Nedap N V PAGSLS User Manual

Metal Detection Pager - Transmitter

Date: 27 May 2004 Version 1.00

This information is furnished for guidance, and with no guarantee as to its accuracy or completeness; its publication conveys no license under any patent or other right, nor does
the publisher assume liability for any consequence of its use; specifications and availability of goods mentioned in it are subject to change without notice; it is not to be
reproduced in any way, in whole or in part, without the written consent of the publisher.

_________________________________________________________________________________________________________
© Nedap Retail Support P.O. Box 102 NL-7140 AC Groenlo the Netherlands

Technical Support:

- [e-mail]

- H. Hammer
[phone]
[e-mail]

- H. Broekhuis
[phone]
[e-mail]

Visitor’s address:

Nedap Retail Support
Parallelweg 2d
Groenlo
Netherlands

Postal address:

Nedap Retail Support
Postbus 102
7140 AC Groenlo

Fax

[phone]

© 2004 Nedap Retail Support - Netherlands
Parallelweg 2d, 7141 DC Groenlo

The software / hardware described in this book / file is furnished under a license agreement and may be used only in accordance with the terms of
the agreement.

Documentation version 1.00

Copyright Notice

All Rights Reserved.
Any technical documentation that is made available by Nedap Retail Support is the copyrighted work of Nedap Retail Support and is owned by Nedap
Retail Support.

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Printed in the Netherlands

MD Pager - Transmitter V1.00 | Nedap Retail Support

2

Table of content

Technical Support: 2

Visitor’s address: 2
Postal address: 2
Fax 2

Table of content 3
General 4
Block diagram 5

Wireless Alarm Transmitter art. No. 8008272 5
Wireless Alarm Receiver art. No. 8008299 5

Transmitter Unit and PCB 6
RX Pager Unit and PCB 7
Datasheet TXM 433 Transmitter Module 8
Datasheet SILRX Receiver Module 19

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General

The Wireless Alarm unit is intended to transmit an alarm, OST or MD, to a small
handheld receiver unit. The Transmitter unit is supplied with 24Vdc from the NCC or IQ
or EQ unit. One of the alarm relays on the NCC , IQ or EQ unit is then wired tot the input
of the transmitter board, for instance connector K3 between GND and input 1. A short
pulse of a normally open contact is enough to trigger a short burst of data onto 433Mc.
This data consists of an address and alarm number (1, 2, 3 or 4).
In the handheld receiver this burst is detected and the alarm will sound in addition one of
the led’s will light for a couple of seconds which indicates the alarm input that is
triggered.

If necessary an opto coupled input is also available on the transmitter. In this case 24V
has to be supplied to the appropriate input.

Both, the transmitter and the receiver are equipped with an address switch to its possible
to use more than one transmitter receiver combinations in the same “shop”.

The battery in the receiver has to be charged regularly, for this purpose the receiver has
a battery charge input with charge led. While charging the pager does not function.

The working range depends on the location of the transmitter and the total construction
of the building. A range of 10 to 20 meters is practical and must give a sure alarm.

MD Pager - Transmitter V1.00 | Nedap Retail Support

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Block diagram

Wireless Alarm Transmitter art. No. 8008272

oc in

opto

coupler

4x

pic

TX mod.

TXM-433

16c84

in

3,84MHz

Either an opto coupled or a normal input is triggered and translated in a code by the pic.
This code will be transmitted via a standard transmitter module on 433 MHz.

Wireless Alarm Receiver art. No. 8008299

4x

RX mod.

SILRX-433

pic

16c84

3,84MHz

A standard 433 MHz receiver module receives the alarm data and output it to a pic
16c84. The pic will read the code and will turn on the appropriate led and gives audible
alarm.

