SAMPLE 1 30
* Generate the time-varying coefficients
GENR AI=TIME(0) 
GENR B1=.5*SIN(AI*2*$PI/30) 
GENR B2=SIN( (AI*2*$PI/30) + $PI/2)
* Generate the data
GENR X1=1
GENR X2=1
SAMPLE 2 30
GENR X1=SIN(10+AI)+.01
* The next command uses the SIN function to generate COS(10 + AI)
GENR X2=SIN(10.0+AI + $PI/2) 
SAMPLE 1 30
GENR Y=B1*X1+B2*X2
* Get the FLS estimates
FLS Y X1 X2 / NOCONSTANT PCOEF
STOP