Transmitter for multi-format data
A data transmitter (A, B, C, D) wherein, in a first operating mode, the first and second carrier signals are mutually phase-shifted, and the data module generates said first and second data signals based on different data, so as to produce, at the transmitter's output, a modulated signal exhibiting a first constellation of states (A, B, C, D) in a complex plane, and, in a second operating mode of the transmitter, the data module generates said first and second data signals correlated with one another based on common data, so as to produce, at the transmitter's output, a modulated signal exhibiting a second constellation of states (A, D; E, F) in the complex plane that is more reduced and more dispersed then said first constellation of states.
1. A data transmitter comprising:
a first amplitude modulator capable of modulating a first carrier signal based on a first data signal;
a second amplitude modulator capable of modulating a second carrier signal based on a second data signal;
a signal combiner capable of directing towards an output of the data transmitter a combination of the first modulated carrier signal coming from the first amplitude modulator and the second modulated carrier signal coming from the second amplitude modulator;
a data module capable of generating the first data signal and the second data signal with a common modulation pace; and
a signal splitter capable of producing the first carrier signal and the second carrier signal by splitting a source optical signal by directing a first fraction of the source optical signal to a first transmission branch comprising the first amplitude modulator and a second fraction of the source optical signal to a second transmission branch comprising the second amplitude modulator;
wherein in a first operating mode of the data transmitter, the first carrier signal and the second carrier signal are mutually phase-shifted, and the data module generates the first data signal and the second data signal based on different data to produce, at the output of the data transmitter, a modulated signal exhibiting a first constellation of states in a complex plane; and
wherein in a second operating mode of the data transmitter, the data module generates the first data signal and the second data signal correlated with one another based on common data to produce, at the output of the data transmitter, a modulated signal exhibiting a second constellation of states in the complex plane that is more reduced and more dispersed than the first constellation of states; and
wherein the data module comprises a data input interface configured to receive a data flow to be transmitted and a plurality of parallel input lines for receiving parallel incoming flows that compose the data flow to be transmitted, and wherein the data module is capable of selectively disabling a subset of the plurality of parallel input lines in the second operating mode of the data transmitter.
2. The data transmitter according to claim 1 , wherein the second constellation of states is a subset of the first constellation of states.
3. The data transmitter according to claim 1 , wherein the first carrier signal and the second carrier signal are about in quadrature-phase in the first operating mode of the data transmitter.
4. The data transmitter according to claim 3 , wherein the first constellation of states is a quadrature phase-shift keying (QPSK) constellation.
5. The data transmitter according to claim 4 , wherein the second constellation of states is a quadrature amplitude modulation (QAM) constellation.
6. The data transmitter according to claim 3 , wherein the first carrier signal and the second carrier signal are about quadrature in the second operating mode of the data transmitter.
7. The data transmitter according to claim 3 , wherein the first carrier signal and the second carrier signal are about in phase in the second operating mode of the data transmitter.
8. The data transmitter according to claim 1 , wherein the data transmitter comprises a phase-shifted device disposed in at least one of the transmission branches and capable of applying a phase-shift between the first carrier signal and the second carrier signal.
9. The data transmitter according to claim 8 , wherein the phase-shift is capable of applying an adjustable phase shift.
10. The data transmitter according to claim 1 , wherein the amplitude modulators comprise Mach-Zehnder modulators.
11. The data transmitter according to claim 1 , wherein the data transmitter comprises a command interface capable of receiving a command signal for selectively placing the data transmitter into the first or second operating mode.
12. The data transmitter according to claim 1 , wherein the data module further comprises a processing module capable of processing the data flow to be transmitted in order to generate the first data signal and the second data signal, the processing module being capable of processing a data flow at a first bit rate in the first operating mode, and a data flow at a second, lower bit rate in the second operating mode of the data transmitter.
13. The data transmitter according to claim 12 , wherein the processing module comprises a parallel-serial conversion module configured to produce the first data signal and the second data signal based on a plurality of the parallel incoming flows, the plurality of the parallel incoming flows exhibiting a common data rate less than a modulation rate of the first data signal and the second data signal.
14. A data transmitter comprising:
a first amplitude modulator configured to modulate a first carrier signal based on a first data signal;
a second amplitude modulator configured to modulate a second carrier signal based on a second data signal;
a signal combiner configured to direct towards an output of the data transmitter a combination of the first modulated carrier signal coming from the first amplitude modulator and the second modulated carrier signal coming from the second amplitude modulator; and
a data module configured to generate the first data signal and the second data signal with a common modulation pace;
wherein the data module comprises a data input interface configured to receive a data flow to be transmitted and a processing module configured to process the data flow to be transmitted in order to generate the first data signal and the second data signal, and wherein the processing module comprises a parallel-serial conversion module configured to produce the first data signal and the second data signal based on a plurality of the parallel incoming flows, the plurality of the parallel incoming flows exhibiting a common data rate less than a modulation rate of the first data signal and the second data signal.
15. The data transmitter according to claim 14 , wherein the carrier signals are optical signals.
16. The data transmitter according to claim 14 , wherein the processing module comprises an encoding module configured to apply a forward error correction code to the data flow to be transmitted.
17. The data transmitter according to claim 14 , further comprising:
a signal splitter configured to produce the first carrier signal and the second carrier signal by splitting a source signal by directing a first fraction of the source signal to a first transmission branch comprising the first amplitude modulator and a second fraction of the source signal to a second transmission branch comprising the second amplitude modulator.