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FMR-05
27MHz FM Receiver for Manchester Data Format
Features
• Small Size
• Low Voltage & Current Operation
Application
• Telecommand Systems
• Security Systems
• Alarms
• Radio Data Communications
• Commercial / Industrial Telemetry
FMR-05 & FMT-2712 can be combined to form a transceiver. This is possible by using Elsema's FMTR-27 printed circuit board. |
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 Download Datasheet
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Technical Note
The data output pin toggles randomly (1 msec noise) on the receiver when no carrier is received. This presents a problem when the decoding on the data pin decodes this noise as data. It is not possible to stop this noise since the receiver is constantly checking the noise for a valid data. To solve this problem you should start to decode the data, on the receiver, after a valid start pulse was decoded. This valid start pulse should be a minimum 70ms long pulse. Since the noise is made up of pulses less then 70ms the decoding only decodes valid data. The transmitter would have to transmit the start pulse.
RX-Data Slicer is set for Elsema Remote Control Signal (Average 66%L-33%H). Other duty cycles may need an increase of the 22Kohms in the FMR-05. This 22Kohms is located to the left of the 10Kohnm SMD (looking from the SMD side). Other recommended values are 27 or 33Kohms.
NB: Care should be taken that a data signal of 66/33% duty cycle is used.
Compatibility
All Elsema Type FMT-... series:
FMT-2712
Technical Data
Supply Voltage |
4.75 - 5.25 VDC, absolute max 7VDC |
Current Consumption |
5mA at 5VDC |
Receiving Frequency |
27.145MHz (Other freq. available: 27.045, 27.195 & 27.455MHz. NB. 27.455 freq. is not available for Australia ) |
Type of Crystal Used |
26.690MHz, 3rd Overtone, 20pF, 30ppm at 0-50 deg C |
IF Freq |
455kHz |
Selectivity |
At least -40dB at ±10kHz |
Sensitivity |
Better than 1uV |
Type of Demodulation |
Narrow-bandwidth Frequency Modulation (FM) |
Bandwidth |
±2.5kHz |
Baud rate |
300-2400bps with 66/33% duty cycle (other duty cycles will degrade sensitivity) |
Data Output Level |
Open collector (Digital) |
Connections |
1mm socket 0.1" spacing |
Antenna |
50 Ohms, 27MHz CB-Antenna or piece of approximately 1m of wire |
Dimensions |
50 x 33 x 15mm |
Weight |
14g |
Circuit Diagram & Pin Connections
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