elsema 27.195mhz fsk radio data receiver , R2705 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 4800b ps with reduced sensitivity). the low cost, small size, low curren t consumption makes it ideal for various applications. technical data supply voltage 4.5 - 5.5 vdc absolute maximum 6.5vdc. current consumption 3.5ma receiver type dual conversion superheterodyne receiving freq 27.195mhz (o ther freq available on 27.0 45, 27.145, & 27.455mhz. the 27.455 freq is not available for australia) oscillation system vco with 10ppm crystal controlled reference oscillator operating temperature range -5 to 50c if freq 10.7 mhz and 455khz selectivity -6db at 5khz -20db at 6khz sensitivity better than -107dbm or 1v type of demodulation frequency shift keying. (fsk) occupied band width 25khz at -20db. baud rate 2400 bps with 50% duty cycle (can be used to 4800bps with reduced sensitivity) data output level 0-5v frequency response 150 to 2400 hz with 50% duty cycle (other duty cycles will degrade sensitivity) dimension 39 x 25 x 12mm weight 13 grams usable transmitter fmt-2712 data transmitter antenna 50 ohms, 27mhz antenna 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
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 se nsitivity which will result in a re duced transmission range. the R2705 receiver data slicer is set for 50/50-duty cycle, th erefore the ?data in? should have a 50/50-duty cycle. the 50/50-d uty 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 exam ple 66/33 ( manchester format) the data s licer in the receiver will try to adjust it self 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 sens itivity. see diagram below : if 66/33 format is to be used the R2705e module is rec ommended. *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
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