cp0301_ppm_sin.m

这是一本超宽带通信书籍< 超宽带无线通信>>的原代码,ds_uwb,mb_ofdm,脉冲信号的形成

%
% FUNCTION 3.1 : "cp0301_PPM_sin"
%
% Generation of a PPM-UWB signal in the case of a 
% sinusoidal modulating signal and rectangular pulses
%
% Transmitted Power is fixed at 'Pow'.
% The signal is sampled with frequency 'fc'.
% 'np' is the number of generated pulses.
% 'Ts' is the average pulse repetition period.
% Each rectangular pulse has time duration 'Tr'
% The modulating signal is a sinusoid with
% amplitude 'A' and frequency 'f0'
%
% The function returns the generated signal 'Stx'
% and the corresponding sampling frequency 'fc'
%
% Programmed by Guerino Giancola
%

function [Stx,fc]=cp0301_PPM_sin;

% ----------------------------
% Step Zero - Input Parameters
% ----------------------------

Pow = -30;  % Average transmitted power (dBm)

fc = 1e11;  % sampling frequency

np = 10000; % number of pulses

Tr = 0.5e-9;% time duration of the rectangular pulse [s]

Ts = 2e-9;  % average pulse repetition period [s]
A = Ts/2;   % maximum time-shift provided by the
            % modulation [s]
f0 = 5e7;   % frequency of the modulating signal [Hz]

% ----------------------------------------
% Step One - Simulating Transmission Chain
% ----------------------------------------

dt = 1 / fc;         % sampling period
sTs = floor(Ts/dt);  % number of samples per frame 
sTot = sTs * np;     % total number of samples
Stx = zeros(1,sTot); % output vector

% pulse position modulation
j = (0:1:np-1);
M0 = A.*cos((2*pi*f0).*(j.*Ts));
M1 = j.*Ts;
Mtot = M0 + M1;
for k = 1 : np
  Stx(1+floor(Mtot(k)/dt))=1;
end

% shaping filter
sP = floor(Tr/dt);   % number of samples per
                     % pulse
p0 = (1/sqrt(Tr)).*ones(1,sP); % energy normalized rect
power = (10^(Pow/10))/1000;    % average transmitted power
                               % (Watt)
Ex = power * Ts;        % energy per pulse
ptx= p0 .* sqrt(Ex);    % pulse waveform

Stx = conv(Stx,ptx);
Stx = Stx(1:sTot);