1. A method, a sensor array that employs a parameter to induce a time-varying phase angle \u03c6 on an optical signal that comprises a phase generated carrier, the method comprising the steps of:
calculating a quadrature term Q through employment of one or more of a plurality of samples that are based on the optical signal;
calculating a peak value Qp of the quadrature term Q;
calculating an in-phase term I through employment of one or more of the plurality of samples that are based on the optical signal;
calculating a peak value In of the in-phase term I;
I
p
\u2061
(
M
,
\u03b2
)
=
2
\xb7
B
\xb7
(
cos
\u2061
(
M
\xb7
sin
\u2062
\u2003
\u2062
\u03b2
)
–
cos
\u2061
(
M
\xb7
sin
\u2061
(
\u03c0
2
+
\u03b2
)
)
)
.
wherein M is a modulation depth and \u03b2 is a demodulation phase offset of the phase generated carrier;
calculating an operating point that comprises the modulation depth M and the demodulation phase offset \u03b2 of the phase generated carrier through employment of the peak value Ip of the in-phase term I and the peak value Qp of the quadrature term Q; and
calculating the phase angle \u03c6 through employment of the quadrature term Q; and the in-phase term, wherein the quadrature term Q and the in-phase term I are based on the optical signal.
2. The method of claim 1, wherein the step of calculating the phase angle \u03c6 through employment of the in-phase term I and the quadrature term Q comprises the step of:
calculating the phase angle \u03c6 through employment of the in-phase term I and the quadrature term Q at the operating point.
3. The method of claim 1, wherein the step of calculating the chase angle \u03c6 through employment of the in-phase term I and the quadrature term Q comprises the step of:
calculating the phase angle \u03c6=arctangent(QI).
4. The method of claim 1, wherein the phase generated carrier comprises a period Tpgc, the method further comprising the step of:
sampling an output signal from the sensor array to obtain the plurality of samples from a same instance of the period Tpgc.
5. The method of claim 4, wherein the plurality of samples comprise samples S0, S1, S2, and S3, wherein the step of calculating the in-phase term I through employment of the one or more of the plurality of samples comprises the step of:
calculating the in-phase term I:
I=(S0+S2)\u2212(S1+S3).
6. The method of claim 5, wherein the step of calculating the quadrature term Q through employment of one or more of the plurality of samples that are based on the optical signal comprises the step of:
calculating the quadrature term Q:
Q=2*(S0\u2212S2):
wherein the step of calculating the peak value Qp of the quadrature term Q comprises the step of:
calculating the peak value Qp of the quadrature term Q:
Qp(M, \u03b2)=4\xb7B\xb7sin(M\xb7sin \u03b2).
7. The method of claim 5, wherein the step of calculating the quadrature term Q through employment of one or more of the plurality of samples that are based on the optical signal comprises the step of:
calculating the quadrature term Q:
Q=\u2212(S0\u2212S2):
wherein the step of calculating the peak value Q2 of the quadrature term Q comprises the step of:
calculating the peak value Qp of the quadrature term Q:
Qp(M, \u03b2)=2\xb7B\xb7sin(M\xb7\u03b2).
8. A method, a sensor array that employs a parameter to induce a time-varying phase angle \u03c6 on an optical signal that comprises a phase generated carrier, wherein the phase generated carrier comprises a period Tpgc, the method comprising the steps of:
calculating the phase angle \u03c6 through employment of a quadrature term Q and an in-phase term I, wherein the quadrature term Q and the in-phase term I are based on the optical signal;
wherein the phase generated carrier comprises a period Tpgc, the method further comprising the step of:
sampling an output signal from the sensor array to obtain the plurality of samples from a same instance of the period Tpgc;
wherein the step of calculating the phase angle \u03c6 through employment of the quadrature term Q and the in-phase term I comprises the steps of:
calculating the in-phase term I through employment of one or more of the plurality of samples;
calculating a quadrature term Q through employment of one or more of the plurality of samples; and
calculating the phase angle \u03c6 through employment of the in-phase term I and the quadrature term Q;
further comprising the steps of:
calculating a peak value Ip of the in-phase term I;
calculating a peak value Qp of the quadrature term Q; and
calculating an operating point that comprises a modulation depth M and a demodulation phase offset \u03b2 of the phase generated carrier through employment of the peak value Ip of the in-phase term I and the peak value Qp of the quadrature term Q;
wherein the plurality of samples comprise samples S0, S1, S2, and S3, wherein the step of calculating the in-phase term I through Qp employment of the one or more of the plurality of samples comprises the step of:
calculating the in-phase term I:
I=(S0+S2)\u2212(S1+S3);
wherein the step of calculating the peak value Ip of the in-phase term I comprises the step of:
calculating the peak value Ip of the in-phase term I:
I
p
\u2061
(
M
,
\u03b2
)
=
2
\xb7
B
\xb7
(
cos
\u2061
(
M
\xb7
sin
\u2062
\u2003
\u2062
\u03b2
)
–
cos
\u2061
(
M
\xb7
sin
\u2061
(
\u03c0
2
+
\u03b2
)
)
)
.
9. The method of claim 8, wherein the step of calculating the quadrature term Q through employment of the one or more of the plurality of samples comprises the step of:
calculating the quadrature term Q:
Q=\u2212(S0\u2212S2).
10. The method of claim 9, wherein the step of calculating the peak value Qp of the quadrature term Q comprises the step of:
calculating the peak value Qp of the quadrature term Q:
Qp(M, \u03b2)=2\xb7B\xb7sin(M\xb7sin \u03b2).
11. The method of claim 10, wherein the step of calculating the phase angle \u03c6 through employment of the in-phase term I and the quadrature term Q comprises the step of:
calculating the phase angle \u03c6 arctangent(QI).
12. The method of claim 8, wherein the step of calculating the quadrature term Q through employment of the one or more of the plurality of samples comprises the step of:
calculating the quadrature term Q:
Q=\u22122*(S0\u2212S2).
13. The method of claim 12, wherein the step of calculating the peak value Qp of the quadrature term Q comprises the step of:
calculating the peak value Qp:
Qp(M, \u03b2)=4\xb7B\xb7sin(M\xb7sin \u03b2).
14. The method of claim 13, wherein the step of calculating the phase angle \u03c6 through employment of the in-phase term I and the quadrature term Q comprises the step of:
calculating the phase angle \u03c6=arctangent(QI).
15. An apparatus, a sensor array that employs a parameter to induce a time-varying phase angle \u03c6 on an optical signal that comprises a phase generated carrier, the apparatus comprising:
a processor component;
wherein the processor component employs one or more of a plurality of samples that are based on the optical signal to calculate an in-phase term I;
wherein the processor component employs one or more of the plurality of samples to calculate a quadrature term Q;
wherein the processor component calculates a peak value Ip of the in-phase term I as
I
p
\u2061
(
M
,
\u03b2
)
=
2
\xb7
B
\xb7
(
cos
\u2061
(
M
\xb7
sin
\u2062
\u2003
\u2062
\u03b2
)
–
cos
\u2061
(
M
\xb7
sin
\u2061
(
\u03c0
2
+
\u03b2
)
)
)
;
wherein M is a modulation depth and \u03b2 is a demodulation phase offset of the phase generated carrier;
wherein the processor component calculates a peak value Qp of the quadrature term Q;
wherein the processor calculates an operating point that comprises the modulation depth M and the demodulation phase offset \u03b2 of the phase generated carrier through employment of the peak value Ip of the in-phase term I and the peak value Qp of the quadrature term Q;
wherein the processor component employs the quadrature term Q and the in-phase term I to calculate the phase angle \u03c6, wherein the quadrature term Q and the in-phase term I are based on the optical signal.
16. The apparatus of claim 15, wherein the phase generated carrier comprises a period Tpgc, wherein the processor component obtains the plurality of samples from an output signal from the sensor array within a same instance of the period Tpgc.
17. The apparatus of claim 16,
wherein the processor component employs the in-phase term I and the quadrature term Q to calculate the phase angle \u03c6 at the operating point.
18. The apparatus of claim 16,
wherein the plurality of samples comprises four samples that are based on the optical signal;
wherein the processor component obtains the four samples from the output signal from the sensor array within the same instance of the period Tpgc.
19. The apparatus of claim 16, wherein the plurality of samples comprise samples S0, S1, S2, and S3;
wherein the processor component calculates the in-phase term I:
I=(S0+S2)\u2212(S1+S3);
wherein the processor component calculates the quadrature term Q:
Q=\u2212(S0\u2212S2);
wherein the processor component calculates the phase angle \u03c6:
\u03c6=arctangent(QI).
