公开(公告)号：US09651450B2

公开(公告)日：2017-05-16

申请号：US15156142

申请日：2016-05-16

Applicant: Texas Instruments Incorporated

Inventor： Nagarajan Viswanathan

IPC: G01M11/00

CPC classification number: G01M11/3145

Abstract: Optical time domain reflectometer (OTDR) systems, methods and integrated circuits are presented for locating defects in an optical cable or other optical cable, in which a first optical signal is transmitted to the cable and reflections are sampled over a first time range at a first sample rate to identify one or more suspected defect locations, and a second optical signal is transmitted and corresponding reflections are sampled over a second smaller time range at a higher second sample rate to identify at least one defect location of the optical cable for relaxed memory requirements in the OTDR system.

公开(公告)号：US09479186B1

公开(公告)日：2016-10-25

申请号：US14871373

申请日：2015-09-30

Applicant: Texas Instruments Incorporated

Inventor： Srinivas Kumar Reddy Naru ,  Nagarajan Viswanathan ,  Visvesvaraya Pentakota

IPC: H03M1/12 ,  H03M1/06 ,  H03M1/00 ,  H03M1/36

CPC classification number: H03M1/0609 ,  H03M1/203 ,  H03M1/361

Abstract: In described examples, an analog to digital converter (ADC) includes a main ADC and a reference ADC. The main ADC generates a zone information signal and a digital output in response to an input signal. The reference ADC receives a plurality of reference voltages from the main ADC. The plurality of reference voltages includes a first reference voltage and a second reference voltage. The reference ADC generates a reference output in response to the input signal, the first reference voltage and the second reference voltage. A subtractor generates an error signal in response to the digital output and the reference output. A logic block generates one of a first offset correction signal, a second offset correction signal and a gain mismatch signal in response to the zone information signal, the error signal and the reference output.

Abstract translation: 在所描述的示例中，模数转换器（ADC）包括主ADC和参考ADC。 主ADC响应于输入信号产生区域信息信号和数字输出。 参考ADC从主ADC接收多个参考电压。 多个参考电压包括第一参考电压和第二参考电压。 参考ADC根据输入信号，第一参考电压和第二参考电压产生参考输出。 减法器响应于数字输出和参考输出产生一个误差信号。 响应于区域信息信号，误差信号和参考输出，逻辑块产生第一偏移校正信号，第二偏移校正信号和增益失配信号中的一个。

公开(公告)号：US20160258838A1

公开(公告)日：2016-09-08

申请号：US15156142

申请日：2016-05-16

Applicant: Texas Instruments Incorporated

Inventor： Nagarajan Viswanathan

IPC: G01M11/00

CPC classification number: G01M11/3145

Abstract: Optical time domain reflectometer (OTDR) systems, methods and integrated circuits are presented for locating defects in an optical cable or other optical cable, in which a first optical signal is transmitted to the cable and reflections are sampled over a first time range at a first sample rate to identify one or more suspected defect locations, and a second optical signal is transmitted and corresponding reflections are sampled over a second smaller time range at a higher second sample rate to identify at least one defect location of the optical cable for relaxed memory requirements in the OTDR system.

公开(公告)号：US20130294295A1

公开(公告)日：2013-11-07

申请号：US13872093

申请日：2013-04-27

Applicant: TEXAS INSTRUMENTS INCORPORATED

Inventor： Nagarajan Viswanathan ,  Visvesvaraya Pentakota ,  Robert Clair Keller ,  Thomas Neu ,  Francesco Dantoni

IPC: H04L5/14

CPC classification number: H04L5/1461 ,  H04B1/525

Abstract: Apparatus and methods disclosed herein implement an RF receive-band filter at a receive chain input of a wireless base station with a co-located transmitter and receiver. The RF receive-band filter includes an adaptive filter component to perform filtering operations on samples of a digital baseband or intermediate frequency signal x(n) from a transmit chain associated with the wireless base station. An adaptive filter transfer function is determined in real time such that samples of the baseband transmit signal x(n) are transformed into a cancellation baseband signal z(n). The digital cancelation baseband signal z(n) is then digital-to-analog converted and the resulting analog baseband signal z(t) is up-converted to obtain a subtractive RF cancelation signal c(t). C(t) is summed with a desirable received signal RF component r(t) and an undesirable transmitter leakage RF signal component l(t) appearing at the input to the base station receiver. C(t) cancels l(t), leaving r(t) to be processed by the receiver section of the base station.

Abstract translation: 本文公开的装置和方法在具有共位发射器和接收器的无线基站的接收链输入端实现RF接收带滤波器。 RF接收带滤波器包括自适应滤波器组件，用于对与无线基站相关联的发射链进行数字基带或中频信号x（n）的采样执行滤波操作。 实时地确定自适应滤波器传递函数，使得基带发送信号x（n）的采样被变换为消除基带信号z（n）。 然后对数字消除基带信号z（n）进行数模转换，并将所得到的模拟基带信号z（t）上变频以获得减法RF消除信号c（t）。 C（t）与期望的接收信号RF分量r（t）和出现在基站接收机的输入处的不期望的发射机泄漏RF信号分量l（t）相加。 C（t）取消l（t），使r（t）由基站的接收机部分处理。