MD Pager - Transmitter V1.00 | Nedap Retail Support

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Transmitter Unit and PCB

MD Pager - Transmitter V1.00 | Nedap Retail Support

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RX Pager Unit and PCB

MD Pager - Transmitter V1.00 | Nedap Retail Support

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Datasheet TXM 433 Transmitter Module

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Radiometrix

Issue 5, February 2002 TXM-433

UHF Radio Telemetry Transmit Module

UHF Radio Telemetry Transmit Module

UHF Radio Telemetry Transmit ModuleUHF Radio Telemetry Transmit Module

Hartcran House, Gibbs Couch, Watford, WD19 5EZ, England

Tel: [phone], Fax: [phone]

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
RX2-433-40 receiver a one-way radio data link can be
achieved over a distance up to 200 metres on open
ground.

Typical features include:

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
High data rates, 5kbps and 10kbps versions
Analogue or Digital data input
Wide supply range 2.7V-4.0 or 6.0V-9.0V @ <17mA

The transmitter modules are mo st commonly emplo yed in Wireless Securi ty systems. The transmitter
and the matching receiver (RX2) 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 ap plications includin g car an d buildin g security , EPOS and inv entor y tracking, re mote
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 hand­held terminals.

Typical applications include :-

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 environments
Lighting control, Garage door openers
Fire alarms
Picture / antique protection alarms
Remote control, Access control

TXM-433-10 transmitter (back & front view)

Radiometrix Ltd, TXM Data Sheet page 1

Brief description

The TXM is designed to work with the matchin g SILRX receiver. With th e addition of simple antenn a
the pair may be used to transf er serial d ata up to 200m. The range of the radio link is very variable and
depends upon many factors, principally, the type of antenna employed and the operating environment.
The 200m quoted range is a reliable operating distance ove r open ground using 1/4 whip antenna at
both ends of the link at 1.5m above ground. Smaller an tenna, interference or obstacles (e.g. buildin g
etc.) will reduce the re liable working range (d own to 30m in extreme cases). Increased anten na height,
slow data or a larger receive antenna will increase the range (our best is 3km).

figure 1: TXM’s block diagram

figure 2: mechanical dimensions

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 50Ω.
pin 3 Vcc Positive supply , supply voltages from +6V 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.

Radiometrix Ltd, TXM Data Sheet page 2

Performance data TXM-433-5

Absolute Maximum Ratings:

Supply voltage Vcc pin 3 -0.7V to + 12V
Modulation input pin 5 -0.7V to + 9V
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 otherwis e
test circuit: figure 3

Parameter Min Typical Max 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 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 / 433.92 MHz -
Initial frequency accuracy -80 - +80 kHz -
Overall frequency accuracy -95 - +95 kHz 2
Spurious radiation Meets the EN300 220-1 standard 3
FM deviation (+/-) 15 25 40 kHz 4
Modulation Bandwidth (-3dB) analogue DC - 10 kHz 4
Modulation digital pulse width 100 - -

µs

5

Notes

1. Module on 50mm square ground plane, helical antenna

2. Supply 6V to 9V, temp -10°C to +55°C.

3. <-54 dBm in bands 41-68, 87.5-118, 162-230 & 470-862 MHz
<-36 dBm else where below 1GHz , <-30dBm above 1GHz

4. Standard modulation: 2kHz square wave, 0 to Vcc

5. High or Low pulse.

figure 3: TXM 5kbps version test circuit

Radiometrix Ltd, TXM Data Sheet page 3

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

Parameter Min Typical Max 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 5.0 10.0 17.0 mA -

Conducted power in to 50 Ω, Vcc = 2.7V

- -5 - dBm 1

Vcc = 3.6V - 0 - dBm 1

Transmit frequency (Frf) 433.92 MHz ­Initial frequency accuracy -85 0 +85 kHz ­Overall frequency accuracy -95 0 +95 kHz 1
Spurious radiation 2
FM deviation (+/-) 15 25 40 kHz 3
Modulation Bandwidth (-3dB) analogue DC - 20 kHz 3
Modulation digital pulse width 50 - -

µs

4

Notes

1. Supply 2V to 3.6V, temp -10°C to +55°C.

2. <-54 dBm in bands 41-68, 87.5-118, 162-230 & 470-862 MHz
<-36 dBm else where below 1GHz , <-30dBm above 1GHz

3. Standard modulation: 2kHz square wave, 0 to Vcc

4. High or Low pulse.

Radiometrix Ltd, TXM Data Sheet page 4

figure 4: TXM 10kbps version test circuit

figure 5: Typical performance curves

The TXM-UHF transmitter requires only a data modulation input, supply, ground and an antenna.
Power supply requirements

• The module will operate over the range 6V to 9V and is typically powered by either 9 Volt 'PP3'.

