I have got a code from (www.simsonic.fr) which takes input as fractional BW, time and centre frequency, and gives in phase pulse and envelope as output. But my concern is how can I check if the signal is correct. I tried to use the fft command using which I got 2 peaks(one for the negative and one for the positive side). and also can anybody explain what fractional bandwidth really is? I have taken the Fractional BW as 1, because this gives me a bandwidth of 500Khz if my centre frequency is 500Khz, What I desire: to get a signal with centre frequency at 500Khz with 500Khz extended on either side. FBW=BW/Fc, if I keep FBW as 1 and Fc as 500k I get a BW of 500k, is this correct? The code for the same is attached below. I also need to check the corresponding signal in frequency domain, if I am getting the desired bandwidth, but I am not getting the same. Can anybody please help.
f0=0.5; % central frequency, MHz t0=1.5; % pulse center time bndwdth=1; % pulse -6dB bandwidth duration=2*t0; % signal length timebase=(0:round(duration/dt)-1)'*dt; [signalI,signalQ,signalE]=gauspuls(timebase-t0,f0,bndwdth); signal=signalQ; figure(9) subplot(2,1,1); plot(timebase,signalQ,'.-') title('source signal') xlabel('time (µs)') figure(9) midf=5e5; L=1000; fs=midf*2; Mb = fft(signal); %Mb = fftshift(Mb); f = fs*linspace(-0.5,0.5,length(Mb)); %Frequency Vector subplot(2,1,2); plot(f,abs(Mb)) title('Gaussian Pulse in Frequency Domain in bone') xlabel('Frequency (f)') ylabel('|Magnitude(f)|')