Check out this press release from Spektrum:
Spektrum DSMX: True Evolution
Spektrum launched the 2.4GHz RC revolution and remains the leader of it for one simple reason – RC is our sole focus. It’s why Spektrum has made more innovations in RC in the last 5 years than anyone else.
DSMX is just such an innovation. It is a new, frequency-agile evolution of Spektrum™ 2.4GHz technology that matches the consistently superior speed and data capacity of DSM2 with the most advanced frequency shifting algorithm to date. The result is the fastest, most precise response in heavily congested 2.4GHz environments you will find anywhere.
A Solid Foundation: Wideband DSSS
DSMX is built on the same foundation as DSM2—the superior on-channel interference resistance and coding gain of wideband 2.4GHz DSSS technology. Compared to the wideband signal of a DSM2™ or DSMX™ system, the narrow-band signal of other 2.4 transmitters is more likely to suffer crucial data loss in the event of on-channel interference. Think of wideband 2.4 as a river and narrow-band 2.4 as a stream. It takes much more interference to stop a river than it does to stop a stream.
The big reason wideband is so robust is coding gain. Essentially what this means is that the unique coding in a DSM2 or DSMX wideband signal allows it to be heard well above the noise of surrounding 2.4GHz signals without requiring any more power. In fact, a Spektrum wideband signal can achieve as much as 3X the range of its narrow-band competition using the same amount of power.
The ‘X’-tra Benefit of Agility
What DSMX adds to the tried and true wideband technology of DSM2 is the extra interference protection and faster reconnection times of frequency agility. But DSMX is anything but a common frequency hopping system.
Agile: quick and well-coordinated in movement
DSMX frequency shifts are coordinated using the most advanced spread spectrum algorithm ever seen in an RC application. Unlike other FHSS transmitters that all hop in the same fixed patterns, every DSMX transmitter has its own unique frequency shift pattern calculated using its GUID (Globally Unique Indentifier). And each pattern uses just 23 channels in the 2.4GHz spectrum.
By adding the agility of unique frequency shifts to the superior interference-resistance of a wideband signal, and limiting those shifts to a smaller portion of the 2.4 band, DSMX transmitters provide quicker reconnection times and superb response in the noisiest 2.4GHz environments.