AUREL XTR-915 User manual
XTR-915
Instruction Manual
Technical features are subject to change without notice. AUR°EL S.p.A does not assume responsibilities for any damage caused by the device’s misuse.
AUREL S.p.A. Via Foro dei Tigli, 4 -47015 Modigliana (FC) –ITALY Rev. A, January 11th 2002
Tel.: +390546941124 –Fax: +390546941660 Pag 1of 6
XTR-915 mod. Transceiver
Miniaturized data transceiver module, 100 Kbps maximum speed, 914,50 MHz operating frequency.
Especially suitable for use in North America Countries where the band assigned to short range devices (SRD)
is 902–928 MHz.
Pin-Out and block diagram Mechanical dimensions
1 GND
3 GND
9 GND
18 GND
10 GND
2 Antenna
4 NC
5 NC
6 NC
7 NC
8 NC
17 Vcc
16 Rx EN
15 Tx EN
14 Mod. in
13 Analog out
12 Data out
11 C.D.
RX-TX
switch
Preamp
BPF
Saw Filter
PLL
Controlled
O.L.
IF limiter
Demod.
Mixer
PLL
50 KHz Buffer
Slicer
Ampl.
PLL Controlled
Oscillator Power Supply
RX-TX
RX-TX
Enable switch
Rx Enable
Tx Enable
Vcc Tx-Rx
Connections
Pin 1-3RF GND RF circuit GND
Pin 2 Antenna 50Ωimpedance antenna connection
Pin 9-10-18 GND Connections to GND. Internally connected also to the module’s
shield.
Pin 11 CD Carrier Detect. With enabled receiver, a low signal (voltage level 0V),
indicates that the receiver detects an RF carrier. The line activates
with an RF signal of minimum –96dBm applied to pin 2 (antenna).
High impedance output available only for loads under CMOS logic.
Pin 12 RXD Receiver data output. Load impedance allowed: over 100KΩwithout
any capacitor in parallel.
Pin 13 AF Filtered and buffered output of the FM detector. Load impedance
allowed: over 2KΩand less than 100pF.
Pin 14 TXD Input to transmitter; accepts serial data in TTL logic (0 ÷ 5V) with a
10KΩload impedance.
Pin 15 TX ENABLE Active when low, (voltage level 0V), enables the transmitter circuit.
Max 1mA
Pin 16 RX ENABLE Active when low, (voltage l
evel 0V), enables the receiver circuit.
Max. 0,5 mA
Pin 17 Vcc Connection to the positive pole of the supply voltage (+5V ±10%)
The technical tests and reports have been carried out and obtained by the laboratories of:
Messrs PRIMA RICERCA & SVILUPPO –via Campagna, 58 –22020 Gaggino Faloppio (CO).
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XTR-915
XTR-915
Instruction Manual
Technical features are subject to change without notice. AUR°EL S.p.A does not assume responsibilities for any damage caused by the device’s misuse.
AUREL S.p.A. Via Foro dei Tigli, 4 -47015 Modigliana (FC) –ITALY Rev. A, January 11th 2002
Tel.: +390546941124 –Fax: +390546941660 Pag 2of 6
Technical features [@5V T=25°C]
Characteristics Min Typical Max Unity Remarks
Voltage supply 4.5 55.5 Vdc
Absorbed current (TX ON) 24 28 32 mA
Absorbed current (RX ON) 10 11 12 mA
Absorbed current (TX/RX OFF) 100 nA
RX Section
Reception frequency 914.50 MHz
RF sensitivity -100 -102 dBm See note 1
IF passband 150 KHz
Interferences rejection
[±±5% band’s extremities] -80 dBm
RF spurious emissions in antenna ETS 300 220 compliance See note 2
Output square wave 50 KHz
Output low logic level 0,1 VSee note 4
Output high logic level 3,5 VSee note 4
Carrier Detect (CD) threshold -96 -98 dBm
RX Switch-on time 1mS
TX Section
Transmission frequency 914.50 MHz
Modulation passband 50 KHz
FM deviation ±25 KHz
TX output power 0dBm
Antenna impedance 50 Ω
TX Switch-on time 1mS
Operating temperature -20 +80 °C
Working temperature [ETS 300 220] -20 +55 °C
Dimensions 33 x 23 x 8 mm
Note1: Values have been obtained by test as per Fig. 3 at RF IN –100 dBm, ±25KHz FM deviation, and with a 40 KHz modulating
frequency.
