BiM1,
TX1H |
The VHF BiM1 transceiver modules offer a 100mW RFoutput
VHF bi-directional data link in Radiometrix transceiver
standard pin-out and footprint. This makes the BiM1 ideally
suited to those low power applications where existing
wideband modules have insufficient range. |
Figure 1: BiM1-173.250-10
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Features
- Conforms to EN 300 220-3 and EN 301
489-3 (10mW version only)
- Standard frequency 151.300MHz
- Other frequencies from 120MHz to 180MHz
- Available separately as BiM1T transmitter
and BiM1R receiver
- TX1H is a BiM1T in TX1 pin-out
- Data rates up to 10kbps for standard
module
- Usable range over 10km
- Fully screened
- Feature-rich interface (RSSI, analogue
and digital baseband)
- Low power requirements
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| The BiM1 is a half duplex radio transceiver
module for use in long range bi-directional data transfer applications
at ranges up to 10kilometres. The module operates on the UK
licence exempt frequency of 173.225/173.250MHz with 10mW RF
output and Australian frequency of 151.300MHz with 100mW RF
output. The small footprint of 23 x 33mm and low profile of
10mm together with low power requirements of <80mA (for 100mW)
at 3.8V enable convenient PCB installation. BiM1 is also available
as separate BiM1T transmitter and BiM1R receiver which can be
used as dual-in-line equivalents of TX1 transmitter and RX1
receiver respectively. |
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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
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Technical Summary
- Size: 33 x 23 x 10mm
- Operating frequency: 151.300MHz
- Transmit power: 20dBm (100mW) nominal
- Supply range: 3.8V - 15V @ 100mW; 3.0V-16V
@ 10mW
- Current consumption: 80mA transmit @
100mW, 8mA receive
- Data bit rate: 10kbps max. (standard
module)
- RSSI output with >60dBm range
- 10kbps, -120dBm sensitivity (for 12
dB SINAD)
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| Evaluation Platform: Universal
Evaluation kit or Narrow
Band Evaluation Kit |
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 Figure
2: BiM1 block diagram
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Figure
3: TX1H block diagram
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BiM1 transceiver contains BiM1T transmitter
circuit and BiM1R receiver circuit with their RF output and
input connected to a common RF pin via an internal RF switch.
TX1H transmitter circuit is the BiM1T transmitter
circuit in the TX1 pin-out with slightly enlarged dimension
to accommodate extra Power Amplifier circuit to produce 100mW
RF output.
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| Functional description
The transmit section of the BiM1 consists
of a frequency modulated Voltage Controlled Crystal Oscillator
(VCXO) feeding a frequency doubler with two stage amplifier
and RF filter. Final Power Amplifier stage is factory pre-set
to appropriate band power level. Operation is controlled by
a Tx Select line, the transmitter achieving full RF output
typically within 5ms of this line being pulled low. The RF
output is filtered to ensure compliance with the appropriate
radio regulations and fed via a fast Tx/Rx changeover switch
to the 50W antenna pin.
The receive section is a double conversion
FM superhet with IF at 21.4MHz and 455kHz fed by a Low Noise
Amplifier (LNA) on the RF front-end. The receiver is controlled
by RX Select line and will power up typically <2ms. Quadrature
detector output is available as Audio Frequency (AF) output
and transmitted digital data is regenerated from AF using
adaptive data slicer. A Received Signal Strength Indicator
(RSSI) output with some 60dB of range is provided.
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User interface
Figure
4: BiM1 pin-out and dimension
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Figure
5: TX1H pin-out and dimension
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| BiM1pin |
TX1H pin |
Name |
Function |
| 1, 3, 9, 10, 8 |
1, 3, 6 |
0V |
Ground |
| 17 |
5 |
Vcc |
3.8 - 15V DC power supply |
| 16 |
- |
RX select |
Pull low to
enable Receiver |
| 15 |
4 |
TX select
EN
|
Pull low to enable Transmitter
Pull high to enable Transmitter |
| 14 |
7 |
TXD |
DC coupled input for 3V
CMOS logic. Rin = 100kW |
| 13 |
- |
AF |
500mV pk-pk audio. DC
coupled, approx 0.8V bias |
| 12 |
- |
RXD |
Received
Data output from the internal data slicer. Suitable for
Biphase codes. Output will have a 2.8Vpk-pk (i.e. 3v logic
compatible) swing as default. Add a 10K pull-up resistor
to Vcc to get the bigger swing (i.e. 0 - Vcc depending
on the supply voltage). |
| 11 |
- |
RSSI |
DC level between 0.5V
and 2.4V. 60dB dynamic range |
| |
NOTES:
1. RX select and TX
select have (10kW approx.)
