Narrowband VHF/UHF Multichannel Transmitter/Receiver Modules

Thanks to inclusion of easy to use, single-function controllers/actuators the CXT and CXR modules are highly suited to tasks that just call for a simple on/off control function (such as flood light control, machine override shutdown, etc), without the need for any additional external circuitry (such as a microprocessor or dedicated encoder/decoder IC). This keeps the size, bill of materials cost and software overhead associated with system designs that employ these modules to a minimum.

Supporting data rates of up to 5 kbps, the modules are built on the radio hardware of the company’s successful LM series. Like the LM series, they provide 32 frequency channel operation (12.5KHz or 25 kHz channels) in any of the 173.200 MHz - 173.325 MHz (UK), 150.825 MHz - 152.450 MHz (Australia), 433.875 MHz - 434.650 MHz (EU), or 458.525 MHz - 459.1 MHz (UK) frequency bands (plus other custom VHF bands on request), allowing them to meet the RF requirements of many different geographical regions.

The CXR receiver has a better than -118dBm usable calling sensitivity, while drawing only 20 mA from a 3.1 V -15 V rail. The matching CXT transmitter can be offered in 10mW (35 mA from 3.1 V -15 V) or 100mW (95 mA from 4.1 V -15 V) versions, depending on specific band regulations.

The integrated control coder/decoder uses a highly noise-tolerant biphase coded data stream, including generous preamble/framing sequences, CRC error detection to minimise false activations and a 16 bit user programmable address. All operating parameters (channel, address, frequency table setup) can be easily programmed by the user, via a simple serial interface. Put together, these features give the user a reliable remote actuator with an operating range of up to 1km.

The CXT and CXR come in compact shielded housings, measuring 33 mm x 23 mm x 9 mm and 46 mm x 23 mm x 9 mm respectively, with pins for PCB mounting. The modules have an operating temperature range of -20 °C to +55 °C and conform fully with EN 300 220-3 and EN 301 489-3 standards. Class one (to EN300-220-v2.3.1) receiver versions are also available.

Key applications for this transmitter/receiver pair include lighting control, security/fire/lone-worker alarms, ‘machine stop’ systems and generic industrial quality on/off switching mechanisms.