RPC-418-5

Radiometrix Hartcran House, Gibbs Couch, Watford, WD19 5EZ, England Issue 3, 13 April 2001 Tel: +44 (0) 20 8428 1220, Fax: +44 (0) 20 8428 SILRX-UHF UHF Radio Telemetry Receiver Module UK version: Euro version: SILRX-418-5 / SILRX-418-10 SILRX-433-5 / SILRX-433-10 The SILRX-418-5 and SILRX-433-5 integrate a complete FM superhet UHF radio receiver on a small module. Together with the matching TXM418-5 or TXM-433-5 transmitter a one-way radio data 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 • 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 modules capable of transferring analogue or digital data up to a distance of 200m. The SILRX receiver module is particularly suitable for battery powered portable applications where it’s low power requirements 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 Line powered telephone auto diallers Guard patrol/lone worker protection Mobile panic attack Battery powered half duplex data networks Lighting control, Garage door openers Picture/antique protection alarms Radiometrix Ltd, SILRX-UHF Data Sheet left: TXM-418-5 transmitter right: SILRX-418-5 receiver Paging car alarms Domestic and commercial security Medical Alert/Nurse Call system Remote industrial process monitoring Data transfer through hazardous environments Fire alarms Remote control, Access control 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 carrier detect signal is available to indicate to external circuits that a signal is present. This signal is extremely useful when implementing duty cycle power save circuits (see fig 4) or to indicate to external logic that a signal is being received. It is internally derived from the degree of 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 environment. The 200m quoted range is a reliable operating distance over open ground 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 evaluation kit, EVAL-418-A, can be used to assess the reliable working 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 pin pin 1 2 3 RF IN RF GROUND DETECT The receiver antenna connects to this input. It has nominal RF impedance of 50Ω and is capacitively isolated from the internal circuit This pin should be connected to any ground plane against which the antenna works. It is internally connected to pin 4. This pin may be used to derive a carrier detect to enable external circuits when a signal is being received. If the 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. Ground for supply. Positive supply of 4V to 9V 13 mA. The supply must be clean (10mm It is desirable, but not essential, to earth plane all unused area around the module. Mount as far as possible from high frequency interference sources, Microprocessors with external busses are totally incompatible with sensitive radio receivers and must be keep at least 1 metre from the receive antenna. Single chip micros are not a problem. In some applications it is advantageous to remote the receiver and it’s antenna away from the main equipment. This avoids any interference problems and allows flexibility in the sighting of the receive antenna for optimum RF performance. 6. Using the DETECT output Pin 3 of the module may be used in several ways:1. 2. 3. Pulled up to pin 5 (Vcc) with a 47 kΩ resistor unmutes the AF and DATA outputs for normal operation. Pulled down to 0 Volts with a 47 kΩ mutes the AF and DATA Outputs (both go to 0V). 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 detect 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 transient 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 receive modules have no internal digital coding/decoding thus allowing the flexibility 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 demodulator’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 requires a clean supply. Noise 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 BS 4737 MPT1340 Trade ARRL Handbook ARRL Antenna Book British standard for Wire-free intruder alarm systems British standard for intruder alarm systems in buildings from British standards institution - Tel. 44 171 629 900 DTI type approval specification for 418 MHz Telemetry from department of and Industry - 44 171 211 0502/0505 Excellent radio engineering text 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 and should be selected to suit the application 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 TXM-418-10 RXM-418-5 SILRX-418-5 BiM-418-10 RPC-418-5 Controller EVAL-418-A EVAL-418-B BiM-KIT UK Transmitter on 418 MHz, Type approved to MPT1340 Fast transmitter on 418 MHz, Type approved to MPT1340 matching UK receiver module on 418 MHz Low current UK receiver module on 418 MHz Bi-directional short range module on 418 MHz Self-contained module wich integrates the BiM transceiver with a Radio Packet Evaluation kit for TXM & RXM SILRX supplementary PCB for EVAL-418-A 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 Radiometrix Ltd Hartcran House Gibbs Couch Watford WD19 5EZ ENGLAND Tel: +44 (0)20 8428 1220 Fax: +44 (0)20 8428 1221 info@radiometrix.co.uk www.radiometrix.co.uk 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: +44 (0)20 7211 0502/0505 Fax: +44 (0)20 7211 0507 library@ra.gsi.gov.uk For further information on radio matters contact the Agency's 24 Hour Telephone Enquiry Point: +44 (0)20 7211 0211 European Radiocommunications Office (ERO) Midtermolen 1 DK 2100 Copenhagen Denmark Tel. +45 35250300 Fax +45 35250330 ero@ero.dk www.ero.dk