EDAG Engineering + Design AG 825381 사용자 설명서
Hella KGaA Hueck & Co
59552 Lippstadt
Date:
2005-07-25
2005-07-25
Processed: K. Bödeker EE-324
Checked:
Replacement for version dated:
Page 2 of 3
Function description: PLL fold-away RF transmitter Bugatti 5B0 825 381A
The transmitter operates at a nominal operating frequency of 315.0 MHz. The
frequency-determining element is a quartz crystal-stabilised PLL circuit. The reference
quartz crystal oscillates with a nominal frequency of 9.84375 MHz, the maximum
frequency deviation is ±100 ppm.
A type U2741B single-chip transmitter (Atmel) is used as the active transmitter element.
This module also contains all active PLL components. The loop filter (C4, C5 and R5),
the quartz crystal (Q1) and the adaptations to the integrated circuit board antenna
(C8,C10 and C11) are required as external elements.
The transmitter is amplitude-modulated (Amplitude Shift Keying [ASK], ON Off Keying
[OOK]). The transmitter is modulated via the AM input of the IC2 U2741B. The
modulation signal is supplied by microcontroller IC1 (ROM versions ATAR890 or
ATAR892 or identically functioning MTP versions, Atmel).
The clock signal for the microcontroller is provided by the PLL- IC U2741B.
The transmitter is equipped with 2 buttons (see "Technical data" table).If no button is
pressed, the microcontroller is in "sleep mode", and the transmitter's RF stage is
disabled. When a button is pressed, the microcontroller wakes up and and switches on
the PLL circuit. After stabilisation of the PLL the microcontroller outputs a coded signal
to the RF transmitter. Transmission of the RF signal continues until all buttons are
released, but not longer than 60 seconds.
Coding is accomplished using a combination of fixed and rolling code.
The transmitter is supplied by one lithium battery (type CR2032, nominal voltage 3V).
Figure 1: Block diagram of the transmitter
Integrated circuit
board antenna
PLL-
transmitter
U 2741B
Coding
µC
ATAR89x
Voltage supply
3 V
Modulation
S1
S2
Clock
9.84375 MHz
PLL on / off