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NRX2-434.650-10

器件型号:NRX2-434.650-10
文件大小:259.98KB,共0页
厂商名称:RADIOMETRIX [Radiometrix Ltd]
厂商官网:http://www.radiometrix.com
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NRX2-434.650-10器件文档内容

NEW                     Radiometrix

                        Hartcran House, 231 Kenton Lane, Harrow, HA3 8RP, England

Issue B, 17 March 2005  Tel: +44 (0) 20 8909 9595, Fax: +44 (0) 20 8909 2233       NTX2/NRX2

       UHF Narrow Band FM TX & RX

The NTX2 transmitter and NRX2
receiver offer a low power, reliable
data link in a Radiometrix SIL
standard pin out and foot print. This
makes the NTX2/NRX2 pair ideally
suited to those low power applications
where existing single frequency
wideband UHF modules have
insufficient range.

                        Figure 1: NRX2-434.650-10                                  NTX2-434.650-10

Features

      Conforms to ETSI EN 300 220-3 (radio) and EN 301 489-3 (EMC)
      Standard frequencies: 434.075MHz, 434.650MHz and 458.700MHz
      Custom frequencies available in 433MHz (EU) and 458MHz (UK) band
      Data rates up to 10kbps
      Usable range over 500m
      25kHz Channel spacing
      Longer range compared to Wide Band FM modules

Available for licence-exempt operation in the 433MHz (EU) and 458MHz (UK) bands, the NTX2 &

NRX2 modules combine effective screening with internal filtering to minimise spurious radiation and
susceptibility thereby ensuring EMC compliance. They can be used in existing low data rate (<10kbps)
applications where the operating range of the system using TX2 transmitter and RX2 receiver need to
be extended. They are particularly suitable for point-to-point and point-to-multipoint wireless links
where longer ranges are required at low data rates. Applications include sensor nodes, EPOS and

inventory tracking, remote industrial process monitoring, telemetry, telecommand and telecontrol.
Because of their small size and low power consumption, both modules are ideal for use in battery-
powered portable applications such as handheld terminals.

Transmitter NTX2
      3 stage crystal controlled VCXO
      Supply 2.9V - 15V @ 18mA (internal 2.8V voltage regulator)
      Data bit rate: 10kbps max.
      Transmit power: +10dBm (10mW)

Receiver NRX2
      Double conversion FM superhet
      SAW band pass filter, image rejection: 50dB
      Intermediate Frequencies (IF): 21.4MHz, 455kHz
      Supply range: 2.9V - 15V @ 14mA (internal 2.8V voltage regulator)
      Data bit rate: 10kbps max.
      Receiver sensitivity: -118dBm (for 12dB SINAD)
      Receiver sensitivity: -112dBm (for 1ppm BER)
      Local Oscillator (LO) re-radiation: <-60dBm
      Adjacent Channel: -70dBm
      Blocking: -84dB

Radiometrix Ltd.,       NTX2/NRX2 data sheet                                       Page 1
Functional description

The NTX2 transmitter consists of a Frequency Modulated (FM) Voltage Controlled Crystal Oscillator
(VCXO) feeding a frequency multiplier with two stage amplifier and RF filter. Operation can be
controlled by the EN (Enable) line, the transmitter achieving full RF output typically within 5ms of this
line being pulled high. The RF output is filtered to ensure compliance with the appropriate radio
regulations and fed to the 50 antenna pin.

The NRX2 module is a double conversion NBFM superhet receiver capable of handling data rates of up
to 10kbps. It will operate from a supply of 2.9V to 15V and draws 14mA when receiving. A signal
strength (RSSI) output with greater than 60dB of range is provided. The SIL style NRX2 measures 47 x
17 x 8 mm excluding the pins.

