Data Sheet(pdf)

W
E
N
Radiometrix
Hartcran House, 231 Kenton Lane, Harrow, HA3 8RP, England
Issue 1, 02 March 2009
Tel: +44 (0) 20 8909 9595, Fax: +44 (0) 20 8909 2233
ENX1
VHF 12.5kHz channel NBFM TRANSCEIVER
The ENX1 transceiver module offers a
100mW RF output VHF data link in a
DIL pin-out and footprint. This makes
the ENX1 ideally suited to those low
power applications where existing
narrow
band
and
wideband
transmitters
provide
insufficient
range. A half duplex radio data link
can be achieved over a distance up to
10km+ with suitable choice of data
rate and antennas.
Features
!
!
!
!
!
!
!
Figure 1: ENX1-169.44375-3
Standard frequency 169.40625MHz and 169.44375MHz
Other frequencies from 120MHz to 180MHz
12.5 kHz channel spacing
Data rates up to 3kbps
Usable range over 10km
Fully screened
Low power requirements
The ENX1 is a narrow band radio transceiver module for use in long range data transfer applications at
ranges up to 10kilometres.
Applications
•
•
•
•
•
•
•
•
EPOS equipment, barcode scanners
Data loggers
Industrial telemetry and telecommand
In-building environmental monitoring and control
High-end security and fire alarms
DGPS systems
Vehicle data up/download
Automatic meter reading (AMR)
Technical Summary
•
•
•
•
•
•
•
•
•
•
•
Size: 49 x 34 x 8.7mm
Operating frequency (standard): 169.40625MHz
Supply range: 5v
Current consumption: 75mA TX
Current consumption: 12mA RX
Data bit rate: 3kbps max.
Transmit power: 20dBm (100mW) nominal
Double conversion FM superhet
SAW front end filter gives >80dB image rejection
-115dBm sensitivity @ 1ppm BER
RSSI output with 50dB range
Radiometrix Ltd.,
ENX1 high power transmitter data sheet
Page 1
Radiometrix Ltd.,
ENX1 high power transmitter data sheet
Page 2
RF
AMP
RF
SWITCH
BPF
SAW
FILTER
PA
PA
CONTROL
RF
AMP
LO
PRE
AMP
SAW
FILTER
Mixer
Figure 2: ENX1 Block diagram
ANTENNA
20.945MHz
21.4MHz
FILTER
MULTIPLIER
IF AMP
DEMOD
455KHz
FILTER
VCTCXO
TX
BPF
DATA
SLICER
TX/RX
LOGIC
RX
REGULATOR
TX
REGULATOR
RSSI
RX
DATA
AF
OUTPUT
TX
DATA
INPUT
TXRX
5V
SUPPLY
Functional description
The ENX1 transceiver consists of a frequency modulated Voltage Controlled Temperature Controlled
Crystal Oscillator (VCTCXO) feeding a frequency multiplier with two stage amplifier and RF filter.
Final Power Amplifier stage is factory pre-set to appropriate band power level. Operation can be
controlled by the TXRX (Enable) line, the transmitter achieving full RF output typically within 7ms of
this line being pulled LOW. The RF output is filtered to ensure compliance with the appropriate radio
regulations and fed to the 50Ω antenna pin. The receiver uses a saw filter to give high rejection of unwanted signals. Double conversion and narrow filtering ensures that signals in adjacent channels are
also rejected.
User Interface
Figure 3: ENX1 pin-out and dimension
ENX1 pin
Name
Function
1
Vcc
5v Supply
2
TXRX
Low = TX, High = RX (Note 1)
3
TXD
DC coupled input for 5V CMOS logic. Rin = 100kΩ
4
0V
Ground
5
RSSI
RSSI
6
0V
Ground
7
AF
Receiver AF output
8
RXD
RX data output
9
0V
Ground
10
0V
Ground
11
RF in/out
Antenna connection
12
RF GND
RF Ground
NOTES:
1. TXRX pin should not be left floating
Radiometrix Ltd.,
ENX1 high power transmitter data sheet
Page 3
Absolute maximum ratings
Exceeding the values given below may cause permanent damage to the module.
Operating temperature
Storage temperature
-20°C to +60°C
-30°C to +70°C
RF in (pin 11)
All other pins
±50V @ <10MHz, +13dBm @ >10MHz
-0.3V to +5.5V
Performance specifications Transmitter:
(Vcc = 5V / temperature = 20°C unless stated)
General
DC supply
Supply voltage
TX Supply current @ 100mW
Antenna pin impedance
RF centre frequency (100mW)
Channel spacing
Number of channels
RF
RF power output
Spurious emissions
Adjacent channel TX power
Frequency accuracy
FM deviation (peak)
pin
min.
typ.
max.
units
1
4.5
5
75mA
50
169.40625
12.5
1
5.5
V
mA
Ω
MHz
kHz
+19
+20
+21
-1.5
±1.4
-40
0
±1.5
+1.5
±1.6
dBm
dBm
dBm
kHz
kHz
2
3
4
4
12
12
Baseband
Modulation bandwidth @ -3dB
TXD input level (logic low)
TXD input level (logic high)
3
3
2
0
5
kHz
V
V
Dynamic timing
TX select to full RF
2
7
ms
Notes:
1.
