Dear Csounders,

Last night, I was studying _table_ opcode, using the following Csound
program:

;orchestra file
instr 1
a1	oscil	255,440,1	;sine wave
aout	table	a1,2		;transfer function
	out	aout*800
endin
	
;score file
f1 0 8192 10 1		; sinus
f2 0 512 -7 -1 512 1	; f(x)=x

i1 0 2

As far as I know, the second parameter of _table_ opcode can be used
to be a transfer function.  In my Csound score file, I define function
table 1 as a sinusoid, which means a1 is a signal like the following:
	a1 = sin(t)
Then I use _table_ to transfer a1 into aout.  Since function table 2
is f(x)=x, aout should be:
	aout = sin(t)
Right?

The question is I really got a signal other than a sine wave!!!  It
waveshape is half sinus half line!  What is wrong?  Could some help
me?  I am totally confused with what I've got.



==
Qian Chen

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> ;orchestra file
> instr 1
> a1	oscil	255,440,1	;sine wave
> aout	table	a1,2		;transfer function
> 	out	aout*800
> endin
> 	
> ;score file
> f1 0 8192 10 1		; sinus
> f2 0 512 -7 -1 512 1	; f(x)=x
> 
> i1 0 2
> 
> As far as I know, the second parameter of _table_ opcode can be used
> to be a transfer function.  In my Csound score file, I define function
> table 1 as a sinusoid, which means a1 is a signal like the following:
> 	a1 = sin(t)
> Then I use _table_ to transfer a1 into aout.  Since function table 2
> is f(x)=x, aout should be:
> 	aout = sin(t)
> Right?
> 
> The question is I really got a signal other than a sine wave!!!  It
> waveshape is half sinus half line!  What is wrong?  Could some help
> me?  I am totally confused with what I've got.
> 

you must place the origin of the table at the halfmark of the 
table...since the driving oscilator goes positive and negative... you are 
only partially confused, not totally...

aout table	a1,2,0,256 (you may want to check this i 'm not certain this 
is the correct parameter order...

Good luck

_____________________________________________________________________________
                                                                   Jean Piche
                                                                Musique - UdM
                                                      pichej@ERE.Umontreal.ca