• The module is not reverse polarity protected. Reverse supply voltages higher than 2V will cause

damage and must therefor be externally protected against.

Modulation requirements

• The TXM-UHF transmitter has a DC to 10kHz modulation bandwidth and will accept direct
analogue (AFSK) or digital data. A modulation low-pass filter (10kHz @ -6dB, 1st order) is use
internally.

• Altho ugh the m odu lation band width of th e tran smitter e xte nds do wn to DC as d oes th e AF ou tput of
the receiver s, it is not possible to pass data with a DC compone nt due to frequency errors & drifts
between the tran smitter and receiver. Frequenc y differences between th e transmitter and receiver
will produce a DC offset e rror which causes the data slicer in the receiv er 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.

Radiometrix Ltd, TXM Data Sheet page 5

• 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

• 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 5V 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

Antenna requirements

Three types of integral ant enna 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) K eep he ope n circuit (hot) end well
away from metal components to prevent serious de-tuning. Whips are ground plane
sensitive and w ill ben efit fro m in ternal 1/4 wave earthe d radial(s) if the p rodu ct is small
and plastic cased

Antenna selection chart

A B C

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.

Radiometrix Ltd, TXM Data Sheet page 6

figure 6: Antenna configurations

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.

Radiometrix Ltd, TXM Data Sheet page 7

Ordering information

The following are standard:

TXM-433-5 5kbps data rate Transmitter
RX2-433-14-5V 14kbps data rate matching Receiver
RX2-433-40-5V 40kbps data rate matching Receiver
SILRX-433-5 5kbps data rate matching Receiver

TXM-433-10 10kbps data rate Transmitter
RX2-433-14-5V 14kbps data rate matching Receiver
RX2-433-40-5V 40kbps data rate matching Receiver
SILRX-433-10 10kbps data rate matching Receiver

3V versions of the RX2 receivers are available and should be ordered with a -3V suffix on the part
number. (e.g. RX2-433-14-3V is set-up for 3V to 4V operation)

All modules are available in a 418MHz version for UK use.

Radiometrix Ltd, TXM Data Sheet page 8

CE Certificate of TXM and its variants

Radiometrix Ltd, TXM Data Sheet page 9

Copyright notice

This product data sheet is the original work and copyrighted property of Radiometrix Ltd.
Reproduction in whole or in part must give clear acknowledgement to the copyright owner.

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 Radiocommunications Agency (RA) web site:

http://www.radio.gov.uk/topics/conformity/conform-index.htm

The Library and Information Service
The Radiocommunications Agency
Wyndham House
189 Marsh Wall
London
United Kingdom
E14 9SX
Tel: [phone]/0505
Fax: [phone]
[e-mail]. uk

For further information on radio matters
contact the Agency's 24 Hour Telephone

Enquiry Point:

[phone]

Radiometrix Ltd

Hartcran House, Gibbs Couch,

Watford, WD19 5EZ, ENGLAND

Tel: [phone],
Fax: [phone]

[e-mail]

www.radiometrix.co.uk

European Radiocommunications Office (ERO)
Midtermolen 1
DK 2100 Copenhagen
Denmark
Tel. [phone]
Fax [phone]
[e-mail]
www.ero.dk

Datasheet SILRX Receiver Module

MD Pager - Transmitter V1.00 | Nedap Retail Support

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c

d

Radiometrix

Hartcran House, Gibbs Couch, Watford, WD19 5EZ, England

Issue 3, 13 April 2001 SILRX-UHF

Tel: [phone], Fax: [phone]

