R2705

ELSEMA 27.195MHz FSK Radio Data Receiver , R2705 R2705 27.195MHz FSK Radio Data Receiver Features • Receives digital data • Baud rates 300 - 2400bps • Low cost, small size, low current consumption Application • Telecommand Systems • Security Systems • Alarms • Radio Data Communications • Commercial / Industrial Telemetry Description The R2705 is a radio data receiver to receive digital data. Baud rates of 300 to 2400 bps can be received (Can be used to 4800bps with reduced sensitivity). The low cost, small size, low current consumption makes it ideal for various applications. Technical Data Supply Voltage Current Consumption Receiver Type Receiving Freq Oscillation System Operating Temperature Range IF Freq Selectivity Sensitivity Type of Demodulation Occupied Band Width Baud Rate Data Output Level Frequency Response Dimension Weight Usable Transmitter Antenna 4.5 - 5.5 VDC Absolute maximum 6.5VDC. 3.5mA Dual Conversion Superheterodyne 27.195MHz (Other freq available on 27.045, 27.145, & 27.455MHz. The 27.455 freq is not available for Australia) VCO with 10ppm Crystal Controlled reference Oscillator -5 to 50°C 10.7 MHz and 455KHz -6dB at ±5kHz -20dB at ±6kHz Better than -107dBm or 1µV Frequency Shift Keying. (FSK) 25KHz at -20dB. 2400 bps with 50% duty cycle (Can be used to 4800bps with reduced sensitivity) 0-5V 150 to 2400 Hz with 50% duty cycle (Other duty cycles will degrade sensitivity) 39 x 25 x 12mm 13 grams FMT-2712 Data Transmitter 50 ohms, 27MHz Antenna ELSEMA 27.195MHz FSK Radio Data Receiver , R2705 Connection R2705 Data Format It is important to input the correct data format otherwise the receiver will have a lower sensitivity which will result in a reduced transmission range. The R2705 receiver data slicer is set for 50/50-duty cycle, therefore the “data in” should have a 50/50-duty cycle. The 50/50-duty cycle data can be pulse-width modulated to transmit resets, 0's or 1's. See diagram below : A 50/50-duty cycle will have an average DC signal resulting in a constant reference for the data slicer. Users should use pulse-width modulation to transmit data with logic 1's or 0's. If a different duty cycle is used, for example 66/33 ( Manchester format) the data slicer in the receiver will try to adjust itself to the average DC signal. Since this average DC signal is changing with different data bits this will result in a constantly changing reference for the data slicer, resulting in lower sensitivity. See diagram below : If 66/33 format is to be used the R2705E module is recommended. *Only 50/50 duty cycle data is suitable for the R2705 receiver. Manufactured by Elsema Pty Ltd 3/10 Hume Rd, Smithfield NSW 2164 Ph: 02 9609 4668 Fax: 02 9725 2663 Website: http://www.elsema.com ELSEMA 27.195MHz FSK Radio Data Receiver , R2705