S-BAND / UHF TRANSCEIVER – USER MANUAL
ENDUROSAT
8
The
UHF
transceiver works in the frequency range 430 – 440 MHz with GFSK modulation. In the
core of this UHF transceiver there is a high performance IC which is a zero-IF transceiver. It is
responsible for the output signal forming and also downconverting and demodulating of the input
signal. It contains very flexible packet manager that handles the data packets. The reference signal
source for its integrated frequency synthesizer is at 26 MHz. There is a PA in the Tx signal chain,
which boosts the output signal up to 1.5 W. In the Rx signal chain there is a LNA followed by BPF.
There is also a Tx/Rx switch since the device is half-duplex. The communication with the OBC (or
payload) is accomplished by UART / I2C interface of the MCU. The supply voltage to the transceiver
must be in the range 3.2 – 3.4 V and is directly connected to the PA. There is an LDO, which
reduces the voltage for the rest of the schematic to 3 V. The connector used is PC-104 suitable for
stackable configurations. The connector for the antenna is MCX.
Figure 3 - Block Diagram of the UHF transceiver
