1. A method for further reducing cyclostationary content in a chaotic spread spectrum data communication channel, comprising:
digitally generating a first chaotic sequence of values to form a spreading code;
using said spreading code to form a digital intermediate frequency (IF) spread spectrum signal having a uniform sampling interval;
converting said digital IF spread spectrum signal to a sampled analog IF spread spectrum signal at a conversion rate;
selectively varying a duration of said uniform sampling interval in said sampled analog IF spread spectrum signal in accordance with a first pseudo-random sequence to introduce a known dither in said sampled analog IF spread spectrum signal; and
subsequent to introducing said known dither, converting the sampled analog IF spread spectrum signal to a continuous IF signal, upconverting said continuous IF signal to an analog RF spread spectrum signal.
2. The method according to claim 1, further comprising where said first pseudo-random sequence comprises a second chaotic sequence.
3. The method according to claim 1, further comprising:
transmitting said analog RF spread spectrum signal to a receiver;
converting said analog RF spread spectrum signal to a received sampled analog IF spread spectrum signal;
generating at said receiver a second pseudo-random sequence which is identical to said first pseudo-random sequence; and
using said second pseudo-random sequence to remove said known dither in said received sampled analog IF spread spectrum signal.
4. The method according to claim 3, further comprising synchronizing said second pseudo-random sequence and said first pseudo-random sequence.
5. The method according to claim 3, further comprising:
using said second pseudo-random sequence to generate a uniform received analog IF spread spectrum signal having said uniform sampling interval;
converting said uniform received analog IF spread spectrum signal to a uniform received digital IF spread spectrum signal having said uniform sampling interval;
generating at said receiver a de-spreading code which is identical to, and substantially synchronized with, said spreading code; and
de-spreading said uniform received digital IF spread spectrum signal using said de-spreading code.
6. The method according to claim 1, wherein said step of selectively varying a duration of said uniform sampling interval further comprises:
sampling and holding each sample of said analog IF spread spectrum signal for a sample time duration; and
selectively varying said sample time duration responsive to a dither control signal.
7. The method according to claim 6, further comprising generating said dither control signal responsive to said first pseudo-random sequence.
8. A system for further reducing cyclostationarity in a chaotic spread spectrum data communication channel, comprising:
a first digital generator configured for producing a first chaotic sequence of values to form a spreading code;
a modulator configured for using said spreading code to form a digital intermediate frequency (IF) spread spectrum signal having a uniform sampling interval defined by a sampling rate;
a digital-to-analog converter configured for accepting said digital IF spread spectrum signal, and producing a sampled analog IF spread spectrum signal at a conversion rate substantially equal to said uniform sampling interval;
a timing variation apparatus configured for selectively varying a duration of said uniform sampling interval in accordance with a first pseudo-random sequence to introduce a known dither in said analog IF spread spectrum signal; and
an anti image filter to convert the sampled analog IF signal to a continuous analog signal and an upconverter configured for accepting said analog IF spread spectrum signal, and producing an analog RF spread spectrum signal.
9. The system according to claim 8, wherein the first pseudo-random sequence is a chaotic sequence.
10. The system according to claim 8, further comprising a receiver configured for receiving said analog RF spread spectrum signal, said receiver comprising:
a down-converter configured for converting said analog RF spread spectrum signal to a received analog IF spread spectrum signal;
a second digital generator configured for producing a second pseudo-random sequence which is identical to said first pseudo-random sequence;
a dither removal circuit configured for using said second pseudo-random sequence to remove said known dither in said received and sampled analog IF spread spectrum signal and thereby generate a uniform received sampled analog IF spread spectrum signal having said uniform sampling interval; and
an analog to digital converter configured for converting said received analog IF spread spectrum signal to a received digital IF spread spectrum signal.
11. The system according to claim 10, further comprising a synchronizer configured for synchronizing said first pseudo-random sequence and said second pseudo-random sequence.
12. The system according to claim 10, further comprising:
a demodulator configured for de-spreading said received digital IF spread spectrum signal using a de-spreading code which is identical to, and synchronized with, said spreading code.
13. The system according to claim 8, wherein said timing variation apparatus further comprises:
a first voltage generator configured for producing a voltage responsive to said first pseudo-random sequence;
a second voltage generator configured for producing a periodic signal; and
a comparator configured for accepting said voltage responsive to said first pseudo-random sequence and said periodic signal, and producing a dither control signal to vary a duration of said sampling interval.
14. An apparatus for further reducing cyclostationarity in a chaotic spread spectrum data communication channel, comprising:
a first digital chaos generator configured for producing a first chaotic sequence of values to form a spreading code;
a modulator configured for using said spreading code to form a digital intermediate frequency (IF) spread spectrum signal having a uniform sampling interval;
a digital to analog converter configured for accepting said digital IF spread spectrum signal, and producing a sampled analog IF spread spectrum signal at a conversion rate; and
a timing variation apparatus configured for selectively varying a duration of said sampling interval in accordance with a first pseudo-random sequence to introduce a known dither in said sampled analog IF spread spectrum signal.
