TDH2-433-4 [RADIOMETRIX]
UHF Multi Channel Hi Power Radio Modem; UHF多通道高功率无线调制解调器
| 型号： | TDH2-433-4 |
| 厂家： | 
RADIOMETRIX LTD |
| 描述： | UHF Multi Channel Hi Power Radio Modem |
| 文件： | 总11页 (文件大小：351K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
Radiometrix
Hartcran House, 231 Kenton Lane, Harrow, HA3 8RP, England
Tel: +44 (0) 20 8909 9595, Fax: +44 (0) 20 8909 2233
Issue 2, 06 October 2006
TDH2
UHF Multi Channel Hi Power Radio Modem
The TDH2 is a 9600baud half-duplex multi
channel OEM radio modem with a power output
of 25mW. It is a 100% pin-compatible drop-in
replacement for the Radiometrix TDL2A and
can be used to replace the TDL2A in
applications where greater radiated power is
desired. TDH2 acts as a transparent serial
cable to attached host. TDH2 is an intermediate
level OEM radio modem which is in between a
raw FM radio module like BiM2 and a
sophisticated OEM radio modem like SPM2. It
takes care of preamble, synchronisation, bit
balancing and error checking along with
automatic noise squelching.
Figure 1: TDH2-433-9 radio modem
Provided no two devices attempt to transmit simultaneously no further restrictions on data transmission
need be made, as all transmit timing, valid data identification and datastream buffering is conducted by
the unit. Synchronisation and framing words in the packet prevent the receiver outputting garbage in
the absence of wanted RF signal or presence of interference. For multiple radio systems (polled networks)
a TDH2 can be set to 1 of 8 unique addresses. As well as having unique addresses, the TDH2 allows
operation on one of 5 pre-set frequencies in the 433MHz band. These frequencies are non-overlapping
and simultaneous operation of TDH2s in the same area on different channels will be possible. Units are
supplied on 433.925MHz (Ch0) as default.
Features
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Conforms to Australian/New Zealand AS/NZS 4268:2003
High quality, stable crystal reference
Low noise synthesiser / VCO
SAW front-end filter and multi-stage ceramic IF filtering
Single conversion superhet
Serial modem baud rate at 9600bps (half-duplex)
Addressable point-to-point
5 serial select wideband channels
Available as TDH2T transmitter and TDH2R receiver for one way communication
Applications
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PDAs, organisers & laptops
Handheld / portable terminals
EPOS equipment, barcode scanners
In-building environmental monitoring and control
Remote data acquisition system, data logging
Fleet management, vehicle data acquisition
Technical Summary
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Operating frequency: 433.925MHz (default)
Modulation: 16kbps bi-phase FSK
Supply: 5V at 50mA transmit, 22mA receive/idle
Transmit power: +14dBm (25mW)
Receiver sensitivity: -105dBm (for 1% BER)
32 byte data buffer
Adjacent channel rejection: 60dB @ ±320kHz
Radiometrix Ltd
TDH2 Data Sheet
page 1
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Radiometrix Ltd
TDH2 Data Sheet
page 2
side view (with can)
side view (through can)
8 mm
top view (without can)
3.5mm
RF GND 1
18 GND
Antenna
RF GND
2
3
4
5
6
7
8
9
Vcc
ENABLE
SETUP
17
16
15
14 TXD
13 NC
12 RXD
11 STATUS
10 GND
No pin
2.2mm
recommended PCB hole size: 1.2 mm
module footprint size: 26 x 37mm
pin pitch: 2.54 mm
30.48mm
pins 4, 5, 6, 7, 8 & 9 are not fitted
Figure 3: TDH2 footprint (top view)
Pin description
Pin
18
17
16
15
14
13
12
11
10
Name
GND
Vcc
ENABLE
SETUP
TXD
NC
RXD
STATUS
GND
Function
Ground
5V (regulated power supply)
Enable or DTR (5V CMOS logic level input)
Test/Setup mode selection
Transmit Data (Inverted RS232 at 5V CMOS logic level)
No Pin
Receive Data (Inverted RS232 at 5V CMOS logic level)
Busy or CTS (5V CMOS logic level output)
Ground
RF GND
pin 1 & 3
RF Ground pin, internally connected to the module screen and pins 10 and 18 (0V). This pin should be
connected to the RF return path (e.g. co-axial cable braid, main PCB ground plane, etc).
