal.