QM Radio Transmitter Module
Connection Details
General Information
QFMT1-XXX
Quasar
UHF Radio Transmitter
The transmitter module implements a unique
quasi AM/FM modulation scheme that puts the
baseband data signal onto the RF carrier in two
different ways. Firstly the carrier is shifted in
frequency (typically 20 KHz) which generates the
normal FSK spectrum, but simultaneously the RF
carrier is also amplified thus yielding the ASK
spectrum.
1
2
3
4
5
Figure 1: Transmitter
Utilising the quasi AM/FM modulation technique
with one of the compatible receivers will yield a
highly efficient wireless link.
Pin Description:
RF GND
(pin 1)
RF ground pin, internally connected to pin 4 (0V).
This pin should ideally be connected to the
nearest ground plane (e.g. coax braid, main PCB
ground plane etc.)
RF OUT
(pin2)
50Ω RF antenna output. To achieve best results
the antenna impedance must match that of the
module.
V
CC
(pin 3)
+Ve supply pin (3.0 to 9.0 volts). The module will
generate RF when V
CC
is present. It is strongly
recommended that a 100nF capacitor decouples
the supply rail as close as possible to this pin.
GND
(pin 4)
Supply and data ground connection, connected to
pin 1.
Data IN
(pin 5)
This input has an impedance of 47KΩ and should
ideally be driven by a CMOS logic drive or
compatible. The drive circuitry should be supplied
with the same supply voltage as the Tx module.
Note:
Because of the way Quasi Modulation
operates the QMR1 and the QFMT1 will not work
reliably in close proximity to each other.
DS301-2
Oct 02
©2000
REG No 277 4001, England.
Page 3
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