The word soaking in Paragraph 3 is closest in meaning to ______.A.wettingB.drainingC.freez
The word soaking in Paragraph 3 is closest in meaning to ______.
A.wetting
B.draining
C.freezing
D.raining
The word soaking in Paragraph 3 is closest in meaning to ______.
A.wetting
B.draining
C.freezing
D.raining
A、a difference in pay due to nonmonetary characteristics of jobs.
B、an high wage paid by employers to entice workers to be more productive.
C、the difference between the quantity of labor supplied and the quantity of labor demanded at the minimum wage.
D、equivalent to a union wage.
Write MATLAB codes to implement DSSS system sinmulation, The system is a 2-user system with a 2-path frequency selective fadingchannel for each user, The power for each path is half the total transmit power for each user. A RAKR receiver with ideal channel estimation should be used in the receiver for each user. The relative delay between two paths is 1 chip. BPSK modulation is assumed. The BER-versus SNR curve should be drawn for both users. The SNR is defined by, and is assumed to change from 0 dB to 10 dB with step 1 dB. The simulation results should be compared with the theoretical BER versus SNR curve in flat Rayleigh fading channel.
A、N_Trials=300; N_number=100; N_snr=10; N_users=2; N_path=2; Delay=1; Q=16; N_samples=N_number*Q; E_M=0; for trials=1:N_Trials trials noise=randn(N_users.*N_path,Q*N_number)+j.*randn(N_users*N_path,Q*N_number); s10=round(rand(N_users,N_number)); ss_user=s10*2-1; % without consideration of delayed path pn01=round(rand(N_users,Q)); pn=(pn01.*2-1)./sqrt(Q); S_spread=[]; for user=1:N_users s=kron(ss_user(user,:), pn(user,:)); S_spread=[S_spread; s]; end S_multipath=[]; for user=1:N_users s_user=S_spread(user,:); Suser_delayed=[zeros(1,Delay), s_user(1,1:(N_samples-Delay))]; S_multipath=[S_multipath; [s_user;Suser_delayed]]; end %___________the following is to generate Rayleigh fading coefficients N=N_users.*N_path; fad_c=fading(8,0.005,N_samples, N); fad=fad_c.'; % only use the amplitude; %phase is not used, which is equivalent to have an ideal phase %compensation by using channel equalization S_spread=S_multipath.*fad; %S_spread is the signal matrix of size users x N_number sgma=1; Error_M=[ ]; for snr_db=0:1:N_snr snr=10.^(snr_db./10)/2; %Evaluate the SNR from SNR in dB N0=2*sgma.^2; Eb=snr.*N0; yy=sqrt(Eb./2)*S_spread+noise; %received spread signals in the baseband Error_v_user=[]; for user=1:N_users y_path1=yy((user-1).*N_path+1, :); y_path_temp=yy((user-1).*N_path+2, :); y_path2=[y_path_temp(1,Delay+1:N_samples), zeros(1,Delay)]; Y_M_path1=[ ]; Y_M_path2=[]; for k=1:N_number ym1=y_path1(1,(k-1)*Q+1:k*Q); ym2=y_path2(1,(k-1)*Q+1:k*Q); Y_M_path1=[Y_M_path1;ym1]; Y_M_path2=[Y_M_path2;ym2]; end % Y_M is a matrix of size N_number x Q, each row correspinding to a % BPSK symbol ys=Y_M_path1*pn(user,:).'+Y_M_path2*pn(user,:).'; %despreading for a user y=ys.'; y_real=real(y); s_e=sign(y_real); s_e10=(s_e+1)./2; Error_snr=sum(abs(s10(user,:)-s_e10)); Error_v_user=[Error_v_user;Error_snr./N_number]; %A BER collumn vector for all the users and for each snr end %for user Error_M=[Error_M,Error_v_user]; %BER matrix for all users and for all the SNRs end % end for snr E_M=E_M+Error_M ; end % end for trials BER=E_M./N_Trials; BER_T=[ ]; for snr_db=0:1:N_snr snr=10.^(snr_db./10); temp=sqrt(snr./(1+snr)); BER_THEROY=(1-temp)/2; BER_T=[BER_T,BER_THEROY]; end i=0:1:N_snr; semilogy(i,BER(1,:),'-r',i,BER(2,:),'ob',i,BER_T ,'*g'); xlabel('E_b/N_0(dB)') ylabel('BER') legend('User1 RAKE','User2 RAKE', 'Theoretical flat fading');
B、no need
C、no need
D、no need
A.The gold coins circulated in the U. S. before 1933.
B.The U. S. note issued during the American Civil War.
C.The coins and bills used in the U. S. today.
D.The gold or silver used in primitive societies.
A.slight
B.important
C.abundant
D.significant
A.Meaning and dignity on their existence.
B.The spiritual experience from masterpieces.
C.The healthy development of the art.
D.The spiritual experience from mediocre works.
A.What is unique in human aspiration.
B.The pursuit of fame and romantic love
C.A seemingly impossible goal.
D.The athletic perfection.
A.They brought into light valuable treasures for ordinary people to enjoy.
B.They stored the valuable treasures in the Cairo Museum.
C.They sold the valuable treasures to art lovers.
D.They put back the valuable treasures in the tomb.
A.the fighter and the hunter have different movements
B.the fighter may not necessarily kill its rival but the hunter does
C.the fighter and the hunter have different motives
D.the fighter and the hunter face different rivals
A.By discussing the relationship between the U.S. government and the Cherokee people.
B.By explaining the term used to label miners who moved to Dahlonega in 1828.
C.By indicating how much money a miner could make in Dahlonega.
D.By telling several accounts of the discovery of gold there in 1828.
A.the one
B.who was the
C.another
D.one of the
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