UHF Radio Telemetry Receiver Module

UK version: SILRX-418-5 / SILRX-418-10
Euro version: SILRX-433-5 / SILRX-433-10

The SILRX-418-5 and SILRX-433-5 integrate a

omplete FM superhet UHF radio receiver on a
small module. Together with the matching TXM­418-5 or TXM-433-5 transmitter a one-way radio

ata link can be achieved over a distance upto 200

metres on open ground

Typical features include:

• PCB mounting, space saving SIL style

• 418 MHz SAW controlled wide band FM reception

left: TXM-418-5 transmitter right: SILRX-418-5 receiver

• Selective double conversion superhet

• Sensitive typ. 0.5µV (-113 dBm) for 20 dB S/N

• High data rates, 5kbps and 10kbps

• Analogue and Digital data outputs

• Carrier detect output

• Fast enable time,< 3ms for duty cycle power save use

• Wide supply range, 4.0V to 9.0V

• Low current, 13 mA continuous, 130µA on power save (100:1)

• The SILRX radio receiver and the matching DTI (RA) approved transmitter (TXM-418-5) are self

contained, PCB mounting modu les capable of transferring analog ue or digital data up to a distance
of 200m.

The SILRX receiver module is particu larly suitable f or battery pow ered po rtable applications w here it’s
low power re quirements and small size are of advantage. It may also be used as a lower cost option to
the RXM-418-10 in fixed applications where the higher data rates and signal strength output of the
RXM-418-10 are not required.

Typical applications include:-
Site paging receivers Paging car alarms
Line powered telephone auto diallers Domestic and commercial security
Guard patrol/lone worker protection Medical Alert/Nurse Call system
Mobile panic attack Remote industrial process monitoring
Battery powered half duplex data networks Data transfer through hazardous environments
Lighting control, Garage door openers Fire alarms
Picture/antique protection alarms Remote control, Access control

Radiometrix Ltd, SILRX-UHF Data Sheet page 1

Brief description

The SILRX receiver is a double conversion FM superhet with a data slicer driven by the AF output.
Additionally a fast acting carrie r d ete ct sig nal is av ailable to in dicate to ex te rnal circu its that a sig nal is
present. This signal is extremely useful when implementing duty cycle power save circuits (see fig 4) or
to indicate to external lo gic that a signal is being received. It is internally d erived from the degree o f
noise quieting due to the presence of a receive carrier.

The SILRX-418 is designed to work with the matching transmitter (TXM-418). With the addition of
simple antenna the pair may be used to transfer serial data up to 200m. The range of the radio link is
very variable and depends upon many factors, principally, the type of antenna employed and the
operating env ironment. The 200m quoted rang e is a reliable o perating distan ce over open gr ound using
1/4 whip antenna at both ends of the link at 1.5m above ground. Smaller antenna, interference or
obstacles (e.g. building etc.) will reduce the reliable working range (down to 30m in extreme cases).
Increased antenna height, slow data or a larger receive antenna will increase the range (our best is
3km).

We recommend that the module ev aluation kit, EVAL-418-A, can be use d to assess the reliable w orking
range under the anticipated conditions of use.

The following figure shows the receiver’s block diagram.

figure 1: Block diagram

figure 2: Test cicuit

Radiometrix Ltd, SILRX-UHF Data Sheet page 2

Pin Description

pin 1 RF IN The receiver antenna connects to this input. It has nominal RF

impedance of 50Ω and is capacitively isolated from the internal circuit

pin 2 RF GROUND This pin should be connected to any ground plane against which the

antenna works. It is internally connected to pin 4.

pin 3 DETECT

This pin may be used to derive a carrier detect to enable external circuits
when a signal is be ing received. If th e detect function is not being used a
10 kΩ pull-up to pin 5 (Vcc) should be connected. Refer to applications

note for further details on the use of this pin.
pin 4 0 volt Ground for supply.
pin 5 Vcc Positive supply of 4V to 9V 13 mA. The supply must be clean (<2mV pp)

stable and free of high frequency digital noise. A supply filter is

recommended unless the module is driven from it’s own regulated supply.
pin 6 AF This is the FM demodulator output. It has an standing DC bias of

approximately 1.4V and may be used to drive analogue data detectors

such as modem chips or DTMF decoders. Load impedances as low as 2 kΩ

and up to 100 pF can be driven
pin 7 DATA This digital output from the internal data slicer is a square d version of

the signal on pin 6 (AF) This signal is used to drive external digital

decoders, it is true data ( i.e. as fed to the tr ansmitters data input). Load

impedances as low as 1 kΩ and up to 1 nF can be driven
.

