RF / IR Encoder / Decoder Chipset
RF Evaluation Boards,
Transmitter Encoder RF600E
Operational Description
RF600E
RF600D
The RF600E is a simple device to use. As shown in the typical application circuits, it requires only the
addition of input switches and RF circuitry for use as the transmitter in the end application. Transmission is
automatic without user intervention.
The RF600E will wake up upon detecting a switch closure and then delay approximately 6.5 ms for switch
debounce. The encrypted or hopping code portion of the transmission will change every time a button is
pressed, even if the same button is pushed again.
Achieving Optimum Range
Range is dependant on many factors including
1. RF Power output
2. Receiver sensitivity
3. Antenna efficiency
4. Local environmental conditions and any local Interference
5. Data Type which is being transmitted.
Whilst items 1-4 are dependant on the system hardware design, item ‘5’ is equally important and often
overlooked.
Given that there is a legal maximum power output which can be transmitted, and a limit on the sensitivity
of the receiver (usually constrained by cost), and that the antenna can never achieve 0dB loss (100%
efficiency), then the data type is an important aspect of the design.
The RF600E/D chipset use a fully balanced Manchester encoded data protocol designed for optimum use
of the radio transmission path.
The data format automatically includes a pre-amble, synchronisation header, followed by the encrypted
and fixed code data then a CRC check. The actual packet size is 67 bits. Each transmission is followed by
a guard period before another transmission can begin.
The data encryption provides up to four billion changing code combinations and includes the function bits
(based on which buttons were activated) along with other data and synchronization information that the
decoder uses.
Manchester encoding the data enables the superhetrodyne receiver ‘data slicer’ to maintain efficiency for
the duration of the data packet, (unlike many other encoder/decoder systems) which results in reduced bit
errors and therefore ensures maximum range.
Low Battery Indication
The RF600E reads the battery status (voltage) on each operation. If the voltage is detected as being
below 3.8 volts (typical) then a flag bit is transmitted to the decoder where it is made available.
Custom Versions
Custom versions of the RF600E / D chipset are available, programmed with a unique ‘Manufacturers Key’
which means that the transmitter and receiver will respond only to other devices with the same unique
manufacturers key. This provides a bespoke remote chipset for OEM applications. Please contact our
sales department for further information.
DS600-9 Sept ‘04
©2004 Reg. No. 227 4001, ENGLAND
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