iseed = -1

!p.charsize=2

fn = 'circlsq'

; make a ps file? 


omega = 2 * !pi ; radians per sec

npts = 21
t = 0.1 + 1.8* findgen(npts)/npts




a0 = 1.0
a1 = 1./sqrt(2)
 
x = a0 + a1 * sin(omega * t) + 0.25*randomn(iseed,npts)




plot,t,x,ps=1,xtit = 'Time [s]',ytit = 'x [m]'


b = transpose([[replicate(1,npts)],[sin(omega*t)] ])
y = transpose(x)
psi = invert( transpose(b) ## b)
ans = psi ## transpose( b) ## y


npts = 200
ti = 2*findgen(npts)/npts

oplot,ti,ans[0] + ans[1]*sin(omega*ti)



end