2.
3.
4.
5.
0
notes
1
5
Measured into 50Ω resistive load.
Total over full supply and temperature range.
With 0V – 5.0V modulation input.
To achieve specified FM deviation.
Meets EN300-220
Radiometrix Ltd.,
ENX1 high power transmitter data sheet
Page 4
Performance specifications Receiver:
(Vcc = 5V / temperature = 20°C unless stated)
pin
min.
typ.
max.
units
1
4.5
10
5.0
12
5.5
15
V
mA
12
12
5
-
-118
70
-54
-120
-115
50
7.5
89
-65
<-70
>80
-
dBm
dBm
dB
kHz
dB
dBm
dB
dB
7
7
7
7
7
0
300
0.5
-
400
0.75
3
-
3
450
1.25
5
100
kHz
mVP-P
V
%
pF
Power up with signal present
Power up to valid RSSI
Power up to stable data
5
8
-
6.5
10
7.5
13
ms
ms
Signal applied with supply on
RSSI response time (rise/fall)
Signal to stable data
5
8
-
100
3.5
-
us
ms
DC supply
Supply voltage
Supply current
RF/ IF
RF sensitivity for 12dB (S+N/N)
RF sensitivity for 1ppm BER
RSSI range
IF bandwidth
Image rejection
LO leakage, conducted
Adjacent channel rejection
Blocking
Baseband
Baseband bandwidth @ -3dB
AF level
DC offset on AF out
Distortion on recovered AF
Load capacitance, AFout/RXD
1
notes
1,2
1,2
1
1,2
DYNAMIC TIMING
Notes:
Radiometrix Ltd.,
1. For received signal with ±1.5kHz FM deviation.
2. Typical figures are for signal at centre frequency
ENX1 high power transmitter data sheet
Page 5
Received Signal Strength Indicator (RSSI)
The module incorporates a wide range RSSI which measures the strength of an incoming
signal over a range of approximately 50dB. This allows assessment of link quality and
available margin and is useful when performing range tests.
The output on pin of the module has a standing DC bias in the region of 0.6V with no signal,
rising to around 1.75V at maximum indication. The RSSI output source impedance is high
(~100kΩ) and external loading should therefore be kept to a minimum.
Typical RSSI characteristic is as shown below:
1800
1600
RSSI Voltage
1400
1200
1000
800
600
400
200
0
-137 -130 -125 -120 -115 -110 -105 -100
-95
-90
-85
-80
-75
-70
-65
RF input level (dBm)
Figure 4: RSSI level with respect to received RF level at ENX1 antenna pin
Radiometrix Ltd.,
ENX1 high power transmitter data sheet
Page 6
Applications information
TX modulation requirements
The module is factory-set to produce the specified FM deviation with a TXD input of 5V amplitude, i.e.
0V “low”, 5V “high
If the data input level is greater than 5V, a resistor must be added in series with the TXD input to limit
the modulating input voltage to a maximum of 5V. TXD input resistance is 100kΩ to ground.
Expected range
Predicting the range obtainable in any given situation is notoriously difficult since there are many
factors involved. The main ones to consider are as follows:
•
•
•
•
•
Type and location of antennas in use
Type of terrain and degree of obstruction of the link path
Sources of interference affecting the receiver
“Dead” spots caused by signal reflections from nearby conductive objects
Data rate and degree of filtering employed
The ENX1’s TXD input is normally driven directly by logic levels but will also accept analogue drive
(e.g. 2-tone signalling). In this case it is recommended that TXD be DC-biased to 2.5V approx. with the
modulation ac-coupled and limited to a maximum of 5Vp-p to minimise distortion over the link.
Although the modulation bandwidth of the ENX1 extends down to DC it is not advisable to use data
containing a DC component. This is because frequency errors and drifts between the transmitter and
receiver occur in normal operation, resulting in DC offset errors on the receiver’s audio output.
Antennas
The choice and positioning of transmitter and receiver antennas is of the utmost importance and is the
single most significant factor in determining system range. The following notes are intended to assist
the user in choosing the most effective antenna type for any given application.