NTX2 Transmitter

                              Figure 2: NTX2 block diagram

                                    43mm                            8mm

                                   32mm

                        15mm       NTX2                   23.5mm

                              15.24mm (0.6")                      1 = RF gnd
                                                                  2 = RF out
                              123                 4 5 67          3 = RF gnd
                                                                  4 = En
                                 7 holes of 0.7mm dia.            5 = Vcc
                              pin spacing 2.54mm (0.1")           6 = 0V
                                                                  7 = TXD

                              Figure 3: NTX2 pin-out and dimension

User interface

NTX2 pin Name                 Function
                              RF ground is internally connected to the module screen and pin 6
1, 3               RF gnd     (0V). These pins should be directly connected to the RF return path
                              - e.g. coax braid, main PCB ground plane etc.
2                  RF out
                              50 RF output to the antenna
4                  EN         Pull high to enable Transmitter (3V CMOS logic)

5                  Vcc        2.9 15V DC power supply
                              Ground
6                  0V
                              DC coupled input for 3V CMOS logic. Rin = 100k
7                  TXD

Notes:
          1. EN pin should not be left floating
          2. Pinout footprint is as TX1H.
          3. Compatible with RX2M, RLC2 and NRX2

Radiometrix Ltd.,                  NTX2/NRX2 data sheet                                            Page 2
NRX2 receiver

                                    Figure 4: NRX2 block diagram

                                    47mm                                         8mm

                   17mm

                              NRX2                    Radiometrix

                                    30.48mm (1.2")

                              12                      3 4 567                    1 = RF in
                                                                                 2 = RF gnd
                                 7 holes of 0.7mm dia pin spacing 2.54mm (0.1")  3 = RSSI
                                                                                 4 = 0V
                                       Figure 5: NRX2 pin-out and dimension      5 = Vcc
                                                                                 6 = AF
                                                                                 7 = RXD

User interface NRX2

NRX2 pin Name                     Function

1                        RF in    50 RF input from the antenna
                                  RF Ground is internally connected to the module screen and pin
2                        RF gnd   4 (0V). These pins should be directly connected to the RF return
                                  path - e.g. coax braid, main PCB ground plane etc.
3                        RSSI
                                  Received Signal Strength Indicator with >60dB range.
4                        0V       DC level between 0.5V and 2V

5                        Vcc      Ground

6                        AF       2.9 15V DC power supply

7                        RXD      500mVpk-pk audio. DC coupled, approx 0.8V bias

                                  Received Data output from the internal data slicer. The data is
                                  squared version of the Audio signal on pin 6 and is true data, i.e.
                                  as fed to the transmitter. Output is "open-collector" format with
                                  internal 10kpull-up to Vcc (pin 5). Suitable for bi-phase codes

Notes:
          1. Pinout is as our wideband RX2A receiver

Radiometrix Ltd.,                   NTX2/NRX2 data sheet                                               Page 3
Absolute maximum ratings

Exceeding the values given below may cause permanent damage to the module.

Operating temperature            -10C to +60C
Storage temperature              -30C to +70C

NTX2                             -0.3V to +16.0V
Vcc, TXD (pins 5,7)              -0.3V to +Vcc V
En (pin 4)
                                 50V @ <10MHz, +20dBm @ >10MHz
RF out (pin 2)

NRX2                             -0.3V to +16.0V
Vcc, RXD (pins 7,9)              -0.3V to +Vcc V
En, RSSI, AF (pins 4,5,8)
                                 50V @ <10MHz, +13dBm @ >10MHz
RF in (pin 1)

Performance specifications: NTX2 transmitter
(Vcc = 3V / temperature = 20C unless stated)

General                       pin  min.           typ.     max. units notes
                                    2.9
DC supply
                                      -
Supply voltage                5                   3.0      15               V

TX Supply current             5                   18       -                mA

Antenna pin impedance         2                   50       -               

RF                                             -           -                MHz  1
RF centre frequency

NTX2-434.650-10                                   434.650

NTX2-434.075-10                                   434.075

NTX2-458.700-10                                   458.700

Channel spacing                                -  25       -                kHz

Number of channels                             -  1        -

RF power output               2                9  10       11               dBm  2

Spurious emissions            2                -  -        -40              dBm

Adjacent channel TX power                      -  -37      -                dBm

Frequency accuracy                             -  -        2.5             kHz  3

FM deviation (peak)                2.5           3.0     3.5             kHz  4

Baseband

Modulation type                                -  FSK      -                     F3D

Modulation bandwidth @ -3dB                    0  -        5                kHz

TXD input level (logic low)   7                -  0        -                V    5

TXD input level (logic high)  7                -  3.0      -                V    5

Distortion                                        TBA                       %    6

Dynamic timing                                 -  -        5                ms
TX Enable to full RF

Notes:
     1. Available in 25kHz channel steps on other custom frequencies in 433MHz/458MHz band

     2. Measured into 50 resistive load.
     3. Total over full supply and temperature range.
     4. With 0V 3.0V modulation input.

