Documents.zip_NT2_斜阶跃关断_瞬变电磁_瞬变电磁 关断_瞬变电磁响应

clear clc format long %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%孙 %%%%%%%天 %%%%%%%才 %%%%%%%文 %%%%%%%章 %%%%%%%计 %%%%%%%算 %%%%%%%晚期视电阻率噪声 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %% %%%%%孙天财 a = 100; I = 1; t0 = 50*1e-5; t = (1e-6:1e-6:0.1); rho = 100; u0 = 4*pi*1e-7; u = a/2*sqrt(u0./(t.*rho)); nn = size(t,2); for i = 1:nn v1 = I./a.*(3./(4.*t0.*u.^2)-1./(2.*t0)+3./(4.*t.*u.^2)).*erf(u./sqrt(1+(t0./t))); v2 = 3.*I.*exp(-u.^2./(1+(t0./t)))./(2.*a.*t0.*u.*sqrt(pi.*(1+(t0./t)))); v3 = I./a./t0.*(1/2-3./4.*u.^2).*erf(u); v4 = 3.*I./2./a./t0./u./sqrt(pi).*exp(-u.^2); end v = v1+v2+v3+v4; %% %%%%%白登海 clear clc rho = 0.1; u0 = 4*pi*1e-7; a = 1; t = (1e-6:1e-6:1); Z = a/2*sqrt(u0/rho./t); %% %% f0 = f0_V(1); s1 = 3*cos(2*pi*(f0*fs/N)*t); for m0 = 1:length(SNR_V) SNR = SNR_V(m0); for m1 = 1:length(f1_V) f1 = f1_V(m1); for m2 = 1:length(beta_V) beta = beta_V(m2); s2 = 3*cos(2*pi*(f1*fs/N)*t + beta); errs = 0; for m3 = 1:1000 S = awgn(s1 + s2,SNR,'measured'); s_w = S.*w; X = fft(s_w); Xn_amp = abs(X(1:floor(N/2))); kp = 5; J = 1; l = kp - J; % 虚拟的局部峰值起始位置 V_S0 = X(l - 1:kp + 1); % “多谱线插值”谱线选取 enta1 = - diff(V_S0(1:end-1),J+1)*(H - l)^2 ... + diff(V_S0(2:end-1),J)*(2*H + J -1)*(2*H + J) ... + diff(V_S0(2:end),J+1)*(H + J + l)^2; enta2 = diff(V_S0,J+2); f_est0 = (sqrt(abs(enta1/enta2))-1); errs = errs + abs(f_est0 - f0)/f0; end errs_V0(m2) = errs/1000; end errs_M(m0,m1) = max(errs_V0); end end %% x_axis = f1_V - f0; figure(1) semilogy(x_axis,errs_M(1,:),'r-.');hold on; % 比值校正法 semilogy(x_axis,errs_M(2,:),'b-.');hold on; % J=0 semilogy(x_axis,errs_M(3,:),'k-.');hold on; % J=1 semilogy(x_axis,errs_M(4,:),'g-.');grid on; % J=2 semilogy(x_axis,errs_M(5,:),'y-.');grid on; % J=3 semilogy(x_axis,errs_M(6,:),'y-');grid on; % J=3