4
1
234
12
34
F
E
D
C
B
A
CX-3158
1.1.2 RF and RFAGC amplifiers
The photo-detector outputs (A + C) and (B + D) are added, amplified, and equalized inside this LSI, and then provided
as the RF signal from the RFI terminal. The RF signal can be used for eye-pattern check.
The low frequency component of the RFO voltage is:
RFO = (A + B + C + D) x 2
The RFO is used for the FOK generation circuit and RF offset adjustment circuit.
The RFI output from the pin 119 is A/C-coupled outside this LSI, and returned to the pin 118 of this LSI. The signal is
amplified in the RFAGC amplifier to obtain the RFAGC signal. This LSI is equipped with the RFAGC auto-adjustment
function as explained below. This function automatically controls the RFO level to keep at 1.5V by switching the feed-
back gain for the RFAGC amplifier.
The RFO signal is also used for the EFM, DFCT, MIRR, and RFAGC auto-adjustment circuits.
Fig. 1.1.2 RF/AGC/FE
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