You can use the following piece of code :
% Sampling Rate
Ts=1E-3; %Tsampling =1ms
% Transfer function
h=zeros(530+1);
h(210+1)=db2mag(-3);
h(320+1)=db2mag(-5);
h(530+1)=db2mag(-7);
But keep in mind that, when you are going to use this transfer function, you must have adopted Ts=1ms into your simulation
On the other hand, if you want to use an arbitrary sampling rate within your simulation model, you can use this :
% Sampling Rate
Fs=256; % 256 Hz
Ts=1/Fs; %Tsampling = 1/Fampling
% calculation of delays expressed in samples
D1=round( (210E-3)/Ts );
D2=round( (320E-3)/Ts );
D3=round( (530E-3)/Ts );
% Transfer function
h=zeros(D3+1);
h(D1+1)=db2mag(-3);
h(D2+1)=db2mag(-5);
h(D3+1)=db2mag(-7);
