公开(公告)号：US08934595B2

公开(公告)日：2015-01-13

申请号：US14156202

申请日：2014-01-15

Applicant: National Instruments Corporation

Inventor： I. Zakir Ahmed ,  Krishna Bharadwaj ,  Ramesh Krishnan ,  Vijaya Yajnanarayana

IPC: H04L7/033 ,  H04L7/00 ,  H03M1/12

CPC classification number: H04L7/033 ,  H03M1/1255 ,  H04L7/0087

Abstract: A low complexity system and method for operating a receiver in order to estimate an offset between the actual sample clock rate 1/TS′ of a receiver and an intended sample clock rate 1/TS. The receiver captures samples of a received baseband signal at the rate 1/TS′, operates on the captured samples to generate an estimate for the clock rate offset, and fractionally resamples the captured samples using the clock rate offset. The resampled data represents an estimate of baseband symbols transmitted by the transmitter. The action of operating on the captured samples involves computing an error vector signal and then estimating the clock rate offset using the error vector signal. The error vector signal may be computed in different ways depending on whether or not carrier frequency offset and carrier phase offset are assumed to be present in the received baseband signal.

Abstract translation: 用于操作接收机以便估计接收机的实际采样时钟速率1 / TS'与预期采样时钟速率1 / TS之间的偏移的低复杂度系统和方法。 接收机以速率1 / TS'捕获接收到的基带信号的采样，对捕获的采样进行操作，以产生时钟偏移量的估计，并且使用时钟速率偏移对所捕获的采样进行分数重新采样。 重采样的数据表示由发射机发射的基带符号的估计。 在捕获的样本上操作的动作包括计算误差矢量信号，然后使用误差矢量信号估计时钟偏移。 取决于载波频率偏移和载波相位偏移是否被假设为存在于接收基带信号中，可以以不同的方式计算误差向量信号。

公开(公告)号：US08755470B2

公开(公告)日：2014-06-17

申请号：US13852291

申请日：2013-03-28

Applicant: National Instruments Corporation

Inventor： I Zakir Ahmed ,  Krishna Bharadwaj ,  Vijaya Yajnanarayana

IPC: H04L27/06 ,  H04L5/12 ,  H04J3/16

CPC classification number: H04L27/3405 ,  H04L27/0014 ,  H04L2027/003

Abstract: A mechanism for jointly correcting carrier phase and carrier frequency errors in a demodulated signal. A computer system may receive samples of a baseband input signal (resulting from QAM demodulation). The computer system may compute values of a cost function J over a grid in a 2D angle-frequency space. A cost function value J(θ,ω) is computed for each point (θ,ω) in the grid by (a) applying a phase adjustment of angle θ and a frequency adjustment of frequency ω to the input signal; (b) performing one or more iterations of the K-means algorithm on the samples of the adjusted signal; (c) generated a sum on each K-means cluster; and (d) adding the sums. The point (θe, ωe) in the 2D angle-frequency space that minimizes the cost function J serves an estimate for the carrier phase error and carrier frequency error. The estimated errors may be used to correct the input signal.

Abstract translation: 一种在解调信号中联合校正载波相位和载波频率误差的机制。 计算机系统可以接收基带输入信号的采样（由QAM解调产生）。 计算机系统可以在2D角度 - 频率空间中计算网格上的成本函数J的值。 通过（a）应用角度和角度的相位调整，计算网格中每个点（＆Theta;，ω）的成本函数值J（＆amp; 以及对输入信号的频率ω的频率调整; （b）对所调整的信号的采样执行K均值算法的一个或多个迭代; （c）在每个K-means集群上产生一个和; 和（d）加总和。 使成本函数J最小化的2D角度 - 频率空间中的点（＆Theta; e，ωe）用于载波相位误差和载波频率误差的估计。 可以使用估计的误差来校正输入信号。

公开(公告)号：US20130215986A1

公开(公告)日：2013-08-22

申请号：US13852291

申请日：2013-03-28

Applicant: National Instruments Corporation

Inventor： I Zakir Ahmed ,  Krishna Bharadwaj ,  Vijaya Yajnanarayana

IPC: H04L27/34

CPC classification number: H04L27/3405 ,  H04L27/0014 ,  H04L2027/003

Abstract: A mechanism for jointly correcting carrier phase and carrier frequency errors in a demodulated signal. A computer system may receive samples of a baseband input signal (resulting from QAM demodulation). The computer system may compute values of a cost function J over a grid in a 2D angle-frequency space. A cost function value J(θ,ω) is computed for each point (θ,ω) in the grid by (a) applying a phase adjustment of angle θ and a frequency adjustment of frequency ω to the input signal; (b) performing one or more iterations of the K-means algorithm on the samples of the adjusted signal; (c) generated a sum on each K-means cluster; and (d) adding the sums. The point (θe, ωe) in the 2D angle-frequency space that minimizes the cost function J serves an estimate for the carrier phase error and carrier frequency error. The estimated errors may be used to correct the input signal.

