DSM FASST How it works

DSSS (Direct Sequence Spread Spectrum)

Using the path analogy in the Overview Distributed Spread Spectrum radio can be likened not to a path but to a motorway where you seem to appear randomly in different lanes. In fact, You appear and disappear so quickly that it almost appears you exist in all lanes at the same time.

The result of this if you encounter another person in the lane you are in, it won't have very much effect. You will still get past when you suddenly appear in another lane which isn't blocked

FHSS (Frequency Hopping Spread Spectrum)

Some Spektrums and Futaba's FASST systems also use high-speed frequency hopping to add to signal security. The signal changes channel every two milliseconds to ensure that signal conflicts don't occur.

In Transmitter terms, this means that the frequency sent by the transmitter doesn't just jump around within the chosen operating channel but also jumps between a whole range of different channels.

Spread spectrum R/C technology is completely closed to any form of interference whatsoever. A Globally Unique Identification Code is assigned to every radio transmitter during manufacture, and this is just one unique code out of millions of possible codes. The receiver is programmed to identify that unique code in what is known as the 'binding process', and so the transmitter and receiver lock together with the same GUIC, blocking out all other codes in the process.

The receiver locks to the transmitter with it binding code every time the system is powered up. This process only takes a couple of seconds. Once locked together, the transmitted signal is spread out over a wide band before being received ,identified and then re-assembled by the receiver, giving maximum security.

This new technology for R/C use has been developed from Direct Sequencing Spread Spectrum, a form of secure radio signal transmission that has been in use by top government bodies (military, NASA etc.) for a while. The R/C version is Basically the same, but it's been changed a bit for the hobby industry. There are a few brand R/C spread spectrum technologies available; DSM / DSM2 was the first to appear in Spektrum systems, while FASST is Futaba's equivalent. They stand for Digital Spectrum Modulation for Spektrum and Futaba Advanced Spread Spectrum Technology for Futaba.