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SMX1
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UK
variant: SMX1-173-5 (10mW)
Non-UK variant: SMX1-XXX-5 (1mW - 50mW) |
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SMX1 is small multi-channel VHF transceiver operating on
173.200MHz-173.325MHz band. SMX1 offers a fast-route to
custom frequency on any VHF band from 130MHz to 180MHz with
25kHz channel spacing.
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Figure 1: SMX1-173-5
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Features
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Conforms to ETSI
EN 300 220-3 and EN 301 489-3
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High
performance double superhet, 128 channel PLL synthesizer
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Data
rates up to 5 kbps for standard module
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Usable
range over 1km
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Fully
screened
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Feature-rich
interface (RSSI, analogue and digital baseband)
- Incorporates a 1200baud dumb modem
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Re-programmable
via RS232 interface
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Low
power requirements
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Handheld
terminals
- Heavy vehicle/machine remote controls
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EPOS
equipment, barcode scanners
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Data
loggers
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Industrial
telemetry and telecommand
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In-building
environmental monitoring and control
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High-end
security and fire alarms
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Vehicle
data up/download
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Technical
Summary
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Operating frequency:
173.200 - 173.325MHz
- Custom variants from 130 - 180MHz
on any 1MHz band
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128 channels controlled
via RS232 interface
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Transmit power:
+10dBm (10mW) nominal. Adjustable 1 - 50mW
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Current consumption:
40mA (10mW) - 65mA (50mW) transmit, 20mA receive
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Data bit rate: 5kbps
max. (standard module)
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Receiver sensitivity:
-120dBm (for 12 dB SINAD)
- Size: 53 x 32 x 12mm
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| Evaluation Platform:
Narrow
Band Evaluation Kit |
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 Figure
2: SMX1 block diagram |
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Figure
3: SMX1 footprint (Top)
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| Pin
Description |
| Pin |
Name |
Function |
| 1a |
RSSI |
DC level between
0.5V and 2.5V. 60dB dynamic range |
| 2a |
Vcc |
DC supply input. (4.2 - 16V
at 40mA nominal) |
| 3a |
TXD |
DC copled input for TTL/COMS
logic |
| 4a |
AF out |
500mVp-p audio. DC coupled,
approx. 0.8V bias |
| 5a |
RXD |
Open collector output of data
slicer. Need external pull-up |
| 6a |
TXE |
Transmit enable. Low = RX.
High = TX (10kW pulldown) |
| 7a |
PGM |
Serial programming / control
input (true RS232) |
| 8a |
0V |
Ground |
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| 1b |
0V |
Ground |
| 2b |
S0 |
Parallel channel select LSB |
| 3b |
S1 |
Parallel channel select |
| 4b |
S2 |
Parallel channel select MSB |
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Pin description
of SMX1 with Modem mode selected
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| The 'modem'
mentioned is a 1200 baud RS232 semi-intelligent unit (Transmit
keyed when valid serial data is present, so no separate TX
control needed. Coding in the datastream also permits the
receiver to ignore noise and only output valid serial data)
This is a half duplex unit, so collisions between transmitted
and received packets must be dealt with by the user (if transmit
data is sent to the unit then a transmit burst commences immediately
and the contents of the receive data buffer is lost) |
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Pin
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Name
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Function
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| 1a |
RSSI |
DC level between 0.5V and
2.5V. 60dB dynamic range |
| 2a |
Vcc |
DC supply input. (4.2 - 16V
at 40mA nom.) |
| 3a |
NC |
Leave unconnected |
| 4a |
NC |
Leave unconnected |
| 5a |
RXD |
Open collector RS232 compatible
data output |
| 6a |
TXD |
RS232 data input |
| 7a |
PGM |
Serial programming/control
input (true RS232) |
| 8a |
0V |
Ground |
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| 1b |
0V |
Ground |
| 2b |
S0 |
Parallel channel select LSB |
| 3b |
S1 |
Parallel channel select |
| 4b |
S2 |
Parallel channel select MSB |
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Notes:
1. No inversion occurs between TXD and RXD. However AF out
is inverted relative to TXD.
2. Parallel channel selects are active LOW and have internal
pullups to 4V
3. There are no pullups on the open collector outputs.
4. The software incorporates a 1200 baud modem, compatible
with that implemented in other Radiometrix narrowband units
( i1200 tones and format ). Modem operation is selected
by the SETMOD command. TXE pin (6a) becomes an RS232 input,
and RS232 compatible data is output on the RXD pin (5a).
If true +/- levels are desired then an inverter and a MAX232
should be used on data out.
5. RS232 input pins (7a and 6a) tolerate true +/- levels.
No buffering is required.
6. If analogue transmit modulation is needed, then connect
a series 1mF cap + 500kW
trimmer in the 'baseband in' circuit. Adjust trimmer for
90% of peak deviation (+/- 2.7KHz) at mean input level.
