Transmission unit, reception unit, and communication system
A transmitter includes: a transmission control circuit that determines whether or not to perform an emphasis on a data signal, based on a transition pattern of the data signal; and a transmission driver that selectively performs the emphasis based on a result of the determination by the transmission control circuit, to generate at least one transmission signal.
1. A transmitter comprising:
a transmission control circuit configured to determine whether or not to perform an emphasis on a data signal, based on a transition pattern of the data signal; and
a transmission driver configured to selectively perform the emphasis based on a result of the determination by the transmission control circuit, to generate at least one transmission signal, wherein
respective ones of the at least one transmission signal make a transition from a first voltage state of a plurality of voltage states to a second voltage state of the plurality of voltage states, and
the transmission control circuit is configured to determine that the emphasis is to be performed on the respective ones of the at least one transmission signal in at least one of the corresponding transitions.
2. The transmitter according to claim 1 , wherein
the data signal indicates a sequence of transmission symbols, and
the transmission control circuit is configured to compare two successive transmission symbols and determine whether or not to perform the emphasis based on a result of the comparison.
3. The transmitter according to claim 1 , wherein the transmission control circuit includes a look-up table indicating a relationship between the transition pattern and a flag indicating whether or not to perform the emphasis, and is configured to determine whether or not to perform the emphasis based on the look-up table.
4. The transmitter according to claim 3 , wherein the look-up table is programmable.
5. The transmitter according to claim 1 , wherein the transmission driver is configured to selectively perform the emphasis to selectively increase a high-frequency component of the at least one transmission signal.
6. The transmission unit according to claim 5 , wherein
the at least one transmission signal is three transmission signals,
the transition from the first voltage state to the second voltage state is a transition from one of a high voltage state, a low voltage state, and an intermediate voltage state to another,
the transmission control circuit is configured to determine that the emphasis is to be performed on a respective transmission signal that makes a transition from the high voltage state or the intermediate voltage state to the low voltage state, and
the transmission control circuit is configured to determine that the emphasis is to be performed on a respective transmission signal that makes a transition from the low voltage state or the intermediate voltage state to the high voltage state.
7. The transmission unit according to claim 6 , wherein the transmission control circuit is configured to determine that the emphasis is to be performed on a respective transmission signal that is maintained in the high voltage state or the low voltage state.
8. The transmission unit according to claim 6 , wherein
the transmission control circuit is configured to determine that the emphasis is not to be performed on a respective transmission signal that makes a transmission from the high voltage state or the low voltage state to the intermediate voltage state, and
the transmission control circuit is configured to determine that the emphasis is not to be performed on a respective transmission signal that is maintained in the intermediate voltage state.
9. The transmission unit according to claim 5 , wherein
the at least one transmission signal is a first transmission signal, a second transmission signal, and a third transmission signal,
the transition from the first voltage state to the second voltage state is a transition from one of a high voltage state, a low voltage state, and an intermediate voltage state to another, and
the transmission control circuit is configured to determine that the emphasis is to be performed on the second transmission signal and the third transmission signal when the first transmission signal makes a transition from the high voltage state to the intermediate voltage state, the second transmission signal makes a transition from the low voltage state to the high voltage state, and the third transmission signal makes a transition from the intermediate voltage state to the low voltage state.
10. The transmission unit according to claim 5 , wherein
the at least one transmission signal is a first transmission signal, a second transmission signal, and a third transmission signal,
the transition from the first voltage state to the second voltage state is a transition from one of a high voltage state, a low voltage state, and an intermediate voltage state to another, and
the transmission control circuit is configured to determine that the emphasis is to be performed when there is a change between respective polarities of a first difference signal between the first transmission signal and the second transmission signal, a second difference signal between the second transmission signal and the third transmission signal, and a third difference signal between the first transmission signal and the third transmission signal.
11. The transmitter according to claim 1 , wherein the transmission driver is configured to selectively perform the emphasis to selectively reduce a low-frequency component of the at least one transmission signal.
12. The transmitter according to claim 11 , wherein
the transition from the first voltage state to the second voltage state is a transition from a first voltage state of a plurality of voltage states to a second voltage state of the plurality of voltage states, and
the transmission control circuit is configured to determine that the emphasis is to be performed on the respective ones of the at least one transmission signal that are maintained in at least one voltage state of the plurality of voltage states.
13. The transmitter according to claim 11 , wherein
the at least one transmission signal is three transmission signals,
the transition from the first voltage state to the second voltage state is a transition from one of a high voltage state, a low voltage state, and an intermediate voltage state to another, and
the transmission control circuit is configured to determine that the emphasis is to be performed on a respective transmission signal that is maintained in the high voltage state or the low voltage state.
14. The transmitter according to claim 13 , wherein the transmission control circuit is configured to determine that emphasis is not to be performed on a respective transmission signal that is maintained in the intermediate voltage state.
15. The transmitter according to claim 1 , wherein
the at least one transmission signal is a plurality of transmission signals, and
the transmission control circuit is configured to individually determine whether or not to perform emphasis on respective ones of the plurality of transmission signals.
16. The transmitter according to claim 1 , wherein
the at least one transmission signal is a plurality of transmission signals, and
the transmission control circuit is configured to collectively determine whether or not to perform emphasis on respective ones of the plurality of transmission signals.
17. An imaging system comprising:
a CMOS image sensor configured to generate the data signal; and
the transmitter according to claim 1 .
18. A communication system comprising:
a transmitter including
a transmit control circuit configured to determine whether or not to perform a pre-emphasis on a data signal, based on a transition pattern of the data signal, and
a transmit driver configured to selectively perform the pre-emphasis based on the determination by the transmit control circuit, to generate at least one transmission signal; and
a selection control circuit configured to select between a first output signal based on the at least one transmission signal and a second output signal based on the at least one transmission signal, based on a transition pattern of the at least one transmission signal, wherein
respective ones of the at least one transmission signal make a transition from a first voltage state of a plurality of voltage states to a second voltage state of the plurality of voltage states, and
the transmission control circuit is configured to determine that the emphasis is to be performed on the respective ones of the at least one transmission signal in at least one of the corresponding transitions.