1. An optical transmitter comprising:
a modulating unit configured to modulate an optical signal based on an input signal input to the modulating unit and output a modulated optical signal;
a first detecting unit configured to detect a first variation in amplitude of a maximum output of the modulated optical signal;
a second detecting unit configured to detect a second variation in amplitude of a minimum output of the modulated optical signal;
a comparing unit configured to perform a comparison of the first variation and the second variation; and
an adjusting unit configured to adjust a bias potential of the input signal based on a result of the comparison.
2. The optical transmitter according to claim 1, further comprising:
a first variation adjusting unit configured to adjust the first variation by performing a calculation on the first variation; and
a second variation adjusting unit configured to adjust the second variation by performing a calculation on the second variation, wherein
the comparing unit performs a comparison of the adjusted first variation and the adjusted second variation.
3. The optical transmitter according to claim 1, wherein the adjusting unit adjusts the bias potential so that the first variation and the second variation become equal when an extinction characteristics curve of the modulating unit is substantially point symmetrical with respect to a point where a slope of the extinction characteristics curve reaches a maximum.
4. The optical transmitter according to claim 1, wherein the adjusting unit adjusts the bias potential so that a product of the first variation and n, where n is a positive integer, and the second variation become equal when an extinction characteristics curve of the modulating unit is point asymmetrical with respect to a point where a slope of the extinction characteristics curve reaches a maximum.
5. The optical transmitter according to claim 1, wherein the adjusting unit adjusts the bias potential so that the first variation and a product of the second variation and n, where n is a positive integer, become equal when an extinction characteristics curve of the modulating unit is point asymmetrical with respect to a point where a slope of the extinction characteristics curve reaches a maximum.
6. The optical transmitter according to claim 1, wherein
the adjusting unit adjusts the bias potential so that a sum of the first variation and the second variation becomes equal to a reference value.
7. The optical transmitter according to claim 1, further comprising:
a calculating unit configured to calculate a logarithm of the modulated optical signal and outputs the logarithm to the first detecting unit and the second detecting unit.
8. The optical transmitter according to claim 1, wherein the modulating unit has extinction characteristics of an electro-absorption modulator.
9. The optical transmitter according to claim 1, wherein the input signal is an electric signal.
10. A method for an optical transmitter, comprising:
modulating an optical signal based on an input signal;
outputting the modulated optical signal;
detecting a first variation in amplitude of a maximum output of the modulated optical signal;
detecting a second variation in amplitude of a minimum output of the modulated optical signal;
performing a comparison of the first variation and the second variation; and
adjusting a bias potential of the input signal based on a result of the comparison.
11. The method according to claim 10, further comprising:
performing a first-variation calculation on the first variation;
adjusting the first variation based on the first-variation calculation;
performing a second-variation calculation on the second variation;
adjusting the second variation based on the second-variation calculation; and wherein
the adjusted first variation and the adjusted second variation are compared in the comparison.
12. The method according to claim 10, wherein
the adjusting adjusts the bias potential so that the first variation and the second variation become equal when an extinction characteristics curve of the modulating unit is substantially point symmetrical with respect to a point where a slope of the extinction characteristics curve reaches a maximum.
13. The method according to claim 10, wherein
the adjusting includes adjusting the bias potential so that a product of the first variation and n, where n is a positive integer, and the second variation become equal when an extinction characteristics curve of the modulating unit is point asymmetrical with respect to a point where a slope of the extinction characteristics curve reaches a maximum.
14. The method according to claim 10, wherein
the adjusting includes adjusting the bias potential so that the first variation and a product of the second variation and n, where n is a positive integer, become equal when an extinction characteristics curve of the modulating unit is point asymmetrical with respect to a point where a slope of the extinction characteristics curve reaches a maximum.
15. The method according to claim 10, wherein
the adjusting includes adjusting the bias potential so that a sum of the first variation and the second variation becomes equal to a reference value.
16. The method according to claim 10, wherein the input signal is an electric signal.
17. An optical transmitter comprising:
a modulating unit configured to modulate an optical signal based on an electric signal input to the modulating unit and to output a modulated optical signal;
a first detecting unit configured to detect a first variation width of a maximum output of the modulated optical signal;
a second detecting unit configured to detect a second variation width of a minimum output of the modulated optical signal;
a comparing unit configured to set a sum of the first variation width and the second variation width to a variable V1, and to perform a comparison of the variable V1 and a reference value V2; and
an adjusting unit configured to adjust a bias potential of the electric signal based on a result of the comparison.