pullups to Vcc
2. EN pin should not be left floating
3. For Vcc greater than 9V, transmit duty cycle must be
limited to 25% or less
4. Avoid RX select and TX
select both low: undefined module operation (but
damage will not result)
5. A 10mW UK version is available on 173.225MHz. (3.0
- 16V operation, 10mA TX)
6. Pinout is as BiM2. On RF connector end only pins 1,
2, 3, 9 are present. |
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| Absolute maximum ratings
Exceeding the values given below may cause
permanent damage to the module.
| Operating temperature |
-10°C to +60°C |
| Storage temperature |
-30°C to +70°C |
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| RF in (pin 1) |
±50V @ <10MHz,
+13dBm @ >10MHz |
| All other pins |
-0.3V to +16.0V |
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| Interface: |
User: 9pin 0.1" pitch
molex |
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RF: 3pin 0.1" pitch
molex |
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Performance specifications:
(Vcc = 3.8V / temperature = 20°C unless stated)
| General |
pin |
min. |
typ. |
max. |
units |
notes |
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| DC supply
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Supply
voltage (100mW BiM1 & BIM1T)
|
17
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3.8
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-
|
15
|
V
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| Supply voltage
(10mW BIMT & BiM1R) |
17
|
3.0
|
-
|
16
|
V
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| TX Supply current @ 100mW |
17
|
-
|
80
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-
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mA
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| TX Supply current @ 10mW |
17
|
-
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25
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-
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mA
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| RX Supply current |
17
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-
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8
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-
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mA
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| Antenna pin impedance |
2
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-
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50
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-
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W
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| RF centre frequency (100mW) |
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-
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151.300
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-
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MHz
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| RF centre
frequency (10mW) |
|
-
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173.225
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-
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MHz
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| Channel spacing |
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-
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25
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-
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kHz
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| Number of channels |
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-
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1
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-
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| Transmitter |
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| RF |
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| RF power output
(100mW) |
2
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+19
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+20
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+21
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dBm
|
1
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| RF power output (10mw) |
2
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+9
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+10
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+11
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dBm
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1
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| Spurious emissions (100mW) |
2
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-
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-40
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-
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dBm
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| Spurious emissions (10mW) |
2
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-
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TBA
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-
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dBm
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2
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| Adja. channel
TX power (100mW) |
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-
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-37
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-
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dBm
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| Adja. channel TX power
(10mW) |
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TBA
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2
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| Frequency accuracy |
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- 2.5
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0
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+2.5
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kHz
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3
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| FM deviation (peak) |
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±2.5
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±3.0
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±3.5
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kHz
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4
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| Baseband |
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| Modulation bandwidth @
-3dB |
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0
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-
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5
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kHz
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| Modulation distortion
(THD) |
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TBA
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%
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| TXD input
level (logic low) |
14
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-
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0
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-
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V
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5
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| TXD input
level (logic high) |
14
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-
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3.0
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-
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V
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5
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| Dynamic timing |
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| TX select to full RF |
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-
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5
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-
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ms
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| Receiver |
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| RF/IF |
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| RF sensitivity
@ 12dB SINAD |
2, 13
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-
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-120
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-
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dBm
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| RF sensitivity @ 1ppm
BER |
2, 12
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-
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-115
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-
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dBm
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| RSSI threshold |