20. The apparatus of claim 19,
wherein the processor component calculates the peak value Qp:
Qp(M, \u03b2)=2\xb7B\xb7sin(M\xb7sin \u03b2)
21. The apparatus of claim 20, wherein the processor component employs the peak value Ip and the peak value Qp to calculate the operating point that comprises a modulation depth approximately equal to 2.75 radians.
22. The apparatus of claim 21, wherein the processor component employs the peak value Ip and the peak value Qp to calculate the operating point that comprises a demodulation phase offset approximately equal to 0.5073 radians.
23. The apparatus of claim 16, wherein the plurality of samples comprise samples S0, S1, S2, and S3;
wherein the processor component calculates the in-phase term I:
I=(S0+S2)\u2212(S1+S3);
wherein the processor component calculates the quadrature term Q:
Q=\u22122\xb7(S0\u2212S2);
wherein the processor component calculates the phase angle \u03c6:
\u03c6=arctangent (QI).
24. The apparatus of claim 23,
wherein the processor component calculates the peak value Qp:
Qp(M, \u03b2)=4\xb7B\xb7sin(M\xb7sin \u03b2).
25. The apparatus of claim 24, wherein the processor component employs the peak value Ip and the peak value Qp to calculate the operating point that comprises a modulation depth approximately equal to 2.49 radians.
26. The apparatus of claim 25 wherein the processor component employs the peak value Ip and the peak value Qp to calculate the operating point that comprises a demodulation phase offset approximately equal to 0.3218 radians.
27. An article, a sensor array that employs a parameter to induce a time-varying phase angle \u03c6 on an optical signal that comprises a phase generated carrier, the article comprising:
one or more computer-readable signal-bearing media;
means in the one or more media for calculating a quadrature term Q through employment of one or more of the plurality of samples that are based on the optical signal;
means in the one or more media for calculating an in-phase term I through employment of one or more of a plurality of samples that are based on the optical signal;
means in the one or more media for calculating a peak value Ip of the in-phase term I as
I
p
\u2061
(
M
,
\u03b2
)
=
2
\xb7
B
\xb7
(
cos
\u2061
(
M
\xb7
sin
\u2062
\u2003
\u2062
\u03b2
)
–
cos
\u2061
(
M
\xb7
sin
\u2061
(
\u03c0
2
+
\u03b2
)
)
)
,
wherein M is a modulation depth and \u03b2 is a demodulation phase offset of the phase generated carrier;
means in the one or more media for calculating peak value Qp of the quadrature term Q;
means in the one or more media for calculating an operating point that comprises the modulation depth M and the demodulation phase offset \u03b2 of the phase generated carrier through employment of the peak value Ip of the in-phase term I and the peak value Qp of the quadrature term Q; and
means in the one or more media for calculating the phase angle \u03c6 through employment of the quadrature term Q and the in-phase term I, wherein the quadrature term Q and the in-phase term I are based on the optical signal.
28. The article of claim 27, wherein the plurality of samples comprise samples S0, S1, S2, and S3, wherein the means in the one or more media for calculating the quadrature term Q through employment of the one or more of the plurality of samples that are based on the optical signal comprises:
means in the one or more media for calculating the quadrature term Q:
Q=\u2212(S0\u2212S2);
wherein the means in the one or more media for calculating the peak value Qp of the quadrature term Q comprises:
means in the one or more media for calculating the peak value Qp of the quadrature term Q:
Qp(M, \u03b2)=2\xb7B\xb7sin(M\xb7sin \u03b2).
29. The article of claim 28, wherein the plurality of samples comprise samples S0, S1, S2, and S3, wherein the means in the one or more media for calculating the quadrature term Q through employment of the one or more of the plurality of samples that are based on the optical signal comprises:
means in the one or more media for calculating the quadrature term Q:
Q=\u22122*(S0\u2212S2);
wherein the means in the one or more media for calculating the peak value Qp of the quadrature term Q comprises:
means in the one or more media for calculating the peak value Qp of the quadrature term Q:
Qp(M, \u03b2)=4\xb7B\xb7sin(M\xb7sin \u03b2).
30. The article of claim 27, wherein the means in the one or more media for calculating the phase angle \u03c6 through employment of the in-phase term I and the quadrature term Q comprises:
means in the one or more media for calculating the phase angle \u03c6=arctangent(QI) at the operating point.
31. The method of claim 4, wherein the step of sampling the output signal from the sensor array to obtain the plurality of samples from the same instance of the period Tpgc comprises the step of:
sampling the output signal from the sensor array to obtain four samples from the same instance of the period Tpgc.