figure 3: Mechanical Dimensions:

Radiometrix Ltd, SILRX-UHF Data Sheet page 3

Performance data SILRX-418-5 and SILRX-433-5

p

ambient temperature: 20°C
supply voltage: + 5 Volt
test circuit: fig. 2

Parameter Min. Typical Max. Units Notes

Operating voltage range (Vcc)
Supply current pin 5 11 14 17 mA ­Receive frequency - 433.92 - MHz ­Overall frequency accuracy - 100 0 + 100 kHz 1
Sensitivity for 20 dB S/N pin 1 - 0.5 1.0
Carrier detect, threshold pin 1 - 0.5 2.0
RF input impedance pin 1 - 50 ­IF bandwidth - 250 - kHz 3
AF output level pin 6 - 500 - mVpp 2, 3
AF bandwidth pin 6 DC - 5 kHz 3
Frequency/voltage conversion pin 6 - 10 - mV/kHz -

Data output, Logic low pin 7 0 0.2 0.8 V 4
Logic high pin 7 4.0 4.5 5 V 5
Data bit duration 0.2 - 20 ms 6
Data Mark:Space 20 % - 80 % 7
Data settling time pin 7 - - 15 ms 8
(minimum preamble duration)
Enable time pin 3 - - 2.5 ms 3, 9
Signal detect time pin 3 - - 0.5 ms 3, 9

in 5 4.0 5. 0 9.0 V -

µV
µV

Ω

2

-

-

Notes: 1. over supply and temperature range

2. ±25kHz deviation, 1 kHz tone

3. 3µV input

4. 1mA sink

5. 1mA source

6. time between transitions

7. (time high / time low) * 100 %, averaged over any 20 m s pe r i o d

8. time from valid carrier detect to stable data output

9. from application of supply to carrier detect low (active)

10. from application of signal to carrier detect low (active)

Absolute maximum ratings:

Supply voltage Vcc, pin 5 - 0.3 to + 10 V
Operating temperature - 10°C to + 50°C
Storage temperature - 40°C to + 100°C
RF input, pin 1 0 dBm
Any input or output pin - 0.3 to Vcc V, ±10 mA

Radiometrix Ltd, SILRX-UHF Data Sheet page 4

Performance data SILRX-418-10 and SILRX-433-10

ambient temperature: 20°C
supply voltage: +5V
test circuit: fig. 2

Parameter

Operating voltage range (Vcc) pin 5 4.0 5.0 9.0 V ­Supply current pin 5 11 14 17 mA ­Receive frequency - 433.92 - MHz ­Overall frequency accuracy - 100 0 + 100 kHz 1
Sensitivity for 20 dB S/N pin 1 - 1.0 2.0
Carrier detect, threshold pin 1 - 2.0 4.0
RF input impedance pin 1 - 50 ­IF bandwidth - 250 - kHz 3
AF output level pin 6 - 500 - mVpp 2, 3
AF bandwidth pin 6 DC - 20 kHz 3
Frequency/voltage conversion pin 6 - 10 - mV/kHz -

Data output, Logic low pin 7 0 0.2 0.8 V 4
Logic high pin 7 4.0 4.5 5 V 5
Data bit duration 0.05 - 2 ms 6
Data Mark:Space 20 % - 80 % 7
Data settling time pin 7 - - 5 ms 8
(minimum preamble duration)
Enable time pin 3 - - 1 m s 3, 9
Signal detect time pin 3 - - 0.3 ms 3, 10

Min. Typical Max. Units Notes

µV
µV

Ω

2

-

-

Notes: 1. over supply and temperature range

2. ±25 kHz deviation, 1 kHz tone

3. 3 µV input

4. 1mA sink

5. 1mA source

6. time between transitions

7. (time high / time low) * 100 %, averaged over any 20 m s pe r i o d

8. time from valid carrier detect to stable data output

9. from application of supply to carrier detect low (active)