RF
pin 2
50Ω RF input/output from the antenna, it is DC isolated internally. (see antenna section for details).
GND
pin 8, 9, 10 and 18
Supply ground connection to ground plane and can.
VCC
pin 17
5V voltage regulator should be used to have a clean 5V supply to the module. A 4V regulator is used
inside for radio circuitry.
ENABLE
pin 16
Active low Enable pin. It has a 47kΩ pull-ups to Vcc. It should be pulled Low to enable the module.
This can also be connected to DTR pin (only if it is asserted by the host) of an RS232 serial port via a
MAX232 or equivalent RS232-CMOS level converter.
Radiometrix Ltd
TDH2 Data Sheet
page 3
SETUP
pin 15
Active low input to enter configuration or diagnostic test mode. It has a 47kΩ pull-ups to Vcc
TXD
pin 14
This is inverted RS232 data input at 5V CMOS logic level. It can be directly interfaced to data output of
a UART in a microcontroller or to a TXD pin of an RS232 serial port via a MAX232 or equivalent
RS232-CMOS level converter. TXD does not have an internal pull-up. If TDH2 is used in Receive only
mode, TXD should be tied to Vcc.
NC
pin 13
There is no pin in this position.
RXD
pin 12
This is inverted RS232 data output at 5V CMOS logic level. It can be directly interfaced to data input of
a UART in a microcontroller or to a RXD pin of an RS232 serial port via a MAX232 or equivalent
RS232-CMOS level converter.
STATUS
pin 11
This pin goes high when valid data is present in the receive buffer. It can be used to trigger an
interrupt in the host to download received data packet instead of waiting for it. It can be also be used as
a primitive CTS signal. It is inverted RS232 data output at 5V CMOS logic level. It can be directly
interfaced to an input of a microcontroller as a Data Detect (DD) or to CTS, DSR, DCD pins of an RS232
serial port via a MAX232 or equivalent RS232-CMOS level converter. This is can only be used to
prevent host from uploading any data before downloading already received data, because transmission
is prioritised over reception and any data to be transmitted will erase received data which is in the
common buffer.
Serial interface – modem operation
To connect to a true RS232 device, inverting RS232-CMOS level shifters must be used. Maxim MAX232
or equivalent are ideal, but simple NPN transistor switches with pull-ups often suffice. With typical
microcontrollers and UARTs, direct connection is possible.
The Radio / data stream interface
A 32 byte software FIFO is implemented in both the transmit and receive sub-routine. At the
transmitting end this is used to allow for the transmitter start up time (about 3mS), while on receiving
end it buffers arriving packets to the constant output data rate. All timing and data formatting tasks
are handled by the internal firmware. The user need not worry about keying the transmitter before
sending data as the link is entirely transparent.
For transmission across the radio link data is formatted into packets, each comprising 3 bytes of data
and a sync code. If less than 3 bytes are in the transmit end FIFO then a packet is still sent, but idle
codes replaces the unused bytes. When the transmit end FIFO is completely emptied, then the
transmitter is keyed off.
Operation: Radio interface.
Raw data is not fed to the radios. A coding operation in the transmit sub-routine, and decoding in the
receiver, isolate the AC coupled, potentially noisy baseband radio environment from the datastream.
The radio link is fed a continuous tone by the modem. As in bi-phase codes, information is coded by
varying the duration consecutive half-cycles of this tone. In our case half cycles of 62.5us and 31.25us
are used. In idle (or 'preamble') state, a sequence of the longer cycles is sent (resembling an 8KHz tone).
A packet comprises the Synchronising (or address) part, followed by the Data part, made up of twelve
Groups (of four half cycles duration). Each Group encodes 2 data bits, so one byte is encoded by 4
Groups.
Radiometrix Ltd
TDH2 Data Sheet
page 4
Figure 4: TDH2 transmitting and receiving
The oscilloscope screen capture shows a single byte being transmitted by TDH2. A BiM2-433-64
transceiver is used to capture the transmitted data The character appears on the serial data output
(RXD) pin of the other TDH2 after about 12.5ms. Busy (STATUS) pin is momentarily set high to
indicate the presence of a valid data in the receive buffer of the TDH2.
It can be clearly seen that unlike raw radio modules, TDH2 does not output any noise when there is not
any transmission. Data fed into the TXD input of a TDH2 appears at the RXD output of another TDH2
within radio range in the original form it was fed.
