     
© Radiometrix Ltd
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| Issue A |
TXM data sheet |
25th April 1997 |
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| Bottom:
TXM-433-5 transmitter Module |
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| The
TXM-433-5 and TXM-433-10 integrate a low power FM UHF radio transmitter
on a small module. Together with the matching RX2-433-14
(or SILRX)receiver a one-way radio data link can be achieved over a distance
up to 200 metres on open ground. |
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Typical features
- 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
- PCB Mounting, space saving SIL style
- SAW controlled wide band FM transmission
- Data rate of up to 10kbps
- Analogue or Digital data input
- Wide supply range 2.7V-4.0 or 6.0V-9.0V @ <17mA
Typical applications
- Domestic and commercial security
- Guard patrol / lone worker protection
- Medical Alert / Nurse Call systems
- Mobile panic attack
- Computer networking
- Remote industrial process monitoring
- Data transfer through hazardous enviroments
- Lighting control, Garage door openers
- Fire alarms
- Picture / antique protection alarms
- Remote control, Access control
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Brief description
The transmitter modules are most commonly employed
in Wireless Security systems. The TXM transmitter and the matching
RX2 receiver are approved to harmonised radio standard ETSI EN 300
220-3 and EMC standard ETSI EN 301 489-3. The TXM and RX2 modules
will suit one-to-one and multi-node wireless links in applications
including car and building security, EPOS and inventory tracking,
remote industrial process monitoring and computer networking. Because
of their small size and low power requirements, both modules are ideal
for use in portable, battery-powered applications such as hand-held
terminals.
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 figure 1: TXM's
block diagram
figure 2: mechanical dimensions
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Pin Description
| pin 1 |
RF GND |
This pin should be
connected to the ground plane against which the integral antenna
radiates. It is internally connected to pin 4 . |
| pin 2 |
RF OUT |
Connects to the integral
antenna. Output impedance is 50W. |
| pin 3 |
Vcc |
Positive supply ,
supply voltages from +6 to +9V may be used. |
| pin 4 |
Vss |
0V connection for
the modulation and supply. |
| pin 5 |
DATA IN |
Should be driven
directly by a CMOS logic device running on the same supply voltage
as the module. |
Performance data TXM-418-5 and
TXM-433-5
Absolute Maximum Ratings:
| Supply voltage Vcc |
pin 3 |
-0.7 |
to |
+ 12V |
| Modulation input |
pin 5 |
-0.7 |
to |
+ 13V |
| Operating temperature |
|
-10°C |
to |
+ 55°C |
| Storage temperature |
|
-40°C |
to |
+ 100°C |
Performance Data:
| ambient temperature: |
20 °C |
| supply voltage: |
+8.0V, unless noted otherwise |
| test circuit: |
figure 3 |
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| Parameter
|
Min
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Typical |
Max
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Units |
Notes |
| Operating supply
range (Vcc) |
6.0 |
- |
9.0 |
V |
- |
| Supply current, Vcc
= 6.0V |
3.0 |
6.0 |
10.0 |
mA |
- |
|
Vcc = 9.0V
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5.0 |
10.0 |
17.0 |
mA |
- |
| Radiated power(ERP)
Vcc=6.0V |
-16 |
-10 |
-7 |
dBm |
1 |
| Vcc
= 9.0V |
-13 |
-8 |
-5 |
dBm |
1 |
| Transmit frequency
(fRF) |
|
418.00/ |
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MHz |
- |
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433.92 |
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| Initial frequency
accuracy |
-80 |
- |
+80 |
kHz |
- |
| Overall frequency
accuracy |
-95 |
- |
+95 |
kHz |
2 |
| Spurious radiation
meets |
MPT |
1340 on |
418 |
MHz |
3 |
| FM Deviation (+/-) |
15 |
25 |
40 |
kHz |
4 |
| Modulation Bandwidth
(-3dB) analogue |
DC |
- |
10 |
kHz |
4 |
| Modulation digital
pulse width |
100 |
- |
- |
µs |
5 |
Notes:
- Module on 50mm square ground plane, helical
antenna
- Supply 6 to 9V, temp -10°C to + 55°C.