32. The method of claim 8, wherein the step of sampling the output signal from the sensor array to obtain the plurality of samples from the same instance of the period Tpgc comprise the step of:
sampling the output signal from the sensor array to obtain four samples from the same instance of the period Tpgc.
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 collapsible ladder for supporting an elevated hunting platform, the collapsible ladder comprising:
a plurality of telescopically engaging collapsible ladder segments each comprising a first ladder rail, a second ladder rail, and a plurality of rung members pivotally attached to each of the first and second ladder rails in a parallelogram linkage, such that a separation between the first and second ladder rails is adjustable between a collapsed position to an expanded position; and
at least one rigid ladder segment comprising a stabilizing member including at least one rung member rigidly attached to a pair of rail sections attached to at least one of the collapsible ladder segments, the pair of rail sections on the at least one rigid ladder segment are telescopically attached to, and co-linear with, the first and second ladder rails on the collapsible ladder segment to maintain the first and second ladder rails in the expanded position.
2. The collapsible ladder of claim 1 comprising a plurality of spring lock pins retaining the stabilizing member in telescopic engagement with the first and second ladder rails.
3. The collapsible ladder of claim 1 wherein a collapsible ladder segment telescopically engages with the elevated hunting platform and the elevated hunting platform maintains the first and second ladder rails in the expanded position.
4. The collapsible ladder of claim 1 wherein the first and second ladder rails are one of the same or different lengths.
5. The collapsible ladder of claim 1 wherein adjacent ends of the first and second rails are staggered in the expanded position.
6. The collapsible ladder of claim 1 wherein the rung members are attached adjacent to respective exterior surfaces of the first and second ladder rails.
7. The collapsible ladder of claim 1 wherein the rigid ladder segment includes two rung members.
8. The collapsible ladder of claim 1 wherein the first and second ladder rails are approximately the same length and wherein the rung members are pivotally attached to the first and second ladder rails at different respective points along the lengths thereof so adjacent ends of the first and second rails are staggered.
9. The collapsible ladder of claim 1 wherein the rail sections on the stabilizing member are different lengths.
10. The collapsible ladder of claim 1 comprising a removable rail segment releasably attachable to a rail section of the stabilizing member.
11. An elevated hunting stand comprising:
a platform assembly;
a ladder assembly comprising a first ladder rail, a second ladder rail, and a plurality of rung member pivotally attached to each of the first and second ladder rails in a parallelogram linkage, such that a separation between the first and second ladder rails is adjustable between a collapsed position to an expanded position, the platform assembly attaches to adjacent ends of the first and second ladder rails at a first end of the ladder assembly to maintain the first and second ladder rails in the expanded position; and
a rigid ladder segment comprising a stabilizing member having at least one rung member rigidly attached to a pair of rail sections that are telescopically attached to, and co-linear with, the first and second ladder rails at a second end of the ladder assembly to maintain the first and second ladder rails in the expanded position.
12. The elevated hunting stand of claim 11 comprising a plurality of stabilizing members attached to the ladder assembly to substantially fix a separation between the first and second rails.
13. The elevated hunting stand of claim 11 wherein the ladder assembly includes a plurality of ladder sections.
14. A method of assembling an elevated hunting stand comprising the steps of:
converting a first ladder assembly from a collapsed position to an expanded position by separating first and second ladder rails connected by a plurality of pivotally attached rung members in a parallelogram linkage; and
attaching adjacent ends of the first and second rails to a platform assembly to maintain the first and second ladder rails in the expanded position; and
attaching a rigid ladder segment comprising a stabilizing member having at least one rung member rigidly attached a pair of rail sections, to a second end of the first ladder assembly so the first and second ladder rails are telescopically attached to, and co-linear with, the pair of rail sections to maintain the first and second ladder rails in the expanded position.
15. The method of claim 14 comprising telescopically engaging the first and second ladder rails to the platform assembly.
16. The method of claim 14 comprising the steps of:
converting a second ladder assembly from a collapsed position to an expanded position;
telescopically engaging the second ladder assembly to the first ladder assembly; and
attaching the rigid ladder segment to a second end of the second ladder assembly.
17. The method of claim 14 comprising the steps of attaching rail sections rigidly attached to a rung member of a stabilizing member to the second ladder assembly, to maintain the first and second ladder rails in the expanded position.