Figure 5: 16kbps Bi-phase encoded continuous data stream (expanded view)
Continuous serial data at 9600bps (above) is encoded as half-cycles of 8kHz (62.5µs long bit) and 16kHz
(31.25µs short bit).
Radiometrix Ltd
TDH2 Data Sheet
page 5
Programming the TDH2
In order to use all the functions embedded in the TDH2, the user must be aware of the
setup/programming facility, which allow different addresses and frequency channels to be set up, and if
necessary accesses diagnostic test modes.
The TDH2 is programmed through the same RS232 port that is used for sending/receiving data. An
RS232 terminal emulator (such as Aterm or HyperTerminal) is an ideal tool.
To enter program mode, the SETUP pin must be pulled low. In this mode the radio link is disabled,
but characters sent (at 9600 baud, as normal) to the unit are echoed back on the RXD pin.
The unit will only respond to certain command strings:
ADDR0 to ADDR7 <CR>:
CHAN0 to CHAN4 <CR>:
These commands set up one of 8 unique addresses.
These commands select one of 5 preset channels
A TDH2 will only communicate with a unit set to the same address and the same channel.
Address and channel numbers are stored in volatile memory. On power-up the TDH2 reverts to the
default in EEPROM (as supplied this is always address 0 and Channel 0)
SETPROGRAM <CR>:
Writes the current address and current channel into EEPROM as the
new default.
A tilda character (~, ascii 126dec) sent by the unit indicates end of
EEPROM write sequence
(these commands are normally only used for factory diagnostics)
NOTONE <CR>:
LFTONE <CR>:
HFTONE <CR>:
# <CR>:
Transmit unmodulated carrier
Transmit carrier modulated with 8KHz squarewave
Transmit carrier modulated with 16KHz squarewave
Transmitter off
A Carriage Return ‘<CR>’ (00Dhex) should be entered after each command sequence to execute it.
Releasing the SETUP pin to high state returns the TDH2 to normal operation.
Interfacing a microcontroller to TDH2
Figure 6: TDH2 interfaced directly to a microcontroller
TDH2 can be directly interfaced to any microcontrollers. If the microcontroller has a built-in UART, it
can concentrate on its main task and leave the packet formatting, bit balancing and error checking of
serial data to TDH2.
Radiometrix Ltd
TDH2 Data Sheet
page 6
Serial data should be in the following format:
1 start bit, 8 data bits, no parity, 1 or 2 stop bits
9600bps
0V=low, 5V=high
STATUS pin can be connected to one of the port pins which can generate an interrupt on low-to-high
transition (e.g. RB0/INT pin in the PIC). This can be used to enter a receive sub-routine to download
data received from remote TDH2. Therefore, the host does not need to wait in a loop for a packet.
Range test and site survey can be carried out by connecting an LED on the STATUS pin. Every time,
TDH2 is within range to receive valid data, the LED will flicker.
Interfacing RS232 port to TDH2
Figure 7: TDH2 interfaced to an RS232 port via an RS232 line driver/receiver
STATUS pin in this can be connected to CTS, DSR and DCD pin to simulate a flow control signal.
TDH2 is capable of continuously streaming data at 9600bps. Therefore, STATUS pin is not asserted to
stop the Host from sending data as in normal RTS/CTS flow control method, but merely to warn the
host that there is already data in the receive buffer which need to be downloaded before sending any
more data.
Some DTE hosts assert DTR signal when they are active and this can be used via RS232 line receiver to
enable TDH2. Otherwise the ENABLE must be physically pulled-low to activate the TDH2.
NOTE:
An interface board (with MAX232 type buffer, 9 way D connector, 5V voltage regulator and SMA RF
connector) is available. This board is 61mm x 33mm in size.
