ORBCOMM OG2 Modem Integration Manual
14
3.
Radio Frequency Section
The OG2 modem includes:
A VHF Receiver Section which performs RF filtering, frequency conversion and demodulation.
A VHF Transmitter Section which performs modulation, frequency conversion and power
amplification.
A Processing Section that monitors and controls optional I/Os, handles the RF and serial
interface.
LO
ARM M4
Processor
Up to 1M Flash
RTOS
CMULT
Frac
N
Modulator
Direct Convertion
Receiver
Power Amplifier
GPS
3 Axis
Accelerometer
Mini PCI
Express
Interface
Wide Range
Switching
Supply 3v -15v
JTAG
USB
CAN
SD-Card
UART x3
SPI x2
ADC x2
Tamper
ORBCOMM OG2 Modem
Pre Amplifier
SAW Filter
LNA
RF Switch
Harmonic Filter
VHF Antenna
Tx 148.00
– 150.5 MHz
RX 137.00
– 138.00 MHZ
50 channel
-162 dBm
Communication Bus
Digital
TX - Q
TX - I
RX - Q
RX - I
Baseband
Processor
52
BP Filter
-120 dBm sensitivity
Figure 3-1 Modem Block Diagram
The different ports are:
Power Supply
. Capable of handling a wide range of DC input voltages.