- <-54 dBm in bands 41-68, 87.5-118, 162-230
& 470-862 MHz
<-36 dBm else where below 1GHz , <-30dBm above 1GHz
- Standard modulation: 2kHz square wave, 0 to
Vcc
- High or Low pulse.
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Performance data TXM-418-10
and TXM-433-10
Absolute Maximum Ratings:
| Supply voltage Vcc |
pin 3 |
-0.7 |
to |
+ 6V |
| Modulation input |
pin 5 |
-0.7 |
to |
+ 13V |
| Operating temperature |
|
-10 °C |
to |
+ 55 °C |
| Storage temperature |
|
-40 °C |
to |
+ 100 °C |
Performance Data:
| ambient temperature: |
20 °C |
| supply voltage: |
+3.0V, unless noted otherwise |
| test circuit: |
figure 4 |
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| Parameter
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Min
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Typical |
Max
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Units |
Notes |
| Operating supply
range (Vcc) |
2.7 |
3.2 |
4 |
V |
- |
| Supply current, Vcc
= 2.7V |
3.0 |
6.0 |
13.0 |
mA |
- |
|
Vcc = 4.0V
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5.0 |
10.0 |
17.0 |
mA |
- |
| Conducted power in
to 50W |
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| Vcc
= 2.0V |
- |
-5 |
- |
dBm |
1 |
| Vcc
= 3.6V |
- |
0 |
- |
dBm |
1 |
| Transmit frequency
(fRF) |
|
418.00/ |
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MHz |
- |
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433.92 |
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| Initial frequency
accuracy |
-85 |
0 |
+85 |
kHz |
- |
| Overall frequency
accuracy |
-95 |
0 |
+95 |
kHz |
1 |
| Spurious radiation
meets |
MPT |
1340 on |
418 |
MHz |
2 |
| FM deviation (+/-) |
15 |
25 |
40 |
kHz |
3 |
| Modulation Bandwidth
(-3dB) analogue |
DC |
- |
20 |
kHz |
3 |
| Modulation digital
pulse width |
50 |
- |
- |
µs |
4 |
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Notes:
- Supply 2 to 3.6 volt, temp -10 to + 55°C.
- <-54 dBm in bands 41-68, 87.5-118, 162-230
& 470-862 MHz
<-36 dBm else where below 1GHz , <-30dBm above 1GHz
- Standard modulation: 2kHz square wave, 0 to
Vcc
- High or Low pulse.
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figure 4: TXM-433-10 version test
circuit
figure 5: Typical performance curves
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The TXM-UHF transmitter requires only a data modulation
input, supply, ground and an antenna.
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Power supply requirements
- The module will operate over the range 6 to
9V and is typically powered by either 9V 'PP3'.
- The module is not reverse polarity protected.
Reverse supply voltages higher than 2V will cause damage and must
therefor be externally protected against.
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Modulation requirements
- The TXM-UHF transmitter has a DC to 10kHz modulation
bandwidth and will accept direct analogue (AFSK) or digital data.
A modulation lowpass filter (10kHz @ -6dB, 1st order) is used internally.
- Although the modulation bandwidth of the transmitter
extends down to DC as does the AF output of the receivers, it is
not possible to pass data with a DC component due to frequency errors
& drifts between the transmitter and receiver. Frequency differences
between the transmitter and receiverwill produce a DC offset error
which causes the data slicer in the receiver module to give errors
on long high or low pulses which exceed the maximum pulse width,
see the receiver's data sheet for more detailed information.
- Data Input, pin 5, is normally driven directly
by CMOS logic levels from a data encoder IC. There is a wide range
of encoder/decoder IC's available which may be used with the modules:
|
| MM57C200, 57410 |
National Semiconductor |
| UM3750 |
UMC |
| HT12 series |
Holtek |
| MC14026 |
Motorola |
| AS2787 |
Austria Systeme International
GmbH |
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The encoder normally being run on the same
supply voltage as the transmitter. Analogue drive eg. 2 tone FSK, is
also possible, the pk to pk level should be between 5 and 9V peak to
peak and must not drive pin 5 below 0V. There will be some 2nd harmonic
distortion due to the varactor modulator (typ <15%), this may be
reduced if necessary by predistortion of the analogue waveform.
