I have a question about the spreading sequence for CDMA. Normally, we use a PN code but imagine that we use a cosine wave combined with a PN code where the PN code has for length $T * fs$. With $T$ is the duration of the cosine wave, $fs$ the sampling frequency.
My question is about the duration: With a PN code (CDMA) the duration for 1 symbol is $SF/B$ with $SF$ the spreading factor and $B$ the bandwidth. But a combination with a cosine wave, the duration for 1 symbol is $T$ which the duration of the cosine wave or $(T*fs)/B$ with $T*f_s$ the length for the PN code.