Toshiba TC9314F Manual page 25

Phase Comparator, Clock Detection Port
The phase comparator compares the reference frequency signal supplied by the reference frequency divider
with the divided signal output by the programmable counter, and outputs the phase difference. The output of
the phase comparator is used to control the VCO via the low pass filter so as to eliminate the frequency and
phase difference between the two signals.
Data are output from the phase comparator to the tristate buffered DO1 and DO2 pins in parallel. This
enables the optimal filter constants to be designed for both FM and AM bands.
Also, the DO2 pin can be set for general-purpose output by the DO2 control port. The DO2 pin can also be set
to high impedance. By using the DO1 and DO2 pins, PLL loop characteristics, such as the lockup time, can be
improved.
The lock detection port can be used to detect the PLL lock state.
1. DO2 Control Port, Unlock Detection Port
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TC9314F
2003-07-03