In case of turbo coding the Nturbo is the number of bits to generate the turbo codes (Nturbo = 250,506,etc). What my doubt here is that u use only 250 bits, but 256 bits are inputted into the turbo code block. Are the first 3 bits and last 3 bits used to generate the tail bits??
And the middle 250 bits for the data codes.?
If I am mistaken, please explain what set of bits are inputted into the constituent encoder with the clocking position.
(currently referring the book "Designing CDMA2000 systems" )

Thankyou