yht:=1; Tw:=2; t0:=0;y0:=0;
p1:=plot(DynamicSystems:-Sinc(yht,Tw,t0,y0),t=-10..10,color=red):
T:=[seq(t,t=-10..10,0.5)]:
A:=[seq(`if`(t=0,yht,y0 + yht*sin(Pi*(t - t0)/Tw)*Tw/(Pi*(t - t0))),t=-10..10,0.5)]:
p2:=DynamicSystems:-DiscretePlot(T,A,style=stem,color=blue):
plots:-display([p1,p2])
Or
restart;
yht:=1: Tw:=2: t0:=0: y0:=0:
sinc:=(yht,Tw,t0,y0,t)->`if`(t=0,yht,y0 + yht*sin(Pi*(t - t0)/Tw)*Tw/(Pi*(t - t0))):
p1:=plot(sinc(yht,Tw,t0,y0,t),t=-10..10,color=red):
T:=[seq(t,t=-10..10,0.5)]:
A:=[seq(sinc(yht,Tw,t0,y0,t),t=-10..10,0.5)]:
p2:=DynamicSystems:-DiscretePlot(T,A,style=stem):
plots:-display([p1,p2])
They both give