[up,lo] = envelope(data840filter1,1024,'rms');给出具体的envelope函数

以下是一个简单的 Matlab 函数实现，用于计算数据序列的包络线信号：

function [up, lo] = envelope(x, win_size, method)
% Compute the envelope of a signal using a moving window and specified method
% Input:
%   x: input signal
%   win_size: size of the moving window
%   method: 'rms' or 'peak' for computing envelope
% Output:
%   up: upper envelope signal
%   lo: lower envelope signal

% Initialize envelope signals
up = zeros(size(x));
lo = zeros(size(x));

% Compute envelope using moving window
for i = 1:length(x)
    start_idx = max(1, i-win_size+1);
    end_idx = min(length(x), i+win_size-1);
    window = x(start_idx:end_idx);
    
    if strcmp(method, 'rms')
        env_val = rms(window);
    elseif strcmp(method, 'peak')
        env_val = max(abs(window));
    else
        error('Invalid method');
    end
    
    up(i) = env_val;
    lo(i) = -env_val;
end

% Apply a smoothing filter to the envelope signals
up = smooth(up, win_size);
lo = smooth(lo, win_size);
end

该函数使用了一个移动窗口来计算包络线信号，可以通过指定窗口大小和计算方法（'rms' 或 'peak'）来调整包络线的精度和平滑度。函数返回上包络线和下包络线信号。