Yes …they are using the same logic
200/8=25 khz. You can search google
by using the keyword … 200/8=25khz and can see how many in the world supports the above theory.
That is why in my post(last line)…
“How can we say that the in GSM BW per user is 25 Khz”
So…what do you think effective BW should be per user in GSM
I think it should be 400 khz.