7. If parallel channel select is not wanted, the 4 pin connector
'b' can be removed
8. For UK version the following channel assignment is supplied:
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Channel
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Frequency (MHz)
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0
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173.250
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1
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173.275
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2
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173.300
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3
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173.325
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4 -7
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173.225 (only used
for alarm applications)
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8 -127
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173.325
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SMX1 serial interface commands
2400 baud at RS232 level. 8 bit data, no parity,
1 start bit, 1 or 2 stop bits, No flow control.
Transmit (pin 3 on DB9) and Signal Ground (pin 5 on DB9) should
be connected to PGM and and 0V respectively.
| SINGLE nnnnn |
set value of N for single
channel operation (value not stored on EEPROM) |
| GOCHAN xx |
serial select
of channel xx (0 to 127) |
| LOADMX xx |
set highest permitted (serial
selected) channel xx (others default to ch0) |
| LOAD aa nnnnn |
set value of N for channel
aa (channels 0 to 15) |
| LOADTB nnnnn |
set value of N
for channel 16 (channels 17 to 127 then in sequence) |
| RVALUE rrrr |
enter value for R register |
| SETPAR |
channel selected by 3 bit
parallel input (0 to 7). Also Disable modem |
| SETSER |
channel selected by most recent
'gochan' operation |
| SETMOD |
enable internal modem. Frequency
selected by most recent 'gochan' or 'single' |
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| <cr> |
process entry |
| / |
clear all buffers |
xx = a channel number from 00 to 127
aa = a two digit channel number from 00 to 15
nnnnn = a synthesizer N register value, (up to 65535)
rrrr = the synthesizer R register value, (up to 16383)
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| Notes:
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1.
A pause of at least 50ms must be allowed between command strings
(EEPROM programming time).
SINGLE mode does not store the N value in EEPROM. Therefore the
unit is inoperative after a power down until either another valid
SINGLE command is received, or mode is changed by a GOCHAN, SETPAR
or SETSER command. SINGLE mode is intended for frequency agile
applications.
2. /SETPAR command should be issued at the end of channel programming
to put the module back into parallel frequency select mode.
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| Condensed
specifications |
| Frequency |
Any 1MHz band from 130 -180MHz
(173.200 - 173.325 MHz UK standard) |
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Frequency
stability
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+/- 2kHz |
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Channel
spacing
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25kHz
(12.5kHz by special order) |
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Number
of channels
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128 channels
controlled via RS232 interface;
8 channels selected via 3 frequency select pins |
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In UK band, only 173.250,
173.275, 173.300 and 173.325 MHz are used as standard |
| Supply
voltage |
4.2V -
16V |
|
Current |
40mA (10mW);
65mA (50mW) transmit |
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20mA receive
(or modem 'idle') |
| Operating
temperature |
-10 to
+60 °C (Storage -30 to +70 °C) |
| Size |
53 x 32
x 12mm |
| Spurious
radiations |
Compliant
with ETSI EN 300 220-3 and EN 300 686 |
| Interface
user |
8pin 0.1"
pitch molex |
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Power
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4pin 0.1"
pitch molex |
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RF
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3pin 0.1"
pitch molex |
| Recommended PCB
hole size |
1.2mm |
| Intended
approval |
ETSI radio
standard EN 300 220-3 and EMC standard EN 301 489-3 |
| Transmitter
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| Output
power |
UK standard +10dBm(10mW) ± 1dB (factory adjustable:
1 - 50mW)
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| TX on
switching time |
50 ms |
| Modulation
type |
FM, FSK
(F1D, F3D) |
| TX modulation
bandwidth |
DC - 3kHz |
| Deviation |
±2.6kHz to ±3kHz |
| Adjacent
channel TX power |
-37dBm |
| Inputs |
data (CMOS/TTL
compatible) |
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| Receiver
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| Sensitivity |
-112dBm
for 1 part per 1000 BER |
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-120dBm
for 12 dB SINAD |
| image
/ spurious |
-65dB |
| blocking |
-85dB |
| adjacent
Channel |
<-65dB
(Tested per. ETSI EN 301 489-3) |
| outputs |
RSSI,
audio, data |
| Power
on to valid audio |
28ms |
| Power
on to stable data out |
50ms (50:50
mark / space) |
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| Notes: |
1. |
The data slicer
cannot be depended upon for data waveform frequencies below
250Hz |
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2. |
When RX is
on and a transmitter keys up, again a 50ms period is required
to stabilise data output mark/space. i.e. allow at least
50ms of preamble |
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| Application
circuit |
Figure 4: SMX1 interfaced to host microcontroller and serial port
for configuration |
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Figure 5: SMX1 interfaced to PC serial port (0V / 5V RS232 level) |
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Figure 6: SMX1 interfaced to serial port (+10V / -10V RS232 level) |
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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:
Licensing
policy manual
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