RL78/G1H CHAPTER 18 RF TRANSCEIVER
R01UH0575EJ0120 Rev. 1.20 Page 549 of 920
Dec 22, 2016
18.3.2 Analog block
The analog block consists of RF transmission/reception circuits. Figure 18 - 2 shows the block diagram of the RF
transmission/reception block.
Figure 18 - 2 RF Transmission/Reception Block
(1) LNA block
This is a low noise amplifier which input the high frequency signal captured by antenna.
It switches the gain according to the input signal.
(2) MIX block
This is a mixer circuit which uses the high frequency RF output signal from the LNA as input signal and
converts it into low frequency IF (Intermediate Frequency) signal by changing the frequency.
(3) VGA block
This block controls the input amplitudes under the constant state that are transmitted to the AD converter
which is connected to the subsequent stage, by changing the gain depending on the input signal level.
(4) Filter block
This removes unnecessary input signals from antenna.
(5) ADC block
This converts analog signal to digital signal.
(6) VCO and PLL blocks
They generate the carrier frequency which is used upon reception/transmission based on the reference
clock which is input by the crystal oscillator or TCXO.
(7) PA block
This is a power amplifier which is located at the output stage in the analog circuit in order to output the high
frequency signal from antenna.
VC O
HP A
BEF
VC O
block
PA
block
RFOUT
PLL
ΔΣ Modulator
PLL block
ADC
ADC
LPF
LPF
FA
FA
MIX
MIX
MIX block
VGA block
Filter block
LNA block
LNA
Internal
Matching
RFIP
ADC block
Analog block
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