Radiometrix
Hartcran House, 231 Kenton Lane, Harrow, HA3 8RP, England
Issue
VHF
October 2005
FM Data Transmitter and Receiver Modules
RX1
2, 17
Narrow Band
TX1 &
Tel: +44 (0) 20 8909 9595, Fax: +44 (0) 20 8909 2233
VHF Narrow Band FM Transmitter and Receiver
The TX1 and RX1 form a miniature
VHF radio transmitter/receiver pair
designed for PCB mounting and
suitable for extended range data
links at speeds up to 10kbps.
Link ranges of 10km+ are achievable
with suitable choice of data rate and
antennas.
Features:
left: TX1 transmitter
right:RX1receiver
CE Certified by independent Notified Body
Verified to comply with harmonised radio standard ETSI EN 300 220-3 and EMC standard ETSI
EN 301 489-3 by accredited Test Laboratory
Frequencies available as standard: 173.225MHz, 173.250MHz
Other frequencies from 151.300MHz to 173.250MHz available to order
Data rates up to 10 kbps with 25kHz channel spacing
Usable range to 10km+
Screened construction
Available for licence-exempt operation in the UK 173MHz bands, the TX1 & RX1 modules combine
effective screening with internal filtering to minimise spurious radiation and susceptibility thereby
ensuring EMC compliance. They are particularly suitable for one-to-one and multi-node wireless links
where longer ranges are required at low to moderate data rates. Applications include building security,
EPOS and inventory tracking, remote industrial process monitoring and data networks. Because of
their small size and low power consumption, both modules are ideal for use in battery-powered portable
applications such as hand-held terminals.
Transmitter - TX1
2 stage crystal controlled, NBFM modulated at up to 10 kb/s
Operation from 2.2V to 12V @ 9.5mA
Built-in regulator for improved stability and supply noise rejection
Exceptional power efficiency, typically 35% DC
→
RF @ 3V supply
+10dBm (10mW) RF output
Harmonics typically -70dBc
Enable facility
Receiver - RX1
Single conversion NBFM superhet
Image rejection >50dB
Operation from 2.7V to 12V @ 12mA
Built-in regulator for improved stability and supply noise rejection
10kbps, -116dBm sensitivity @ 1ppm BER
RSSI output with >80dB range
Local oscillator leakage <-60 dBm
Enable facility
Radiometrix Ltd., TX1 & RX1 Data Sheet
page 1
Functional description
The TX1 module is a two stage crystal controlled NBFM transmitter operating between 2.2V and 12V
at a current of 9.5mA. At 3V supply it delivers nominally +10dBm RF output. The SIL style TX1
measures 32 x 12 x 3.8 mm excluding the pins.
The RX1 module is a single conversion NBFM superhet receiver capable of handling data rates of up to
10kbps. It will operate from a supply of 2.7V to 12V and draws 12mA when receiving. A signal strength
(RSSI) output with greater than 80dB of range is provided. The SIL style RX1 measures 48 x 17.5 x 5.5
mm excluding the pins.
TX1 transmitter
Supply
regulator
5
Vcc
4
En
VCXO
2
RF out
Lowpass filter
PA
Bandpass filter
x2
7kHz LPF
7
TXD
3
RF gnd
1
RF gnd
100k
6
0V
Fig.1: TX1 block diagram
Pin description
RF gnd
(pins 1 & 3)
RF ground, internally connected to the
module screen and pin 6 (0V). These pins
should be directly connected to the RF
return path - e.g. coax braid, main PCB
ground plane etc.
RF out
(pin 2)
50Ω RF output to antenna. Internally
DC-isolated. See antenna section of
applications notes for details of suitable
antennas / feeds.
12.0
mm
32 mm
3.8 mm
Radiometrix
TX1
pin spacing:
2.54 mm
15.24 mm
1
2
3
4
5
6
7
12.5
mm
PCB level
1 = RF gnd
2 = RF out
3 = RF gnd
4 = En
5 = Vcc
6 = 0V
7 = TXD
7 holes of 0.7 mm dia. pin spacing 2.54 mm
Fig.2: TX1 physical dimensions
En
(pin 4)
Tx enable.
≤0.15V
on this pin disables module (current <1µA),
≥1.7V
enables module. Input impedance
1MΩ approx. Observe slew rate requirements (see applications notes).
Vcc
(pin 5)
DC +ve supply. Max ripple content 0.1V
P-P.
Decoupling is not generally required.
0V
(pin 6)
DC supply ground. Internally connected to pins 1, 3 and module screen.
TXD
(pin 7)
DC-coupled modulation input. Accepts serial digital data at 0V to 3V levels.
See applications notes for suggested drive methods. Input impedance 100kΩ nominal.
Radiometrix Ltd., TX1 & RX1 Data Sheet
page 2
RX1 receiver
Xtal osc/mult.
x2
Bandpass filter
Regulated
Rx supply
Supply
regulator
7
Vcc
4
En
IF amplification / filtering
1
RF in
Bandpass filter
Preamp.
IF1
Mixer
5
RSSI
Adaptive
data slicer
IF2
10k
2
RF gnd
3
RF gnd
9
RXD
6
0V
FM
discriminator
7kHz LPF
AF buffer
8
AF out
Fig.3: RX1 block diagram
Pin description
RF in
(pin 1)
50Ω RF input from antenna.
Internally DC-isolated. See
antenna section of applications
notes for suggested antennas and
feeds.
RF gnd
(pins 2 & 3)
RF ground, internally connected
to the module screen and pin 6
(0V). These pins should be
directly connected to the RF
return path - e.g. coax braid,
main PCB ground plane etc.