     5. To achieve specified FM deviation.
     6. For 1Vpk-pk signal biased at 1.4V

Radiometrix Ltd.,                  NTX2/NRX2 data sheet                                     Page 4
Performance specifications: NRX2 receiver
(Vcc = 3V / temperature = 20C unless stated)

                               pin   min.      typ.           max.  units  notes

DC supply                                                       15    V       1
                                                                 -   mA       1
Supply voltage                 7     2.9       3.0                            2
                                                                 -  MHz       1
Supply current                 7     -         14                -            3
                                                                 -  dBm
RF/IF                                                            -  dBm       4
                                                                 -  dBm
RF centre frequency            1,6                               -    dB
                                                                 -   kHz
NRX2-434.650-10                                434.650           -    dB
                                                                 -    dB
NRX2-434.075-10                                434.075         -60    dB
                                                                      dB
NRX2-458.700-10                                458.700          5   dBm
                                                                 -
RF sensitivity @ 12dB SINAD 1, 6     -         -118              -   kHz
                                                                 -  mVP-P
RF sensitivity @ 1ppm BER      1, 7  -         -112
                                                                 -    V
RSSI threshold                 1, 3  -         -125             10    %

RSSI range                     1, 4  -         55                -    ms
                                                                5     ms
IF bandwidth                         -         TBA            TBA     ms

Blocking                       1     -         84                     ms
                                                                      ms
Image rejection                1     -         55                     ms

Adjacent channel rejection     1     -         70                     ms

Spurious response rejection    1     -         55

LO re-radiation                1     -         -

Baseband

Baseband bandwidth @ -3dB      6     0         -

AF level                       6     -         500

DC offset on AF out            6     -         0.8

Distortion on recovered AF     6     -         TBA

Dynamic timing

Power up with signal present

Power up to valid RSSI         5, 3  -         3

Power up to valid AF           5,6             2

Power up to stable data        5, 7  -         TBA

Signal applied with supply on

Signal to valid RSSI           1, 3  -         2

Signal to valid AF             1,6             1

Signal to stable data          1, 7  -         TBA

Time between data transitions  7     0.1       -

Notes:

1. See applications information for further details.
2. Exceeds EN/EMC requirements at all frequencies.
3. For received signal with 3kHz FM deviation. AF output is inverted with respect to TXD input.
4. For 50:50 mark to space ratio (i.e. squarewave).

Radiometrix Ltd.,                       NTX2/NRX2 data sheet                                      Page 5
Applications information

Power supply requirements

Both modules have built-in regulators which deliver a constant 2.8V to the module circuitry when the
external supply voltage is 2.9V or greater, with 40dB or more of supply ripple rejection. This ensures
constant performance up to the maximum permitted rail, and removes the need for external supply
decoupling except in cases where the supply rail is extremely poor (ripple/noise content >100mVpk-pk).

The Enable pin allows the TX module to be turned on or off under 3V logic control with a constant DC
supply to the Vcc pin. The module current in power-down mode is less than 1A.

The Enable pin should be tied directly to the Vcc pin if this facility is not required.

TX modulation requirements

The module is factory-set to produce the specified FM deviation with a TXD input to pin 7 of 3V
amplitude, i.e. 0V "low", 3V "high

If the data input level is greater than 3V, a resistor must be added in series with the TXD input to limit
the modulating input voltage to a maximum of 3V on pin 7. TXD input resistance is 100k to ground,
giving typical required resistor values as follows:

                            Vcc   Series resistor

                            3V              -
                            3.3V         10 k
                             5V          68k
                             9V         220k

NRX2 Received Signal Strength Indicator (RSSI)

The NRX2 receiver incorporates a wide range RSSI which measures the strength of an incoming signal
over a range of 55dB or more. This allows assessment of link quality and available margin and is useful
when performing range tests.

The output on pin 3 of the module has a standing DC bias of <0.5V with no signal, rising to 2V at
maximum indication.