Integral antennas
These are relatively inefficient compared to the larger externally-mounted types and hence tend to be
effective only over limited ranges. They do however result in physically compact equipment and for this
reason are often preferred for portable applications. Particular care is required with this type of
antenna to achieve optimum results and the following should be taken into account:
1. Nearby conducting objects such as a PCB or battery can cause detuning or screening of the antenna
which severely reduces efficiency. Ideally the antenna should stick out from the top of the product
and be entirely in the clear, however this is often not desirable for practical/ergonomic reasons and
a compromise may need to be reached. If an internal antenna must be used try to keep it away from
other metal components and pay particular attention to the “hot” end (i.e. the far end) as this is
generally the most susceptible to detuning. The space around the antenna is as important as the
antenna itself.
2. Microprocessors and microcontrollers tend to radiate significant amounts of radio frequency hash
which can cause desensitisation of the receiver if its antenna is in close proximity. The problem
becomes worse as logic speeds increase, because fast logic edges generate harmonics across the VHF
range which are then radiated effectively by the PCB tracking. In extreme cases system range may
be reduced by a factor of 5 or more. To minimise any adverse effects situate antenna and module as
far as possible from any such circuitry and keep PCB track lengths to the minimum possible. A
ground plane can be highly effective in cutting radiated interference and its use is strongly
recommended.
Radiometrix Ltd.,
ENX1 high power transmitter data sheet
Page 7
The following types of integral antenna are in common use:
Quarter-wave whip. This consists simply of a piece of wire or rod connected to the module at one end.
At 169MHz the total length should be 421mm from module pin to antenna tip including any
interconnecting wire or tracking. Because of the length of this antenna it is almost always external to
the product casing.
Helical. This is a more compact but slightly less effective antenna formed from a coil of wire. It is very
efficient for its size, but because of its high Q it suffers badly from detuning caused by proximity to
nearby conductive objects and needs to be carefully trimmed for best performance in a given situation.
The size shown is about the maximum commonly used at 169MHz and appropriate scaling of length,
diameter and number of turns can make individual designs much smaller.
Loop. A loop of PCB track having an inside area as large as possible (minimum about 5cm2), tuned and
matched with 2 capacitors. Loops are relatively inefficient but have good immunity to proximity
detuning, so may be preferred in shorter range applications where high component packing density is
necessary.
Integral antenna summary:
Ultimate performance
Ease of design set-up
Size
Immunity to proximity effects
whip
***
***
*
**
helical
**
**
***
*
loop
*
*
**
***
421mm @ 169MHz
RF
Whip antenna
RF
Helical antenna
RF
Ctune
C match
wire, rod, PCB track
or a combination of these
length(mm) = 71250 / freq(MHz)
35-40 turns wire spring
length 120mm, dia 10mm
trim wire length or expand coil
for best results
track width = 1mm
2
min. area 500mm
capacitors may be variable or fixed
(values depend on loop dimensions)
RF GND
Loop antenna
Figure 5: integral antenna configurations
External antennas
These have several advantages if portability is not an issue, and are essential for long range links.
External antennas can be optimised for individual circumstances and may be mounted in relatively
good RF locations away from sources of interference, being connected to the equipment by coax feeder.
Helical. Of similar dimensions and performance to the integral type mentioned above, commerciallyavailable helical antennas normally have the coil element protected by a plastic moulding or sleeve and
incorporate a coax connector at one end (usually a straight or right-angle BNC type). These are compact
and simple to use as they come pre-tuned for a given application, but are relatively inefficient and are
best suited to shorter ranges.
Radiometrix Ltd.,
ENX1 high power transmitter data sheet
Page 8
Quarter-wave whip. Again similar to the integral type, the element usually consists of a stainless
steel rod or a wire contained within a semi-flexible moulded plastic jacket. Various mounting options
are available, from a simple BNC connector to wall brackets, through-panel fixings and magnetic
mounts for temporary attachment to steel surfaces.
A significant improvement in performance is obtainable if the whip is used in conjunction with a metal
ground plane. For best results this should extend all round the base of the whip out to a radius of
300mm or more (under these conditions performance approaches that of a half-wave dipole) but even
relatively small metal areas will produce a worthwhile improvement over the whip alone. The ground
plane should be electrically connected to the coax outer at the base of the whip. Magnetic mounts are
slightly different in that they rely on capacitance between the mount and the metal surface to achieve
the same result.
Metal ground plane
1/4-wave whip
1/ (3-4
4w , eq
av u
e all
ra y
di s p
al
a
el ce
em d )
en
ts
1/4-wave
whip
(469mm long @ 121MHz)
A ground plane can also be simulated by using 3 or 4 quarter-wave radials equally spaced around the
base of the whip, connected at their inner ends to the outer of the coax feed. A better match to a 50Ω
coax feed can be achieved if the elements are angled downwards at approximately 30-40° to the
horizontal.