Note2: The R.F. emission measure has been obtained by connecting the spectrum analyser directly to the XTR module pin 2.
Note3: By switch-on time is meant the time required by the device to acquire the declared characteristics, from the very moment the
enabling is applied.
Note4: Values obtained with an applied 100KΩload.
TX/RX Enabling
Pin 15 (TX ENABLE) and 16 (RX ENABLE) can acquire the following status:
Pin 15 TX ENABLE Pin 16 RX ENABLE Obtained function
11Disabled module
10Enabled receiver
0 1Enabled transmiter
00Not to be used condition
XTR-915
Instruction Manual
Technical features are subject to change without notice. AUR°EL S.p.A does not assume responsibilities for any damage caused by the device’s misuse.
AUREL S.p.A. Via Foro dei Tigli, 4 -47015 Modigliana (FC) –ITALY Rev. A, January 11th 2002
Tel.: +390546941124 –Fax: +390546941660 Pag 3of 6
Considerations over the serial data transceiving
Pulse amplitude time
The circuit characteristics (passband in base band and AC couplings) determine the time has to elapse
between each two consecutive level transitions on the line of the serial signal. For the correct operation of
the XTR-915, such time must be comprised between 10 and 500 µs.
Settling time
The Data Slicer requires that for atleast 1 ms before the data themselves, a preamble, composed by a
square wave, is transmitted in order to consider reliable the data coming out from the RXD line.
Bit ON/Bit OFF relation
The Data Slicer is optimized for a 50:50 duty cycle. It shall continue to operate, even with bigger distortion
and less tolerance to interferences, till a 30:70 or 70:30 duty cycle. It is not possible, therefore, to directly
transmit in RS232 logic unless by caring to balance the ratio 1 and 0 in the output, since the duty-cycle
could be also of the 90% not permitting thus, the correct operation of the receiver.
During the transmiter modulation, while conditioning the input pin [pin 14] by a logic signal, it is
recommended not to exceede the maximum continuous length of 500 µS without transition ON/OFF –
OFF/ON ; this in order not to degrade the receiver’s sentivity. It is therefore necessary to modulate by
means of specific techniques that allow a low duty-cycle like Manchester, coding from 8 to 12 bits or other
suitable techiniques. In lack of balancing techniques on the specifications bit, if it is requested to operate
with RS232 protocol, it is recommended to utilize a minimum 19.200 bps speed in order to take advantage
of the full performances by transmitting, for instance, one byte and its complementary one after the other
[balancing over the byte].
Device Usage
To take advantage of the performances detailed in the Technical Specifications, and in order to comply with
the operating conditions which characterize the Certification, the transmitter must be fitted on a printed
circuit considering the followings:
5 V dc supply:
1. The transceiver must be supplied by a very low voltage safety source, protected against short circuits.
2. Maximum voltage variations allowed: ± 0,5 V
3. De-coupling, next to the transmitter, by means of a minimum 10 ìF capacitor.
4. It is suggested to place in series to the suppl, a 10 Ωresistance, as closer as possible to pin 17.
XTR-915
Instruction Manual
Technical features are subject to change without notice. AUR°EL S.p.A does not assume responsibilities for any damage caused by the device’s misuse.
AUREL S.p.A. Via Foro dei Tigli, 4 -47015 Modigliana (FC) –ITALY Rev. A, January 11th 2002
Tel.: +390546941124 –Fax: +390546941660 Pag 4of 6
Reference Curves
Usage of the devices in net-work systems
XTR-915
Instruction Manual
Technical features are subject to change without notice. AUR°EL S.p.A does not assume responsibilities for any damage caused by the device’s misuse.