2, 11
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-
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-127
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-
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dBm
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| RSSI range |
2, 11
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-
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60
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-
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dB
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| IF bandwidth |
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TBA
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kHz
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| Blocking |
2
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-
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85
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-
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dB
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| Image rejection |
2
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-
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60
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-
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dB
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| Adjacent channel rejection
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2
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-
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70
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-
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dB
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2
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| Spurious response rejection |
2
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-
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65
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-
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dB
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| LO leakage, conducted |
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-
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-70
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-
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dBm
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3
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| LO leakage, radiated |
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-
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-60
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-
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dBm
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3
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| Baseband |
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| Baseband bandwidth @ -3dB |
13
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-
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5
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-
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kHz
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| AF level |
13
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-
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400
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-
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mVp-p
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7
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| DC offset on AF out |
13
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-
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0.8
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-
|
V
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| Distortion
on recovered AF |
12
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TBA
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%
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| Load capacitance, AF /
RXD |
12, 13
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TBA
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pF
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| Dynamic
timing |
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| Power up with signal present
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| Power up to valid RSSI |
16, 11
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TBA
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ms
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| Power up to stable AF
outpu |
16, 13
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-
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2
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-
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ms
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| Power up to stable RXD
output |
16, 12
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-
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10
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-
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ms
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| Signal applied with supply
on |
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| Signal to valid AF |
2, 11
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TBA
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ms
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| Signal to stable data |
2, 12
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TBA
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ms
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| Time between
data transitions |
12
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-
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-
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0.1
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ms
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8
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| Mark : space ratio |
12
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20
|
50
|
80
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%
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8
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Notes:
1. Measured into 50W resistive load.
2. Exceeds EN/EMC requirements at all frequencies.
3. Total over full supply and temperature range.
4. With 0V - 3.0V modulation input.
5. To achieve specified FM deviation.
6. See applications information for further details.
7. For received signal with ±3kHz FM deviation.
8. For 50:50 mark to space ratio (i.e. squarewave). |
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Application Information
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Power supply requirements
The BiM1 have built-in regulators which deliver a constant
3.5V to the transmitter (100mW) and 2.8V to the receiver.circuitry
when the external supply voltage is 3.5V or greater. 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 >0.1Vp-p).
TX modulation requirements
The module is factory-set to produce the specified FM deviation
with a TXD input to pin 14 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 100kW to ground, giving typical
required resistor values as follows:
| Vcc
|
Series
resistor |
| <=3V |
- |
| 3.3V |
10kW |
| 5V |
68kW |
| 9V |
220kW |
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| Reducing the output
power of the BiM1
If the BiM1 is to be used for applications for which the
regulatory Effective Radiated Power (ERP) limit is lower than
100mW its output power can be reduced to comply with relevant
regulatory requirements. This is done by inserting a 10dB
attenuator network between the module and the antenna or feed,
as follows:
|
 Figure
6: 10dB attenuator for BiM1 transceiver, BiM1T transmitter
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| Keep all tracking around the attenuator
network as short as possible, particularly ground paths, and
use matched 50W microstrip lines
for input and output connections (track width of 2.5mm if using
1.6mm thick FR4 PCB).
However, this 10dB attenuator will also reduce the sensitivity
of the BiM1 transceiver by 10dB.
RF output can also be factory set from +5dBm (3mW) to +20dBm
(100mW) depending on minimum order quantity.
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| RX Received Signal
Strength Indicator (RSSI)
The BiM1 wide range RSSI which measures the strength of an
incoming signal over a range of 60dB or more. This allows
assessment of link quality and available margin and is useful
when performing range tests.
The output on pin 11 of the module has a standing DC bias
of up to 0.5V with no signal, rising to 2.4V at maximum indication.
DVmin-max is typically 1V and is largely independent of standing
bias variations. Output impedance is 56kW.
Pin 11 can drive a 100mA meter directly, for simple monitoring.
