TR-916-SC-P Linx Technologies Inc, TR-916-SC-P Datasheet - Page 6

• Manufacturer Part Number: TR-916-SC-P
• Description: TRANSCEIVER RF 916MHZ 1/2-DUPLEX
• Manufacturer: Linx Technologies Inc
• Series: SCr

Specifications of TR-916-SC-P

• Frequency: 916MHz
• Data Rate - Maximum: 33.6kbps
• Modulation Or Protocol: FM, FSK
• Applications: ISM, Garage Door Opener, Remote Controls, 2-way RKE
• Power - Output: -10dBm
• Sensitivity: -94dBm
• Voltage - Supply: 2.7 V ~ 13 V
• Current - Receiving: 15mA
• Current - Transmitting: 19mA
• Data Interface: PCB, Through Hole
• Antenna Connector: RP-SMA
• Operating Temperature: 0°C ~ 70°C
• Package / Case: Module
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Memory Size: -
• Other names: TR-900-SC; TR-900-SC; TR-916-SC; TR-916-SC

TRANSMITTER OPERATION
RECEIVER OPERATION
The transceiver’s transmitter section is a wide-band FM transmitter capable of
generating 1mW of output power into a 50-ohm load.
The transmitter is comprised of a VCO and a crystal-controlled frequency
synthesizer. The frequency synthesizer, referenced to a precision crystal, locks
the VCO to achieve a high-Q, low phase-noise oscillator.
FM modulation is achieved by direct modulation of the reference crystal. By
modulating the transmitter in this manner, a wide modulation bandwidth is
achieved. If the transmitter LO were modulated, the frequency synthesizer would
track out modulation within the bandwidth of the loop filter (this is a common
limitation of most synthesized FM transmitters).
When the transmitter will be used to transmit digital data, the TXDATA is best
driven from a 5-volt source. The transmitter is designed to give an average
deviation of 110kHz with a 5V square wave input. It is possible to successfully
modulate the transceiver with a level as low as 3 volts; however, the reduced
carrier deviation will cause a slight loss in receiver sensitivity and a 10 to 20%
increase in settling times.
Analog sources such as audio should provide a 3V P-P maximum waveform and
should be AC-coupled into the TXDATA pin. The size of the coupling capacitor
should be large enough to insure the passage of all desired frequencies. Since
the modulation voltage applied to the TXDATA pin determines the carrier
deviation, distortion can occur if the TXDATA pin is over-driven. The actual level
of the input waveform should be adjusted to achieve optimum in-circuit results.
The transmitter’s output power is not affected by supply voltage but it can be
externally adjusted from approximately -15dBm to 0dBm using the LVLADJ pin.
When the LVLADJ pin is open, power is at its max and the transmitter will draw
25mA typically. When LVLADJ is at 0V, power is at its minimum and the
transmitter will draw 13mA typically. An internal 1K pull-up resistor holds LVLADJ
high when the transceiver is in transmit mode so no external components are
needed to obtain maximum power. To lower the transmit power, simply place a
resistor from the LVLADJ pin to ground to form a voltage divider. Linx
recommends placing pads for this resistor in case the power needs to be later
reduced for legal compliance.
The receiver is configured as a single conversion superhet FM receiver with a
baseband analog bandwidth of 17kHz.
Low-level RF signals are filtered at the front end by a SAW band-pass filter. This
filter reduces the signal levels of interfering transmitters such as pager towers
and cell phones.
The filtered signal is amplified and down-converted to the 10.7 MHz IF by mixing
it with a LO frequency generated by a PLL locked differential VCO. Then the 10.7
MHz IF is amplified, filtered, and finally demodulated to recover the analog
baseband signal originally transmitted. The analog baseband output is low-pass
filtered and then made available externally via the audio pin. The signal is also
squared by a proprietary data slicer for output of digital information at the RX
Data pin. The data slicer is capable of recreating squared waveforms in the
150Hz to 17kHz band, giving a data-rate bandwidth of 300bps to 33.6Kbps.