Typical RSSI characteristic is as shown below:

Radiometrix Ltd.,           Figure 6: RSSI response curve                                        Page 6

                                              NTX2/NRX2 data sheet
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 following are typical examples but range tests should always be performed before assuming that
a particular range can be achieved in a given situation:

Data rate          Tx antenna  Rx antenna    Environment     Range
10kbps               wave       wave    urban/obstructed  300m

10kbps               wave       wave        Rural/open    500m
10kbps               helical     helical      in-building   100m

Data formats and range extension

The NTX2'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 (pin 7) be DC-biased to 1.2V approx.
with the modulation ac-coupled and limited to a maximum of 2Vp-p to minimise distortion over the link.
The varactor modulator in the NTX2 introduces some 2nd harmonic distortion which may be reduced if
necessary by predistortion of the analogue waveform.

Although the modulation bandwidth of the NTX2 extends down to DC as does the NRX2 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 NRX2's
audio output.

The NRX2 in standard form incorporates a low pass filter with a 5kHz nominal bandwidth. In
conjunction with similar filtering in the NTX2 an overall system bandwidth of 5kHz is obtained. This is
suitable for transmission of data at raw bit rates up to 10kbps.

Radiometrix Ltd.,              NTX2/NRX2 data sheet                 Page 7
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
     UHF 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.

A simple test for interference is to monitor the receiver RSSI output voltage, which should be the same
regardless of whether the microcontroller or other logic circuitry is running or in reset.

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 434MHz the total length should be 164mm 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 434MHz 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 4cm2), 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           whip      helical  loop
                   Ease of design set-up           ***         **      *
                   Size                            ***         **      *
                   Immunity to proximity effects     *         ***    **
                                                    **          *
                                                                      ***

Radiometrix Ltd.,          NTX2/NRX2 data sheet                            Page 8
                                                                   0.5 mm enameled copper wire
                                                                   close wound on 3.2 mm diameter former

                                                        RF

                                                                   433 MHz = 24 turns

                   A. Helical antenna

                                                    C2  RF-GND  Feed point 15% to 25% of total loop length
                                                                track width = 1mm
                                      C3 C4             C1      4 to 10 cm2 inside area

B. Loop antenna                                         RF

                   16.4cm                                       wire, rod, PCB-track or a combination
                                                                of these three

                   C. Whip antenna                      RF      433 MHz = 16.4 cm total from RF pin.

                                    Figure 7: 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, commercially-
available 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/SMA 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.

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/SMA 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 the
length of the whip used (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.

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 50
coax feed can be achieved if the elements are angled downwards at approximately 30-40 to the
horizontal.

Radiometrix Ltd.,                                           NTX2/NRX2 data sheet                            Page 9
Module mounting considerations

The modules may be mounted vertically or bent horizontal to the motherboard. Note that the
components mounted on the underside of the NTX2 and NRX2 are relatively fragile avoid direct
mechanical contact between these and other parts of the equipment if possible, particularly in
situations where extreme mechanical stresses could routinely occur (as a result of equipment being
dropped onto the floor, etc).

Good RF layout practice should be observed. 50 microstrip line or coax or a combination of both should
be used to connect RF pin of the module to RF connector or antenna. It is desirable (but not essential) to
fill all unused PCB area around the module with ground plane.

Variants and ordering information

The NTX2 transmitters and NRX2 receivers are manufactured in the following variants as standard:

                   At 434.650MHz:  NTX2-434.65-10 - Transmitter
                                   NRX2-434.65-10 - Receiver

                   At 434.075MHz:  NTX2-434.075-10 - Transmitter
                                   NRX2-434.075-10 Receiver

                   At 458.700MHz:  NTX2-458.700-10 - Transmitter
                                   NRX2-458.700-10 Receiver

Other frequency variants can be supplied to individual customer requirements in the 433MHz (European) and
458MHz (UK) licence exempt bands

Radiometrix Ltd.,                  NTX2/NRX2 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
                   sales@radiometrix.com
                    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                       European Radiocommunications Office (ERO)
Ofcom                                      Peblingehus
Riverside House                            Nansensgade 19
2a Southwark Bridge Road                   DK 1366 Copenhagen
London SE1 9HA                             Tel. +45 33896300
Tel: +44 (0)845 456 3000 or 020 7981 3040  Fax +45 33896330
Fax: +44 (0)20 7783 4033                   ero@ero.dk
information.requests@ofcom.org.uk          www.ero.dk
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