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PPM-encoding
simplified flow chart within R/C transmitter:
The electronics in the R/C transmitter convert the voltage of the axis
resistors into a binary signal. This is forwarded to the buddy box and
at the RF-part. In the RF-part a modulation of the signal happens on a
bearer frequency of 35 MHz to a spread of 10kHz, that corresponds to
minimum channel distance of
different crystals. The receiver in the model demodulates the signal, it
dismantles it into its 8 channel information and sends these to the
appropriate servo. Only in the servo, the PPM-Signal is decoded and the
servo arm moves. Consequently, the entire transfer trek can be built up
without costly electronics or processors since the PPM-Signal is not
changed during communication.
PPM format:
A complete PPM-Frame has a length of 22.5 ms. It exists of an
overlong start information and 8 channel information. A stop
information with 0.3 ms follows on every channel impulse. The length
of a channel impulse ranges from 0.7 ms to 1.7 ms and corresponds to
the stick position. Consequently, the illustration shows a
transmitter with full amplitude right in channel 1, channel 2 on
full amplitude left, channel 3 on middle,.. the start impulse
supplements the 8 channel impulses, so that
the total length of 22.5 ms emerges.
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