We currently have a radio that is transmitting at the following RF params:
- Modulation: OQPSK
- Data rate: 500Kbps
- Uplink coding: BCH
I am interested in understanding what is the associated uplink bandwidth. From my understanding, the formula is
R = 2B * log2(M) where R is data rate in bps, B is bandwidth in Hz, and M is the symbol level of modulation.
Therefore for OQPSK (4 symbols), the formula would be
500,000 bps = 2B * log2(4), and B = 125 KHz.
However, the answer i received from our radio vendor was that for a roll-off factor of 0.5, the bandwidth is
I have attempted to understand the meaning of roll-off factor in the context of bandwidth and datarates, however, i have not been able to understand it. Can someone explain or provide links to good reading material regarding how the roll-off of 0.5 is accounted for in the equation above, and why the 750 KHz is so different than my 125 KHz calculation