Why use Direct Sequence Spread Spectrum?
There are two main broadcast methods that spread
spectrum manufacturers can utilize. One format is called Frequency Hopping
Spread Spectrum (FHSS). With an FHSS system, the transmitter transmits a narrow
band signal and rapidly jumps from one frequency to the next, spending a few
milliseconds on each frequency. Originally, Spektrum engineers started their
development with FHSS-based systems because they were relatively easy and
inexpensive to develop. However, they soon discovered that FHSS had several limitations
that would prevent it from being the optimal solution for RC. While more
difficult and costly to develop, our engineers began experimenting with Direct
Sequence Spread Spectrum (DSSS) and optimized the modulation scheme to overcome
critical response and re-link issues. DSSS systems transmit on a single
selected frequency but on a very wide band. Only a small portion of that band
is used for specially encoded information. In addition, DSSS offers an increase
of processing gain for significant improvements in range. With years of
development and testing, the DSSS modulation scheme was optimized for RC car
and airplane use, and Spektrum´s DSM 2.4GHz Spread Spectrum Technology was
born. DSSS provided engineers and hobbyists with the safety, security, and
locked-in feeling that is necessary to maintain total and complete control in
any vehicle or aircraft.