Typical RSSI characteristic is as shown below:
|
 Figure
7: RSSI level with respect to received RF level at BiM1 antenna
pin
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| Packet data
In general, data to be sent via a radio link is formed into
a serial "packet" of the form :-
Preamble - Control - Address - Data -
CRC
Where:
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| Preamble: |
This is mandatory for
the adaptive data slicer in the receiver in the BiM1 to
stabilise. The BiM will be stable after 10ms. Additional
preamble time may be desired for decoder bit synchronisation,
firmware carrier detection or receiver wake up. |
| Control: |
The minimum requirement
is a single bit or unique bit pattern to indicate the
start of message (frame sync.). Additionally, decoder
information is often placed here such as: packet count,
byte count, flow control bits (e.g. ACK, repeat count),
repeater control, scrambler information etc. |
| Address: |
This information is used
for identification purposes and would at least contain
a 16/24 bit source address, additionally - destination
address, site / system code , unit number and repeater
address's may be placed here. |
| Data: |
User data , generally
limited to 256 bytes or less (very long packets should
be avoided to minimise repeat overheads on CRC failure
and channel hogging). |
| CRC: |
16/24 Bit
CRC or Checksum of control-address-data fields used by
the decoder to verify the integrity of the packet.
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| The exact makeup of the packet depends upon
the system requirements and may involve some complex air-traffic
density statistics to optimise through-put in large networked
systems. |
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| Networks
BiM1's may be used in many different configurations from
simple pair's to multi-node random access networks. The BiM1
is a single frequency device thus in a multi node system the
signalling protocol must use Time Division Multiple Access
(TDMA). In a TDMA network only one transmitter may be on at
a time, 'clash' occurs when two or more transmitters are on
at the same time and will often cause data loss at the receivers.
TDMA networks may be configured in several ways - Synchronous
(time slots), Polling (master-slave) or Random access (async
packet switching e.g. X25). Networked BiM1's allow several
techniques for range / reliability enhancement:
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| Store and forward Repeaters:
|
If the operating protocol
of the network is designed to allow data path control
then data may be routed via intermediate nodes. The inclusion
of a repeating function in the network protocol either
via dedicated repeater/router nodes or simply utilising
existing nodes allows limitless network expansion. |
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| Spatial Diversity: |
In buildings
multi-path signals create null spots in the coverage pattern
as a result of signal cancellation. In master-slave networks
it is cost effective to provide 2 BiM1's with separate
antenna at the master station. The null spot patterns
will be different for the two BiM1's . This technique
'fills in' the null spots, i.e. a handshake failure on
the first BiM1 due to a signal null is likely to succeed
on the 2nd BiM1. |
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| "RS232"
Serial data
It is possible to transmit "RS232" serial data
directly at 600 to 9600bps baud between a pair of BiM1 transceivers
in half duplex mode. The data must be "packetised"
with no gaps between bytes. i.e. The data must be preceded
by >10ms of preamble (55h or AAh) to allow the data slicer
in the BiM1 to settle, followed by one 00h and one FFh bytes
to allow the receive UART to lock, followed by a unique start
of message byte, (01h), then the data bytes and finally terminated
by a CRC or check sum. The receiver data slicer provides the
best bit error rate performance on codes with a 50:50 mark:space
average over a 5ms period, a string of FFh or 00h is a very
asymmetric code and will give poor error rates where reception
is marginal. Only 50:50 codes may be used at data rates above
1kbps.
We recommend 3 methods of improving mark:space ratio of serial
codes, all 3 coding methods are suitable for transmission
at 10kbps:-
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| Method 1 - Bit coding |
Bit rate , Max 10kbps , Min 250bps
Redundancy (per bit) 100% (Bi-phase)
Each bit to be sent is divided in half, the first half
is the bit to be sent and the second half, it's compliment.
Thus each bit has a guaranteed transition in the centre
and a mark:space of 50:50 . This is Bi-phase or Manchester
coding and gives good results, however the 100% redundancy
will give a true throughput of 5kbps.
Another variation of this code is to encode a '1' as a
long bit with one transition and '0' as a short bit with
two transition or vice versa. Each encoded bit starts with
a guaranteed transition to reverse the voltage level even
if stream of 00h/FFh is encoded. This is called Differential
Manchester Encoding. This encoding method is easier to decode
as the decoder has to sample encoded bit several times and
if the sample value is more than 75% of a long bit period,
then it is decoded as '1' and if there was transition then
it is decoded as '0' or vice versa.
|
 |
| Method 2 - FEC coding |
Bit rate , Max 10kbps, Min 2.4kbps
Redundancy (per byte) 100%
Each byte is sent twice; true then it's logical compliment.
e.g. even bytes are true and odd bytes are inverted. This
preserves a 50:50 balance.
