BIM3B-869-64

EW N 24 April 2007 Radiometrix Hartcran House, 231 Kenton Lane, Harrow, HA3 8RP, England Tel: +44 (0) 20 8909 9595, Fax: +44 (0) 20 8909 2233 BiM3B 869MHz Wide Band FM radio transceiver The BiM3B radio transceiver module is an enhanced high power replacement for the European version BiM3B-869-64. Two frequency variants are available in the European unlicensed band, one with 5mW RF power with no duty cycle restriction other with 25mW RF power with 1% duty cycle restriction. Fig. 1: BiM3B-869.85-64 Features Complies with European harmonised standards EN 300 220 and EN 301 489 869.85MHz 5mW 100% duty cycle or 868.30MHz 25mW 1% duty cycle RF power output +14dBm (25mW) on 868.30MHz +7dBm (5mW) on 869.85MHz Data rates up to 64kbps Crystal controlled PLL FM circuitry for both Tx and Rx SAW front end filter and full screening Receiver Sensitivity: -101dBm for 1ppm BER (64kbps) -104dBm for 1ppm BER (10kbps) Supply: 2.9V - 16V @ 35mA Tx (25mW), 17mA TX (5mW), 11mA Rx Usable range up to 300 metres external, 75 metres in building SAW front end filter and full screening RSSI (standard) or carrier detect option Analogue and digital baseband Low profile with small footprint 33 x 23 x 5mm Applications PDAs, organisers and laptops Handheld terminals EPOS equipment, barcode scanners, belt clip printers Data loggers Audience response systems In-building environmental monitoring and control Security and fire alarms Restaurant ordering systems Vehicle data up/download Radiometrix Ltd, BiM3B Data Sheet page 1 Functional overview The transmit section of the BiM3B consists of a frequency modulated crystal locked PLL feeding a buffer amplifier and RF filter. A Tx select line controls operation. The transmitter achieves full RF output typically within 1ms of this line being pulled low. Modulation is applied at the TXD input and may be either a serial digital stream toggling between 0V and 3V (digital drive) or a high level analogue waveform with the same peak limits (linear drive). Modulation shaping is performed internally by a 2nd order lowpass filter, which minimises spectral spreading. The RF output is filtered to ensure compliance with the appropriate regulations and fed via a Tx/Rx changeover switch to the antenna pin. The receive section is a single conversion FM superhet with an IF of 10.7MHz. A SAW bandpass filter in the receiver front-end provides image rejection and suppression of other unwanted out-of-band signals. Like the transmitter, the receiver is controlled by its own active low RX select line. A post-detection lowpass filter establishes the signal bandwidth and ensures clean operation of the subsequent adaptive data slicer. The slicer is optimised for balanced data such as bi-phase code. The standard module features a received signal strength (RSSI) output with 60dB of range. A version of BiM3B featuring a fast acting Carrier Detect (CD) output on the same RSSI pin is also available. The CD output will indicate the presence of any RF signals on the carrier frequency. matching & lpf PA VCO ÷ 64 Loop Filter φ ref osc 35kHz LPF TXD Antenna Tx/Rx switch ÷ 32 φ Loop Filter ref osc Vcc 2.9 - 16V Regulator & Tx/Rx logic Tx select Rx select VCO RSSI/CD 869MHz BPF LPF data slicer preamp IF Amp Demod RXD Mixer 10.7MHz AF Pin description Fig. 2: Block diagram RF GND pins 1 & 3 RF ground pins, internally connected to the module screen and to pins 5, 9, 10 & 18 (0V). These pins should be connected directly to the RF return path (e.g. coax braid, main PCB ground plane etc). Antenna pin 2 50Ω RF connection to the antenna, DC-isolated. See pages 7 & 8 for details of suitable antennas and feeds. 0V (GND) pins 5, 9, 10 & 18 Supply ground connection and screen. RSSI pin 11 Received Signal Strength Indicator with 60dB range, operational when Rx is enabled. Output voltage nominally 0.15 - 0.40Vdc (no signal), 1.40Vdc (maximum). See page.6 for typical characteristics. CD pin 11 Carrier Detect - When the receiver is enabled, a low indicates a signal above the detection threshold is being received. The output is high impedance (50kΩ) and should only be used to drive a CMOS logic input. Radiometrix Ltd, BiM3B Data Sheet page 2 RXD pin 12 Digital output from internal data slicer. The output is a squared version of the signal on pin 13 (AF) and may be used to drive a decoder directly. The data is true data, i.e. as fed to the transmitter. Output is “open-collector” format with internal 10kΩ pullup to Vcc (pin 17). AF pin 13 Buffered & filtered analogue output from FM demodulator. Standing DC bias of 1V approx. Useful for test purposes or for driving external decoders. External load should be >10kΩ // 50kΩ. TX select pin 15 Active-low Transmit select. 47kΩ internal pull-up to Vcc. RX select pin 16 Active-low Receive select. 47kΩ internal pull-up to Vcc. Pin 15 TX 1 1 0 0 Pin 16 RX 1 0 1 0 Function Power down (