function THfasheji=fashe()
Pow = -30;       % Average transmitted power (dBm)
fc = 50e9;       % sampling frequency
numbits = 2;     % number of bits generated by the source
Ts =5e-9;  
Nh = 3;          % cardinality of the Time Hopping code
Np = numbits;          % periodicity of the Time Hopping code
Tc = 1e-9;       % chip time [s]              
Tm = 2e-9;     % pulse duration [s]
B=4e9;
G = 1;
bits =bits(numbits);


power = (10^(Pow/10))/1000;     % average transmitted power                                %  (watt)
Ex = power * Ts; 
w0=zeros(1,Ts*numbits*fc);
for i=1:numbits
if   bits(i)==0 
    w1=waveformdown(fc,Tm,B)
    w0((Ts*(i-1)*fc+1):(fc*Ts*(i-1)+fc*Tm))=w1(1:fc*Tm);% Energy Normalized pulse
else  
    w2=waveformup(fc,Tm,B);
    w0((Ts*(i-1)*fc+1):(fc*Ts*(i-1)+fc*Tm))=w2(1:fc*Tm);   
end   %  waveform
end
wtx = w0 .* sqrt(Ex);           % pulse waveform

dt=1/fc;
N=length(wtx);
T=N*dt;
df=1/T;
X = fft(wtx);
X = X / N;
mPSD=abs(X).^2/(df^2);
PSD = fftshift(mPSD);
PSD = (1/T).*PSD;

% -----------------------------------
% Step Two - Graphical representation
% -----------------------------------

frequency = linspace(-fc/2,fc/2,length(PSD));
PF=plot(frequency,PSD);
set(PF,'LineWidth',[2]);
axis([0 9e9 0 5e-25]);
AX=gca;
set(AX,'FontSize',12);
X=xlabel('Frequency [Hz]');
set(X,'FontSize',12);
Y=ylabel('Power Spectral Density [V^2/Hz]');
set(Y,'FontSize',12);