NTX0
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Issue 1, 02 November 2012 NTX0 / NRX0 27MHz HF Narrow Band FM TX & RX The 10kHz channel NBFM NTX0 transmitter and NRX0 receiver operate on the licence exempt 27MHz SRD HF allocation. These modules offer a low power, reliable data link in a Radiometrix SIL standard pin out and foot print. This makes the NTX0/NRX0 pair ideally suited to those low power applications where existing single frequency wideband UHF modules have insufficient range, and in parts of the world where other frequency bands are not appropriate Features Conforms to ETSI EN 300 220-3 (radio) and EN 301 489-3 (EMC) and FCC 95.201-95.225 Standard frequency: 27.095MHz Data rates up to 5kbps Usable range over 1km @ 10mW 10/12.5kHz Channel spacing Feature-rich interface (RSSI, analogue and digital baseband) Longer range compared to Wide Band FM modules Applications Radio Control (R/C) Radio Service under FCC Part 95 subpart C Radio model control Telemetry and telecommand Wireless door entry systems Simple On/Off switching In-building environmental monitoring and control Security and fire alarms Vehicle/machinery controls Technical Summary Transmitter – NTX0 3 stage crystal controlled VCXO Supply 2.9V - 15V @ 20mA (10mW) Data bit rate: 5kbps max. Transmit power: +10dBm (10mW), 50mW (+17dBm) or100mW (+20dBm) Size: 43 x 15 x 8mm Receiver – NRX0 Double conversion FM superhet Supply range: 2.9V - 15V @ 12mA Data bit rate: 5kbps max. Receiver sensitivity: -115dBm (for 12dB SINAD) Adjacent Channel: -60dBm Blocking: -85dB Size: 47 x 17 x 8mm Evaluation platforms: NBEK + SIL carrier

Functional description The NTX0 transmitter consists of a Frequency Modulated (FM) Voltage Controlled Crystal Oscillator (VCXO) feeding a two stage amplifier and RF filter. Operation can be controlled by the EN (Enable) line, the transmitter achieving full RF output typically within 5ms of this line being pulled high. The RF output is filtered to ensure compliance with the appropriate radio regulations and fed to the 50Ωantenna pin. The NRX0 module is a double conversion NBFM superhet receiver capable of handling data rates of up to 5kbps. It will operate from a supply of 2.9V to 15V and...

Figure 3: NRX0 pin-out and dimension Function 50Ω RF input from the antenna RF Ground is internally connected to the module screen and pin 4 (0V). These pins should be directly connected to the RF return path - e.g. coax braid, main PCB ground plane etc. Received Signal Strength Indicator with >60dB range. DC level between 0.5V and 2V Ground 2.9 – 15V DC power supply (4.1 – 15V for 50 and 100mW version) 500mVpk-pk audio. DC coupled, approx 0.8V bias Received Data output from the internal data slicer. The data is squared version of the Audio signal on pin 6 and is true data, i.e. as fed to...

Absolute maximum ratings Exceeding the values given below may cause permanent damage to the module. Operating temperature Storage temperature NRX0 Vcc, RXD (pins 7,9) En, RSSI, AF (pins 4,5,8) RF in (pin 1) Performance specifications: NTX0 transmitter (Vcc = 3V / temperature = 20°C unless stated) General DC supply Supply voltage for 10mW TX Supply current @ 10mW Supply voltage for 50mW TX Supply current @ 50mW Supply voltage for 100mW TX Supply current @ 100mW Antenna pin impedance RF RF centre frequency Channel spacing Number of channels RF power output RF power output RF power output...

Performance specifications: NRX0 receiver (Vcc = 3V / temperature = 20°C unless stated) pin DC supply Supply voltage Supply current RF/IF RF centre frequency Frequency accuracy Channel spacing RF sensitivity @ 12dB SINAD RSSI range Blocking Image rejection Adjacent channel rejection Spurious response rejection LO re-radiation Baseband Baseband bandwidth @ -3dB Data rate AF level DC offset on AF out Distortion on recovered AF Dynamic timing Power up with signal present Power up to valid RSSI Power up to valid AF Power up to stable data Time between data transitions Signal applied with supply...

Applications information Power supply requirements Both modules have built-in regulators which deliver a constant 2.8V (4V in 50mW and 100mW version) to the module circuitry when the external supply voltage is 2.9V or greater (4.1V in 50mW and 100mW version), with 40dB or more of supply ripple rejection. This ensures constant performance up to the maximum permitted rail, and removes the need for external supply decoupling except in cases where the supply rail is extremely poor (ripple/noise content >100mVpk-pk). Continuous operation of 100mW version above 9V supply is not recommended. The...

Module mounting considerations The modules may be mounted vertically or bent horizontal to the motherboard. Note that the components mounted on the underside of the NTX0 and NRX0 are relatively fragile – avoid direct mechanical contact between these and other parts of the equipment if possible, particularly in situations where extreme mechanical stresses could routinely occur (as a result of equipment being dropped onto the floor, etc). Good RF layout practice should be observed. 50Ω microstrip line or coax or a combination of both should be used to connect RF pin of the module to RF...

Radiometrix Ltd Hartcran House 231 Kenton Lane Harrow, Middlesex HA3 8RP ENGLAND Tel: +44 (0) 20 8909 9595 Fax: +44 (0) 20 8909 2233 sales@radiometrix.com www.radiometrix.com 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...