samer@34: function [y,phi]=block(o,phi,T,cutoff,f)
samer@34: % block - Generate block of blit signal data
samer@34: %
samer@34: % block :: 
samer@34: %    blit       ~'blit object'
samer@34: %    0--1       ~'initial phase (in cycles)'
samer@34: %    N:natural  ~'number of samples to compute',
samer@34: %    0--1       ~'normalised frequency (1=sampling freq)',
samer@34: %    0--0.5     ~'cutoff harmonics above this frequency [0.5]',
samer@34: % -> [[1,N]]    ~'band-limited impulse train',
samer@34: %    0--1       ~'initial phase for next block'.
samer@34: 
samer@34: m = max(1,2*floor(cutoff/f)-1); % number of harmonics to keep
samer@34: y = m*f*diric(2*pi*(phi+f*(0:T-1)),m)-f;
samer@34: phi = mod(phi+f*T,1);
samer@34: 
samer@34: % If diric is not available then use this
samer@34: % y=zeros(1,T);
samer@34: % phase = pi*(phi+f*(0:T-1));
samer@34: % modcheck=mod(phase,pi);
samer@34: % I=modcheck>0.001 & modcheck<(pi-0.001);
samer@34: % y(~I) = f*m;
samer@34: % y(I)  = f*sin(m*phase(I))./sin(phase(I));
samer@34: 
samer@34: