AFHDS is different than DSSS and FHSS. It is not dual-channel DSSS either. Everybody can define his/her AFHDS scheme, as long as it makes sense to be related to AFHDS. I guess the designer of the 'B' version uses something like the following:
* It uses frame-based bursting transmissions. As for how wide a RF channel is in spectrum, only the designer knows. Or you can measure it if you have a good Spectrum Analyzer.
* The RF module and the receivers can use a few different RF channels. At the start, they both work on the same default channel. During the time slot the RF module is not transmitting, it can sense the signal levels on different channels. If it senses a channel which is much less utilized than the current channel, it will inform the receiver in data frame sent to it to switch to that channel. This process can be repeated; and this qualifies to be called AFHDS. .
http://www.rcgroups.com/forums/showt...35575&page=153