Abstract translation: 一种在解调信号中联合校正载波相位和载波频率误差的机制。 计算机系统可以接收基带输入信号的采样（由QAM解调产生）。 计算机系统可以在2D角度 - 频率空间中计算网格上的成本函数J的值。 通过以下方式计算网格中每个点（θ，ω）的成本函数值J（θ，ω）：（a）将角度θ的相位调整和频率ω的频率调整应用于输入信号; （b）对所调整的信号的采样执行K均值算法的一个或多个迭代; （c）在每个K-means集群上产生一个和; 和（d）加总和。 最小化成本函数J的2D角度 - 频率空间中的点（θe，omegae）用于载波相位误差和载波频率误差的估计。 可以使用估计的误差来校正输入信号。

公开(公告)号：US20140126676A1

公开(公告)日：2014-05-08

申请号：US14156202

申请日：2014-01-15

Applicant: NATIONAL INSTRUMENTS CORPORATION

Inventor： I. Zakir Ahmed ,  Krishna Bharadwaj ,  Ramesh Krishnan ,  Vijaya Yajnanarayana

IPC: H04L7/033

CPC classification number: H04L7/033 ,  H03M1/1255 ,  H04L7/0087

Abstract: A low complexity system and method for operating a receiver in order to estimate an offset between the actual sample clock rate 1/TS′ of a receiver and an intended sample clock rate 1/TS. The receiver captures samples of a received baseband signal at the rate 1/TS′, operates on the captured samples to generate an estimate for the clock rate offset, and fractionally resamples the captured samples using the clock rate offset. The resampled data represents an estimate of baseband symbols transmitted by the transmitter. The action of operating on the captured samples involves computing an error vector signal and then estimating the clock rate offset using the error vector signal. The error vector signal may be computed in different ways depending on whether or not carrier frequency offset and carrier phase offset are assumed to be present in the received baseband signal.

Abstract translation: 用于操作接收机以便估计接收机的实际采样时钟速率1 / TS'与预期采样时钟速率1 / TS之间的偏移的低复杂度系统和方法。 接收机以速率1 / TS'捕获接收到的基带信号的采样，对捕获的采样进行操作，以产生时钟偏移量的估计，并且使用时钟速率偏移对所捕获的采样进行分数重新采样。 重采样的数据表示由发射机发射的基带符号的估计。 在捕获的样本上操作的动作包括计算误差矢量信号，然后使用误差矢量信号估计时钟偏移。 取决于载波频率偏移和载波相位偏移是否被假设为存在于接收基带信号中，可以以不同的方式计算误差向量信号。

公开(公告)号：US08654903B2

公开(公告)日：2014-02-18

申请号：US13866312

申请日：2013-04-19

Applicant: National Instruments Corporation

Inventor： I. Zakir Ahmed ,  Krishna Bharadwaj ,  Ramesh Krishnan ,  Vijaya Yajnanarayana

IPC: H04L27/06

CPC classification number: H04L7/033 ,  H03M1/1255 ,  H04L7/0087

Abstract: A low complexity system and method for operating a receiver in order to estimate an offset between the actual sample clock rate 1/TS′ of a receiver and an intended sample clock rate 1/TS. The receiver captures samples of a received baseband signal at the rate 1/TS′, operates on the captured samples to generate an estimate for the clock rate offset, and fractionally resamples the captured samples using the clock rate offset. The resampled data represents an estimate of baseband symbols transmitted by the transmitter. The action of operating on the captured samples involves computing an error vector signal and then estimating the clock rate offset using the error vector signal. The error vector signal may be computed in different ways depending on whether or not carrier frequency offset and carrier phase offset are assumed to be present in the received baseband signal.

Abstract translation: 用于操作接收机以便估计接收机的实际采样时钟速率1 / TS'与预期采样时钟速率1 / TS之间的偏移的低复杂度系统和方法。 接收机以速率1 / TS'捕获接收到的基带信号的采样，对捕获的采样进行操作，以产生时钟偏移量的估计，并且使用时钟速率偏移对所捕获的采样进行分数重新采样。 重采样的数据表示由发射机发射的基带符号的估计。 在捕获的样本上操作的动作包括计算误差矢量信号，然后使用误差矢量信号估计时钟偏移。 取决于载波频率偏移和载波相位偏移是否被假设为存在于接收基带信号中，可以以不同的方式计算误差向量信号。

公开(公告)号：US20130230114A1

公开(公告)日：2013-09-05

申请号：US13866312

申请日：2013-04-19

Applicant: NATIONAL INSTRUMENTS CORPORATION

Inventor： I. Zakir Ahmed ,  Krishna Bharadwaj ,  Ramesh Krishnan ,  Vijaya Yajnanarayana

IPC: H04L7/00

CPC classification number: H04L7/033 ,  H03M1/1255 ,  H04L7/0087

Abstract: A low complexity system and method for operating a receiver in order to estimate an offset between the actual sample clock rate 1/TS′ of a receiver and an intended sample clock rate 1/TS. The receiver captures samples of a received baseband signal at the rate 1/TS′, operates on the captured samples to generate an estimate for the clock rate offset, and fractionally resamples the captured samples using the clock rate offset. The resampled data represents an estimate of baseband symbols transmitted by the transmitter. The action of operating on the captured samples involves computing an error vector signal and then estimating the clock rate offset using the error vector signal. The error vector signal may be computed in different ways depending on whether or not carrier frequency offset and carrier phase offset are assumed to be present in the received baseband signal.

Abstract translation: 用于操作接收机以便估计接收机的实际采样时钟速率1 / TS'与预期采样时钟速率1 / TS之间的偏移的低复杂度系统和方法。 接收机以速率1 / TS'捕获接收到的基带信号的采样，对捕获的采样进行操作，以产生时钟偏移量的估计，并且使用时钟速率偏移对所捕获的采样进行分数重新采样。 重采样的数据表示由发射机发射的基带符号的估计。 在捕获的样本上操作的动作包括计算误差矢量信号，然后使用误差矢量信号估计时钟偏移。 取决于载波频率偏移和载波相位偏移是否被假定为存在于接收基带信号中，可以以不同的方式计算误差向量信号。