1. In a communication system, a method comprising:
adjusting a variable symbol delay m based on a rate of data demodulation in accordance with a multi-symbol differential phase shift key (DPSK) technique;
comparing a first symbol and a second symbol that are temporally separated by m\u22121 symbols in accordance with the multi-symbol DPSK technique to provide information, wherein m >1; and
delaying the first symbol for a time period corresponding to m symbols to provide the second symbol.
2. An optical communication apparatus comprising:
means for adjusting a variable symbol delay m based on a rate of data demodulation in accordance, with a multi-symbol differential phase shift key (DPSK) technique;
means for comparing a first symbol and a second symbol that are temporally separated by m\u22121symbols in accordance with the multi-symbol DPSK technique to provide information, wherein m >1; and
a multi-symbol delay module to delay the first symbol for a time period corresponding to m symbols to provide the second symbol.
3. In a communication system, a method comprising:
adjusting a variable symbol delay m based on a rate of data demodulation in accordance with a multi-symbol differential phase shift key (DPSK) technique;
receiving a first symbol and a second symbol that are temporally separated by m\u22121symbols, wherein m >1; and
comparing the first symbol and the second symbol in accordance with the multi-symbol DPSK technique to provide information;
wherein the first symbol corresponds with a first portion of an optical signal having a first phase and the second symbol corresponds with a second portion of the optical signal having a second phase.
4. The method of claim 3, wherein comparing the first symbol and the second symbol includes performing a logical exclusive-OR operation based on the first symbol and the second symbol.
5. The method of claim 3, wherein the first symbol is defined as a first single bit, and wherein the second symbol is defined as a second single bit.
6. The method of claim 3, wherein each of the first and second symbols includes more than one bit.
7. The method of claim 3, further comprising:
changing m from a first integer value to a second integer value that is different from the first integer value.
8. In a communication system, a method comprising:
receiving a first symbol at a first time instance t0=0 and a second symbol at a second time instance tm=m, wherein m is a variable symbol delay determined based upon a rate of data demodulation, wherein m is an integer greater than one, and each symbol has a duration of t=1;
delaying the first symbol for a time period \u03c4=M; and
comparing the first symbol and the second symbol in accordance with a differential phase shift key (DPSK) technique to provide information;
wherein the first symbol corresponds with a first portion of an optical signal having a first phase and the second symbol corresponds with a second portion of the optical signal having a second phase.
9. The method of claim 8, wherein comparing the first symbol and the second symbol includes performing a logical exclusive-OR operation based on the first symbol and the second symbol.
10. The method of claim 8, wherein the first symbol is defined as a first single bit, and wherein the second symbol is defined as a second single bit.
11. The method of claim 8, wherein each of the first and second symbols includes more than one bit.
12. The method of claim 8, further comprising:
changing m from a first integer value to a second integer value that is different from the first integer value.
13. A receiver comprising:
a node to receive a first symbol at a first time instance t0=0 and a second symbol at a second time instance tm=m, and to determine a variable symbol delay m based upon a rate of data demodulation, wherein m is an integer greater than one, and each symbol has a duration of t=1;
means for comparing the first symbol and the second symbol in accordance with a differential phase shift key (DPSK) technique to provide information; and
a multi-symbol delay module coupled between the node and the means for comparing to delay the first symbol for a time period \u03c4=m;
wherein the first symbol corresponds with a first portion of an optical signal having a first phase and the second symbol corresponds with a second portion of the optical signal having a second phase.
14. The receiver of claim 13, wherein the multi-symbol delay module includes a differential group delay.
15. The receiver of claim 13, wherein the means for comparing is configured to perform a logical exclusive-OR operation based on the first symbol and the second symbol.
16. The receiver of claim 13, wherein the first symbol is defined as a first single bit, and wherein the second symbol is defined as a second single bit.
17. The receiver of claim 13, wherein each of the first and second symbols includes more than one bit.
18. The receiver of claim 13, wherein the receiver is an interferometer, and wherein m equals a data rate associated with the first and second portions of the optical signal multiplied by a fixed time delay associated with the interferometer.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An image forming device capable of double-side printing to form an image on each of first and second sides of a recording medium, comprising:
a calibration unit configured to perform calibration for modifying quality of the image to be formed;
a first judging unit configured to judge, for each page to be printed, whether the calibration is to be performed;
a second judging unit configured to judge whether a page to be printed is one of a first side in one-side printing and a first side in the double-side printing; and
a control unit configured to control the calibration unit to perform the calibration when the first judging unit judges that the calibration is to be performed, and the second judging unit judges that the page to be printed is one of the first side in the one-side printing and the first side in the double-side printing.