Radiometrix Ltd
TDH2 Data Sheet
page 7
Condensed specifications
Frequency
433.925MHz – CHAN0 (default channel)
433.285MHz – CHAN1
433.605MHz – CHAN2
434.245MHz – CHAN3
434.565MHz – CHAN4
Frequency stability
Channel width
±10kHz
320kHz
Number of channels
Supply Voltage
Current
1 of 5, user programmed
5V
50mA transmit
22mA receive/idle
Operating temperature
-20 °C to +70 °C (Storage -30 °C to +80 °C)
Compliant with Australian/New Zealand AS/NZS 4268:2003
Regulation
Interfaces
User
9pin 0.1" pitch molex
3pin 0.1" pitch molex
37 x 26 x 8mm
RF
Size
Transmitter
Output power
+14dBm (25mW) ±1dB
<4ms
16kbps bi-phase FSK
+/-22KHz
TX on switching time
Modulation type
FM peak deviation
TX spurious
<-40dBm
Receiver
Sensitivity
image
-105dBm for 1% BER
-40dB
spurious / adjacent channel
Blocking
LO re-radiation
-60dB
-80dB nominal
<-60dBm
Interface
Data rate
Format
Levels
Buffers
9600baud, Half duplex
1 start, 8 data, 1 stop, no parity
5V CMOS (inverted RS232. Mark = 5V = idle)
32 byte FIFO
Flow control
Addressing
None (‘RX busy’ pin provided)
1 of 8, user programmed
Data latency
14ms (first byte into TX, to first byte out of RX)
Radiometrix Ltd
TDH2 Data Sheet
page 8
Antenna requirements
Three types of integral antenna are recommended and approved for use with the module:
A) Whip
This is a wire, rod ,PCB track or combination connected directly to RF pin of the
module. Optimum total length is 16cm (1/4 wave @ 433MHz). Keep the open circuit (hot)
end well away from metal components to prevent serious de-tuning. Whips are ground
plane sensitive and will benefit from internal 1/4 wave earthed radial(s) if the product is
small and plastic cased
B) Helical
C) Loop
Wire coil, connected directly to RF pin, open circuit at other end. This antenna is very
efficient given it’s small size (20mm x 4mm dia.). The helical is a high Q antenna, trim
the wire length or expand the coil for optimum results. The helical de-tunes badly with
proximity to other conductive objects.
A loop of PCB track tuned by a fixed or variable capacitor to ground at the 'hot' end and
fed from RF pin at a point 20% from the ground end. Loops have high immunity to
proximity de-tuning.
A
whip
***
***
*
B
helical
**
**
***
C
loop
*
*
**
Ultimate performance
Easy of design set-up
Size
Immunity proximity effects
*
**
***
The antenna choice and position directly controls the system range. Keep it clear of other metal in the
system, particularly the 'hot' end. The best position by far, is sticking out the top of the product. This is
often not desirable for practical/ergonomic reasons thus a compromise may need to be reached. If an
internal antenna must be used, try to keep it away from other metal components, particularly large
ones like transformers, batteries and PCB tracks/earth plane. The space around the antenna is as
important as the antenna itself.
0.5 mm enameled copper wire
close wound on 3.2 mm diameter former
RF
433 MHz = 24 turns
A. Helical antenna
Feed point 15% to 25% of total loop length
track width = 1mm
RF-GND
4 to 10 cm2 inside area
C2
C1
RF
C3
C4
B. Loop antenna
16.4cm
wire, rod, PCB-track or a combination
of these three
RF
433 MHz = 16.4 cm total from RF pin.
C. Whip antenna
Figure 8: Antenna types
Radiometrix Ltd
TDH2 Data Sheet
page 9
Ordering information
The TDH2 radio modem is manufactured in the following variants as standard:
For Australian general applications on 433MHz band
Part Number
TDH2-433-9
TDH2T-433-9
TDH2R-433-9
Description
Frequency band
Maximum baud rate
9.6kbps
9.6kbps
Half duplex modem
Transmitter only
Receiver only
433.925 - 434.565 MHz
433.925 - 434.565 MHz
433.925 - 434.565 MHz
9.6kbps
TDH2-433-4
TDH2T-433-4
TDH2R-433-4
Half duplex modem
Transmitter only
Receiver only
433.925 - 434.565 MHz
433.925 - 434.565 MHz
433.925 - 434.565 MHz
4.8kbps
4.8kbps
4.8kbps
Radiometrix Ltd
TDH2 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
Ofcom
European Radiocommunications Office (ERO)
Peblingehus
Riverside House
Nansensgade 19
2a Southwark Bridge Road
London SE1 9HA
Tel: +44 (0)845 456 3000 or 020 7981 3040
Fax: +44 (0)20 7783 4033
information.requests@ofcom.org.uk
DK 1366 Copenhagen
Tel. +45 33896300
Fax +45 33896330
ero@ero.dk
www.ero.dk
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