A refinement of this simple balancing method is to increase
the stagger between the true and the inverted data streams
and add parity to each byte. Thus the decoder may determine
the integrity of each even byte received and on a parity
failure select the subsequent inverted odd byte. The greater
the stagger the higher the immunity to isolated burst errors.
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| |
| Digitised analogue
data
Linear operation of BiM1 transceivers will allow direct transfer
of analogue data, however in many applications the distortion
and low frequency roll off are too high (e.g. bio-medical
data such as ECG). The use of delta modulation is an excellent
solution for analogue data in the range 1Hz up to 4kHz with
less than 1% distortion. A number of propitiatory IC's
such as Motorola's MC3517/8 provide CVSD Delta mod/demod on
a single chip.
Where the signal bandwidth extends down to DC , such as strain
gauges, level sensing, load cells etc. then Voltage to Frequency
/ Frequency to Voltage chips (such as Nat Semi LM331) provide
a simple means of digitising.
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|
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 |
| 1.2kbps |
half-wave |
half-wave |
rural/open |
10-15km |
| 10kbps |
half-wave |
half-wave |
rural/open |
3-4km |
| 10kbps |
helical |
half-wave |
urban/obstructed |
500m-1km |
| 10kbps |
helical |
helical |
in-building |
100-200m |
|
 |
| Note: The figure for 1.2kbps assumes
that the receiver bandwidth has been suitably reduced by utilising
an outboard sallen-key active audio filter and data slicer or
similar arrangement.
The BiM1 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 14) 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 BiM1 introduces some 2nd harmonic
distortion which may be reduced if necessary by predistortion
of the analogue waveform. At the other end of the link the
BiM1 RXD output is used to drive an external decoder directly.
Although the modulation bandwidth of the BiM1 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 BiM1 audio output.
The BiM1 in standard form incorporates a low pass filter
with a 5kHz nominal bandwidth. This is suitable for transmission
of data at raw bit rates up to 10kbps.
In applications such as long range fixed links where data
speed is not of prime concern, a considerable increase in
range can be obtained by using the slowest possible data rate
together with filtering to reduce the receiver bandwidth to
the minimum necessary.
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| |
|
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.
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 151MHz
the total length should be 471mm 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 151MHz 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:
|
whip
|
helical
|
loop
|
| Ultimate performance |
***
|
**
|
*
|
| Ease of design set-up
|
***
|
**
|
*
|
| Size |
*
|
***
|
**
|
| Immunity to proximity
effects |
**
|
*
|
***
|
|
 |
| |
 Figure
8: 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 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
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.
|
| 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 50W
coax feed can be achieved if the elements are angled downwards
at approximately 30-40° to the horizontal. |
| |
 Fig.
9: 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.
Please note: Using a Yagi or other gain antenna with the
BiM1 will exceed the maximum radiated power permitted by UK
type approval regulations. It can be used in the UK only in
conjunction with the BiM1R receiver.
For best range in UK fixed link applications use a half-wave
antenna on BiM1T transmitter and a half-wave or Yagi on BiM1R
receiver, both mounted as high as possible and clear of obstructions.
|
 |
| |
| Module mounting considerations
Good RF layout practice should be observed. If the connection
between module and antenna is more than about 20mm long use
50W 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.
|
| |
|
Variants and ordering information
The BiM1 transceiver is manufactured in the following variants
as standard:
|
For Australian general applications on 151.300MHz (100mW
RF output power)
TX1H-151.300-10 Transmitter
BiM1T-151.300-10 Transmitter
BiM1R-151.300-10 Receiver
BiM1-151.300-10 Transceiver
For UK alarm applications on 173.225MHz:
BiM1T-173.225-10 Transmitter
BiM1R-173.225-10 Receiver
BiM1-173.225-10 Transceiver
For UK general applications on 173.250MHz:
BiM1T-173.250-10 Transmitter
BiM1R-173.250-10 Receiver
BiM1-173.250-10 Transceiver
|
| Other variants can be supplied to individual
customer requirements at frequencies from 120MHz to 180MHz and/or
opitomized for specific data speeds and formats. However these
are subject to minimum order quantity (MOQ) and long lead time.