50 Ω coax feed
30
-40
de
g.
50 Ω coax feed
Fig.6: Quarter wave antenna / ground plane configurations
Half-wave. There are two main variants of this antenna, both of which are very effective and are
recommended where long range and all-round coverage are required:
1. The half-wave dipole consists of two quarter-wave whips mounted in line vertically and fed in the
centre with coaxial cable. The bottom whip takes the place of the ground plane described previously.
A variant is available using a helical instead of a whip for the lower element, giving similar
performance with reduced overall length. This antenna is suitable for mounting on walls etc. but for
best results should be kept well clear of surrounding conductive objects and structures (ideally >1m
separation).
2. The end-fed half wave is the same length as the dipole but consists of a single rod or whip fed at the
bottom via a matching network. Mounting options are similar to those for the quarter-wave whip. A
ground plane is sometimes used but is not essential. The end-fed arrangement is often preferred
over the centre-fed dipole because it is easier to mount in the clear and above surrounding
obstructions.
Yagi. This antenna consists of two or more elements mounted parallel to each other on a central boom.
It is directional and exhibits gain but tends to be large and unwieldy – for these reasons the yagi is the
ideal choice for links over fixed paths where maximum range is desired.
Radiometrix Ltd.,
ENX1 high power transmitter data sheet
Page 9
Module mounting considerations
Good RF layout practice should be observed. If the connection between module and antenna is more
than about 20mm long use 50Ω microstrip line or coax or a combination of both. It is desirable (but not
essential) to fill all unused PCB area around the module with ground plane.
PCB Layout and design notes:
! Leave 1mm all round module (i.e. PCB footprint area of 25x35mm)
! PCB holes - 1.2mm or socket strips
! Keep AF track away from RXD & TXD - to avoid cross talk.
! Put a test point on the AF pin for simple radio checking with a scope.
! Ground plane all unused PCB area around and under module.
! Position module and antenna as far from high speed logic and SMPS as possible
! Microprocessors with external data/address busses ALWAYS cause interference.
! Provide LED status lights on TX, RX & CD (direct or by plug on test PCB)
! For complex networks - provide software test routines for :-continuous RX, continuous TX, loop
test, Simple master / slave "ping-pong".
Variants and ordering information
The ENX1 transceiver is manufactured in following frequency variants as standard:
Frequency:
169.40625MHz
169.44375MHz
ENX1-xxx-xxxx-3
For other variants please contact the factory.
Other variants can be supplied to individual customer requirements at frequencies from 120MHz to 180MHz
RF output can also be factory set from +5dBm (3mW) to +20dBm (100mW) depending on minimum order quantity.
Radiometrix Ltd.,
ENX1 high power transmitter data sheet
Page 10
Radiometrix Ltd
Hartcran House
231 Kenton Lane
Harrow, Middlesex
HA3 8RP
ENGLAND
Tel: +44 (0) 20 8909 9595
Fax: +44 (0) 20 8909 2233
[email protected]
www.radiometrix.com
Copyright notice
This product data sheet is the original work and copyrighted property of Radiometrix Ltd. Reproduction in whole or in
part must give clear acknowledgement to the copyright owner.
Limitation of liability
The information furnished by Radiometrix Ltd is believed to be accurate and reliable. Radiometrix Ltd reserves the
right to make changes or improvements in the design, specification or manufacture of its subassembly products without
notice. Radiometrix Ltd does not assume any liability arising from the application or use of any product or circuit
described herein, nor for any infringements of patents or other rights of third parties which may result from the use of
its products. This data sheet neither states nor implies warranty of any kind, including fitness for any particular
application. These radio devices may be subject to radio interference and may not function as intended if interference is
present. We do NOT recommend their use for life critical applications.
The Intrastat commodity code for all our modules is: 8542 6000
R&TTE Directive
After 7 April 2001 the manufacturer can only place finished product on the market under the provisions of the R&TTE
Directive. Equipment within the scope of the R&TTE Directive may demonstrate compliance to the essential
requirements specified in Article 3 of the Directive, as appropriate to the particular equipment.
Further details are available on The Office of Communications (Ofcom) web site:
http://www.ofcom.org.uk/radiocomms/ifi/
Information Requests
Ofcom
Riverside House
2a Southwark Bridge Road
London SE1 9HA
Tel: +44 (0)845 456 3000 or 020 7981 3040
Fax: +44 (0)20 7783 4033
[email protected]
European Radiocommunications Office (ERO)
Peblingehus
Nansensgade 19
DK 1366 Copenhagen
Tel. +45 33896300
Fax +45 33896330
[email protected]
www.ero.dk
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