Functional description
The transmit section of the BiM1H 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. A Tx Select line controls the
operation; the transmitter achieves full RF output typically within 8ms 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 50Ω 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.
User interface
side view (with can)
side view (through can)
12 mm
top view (without can)
RF GND
Antenna
RF GND
1
2
3
4
5
6
7
8
9
18 GND
Vcc
17
RX SELECT
TX SELECT
16
15
23 mm
14 TXD
13 AF
12 RXD
11 RSSI
10 GND
No pin
30.48 mm
33 mm
pin pitch: 2.54 mm
pins 4, 5, 6, 7 & 8 are not fitted
recommended PCB hole size: 1.2 mm
module footprint size: 25 x 32 mm
Figure 4: BiM1H pin-out and dimension
BiM1H Pin
Name
Function
1, 3
RF GND
RF ground pin, internally connected to the module screen and pin
5, 9, 10, 18 (0 Volt).
2
17
RF IN/OUT
VCC
50Ω RF input/output from the antenna
+5V regulated DC power supply
16
15
14
13
12
11
9, 10, 18
RX SELECT
TX SELECT
TXD
AF
RXD
Pull low to enable Receiver
Pull low to enable Transmitter
DC coupled input for 5V CMOS logic. Rin = 100kΩ
500mV pk-pk audio. DC coupled, approx 0.8V bias
2.5V pk-pk logic output of data slicer. Suitable for Biphase codes
DC level between 0.5V and 2.4V. 60dB dynamic range
Supply ground connection
RSSI
0V
NOTES:
1. RX SELECT and TX SELECT have internal (10kΩ approx.) pull-up to Vcc
2. Avoid RX SELECT and TX SELECT both low: undefined module operation (but damage will not result)
3. A regulated +5v rail must be used
4. Pin out is as standard BiM1 and BiM2. On RF connector end only pins 1, 2, 3, 9 are present.
Radiometrix Ltd.,
BiM1H transceiver data sheet
Page 3
RADIOMETRIX [ RADIOMETRIX LTD ]