2. The image forming device according to claim 1, further comprising a count unit configured to count a numerical number of sequentially-printed pages,
wherein the first judging unit judges whether the numerical number of sequentially-printed pages is more than a predetermined value for each page to be printed so as to judge whether the calibration is to be performed.
3. The image forming device according to claim 2, further comprising a third judging unit configured to judge whether there is a subsequent page to be sequentially printed,
wherein the count unit includes a parameter of which an initial value is one, the parameter being incremented each time it is judged by the third judging unit that there is a subsequent page to be sequentially printed.
4. The image forming device according to claim 2, further comprising a third judging unit configured to judge whether a subsequent page is to be sequentially printed,
wherein the count unit counts a numerical number of pages that are judged by the third judging unit to be sequentially printed.
5. A calibrating method used for an image forming device configured to perform double-side printing for forming an image on each of first and second sides of a recording medium and to perform calibration for modifying quality of the image to be formed, the method comprising:
a first step of judging whether the calibration is to be performed, for each page to be printed;
a second step of judging whether a page to be printed is one of a first side in one-side printing and a first side in the double-side printing; and
a third step of performing the calibration when it is judged in the first judging step that the calibration is to be performed, and it is judged in the second judging step that the page to be printed is one of the first side in the one-side printing and the first side in the double-side printing.
6. The calibration method according to claim 5, further comprising a fourth step of counting a numerical number of sequentially-printed pages,
wherein, in the first step, it is judged whether the numerical number of sequentially-printed pages is more than a predetermined value for each page to be printed so as to judge whether the calibration is to be performed.
7. The calibration method according to claim 6, further comprising a fifth step of judging whether there is a subsequent page to be sequentially printed,
wherein the fourth step includes a step of counting the numerical number of sequentially-printed pages with a parameter of which an initial value is one, the parameter being incremented each time it is judged in the fifth step that there is a subsequent page to be sequentially printed.
8. The calibration method according to claim 6, further comprising a fifth step of judging whether a subsequent page is to be sequentially printed,
wherein the fourth step includes a step of counting the numerical number of pages that are judged in the fifth step to be sequentially printed.
9. A computer readable medium comprising computer readable instructions stored thereon, which cause a computer, which is configured to perform double-side printing for forming an image on each of first and second sides of a recording medium and to perform calibration for modifying quality of the image to be formed, to perform:
a first step of judging whether the calibration is to be performed, for each page to be printed;
a second step of judging whether a page to be printed is one of a first side in one-side printing and a first side in the double-side printing; and
a third step of performing the calibration when it is judged in the first judging step that the calibration is to be performed, and it is judged in the second judging step that the page to be printed is one of the first side in the one-side printing and the first side in the double-side printing.
10. The computer readable medium according to claim 9,
wherein the computer readable instructions cause the computer to further perform a fourth step of counting a numerical number of sequentially-printed pages, and
wherein, in the first step, it is judged whether the numerical number of sequentially-printed pages is more than a predetermined value for each page to be printed so as to judge whether the calibration is to be performed.
11. The computer readable medium according to claim 10,
wherein the computer readable instructions cause the computer to further perform a fifth step of judging whether there is a subsequent page to be sequentially printed, and
wherein the fourth step includes a step of counting the numerical number of sequentially-printed pages with a parameter of which an initial value is one, the parameter being incremented each time it is judged in the fifth step that there is a subsequent page to be sequentially printed.
12. The calibration method according to claim 10, further comprising a fifth step of judging whether a subsequent page is to be sequentially printed,
wherein the fourth step includes a step of counting the numerical number of pages that are judged in the fifth step to be sequentially printed.
13. An image forming device capable of double-side printing to form an image on each of first and second sides of a recording medium, comprising:
a calibration unit configured to perform calibration for modifying quality of the image to be formed;
a first judging unit configured to judge, for each page to be printed, whether the calibration is to be performed;
a second judging unit configured to judge whether a page to be printed is a second side in the double-side printing; and
a control unit configured to prevent the calibration unit from performing the calibration when the second judging unit judges whether the page to be printed is the second side in the double-side printing, regardless of the judgment of the first judging unit.