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Antenna requirements
Three types of integral antenna are recommended
and approved for use with the module:
A) Helical:
- Wire coil, connected directly to pin 2, open
circuit at other end. This antenna is very efficient given it's
small size (20mm x 4mm dia.). The helical is a high Q antenna, trim
the wire length or expand the coil for optimum results. The helical
de-tunes badly with proximity to other conductive objects.
(B) Loop:
- A loop of PCB track tuned by a fixed or variable
capacitor to ground at the 'hot' end and fed from pin 2 at a point
20% from the ground end. Loops have high immunity to proximity de-tuning.
C) Whip:
- This is a wire, rod, PCB track or combination
connected directly to pin 2 of the module. Optimum total length
is 17cm (1/4 wave @ 418MHz) Keep the open circuit (hot) end well
away from metal components to prevent serious de-tuning. Whips are
ground plane sensitive and will benefit from internal 1/4 wave earthed
radial(s) if the product is small and plastic cased
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Antenna Selection Chart
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A |
B |
C |
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helical |
loop |
whip |
| Ultimate performance |
** |
* |
*** |
| Easy of design set-up |
** |
* |
*** |
| Size |
*** |
** |
* |
| Immunity proximity effects |
** |
*** |
* |
| Range open ground to similar antenna |
80m |
50m |
120m |
The antenna choice and position directly
controls the system range. Keep it clear of other metal in the system,
particularly the 'hot' end. The best position by far, is sticking
out the top of the product. This is often not desirable for practical/ergonomic
reasons thus a compromise may need to be reached. If an internal antenna
must be used try to keep it away from other metal components, particularly
large ones like transformers, batteries and PCB tracks/earth plane.
The space around the antenna is as important as the antenna itself.
figure 6: Antenna configurations
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Duty
Cycle requirements
The duty cycle is defined as the ratio, expressed
as a percentage, of the maximum transmitter "on" time on
one or more carrier frequencies, relative to a one hour period. Where
an acknowledgement message is required, the additional transmitter
"on" time shall be included.
There is a 10% duty cycle restriction on 433.050-434.790
MHz band in most of the EU member states.
The TXM-433 is a RF module intended to be incorporated
into a wide variety of applications and finished products, Radiometrix
has no control over the end use of the TXM-433.The harmonised band
433.050 to 434.790 MHz as detailed in Annex 1 Band E of CEPT/ERC Recommendation
70-03 (which can be downloaded at http://www.ero.dk/scripts/docmanag98/dm.dll/QueryDoc?Cat=Recommendation)
has list of countries where Duty Cycle restriction apply.
Module users should, therefore, ensure that they
comply with the stated Duty Cycle requirements of the version of CEPT/ERC
Recommendation 70-03 in place at the time of incorporation of the
TXM-433 into their product. It should be noted that the stated Duty
Cycle must not be exceeded otherwise any approval granted for the
TXM-433 will be invalidated.
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Limitation of liability
The information furnished by Radiometrix Ltd is
believed to be accurate and reliable. Radiometrix Ltd reserves the
right to make changes or improvements in the design, specification
or manufacture of its subassembly products without notice. Radiometrix
Ltd does not assume any liability arising from the application or
use of any product or circuit described herein, nor for any infringements
of patents or other rights of third parties which may result from
the use of its products. This data sheet neither states nor implies
warranty of any kind, including fitness for any particular application.
These radio devices may be subject to radio interference and may not
function as intended if interference is present. We do NOT recommend
their use for life critical applications.
The Intrastat commodity code for all our modules is: 8542 6000.
R&TTE Directive
After 7 April 2001 the manufacturer can only place
finished product on the market under the provisions of the R&TTE
Directive. Equipment within the scope of the R&TTE Directive may
demonstrate compliance to the essential requirements specified in
Article 3 of the Directive, as appropriate to the particular equipment.
Further details are available on The Office of Communications (Ofcom)
web site:
Licensing
policy manual
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