Please consult the Sales Department for further information.
|
 |
|
Some of the non-standard frequencies readily
available. i.e. no MOQ or long lead time, are as follows:
Part number: BiM1-xxx.xxx-10 (where
xxx.xxx is the operating frequency)
|
| Frequency
(MHz) |
Type approval |
Notes |
| 121.500 |
- |
1, 2, 3 |
| 138.125 |
- |
1, 2, 3 |
| 149.170 |
- |
1, 2, 3 |
| 151.275 |
- |
1, 2, 3 |
| 151.300 |
Yes |
2, 3 |
| 151.775 |
Yes |
2, 3 |
| 152.175 |
Yes |
2, 3 |
| 152.500 |
Yes |
2, 3 |
| 152.575 |
Yes |
2, 3 |
| 152.650 |
Yes |
2, 3 |
| 152.850 |
Yes |
2, 3 |
| 153.8125 |
Yes |
2, 3 |
| 153.9125 |
Yes |
2, 3 |
| 153.925 |
Yes |
2, 3 |
| 154.463 |
Yes |
2, 3 |
| 155.475 |
Yes |
2, 3 |
| 155.715 |
Yes |
2, 3 |
| 155.725 |
Yes |
2, 3 |
| 156.525 |
Yes |
2, 3 |
| 157.420 |
Yes |
2, 3 |
| 159.685 |
Yes |
2, 3 |
| 159.6875 |
Yes |
2, 3 |
| 161.975 |
Yes |
2, 3 |
| 162.025 |
Yes |
2, 3 |
| 162.975 |
Yes |
2, 3 |
| 163.000 |
Yes |
2, 3 |
| 164.525 |
Yes |
2, 3 |
| 167.420 |
Yes |
2, 3 |
| 169.435 |
Yes |
2, 3 |
| 169.41875 |
Yes |
2, 3 |
| 172.420 |
Yes |
2, 3 |
| 173.075 |
Yes |
2, 3 |
| 173.175 |
Yes |
2, 3 |
| 173.200 |
Yes |
2, 3 |
| 173.960 |
- |
1, 2, 3 |
| 180.175 |
- |
1,2, 3 |
|
|
|
|
|
Notes: 1.
|
Complies with the ETSI
standards but NOT approved approved |
|
2.
|
For specialised application,
NOT for general purpose |
|
|
e.g: 121.500MHz is an
international distress frequency |
|
3.
|
NOT an European Harmonised
frequency. Consult local radio requlatory authority. |
|
| Type approval
The BiM1-173 module is meets European harmonised
standard ETSI EN 300 220-3 for UK use within the following
categories:
(a) General applications in the band 173.2-173.35MHz
but excluding 173.225MHz.
(b) Industrial/commercial applications
at the same frequencies as category (a).
(c) Fixed/in-building alarm applications
at 173.225MHz.
(d) Medical/biological applications
(including airborne use for the tracking of birds) in the
band 173.7-174.0MHz.
|
| REQUIREMENTS FOR CONFORMANCE TO ETSI
EN 300 220-3:
1. Transmitted ERP (effective radiated
power) must not exceed the limit of 1mW (0dBm) for category
(a) or 10mW (+10dBm) for categories (b), (c) and (d). Equipment
in category (a) must include a 10dB attenuator between the
TX1 RF output pin and the antenna or feed, as specified on
page 7 of this leaflet.
2. Any type of antenna system may be employed
provided that the applicable ERP limit is not exceeded - i.e.
transmitting antenna structures which exhibit ERP gain (such
as yagis) are not permitted. See pages 10-13 of this leaflet
for details of suitable antennas.
3. The module must not be modified or used
outside its specification limits.
4. The module may only be used to
transmit digital or digitised data. Speech and/or music are
not permitted.
|
| Breaching any of these conditions will
invalidate type approval |
| |
|
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
|
 |