15. The apparatus according to claim 14, wherein the first pseudo-random sequence is a chaotic sequence.
16. A receiver apparatus for receiving an RF spread spectrum signal, having a duration of sampling intervals selectively varied in accordance with a first pseudo-random sequence to introduce a known dither in said RF spread spectrum signal, comprising:
a down-converter configured for converting said RF spread spectrum signal to a received analog IF spread spectrum signal;
a dither removal circuit configured for using a second pseudo-random sequence to remove said known dither in said received analog IF spread spectrum signal and thereby generate a uniform received sampled analog IF spread spectrum signal having a uniform sampling interval; and
an analog to digital converter configured for converting said received analog IF spread spectrum signal to a received digital IF spread spectrum signal.
17. The receiver apparatus according to claim 16, wherein said second pseudo-random sequence is a chaotic sequence.
18. The receiver apparatus according to claim 16, further comprising a demodulator configured for using a de-spreading code to de-spread said RF spread spectrum signal.
19. The receiver apparatus according to claim 18, wherein said de-spreading code is a chaotic sequence.
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 surveillance system, comprising:
a housing comprising a proximal end and a distal end;
a screw thread located at the proximal end of the housing, wherein the screw thread is configurable to rotatably attach to a light socket;
a camera located at the distal end of the housing; and
a cone-shaped mirror located distal to the distal end of the housing such that a tip of the cone-shaped mirror is aligned with an optical axis of the camera.
2. The surveillance system of claim 1, wherein the tip is a first tip, wherein the cone-shaped mirror comprises a second tip located opposite the first tip, and the second tip is aligned with the optical axis of the camera.
3. The surveillance system of claim 2, wherein the cone-shaped mirror defines a first cone that extends from the first tip and a second cone that extends from the second tip, such that a first base of the first cone intersects a second base of the second cone.
4. The surveillance system of claim 1, further comprising a light coupled to the housing and a motion detector coupled to the housing.
5. The surveillance system of claim 1, further comprising a speaker coupled to the housing and a microphone coupled to the housing.
6. The surveillance system of claim 1, further comprising a remote computing device communicatively coupled to the camera, wherein the remote computing device is capable of displaying an image captured by the camera.
7. The surveillance system of claim 1, further comprising at least one support having a proximal end and a distal end, wherein the proximal end of the at least one support is coupled to the distal end of the housing and the distal end of the support is coupled to the cone-shaped mirror.
8. The surveillance system of claim 1, wherein the cone-shaped mirror is devoid of the enclosure around at least 75% of the perimeter of the cone-shaped mirror.
9. A surveillance system, comprising:
a housing having a distal end and a proximal end;
a screw thread located at the proximal end of the housing, wherein the screw thread is configurable to rotatably attach to a light socket;
a camera located at the distal end of the housing, wherein the camera is configurable to detect an object; and
a cone-shaped mirror coupled to the distal end of the housing and positioned such that a tip of the cone-shaped mirror faces the camera, wherein the cone-shaped mirror defines a symmetrical shape.
10. The surveillance system of claim 9, further comprising a support having a distal end and a proximal end, wherein the proximal end of the support is coupled to the distal end of the housing, and the distal end of the support is coupled to the cone-shaped mirror.
11. The surveillance system of claim 10, wherein the support is a first support, the surveillance system further comprising a second support having a distal end and a proximal end, wherein the proximal end of the second support is coupled to the distal end of the housing, and the distal end of the second support is coupled to the cone-shaped mirror.
12. The surveillance system of claim 11, wherein the first support is located opposite the second support.
13. The surveillance system of claim 9, further comprising at least one of an infrared light coupled to the housing, a motion detector coupled to the housing, a light coupled to the housing, and a microphone coupled to the housing.
14. A surveillance system, comprising:
a housing comprising a proximal end and a distal end;
a camera coupled to the housing;
a screw thread located at the proximal end of the housing, wherein the screw thread is configurable to rotatably attach to a light socket; and
a cone-shaped mirror located distal to the distal end of the housing, wherein the cone-shaped mirror comprises a first tip, a second tip located opposite the first tip, a first cone that extends from the first tip, and a second cone that extends from the second tip, wherein a first base of the first cone intersects a second base of the second cone.
15. The surveillance system of claim 14, further comprising a remote computing device communicatively coupled to at least one of the accelerometer and camera, wherein the remote computing device is capable of displaying an image captured by the camera.
16. The surveillance system of claim 15, wherein the surveillance system is configurable to automatically adjust an orientation of the image displayed by the remote computing device.
17. The surveillance system of claim 14, further comprising an infrared light coupled to the housing.
18. The surveillance system of claim 14, further comprising a motion detector coupled to the housing.
19. The surveillance system of claim 14, further comprising a microphone coupled to the housing.
20. The surveillance system of claim 14, further comprising an accelerometer coupled to the housing, wherein the accelerometer is configurable to determine orientation of the camera.