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realfeifei金蟲 (小有名氣)
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[求助]
請(qǐng)教利用sedumi設(shè)計(jì)空間濾波器
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利用二階錐設(shè)計(jì)空間濾波器問(wèn)題請(qǐng)教。! 假設(shè)一個(gè)由12個(gè)各向同性陣元組成的水平均勻線列陣, 從陣列的一端依次編號(hào)為#1, #2, ⋯, #12陣元, 定義基陣法線方向?yàn)?º. 陣元間隔取為1920 Hz的半波長(zhǎng), 系統(tǒng)采樣頻率為fs=6000 Hz, 要求在工作頻帶FP=[960, 1920] Hz內(nèi)形成頻率不變波束. 將觀察扇面[-90º,90º]按2.5º離散化, 以960 Hz的常規(guī)(延遲求和)波束主瓣作為參考波束主瓣, 并選擇其中的5個(gè)方位點(diǎn)={-17.5°, -10°, 0°, 10°, 17.5°}的波束響應(yīng)作為主瓣內(nèi)期望波束響應(yīng). 設(shè)定旁瓣區(qū)域?yàn)镾LΘ= [-90°︰2.5°︰-25°][25°︰2.5°︰90°], 期望旁瓣級(jí)為-25 dB. 下面的程序是用上面的約束條件求1920Hz的陣元加權(quán)系數(shù),以實(shí)現(xiàn)-25dB旁瓣和接近920Hz對(duì)應(yīng)的主瓣. 最終的結(jié)果卻不如所愿,懇請(qǐng)高手指點(diǎn)!! clear all; path(path,'E:\SDM\SeDuMi_1_1'); f_l=960; f_h=1920; c_sound=1500; fs=6000; lamda=c_sound/f_h; d=lamda/2; lamda_l=c_sound/f_l; N=12;%»ùÔªÊý %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% angle = -90:2.5:90; Num = size(angle,2); for i=1:Num signal(1:1:N)=exp(1j*2*pi*((1:N)-1)*d/lamda_l*sin(angle(i)*pi/180)); %%%%%%%%%%%%%%%%%%%%%%%%% Mag_c_ref(i) = signal*ones(N,1) Mag_ref = abs(Mag_c_ref); end figure(1) plot(angle,20*log10(Mag_ref/max(Mag_ref)),'.') ylim([-50 0]) grid on; %%%%%%%%%%%%%%%%%%%%%%%%%%主瓣條件%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% theta_d = [-17.5,-10,0,10,17.5]*pi/180; theta_d_m = [Mag_c_ref(30) Mag_c_ref(33) Mag_c_ref(37) Mag_c_ref(41) Mag_c_ref(44)]/ abs(Mag_c_ref(37)); %%%%%%%%%%%%%%%%%%%%%%%%%旁瓣條件%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% theta_s = [-90:2.5:-25 25:2.5:90]*pi/180; theta_s_m = ones(1,size(theta_s,2))*10.^(-25/20); hold on;%figure(2) theta = [theta_s(1:end/2) theta_d theta_s(end/2+1:end)]; theta_p=abs([theta_s_m(1:end/2) theta_d_m theta_s_m(end/2+1:end)]); plot(theta*180/pi,20*log10(theta_p/max(theta_p)),'k*'); lamda = c_sound/(960*1.5); K.q=[]; M1=size(theta_d,2); c1 = cell(M1,1); %%%%%%%%%%%%主瓣約束二階錐%%%%%%%%%%%%%%%% A = cell(3*M1,1);%%%% for i = 1:M1 c1{i} = [1 2*theta_d_m(i) -1].'; v = exp(-1j*2*pi*((1:N)-1)*d/lamda*sin(theta_d(i))).'; AAA = [0 0 0 0 0]; AAA(i) = 1; q=AAA.'; A{(i-1)*3+1} = [-q.',zeros(1,N)]; A{(i-1)*3+2} = [zeros(1,M1), 2*v.']; A{(i-1)*3+3} = [-q.',zeros(1,N)]; K.q=[K.q,3]; end %%旁瓣約束二階錐 epsro = 10.^(-25/20); M2 = size(theta_s,2); B = cell(2*M2,1); c2 = cell(M2,1); for i = 1:M2 c2{i} = [epsro,0].'; v = exp(-1j*2*pi*((1:N)-1)*d/lamda*sin(theta_s(i))).'; B{(i-1)*2+1} = [zeros(1,M1) zeros(1,N)]; B{(i-1)*2+2} = [zeros(1,M1) -v.']; K.q=[K.q,2]; end %%權(quán)值約束二階錐 gama = 1;%0.7;%1;%0.7; C = cell(2*1,1);%%%%Am' c3= cell(1,1); c3 = [gama 0].'; C{1,1} = [zeros(1,M1) zeros(1,N)]; C{2,1} = [zeros(1,M1) -ones(1,N)]; c1=cell2mat(c1); c2=cell2mat(c2); K.q=[K.q,2]; c = [c1.' c2.' c3.'].'; A=cell2mat(A); B=cell2mat(B); C=cell2mat(C); At=[A.' B.' C.'].'; b = [ones(1,5), zeros(1,12)]'; [x,y,info]=sedumi(At,-b,c,K); info b.'*y %%畫實(shí)際的波束圖 w=y(M1+1:end); angle = -90:2.5:90; Num = size(angle,2); for i=1:Num signal(1:1:N)=exp(1j*2*pi*((1:N)-1)*d/lamda*sin(angle(i)*pi/180)); w_mag=w; w_phase=ones(N,1);%Õýǰ•½Ïàλ¼ÓȨÏàͬ Mag(i) = abs(signal*(w_mag.*w_phase)); end hold on;%figure(3) plot(angle,20*log10(Mag/max(Mag)),'rp') legend('reference beam pattern','desired beam pattern','realized beam pattern') |
新蟲 (初入文壇)
金蟲 (小有名氣)
鐵蟲 (初入文壇)

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