AUREL S.p.A. Via Foro dei Tigli, 4 -47015 Modigliana (FC) –ITALY Rev. A, January 11th 2002
Tel.: +390546941124 –Fax: +390546941660 Pag 5of 6
The device has been designed to allow a minimum switching time between reception and transmission the
minimum transmission speed requested permitting.
The XTR-915 model shows the less possible time, allowing at most in 2mS to be operative after the
inversion Rx/Tx.
It is recommended therefore to evaluate this minimum value during the device use since to a minimum
switching time, it is normally associated the necessity of an ultra high modulation technique with
consequently operating difficulties.
RF Sensitivity
The declared technical features have been obtained by applying the following testing system:
Use suggestions
Ground:
1. It must surround at the best the welded area of the module. The circuit must be double layer, with
throughout vias to the ground planes, approximately each 15 mm.
2. It must be properly dimensioned, especially in the antenna connection area, in case a radiating whip
antenna is fitted in it (an area of approximately 50 mm radius is suggested.)
Power supply
De-coupling
capacitor
50 Ohm line
XTR-915
Instruction Manual
Technical features are subject to change without notice. AUR°EL S.p.A does not assume responsibilities for any damage caused by the device’s misuse.
AUREL S.p.A. Via Foro dei Tigli, 4 -47015 Modigliana (FC) –ITALY Rev. A, January 11th 2002
Tel.: +390546941124 –Fax: +390546941660 Pag 6of 6
50 Ohm Line (connection between antenna and pin 2):
1. It must be as shortest as possible.
2. 1,8 mm wide for 1 mm thick FR4 printed circuits and 2,9 mm wide for 1,6 mm thick FR4 printed circuits.
On the same side, it must be kept 2 mm away from the ground circuit.
3. On the opposite side a ground circuit area must be present.
Antenna connection:
1. It may be utilized as the direct connection point for the radiating whip antenna.
2. It can bear the connection of the central wire of a 50 Ωcoaxial cable. Be sure that the braid is
welded to the ground in a close point.
Antenna:
A whip antenna, 8,25 mm long and approximately 1 mm dia., brass or copper wire made, must be
connected to the RF input of the transceiver.
The antenna body must be keep as much as possible straight and it must be free from other circuits or
metal parts (5 cm minimum suggested distance.)
It can be utilized both vertically and horizontally, provided that a good ground plane surrounds the
connection point between antenna and receiver input.
N.B: As an alternative to the a.m. antenna it is possible to utilize the whip model manufactured by Aurel
(see related Data Sheet ed Application Notes).
By fitting whips too different from the described ones the CE Certification is not assured.
Other components:
1. Keep the transceiver separate from all other components of the circuit (more than 5 mm).
2. Keep particularly far away and shielded all microprocessors and their clock circuits.
3. Do not fit components around the 50 Ohm line. At least keep them at 5 mm distance.
4. If the Antenna Connection is directly used for a radiating whip connection, keep at least a 5 cm radius
free area. In case of coaxial cable connection 5 mm radius will suffice.
Reference Rules
The XTR-915 transceiver is CE certified and in particular it complies with the European Rules EN 300 220,
and EN 301 489. The equipment has been tested according to rule EN 60950 and it can be utilized inside a
special insulated housing that assures the compliance with the above-mentioned rule. The transceiver must
be supplied by a very low voltage safety source protected against short circuits
The use of the transceiver module is foreseen inside housings that assure the overcoming of the Rule EN
61000-4-2 not directly applicable to the module itself. In particular, it is at the user’ s care the insulation of
the external antenna connection, and of the antenna itself since the RF output of the receiver is not built to
directly bear the electrostatic charges foreseen by the a.m. rule.
The device use is foreseen specially for those countries where the band assigned to short range devices
(SRD) is 902–928 MHz.
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