17.5 mm
5.5 mm
48 mm
18.0 mm
RX1
pin spacing: 2.54 mm
25.4 mm
Radiometrix
PCB level
1 = RF in
2 = RF gnd
3 = RF gnd
4 = En
5 = RSSI
6 = 0V
7 = Vcc
8 = AF out
9 = RXD
1
2
3
4
5
6
7
8
9
9 holes of 0.7 mm dia. pin spacing 2.54mm
Fig.4: RX1 physical dimensions
En
(pin 4)
Rx enable.
≤0.15V
on this pin disables module (current <1µA),
≥1.7V
enables module. Input impedance
1MΩ approx. Observe slew rate requirements (see applications notes).
RSSI
(pin 5)
Received Signal Strength Indicator with >80dB range. See applications notes for typical characteristics.
0V
(pin 6)
DC supply ground. Internally connected to pins 2, 3 and module screen.
Vcc
(pin 7)
DC +ve supply. Max ripple content 0.1V
P-P.
Decoupling is not generally required.
AF out
(pin 8)
Buffered and filtered analogue output from the FM demodulator. It has a standing DC bias of 1V and
400mV
P-P
baseband signal. Useful as a test point or to drive external decoders (see applications notes).
External load should be >1kΩ // <100pF.
RXD
(pin 9)
Digital output from internal data slicer (squared version of the signal on pin 8). It may be used to drive
external decoders. The data is true data, i.e. as fed to the transmitter. Output is “open-collector”
format with internal 10kΩ pullup to Vcc (pin 7).
Radiometrix Ltd., TX1 & RX1 Data Sheet
page 3
Absolute maximum ratings
Exceeding the values given below may cause permanent damage to the module.
Operating temperature
Storage temperature
TX1
Vcc, TXD (pins 5,7)
En (pin 4)
RF out (pin 2)
RX1
Vcc, RXD (pins 7,9)
En, RSSI, AF (pins 4,5,8)
RF in (pin 1)
-20°C to +60°C
-40°C to +100°C
-0.3V to +16.0V
-0.3V to +Vcc V
±50V
@ <10MHz, +20dBm @ >10MHz
-0.3V to +16.0V
-0.3V to +Vcc V
±50V
@ <10MHz, +13dBm @ >10MHz
Performance specifications:
TX1 transmitter
(Vcc = 3.0V / temperature = 20
°
C unless stated)
pin
DC supply
Supply voltage
Supply current
RF
RF power output @ Vcc = 2.2V
RF power output @ Vcc
≥
2.8V
Spurious emissions
Frequency accuracy
FM deviation (peak)
Baseband
Modulation bandwidth @ -3dB
Modulation distortion (THD)
TXD input level (logic low)
TXD input level (logic high)
Dynamic timing
Power-up time (En
→
full RF)
Notes:
1.
2.
3.
4.
5.
6.
7.
Measured into 50Ω resistive load.
Exceeds EN/EMC requirements at all frequencies.
Total over full supply and temperature range.
With 0V – 3.0V modulation input.
To achieve specified FM deviation.
Dependent upon TXD conditions during power-up.
See applications information for further details.
5
5
2
2
2
min.
2.2
typ.
3.0
9.5
+6
+10
-70
0
±3.0
max.
12
11
+7.5
+11.5
-55
+2.0
±3.5
7
15
0.2
3.2
5
units
V
mA
dBm
dBm
dBc
kHz
kHz
kHz
%
V
V
ms
1
1
2
3
4
notes
+4.5
+8.5
-2.0
±2.5
0
7
7
-0.2
2.8
10
0
3.0
2
7
5,7
5,7
6,7
Radiometrix Ltd., TX1 & RX1 Data Sheet
page 4
Performance specifications:
RX1 receiver
(Vcc = 3.0V / temperature = 20
°
C unless stated)
pin
DC supply
Supply voltage
Supply current
RF/IF
RF sensitivity @ 10dB (S+N)/N
RF sensitivity @ 1ppm BER
IP
3
at RF input
RSSI threshold
RSSI range
IF bandwidth
Image rejection
Adjacent channel rejection
Spurious response rejection
LO leakage, conducted
LO leakage, radiated
Baseband
Baseband bandwidth @ -3dB
AF level
DC offset on AF out
Distortion on recovered AF
Load capacitance, AFout / RXD
Dynamic timing
Power up with signal present
Power up to valid RSSI
Power up to stable data
Signal applied with supply on
Signal to valid RSSI
Signal to stable data
Time between data transitions
Mark : space ratio
7
7
1, 8
1, 9
1
1, 5
1, 5
1
1
1
1
min.
2.7
typ.
3.0
12
-119
-116
-28
-127
90
15
55
55/60
100
-70
-70
max.
12
14
-115
-112
units
V
mA
dBm
dBm
dBm
dBm
dB
kHz
dB
dB
dB
dBm
dBm
kHz
mV
P-P
V
%
pF
notes
80
50
50
70
1
1
2
3
3
1, 4
5
-65
-60
6
1.3
10
100
8
8
8
8
8, 9
0.05
0.7
400
1.0
1
4, 5
4, 9
1, 5
1, 9
9
9
1.8
20
4
16
0.4
4
50
5
20
0.6
12
0.1
80
ms
ms
ms
ms
ms
%
6
7
8
Notes:
1.
2.
3.
4.
5.
6.
7.
8.
See applications information for further details.
Typically 55dB @ +25kHz offset, 60dB @ -25kHz offset.
Exceeds EN/EMC requirements at all frequencies.
Lower limit can be extended to DC if required, by means of external circuitry.
For received signal with
±3kHz
FM deviation.
Typically 4ms for signal at channel centre, maximum 12ms at
±4kHz
RF offset.
For 50:50 mark to space ratio (i.e. squarewave).
Average over 50ms period at maximum bit rate.
Radiometrix Ltd., TX1 & RX1 Data Sheet
page 5