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. A surface cleaning apparatus comprising:
(a) a dirty air inlet;
(b) a filtration apparatus comprising at least one cyclone and at least one filter mounted in a filter housing;
(c) the filter housing having a lower portion that is openable while secured to the surface cleaning apparatus and the filter is visible when the lower portion is opened, the filter has an upstream filter surface that faces the openable lower portion and is spaced therefrom, whereby a dirt collection area is provided between the upstream filter surface and the openable lower portion;
(d) a suction motor; and,
(e) a clean air outlet downstream from the suction motor.
2. The surface cleaning apparatus of claim 1 wherein the filter housing is openable while the filter housing is mounted to the filtration apparatus.
3. The surface cleaning apparatus of claim 1 further comprising an openable cyclone dirt collection chamber and the filter housing is openable independently of the cyclone dirt collection chamber.
4. The surface cleaning apparatus of claim 1 further comprising an openable cyclone dirt collection chamber and the filter housing is openable concurrently with the cyclone dirt collection chamber.
5. The surface cleaning apparatus of claim lwherein the filter housing is mounted to the at least one cyclone.
6. The surface cleaning apparatus of claim 1 wherein the filter housing is removably mounted to the filtration apparatus.
7. The surface cleaning apparatus of claim 1 wherein the filter housing is positioned below the cyclone.
8. The surface cleaning apparatus of claim 1 wherein the filter housing is positioned adjacent the cyclone.
9. The surface cleaning apparatus of claim 1 wherein the cyclone is openable and the filter housing is openable concurrently with the cyclone.
10. A surface cleaning apparatus comprising:
(a) a dirty air inlet;
(b) a filtration apparatus comprising at least one cyclone and at least one filter mounted in a filter housing;
(c) the filter housing having a lower portion that is openable while secured to the surface cleaning apparatus and the filter is visible when the lower portion is opened;
(d) first and second housings positioned side by side, the first housing comprising the at least one cyclone and the second housing comprising the filter housing, the first housing has a first housing bottom that is openable and the openable lower portion comprises the bottom of the second housing and wherein the first housing bottom is connected to the second housing bottom, whereby both the first housing bottom and the second housing bottom are moveable concurrently;
(e) a suction motor; and,
(f) a clean air outlet downstream from the suction motor.
11. The surface cleaning apparatus of claim 10 wherein the first housing further comprises a dirt collection chamber positioned around at least a portion of the cyclone, the dirt collection chamber has a moveable dirt collection chamber floor, the cyclone has a lower moveable cyclone floor, whereby both the dirt collection chamber and the cyclone are concurrently emptied when the first housing bottom and the second housing bottom are opened concurrently.
12. The surface cleaning apparatus of claim 11 further comprises a dirt collection chamber positioned around at least a portion of the cyclone and the cyclone floor includes a vortex finder mounted thereto.
13. A surface cleaning apparatus comprising:
(a) a dirty air inlet;
(b) a filtration apparatus comprising at least one cyclone and at least one filter mounted in a filter housing;
(c) the filter housing having a lower portion that is openable while secured to the surface cleaning apparatus and the filter is visible when the lower portion is opened;
(d) first and second housings positioned side by side, the first housing comprising the at least one cyclone and the second housing comprising the filter housing, the first housing has a first housing bottom and the second housing has a second housing bottom and the first housing bottom and the second housing bottom form part of an airflow passage from a cyclone outlet to an upstream side of the filter;
(e) a suction motor; and,
(f) a clean air outlet downstream from the suction motor.
14. The surface cleaning apparatus of claim 13 wherein at least a portion of the airflow passage is transparent.
15. A surface cleaning apparatus comprising:
(a) a dirty air inlet;
(b) a filtration apparatus comprising at least one cyclone and at least one filter mounted in a filter housing;
(c) the filter housing having a portion that is openable while secured to the surface cleaning apparatus and the filter is visible when the portion is opened;
(d) a mechanical filter-cleaning member connected to the filter wherein the mechanical filter-cleaning member is actuated when the openable portion of the filter housing is opened;
(e) a suction motor; and,
(f) a clean air outlet downstream from the suction motor.
16. The surface cleaning apparatus of claim 15 wherein the mechanical filter-cleaning member comprises a vibrator connected to the filter.
17. The surface cleaning apparatus of claim 15 wherein the mechanical filter-cleaning member comprises a wiper positioned on an upstream side of the filter.
18. The surface cleaning apparatus of claim 15 wherein the mechanical filter-cleaning member is battery powered.
19. A surface cleaning apparatus comprising:
(a) a dirty air inlet;
(b) a filtration apparatus comprising at least one cyclone and at least one filter mounted in a filter housing;
(c) the filter housing having a portion that is openable while secured to the surface cleaning apparatus and the filter is visible when the lower portion is opened, the filter has an upstream filter surface that faces a dirt collection surface and is spaced therefrom, whereby a dirt collection area is provided between the upstream filter surface and the dirt collection surface;
(d) a suction motor; and,
(e) a clean air outlet downstream from the suction motor.