如何为不同数量的样本重新采样数据输入信号？

Question

我在 MacOS 上使用 MATLAB R2020a。我有一个采样频率为 1kHz 的 ECG 信号。从一个周期到另一个周期，由于周期长度不同，因此样本数量不同。但是，我希望有一个数组，每个循环的样本数量相同（大约 800 个），这样 800 个样本点就会自动拟合到原始样本点，而不管原始样本点的数量。我知道重采样函数允许以输入信号频率的一小部分进行重采样，但我不确定这将如何帮助我实现我的目标，因为我想对固定数量的点进行重采样。如果有任何建议，我将不胜感激。提前致谢

这是我的代码：

% Delimit cycles in original maximum amplitude signal using indices from
% Pan Tompkins algorithm
number_cycles = round(length(qrs_i_raw)/2);
number_samples = 900;
cycle_points_maxamp = zeros(number_cycles, length(number_samples));

x_eachcycle = zeros(number_cycles, length(number_samples));
values_x = zeros(length(number_samples), 1);

y_eachcycle = zeros(number_cycles, length(number_samples));
values_y = zeros(length(number_samples), 1);

z_eachcycle = zeros(number_cycles, length(number_samples));
values_z = zeros(length(number_samples), 1);

v_eachcycle = zeros(number_cycles, length(number_samples));

w_eachcycle = zeros(number_cycles, length(number_samples));

for currentcycle = 1:length(number_cycles)
    
    values_maxamp = maxamp(qrs_i_raw(currentcycle):qrs_i_raw(currentcycle + 1)); % need to resample to only generate 900 samples 
    cycle_points_maxamp(currentcycle, 1:length(values_maxamp)) = values_maxamp;
    
    values_z(1 + 2*tau_milli_rounded(currentcycle):end) = cycle_points_maxamp(currentcycle, 1:end - 2*tau_milli_rounded(currentcycle));
    z_eachcycle(currentcycle, 1:length(values_z)) = values_z;
    
    values_y(1 + tau_milli_rounded(currentcycle):end) = cycle_points_maxamp(currentcycle, 1:end - tau_milli_rounded(currentcycle));
    y_eachcycle(currentcycle, 1:length(values_y)) = values_y;
    
    values_x(1:end) = cycle_points_maxamp(currentcycle, 1:end);
    x_eachcycle(currentcycle, 1:length(values_x)) = values_x;
    
    values_v = ((1/sqrt(6))*(x_eachcycle(currentcycle, 1:length(values_x))) + (y_eachcycle(currentcycle, 1:length(values_y))) - 2*(z_eachcycle(currentcycle, 1:length(values_z))));
    v_eachcycle(currentcycle, 1:length(values_v)) = values_v;
    
    values_w = ((1/sqrt(2))*(x_eachcycle(currentcycle, 1:length(values_x))) - (y_eachcycle(currentcycle, 1:length(values_y))));
    w_eachcycle(currentcycle, 1:length(values_w)) = values_w;
    
end

以下是相关变量： maxamp qrs_i_raw

cyclepointsarray

Answer 1

要对信号的单个周期进行重新采样以使其长度为 800 points/samples，可以将 resample() 函数与参数 800 和 length(Random_Cycle) 一起使用。这里我随意使用了一个sinc信号。 resample() 函数将根据原始信号中可用采样点的数量进行插值（上采样）或抽取（下采样）。我会首先将您的信号分成单独的周期应用这种类型的重采样连接重采样分量以生成完整的重采样 ECG 信号。

Random_Cycle = sinc(-2*pi:0.5:2*pi);
subplot(1,2,1); stem(Random_Cycle);
title("Number of Samples: " + num2str(length(Random_Cycle)));

Resampled_Signal = resample(Random_Cycle,800,length(Random_Cycle));
subplot(1,2,2); stem(Resampled_Signal);
title("Number of Samples: " + num2str(length(Resampled_Signal)));

运行使用 MATLAB R2019b

如何为不同数量的样本重新采样数据输入信号？

How to resample data input signal for a different number of samples?

matlab

signals