10. from application of signal to carrier detect low (active)

Absolute maximum ratings:

Supply voltage Vcc, pin 5 - 0.3 to + 10 V
Operating temperature - 10°C to + 50°C
Storage temperature - 40°C to + 100°C
RF input, pin 1 0 dBm
Any input or output pin - 0.3 to Vcc V, ±10 mA

Radiometrix Ltd, SILRX-UHF Data Sheet page 5

figure 4: Typical performance curves

figure 5: Timing wave forms

Radiometrix Ltd, SILRX-UHF Data Sheet page 6

Antenna configurations
The positioning of the antenna is of the up most importance and is one of the main factors in

determining system range.
The following notes should assist in obtaining optimum performance:-

1. Keep it clear of other metal in the system, particularly the ‘hot’ (top) end.

2. 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 my need to be reached.

3. If an internal antenna must be use d try to keep it away from other metal compone nts, particularly

large ones like transformers, batteries and PCB tracks/earth plane. The space around the antenna is
as important as the antenna itself.

4. Keep it away from interference sources, bad interference can easily reduce system range by a factor

of 5. High speed logic is one of the worst in this respect fast logic edges have harmonics which extend
into the UHF band and the PCB tracks radiate these harmonics most efficiently. Single chip
microprocessors and ground planed logic boards reduce this problem significantly.

The next diagrams (fig 6) show three different antenna configurations which can be used on both the
transmitter and the rece iver. Additionally a coax fed ex ternal dipole or 1/4 wave groun d plane antenna
may be considered if system range is paramount.

figure 6: Antenna configurations

Radiometrix Ltd, SILRX-UHF Data Sheet page 7

Module Mounting considerations

1. The module may be mounted vertically or bent horizontal to the motherboard.

2. No conductive items should be placed within 4 mm of the modules’ component side to prevent
detuning.

3. Observe RF layo ut p ractice betw e en the mo du le an d it’s an ten na i.e . < 10 mm un scree ne d track,

use 50Ω microstrip or coax for >10mm

4. It is desirable, but not essential, to earth plane all unused area around the module.

5. Mount as far as possible from high frequency interference sources, Microprocessors with

external busses are to tally incompatible with se nsitiv e rad io rece iv er s and must be ke ep at least
1 metre from the receive antenna. Single chip micros are not a problem.

6. In some applications it is advantage ous to remote the receive r and it’s antenna away from th e

main equipment. This av oids any interfere nce problems and allo ws flexibility in the sig hting of
the receive antenna for optimum RF performance.

Using the DETECT output
Pin 3 of the module may be used in several ways:-

1. Pulled up to pin 5 ( Vcc) with a 47 kΩ resistor unmutes the AF and DATA outputs for normal
operation.

2. Pulled down to 0 Volts with a 47 kΩ mutes the AF and DATA Outputs (both go to 0V).

3. To drive the base of a PNP transistor (see fig 2) to derive a logic compatible carrier detect. The

data detect output on pin 3 may be used for duty cycle power saving control in portable
equipment where battery life is a problem. By pulsing the receiver on/off the average supply
current may often be reduced by a factor of 20 or more depending upon the system
requirements the data dete ct output is valid 1.5 ms (2.5 ms worst case ) after application
of the supply and is used to inhibit the power saving while data decoding is done.

Internal data slicer
A CMOS compatible data output is available on pin 7, this output is normally used to drive a digital

decoder IC or a microprocessor which is performing the data decoding. The data slicer in the receive
module is designed to accept data with a wide range of pulse widths and mark: space ratio’s, see
specification table for limiting values. The data slicer has a 10 ms transie nt response time this is the
settling time of the adaptive comparator, i.e. the first 10 ms of signal may be corrupt at the data output.

