var SinCosTableGenerator = function (length, sinAmp, cosAmp, frequency){ 
if (sinAmp === undefined) { 
sinAmp = 1; 
} 
if (cosAmp === undefined) { 
cosAmp = 1; 
} 
if (frequency === undefined) { 
frequency = 1; 
} 
frequency *= Math.PI / length; 
var cos = [] ; 
var sin = [] ; 
for (var c = 0; 
c < length; c++ ){ 
cosAmp -= sinAmp * frequency; 
sinAmp += cosAmp * frequency; 
cos[c] = cosAmp; 
sin[c] = sinAmp; 
} 
return { 
sin: sin,
cos: cos,
length: length}
; 
} 
; 
module.exports = SinCosTableGenerator;