System coding
The transmit and re ceive mod ules have no internal digital codin g/decoding thus allowing the f lexibility

to send many types of data. Encoder and decoder IC’s are required to give the system a high degree of
protection from false triggers due to noise/interference/neighbouring systems and often for security
reasons. There are wide range of suitable encoder/decoder IC’s which may be used with the modules,
including :-

MM57C200, MM57410,National Semiconductor
UM3750, UMC
HT12 series, Holtek
MC145026 series, Motorola
AS2787, Austria Mikro Systeme International GmbH
Additionally IR. remote control, DTMF, Selcall and modem IC’s can be easily interfaced to the modules.

Radiometrix Ltd, SILRX-UHF Data Sheet page 8

AF output
This output is the FM demo dulator’s output after buffering and filtering . Since it is taken before the

data slicer in the module, it may be used to drive external data slicers / demodulator’s in cases where
the internal data slicer is not suitable. This is the case where an analogue subcarrier is being employed
e.g. 2 tone AFSK or DTMF tones. In these cases the AF output is used to drive the FSK / DTMF decoder
directly.

The AF output is also a very useful test point for monitoring signals or interference. The AF output is
DC coupled to the FM demodulator thus the DC level Varies with the frequency of the incoming signal.

Supply requirements

The module re quires a clean supply. No ise and ‘hash’ in the 5 to 500 kHz band and 16 MHz ±1 MHz
must be less than 2 mV, We recommend a 10 µF capacitor to ground on pin 5 (Vcc) and a 10Ω series feed
resistor in cases where the cleanness of the supply is in doubt.

Warning: Don’t be tempted to adjust the trimmer on the module, it controls the receive

.

frequency and can only be correctly set-up with an accurate RF signal generator!

Additional Reading
BS 0799 British standard for Wire-free intruder alarm systems
BS 4737 British standard for intruder alarm systems in buildings from British standards

institution - Tel. [phone]
MPT1340 DTI type approval specification for 418 MHz Telemetry from department of

Trade and Industry - 44 171 211 0502/0505
ARRL Handbook Excellent radio engineering text
ARRL Antenna Book Practical antenna design book

Radiometrix Ltd, SILRX-UHF Data Sheet page 9

Applications note

Four Channel Receiver with battery saver

Fig 7 shows a simple four channel paging receiver with 256 setable codes. The CMOS 555 timer
provides a duty cycle power save circuit which latches ON when a signal is present. The values used in
the example give 4ms ON; 400 ms OFF, i.e. 1:100 duty cycle. The total quiescent current is less than
200µA, thus a 9V alkaline battery (500 mA/hr) will give a life of over 2000 hours. The ON time is
determined by the receiver’s power up settling time (3 ms worst case) + any tolerance of the duty cycle
oscillator. The OFF time is controlled by R8 in the circuit an d sho uld be se lected to suit th e applicatio n
depending upon the required response time and any limits imposed upon the duration of the
transmission. It is recommended that the OFF time be no longer than 1/2 for the transmission
preamble duration.

figure 7: Four Channel Receiver with power save

Ordering information
SAW based OEM Transmit and Receive modules.

TXM-418-5 UK Transmitter on 418 MHz, Type approved to MPT1340
TXM-418-10 Fast transmitter on 418 MHz, Type approved to MPT1340
RXM-418-5 matching UK receiver module on 418 MHz
SILRX-418-5 Low current UK receiver module on 418 MHz
BiM-418-10 Bi-directional short range module on 418 MHz
RPC-418-5 Self-contained module wich integrates the BiM transceiver with a Radio Packet

Controller
EVAL-418-A Evaluation kit for TXM & RXM
EVAL-418-B SILRX supplementary PCB for EVAL-418-A
BiM-KIT Evaluation kit for BiM-UHF modules.

All modules are available in a 433.92 MHz version for use in other European countries.

Radiometrix Ltd, SILRX-UHF Data Sheet page 10

Copyright notice

This product data sheet is the original work and copyrighted property of Radiometrix
Ltd. Reproduction in whole or in part must give clear acknowledgement to the
copyright owner.

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 Radiocommunications Agency (RA) web site:

http://www.radio.gov.uk/topics/conformity/conform-index.htm

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