1. A method for placing a first load and a second load on a printed circuit board of a high-speed system, comprising:
placing the first load and the second load on a first side and a second side of the printed circuit board, respectively, further including
vertically aligning a first signal pin of the first load with a second signal pin of the second load with an offset; and
connecting the first signal pin, the second signal pin, and a terminating end of a trace connected to a driver on the printed circuit board at a T-point;
directly connecting a first decoupling capacitor on the second side of the printed circuit board to a first power pin of the first load; and
directly connecting a second decoupling capacitor on the first side of the printed circuit board to a second power pin of the second load.
2. The method of claim 1, further comprising minimizing the distances between the first decoupling capacitor and the first load and between the second decoupling capacitor and the second load.
3. The method of claim 1, further comprising connecting the first signal pin, the second signal pin, and the terminating end of the trace to a via, wherein the offset corresponds to the sum of a first distance between the first signal pin and the via and a second distance between the second signal pin and the via.
4. The method of claim 2, wherein the connection between the first decoupling capacitor and the first power pin is substantially perpendicular to the first load.
5. The method of claim 2, wherein the connection between the second decoupling capacitor and the second power pin is substantially perpendicular to the second load.
6. The method of claim 3, further comprising placing the first load and the second load on the printed circuit board such that the length of a first stub including the distance between the first signal pin and the T-point and the length of a second stub including the distance between the second signal pin and the T-point are minimized.
7. The method of claim 3, wherein the offset is substantially shorter than the length of the first load.
8. The method of claim 3, wherein the offset is substantially shorter than the length of the second load.
9. The method of claim 6, further comprising positioning the via away from the first signal pin and away from the second signal pin.
10. A high-speed system, comprising:
a printed circuit board,
a first load with a first signal pin and a first power pin on a first side of the printed circuit board,
a second load with a second signal pin and a second power pin on a second side of the printed circuit board,
a driver, coupled to a trace, wherein
the first load and the second load are positioned such that the first signal pin is vertically aligned to the second signal pin with an offset, and the terminating end of the trace is connected to the first signal pin and the second signal pin;
a first decoupling capacitor on the second side of the printed circuit board is directly connected to the first power pin; and
a second decoupling capacitor on the first side of the printed circuit board is directly connected to the second power pin.
11. The high-speed system of claim 10, wherein the distances between the first decoupling capacitor and the first load and between the second decoupling capacitor and the second load are minimized.
12. The high-speed system of claim 10, further comprising a via connecting to the first signal pin, the second signal pin, and the terminating end of the trace, wherein the offset corresponds to the sum of a first distance between the first signal pin and the via and a second distance between the second signal pin and the via.
13. The high-speed system of claim 11, wherein the connection between the first decoupling capacitor and the first power pin is substantially perpendicular to the first load.
14. The high-speed system of claim 11, wherein the connection between the second decoupling capacitor and the second power pin is substantially perpendicular to the second load.
15. The high-speed system of claim 12, wherein the placement of the first load and the second load on the printed circuit board results in the minimization of the length of a first stub including the distance between the first signal pin and the T-point and the length of a second stub including the distance between the second signal pin and the T-point.
16. The high-speed system of claim 12, wherein the offset is substantially shorter than the length of the first load.
17. The high-speed system of claim 12, wherein the offset is substantially shorter than the length of the first load.
18. The high-speed system of claim 15, wherein the via is positioned away from the first signal pin and away from the second signal pin.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
We claim:
1. A method for obtaining the fingerprint of a received waveform comprising the steps of:
(a) sampling the received waveform to thereby obtain a predetermined number of samples of an attribute of the received waveform; and
(b) estimating a multidimensional higher-order nonzero-lag auto-cumulant of the received waveform attribute samples to thereby obtain the fingerprint of the received waveform.
2. The method of claim 1 wherein the attribute is a random process.
3. The method of claim 2 wherein the random process is stationary with statistical properties up to order N1 that are invariant to shift in the origin over the sample observations for a fingerprint of dimension N.
4. The method of claim 2 wherein the random process is zero-mean.
5. The method of claim 2 wherein the attribute is selected from the group consisting of phase, frequency, amplitude, power spectral density, symbol rate, symbol energy, bandwidth, modulation, phase jitter, timing jitter, signal constellation, pulse shape and frequency offset.
6. The method of claim 1 wherein the auto-cumulant is a fourth order cumulant.
7. The method of claim 1 wherein the auto-cumulant is determined as a function of three lags.
8. The method of claim 1 wherein the fingerprint is used to classify the received waveform.
9. The method of claim 1 wherein the fingerprint is used to characterize the received waveform.
10. The method of claim 1 wherein the fingerprint is used to identify the received waveform.
11. The method of claim 1 wherein the fingerprint is used to intercept the received waveform.
12. The method of claim 1 further comprising the steps of:
(c) comparing the estimated auto-cumulant of the received waveform attribute samples with a multidimensional higher-order nonzero-lag auto-cumulant of a known waveform to thereby obtain the fingerprint of the received waveform.
13. The method of claim 12 wherein the auto-cumulant of the known waveform is obtained from a database.
14. The method of claim 12 wherein the auto-cumulant of the known waveform is obtained from a lookup table.
15. A method for classifying a received waveform comprising the steps of:
(a) sampling the received waveform to thereby obtain a predetermined number of samples of an attribute of the received waveform;
(b) estimating a multidimensional higher-order nonzero-lag auto-cumulant of the received waveform attribute samples; and
(c) comparing the estimated auto-cumulant of the received waveform attribute samples with a multidimensional higher-order nonzero-lag auto-cumulant of a known waveform to thereby classify the received waveform.
16. The method of claim 15 wherein the attribute is a random process.
17. The method of claim 16 wherein the random process is stationary with statistical properties up to order N1 that are invariant to a shift in the origin over the sample observations for a fingerprint of dimension N.
18. The method of claim 16 wherein the random process is zero-mean.
19. The method of claim 16 wherein the attribute is selected from the group consisting of phase, frequency, amplitude, power spectral density, symbol rate, symbol energy, bandwidth, modulation, phase jitter, timing jitter, signal constellation, pulse shape and frequency offset.
20. The method of claim 15 wherein the auto-cumulant is a fourth order cumulant.
21. The method of claim 15 wherein the auto-cumulant is determined as a function of three lags.
22. The method of claim 15 wherein the received waveform is classified by modulation type.
23. The method of claim 22 wherein the modulation types are selected from the group consisting of PSK, PAM, and QAM.
24. The method of claim 23 wherein the PSK modulation types are selected from the group consisting of BPSK, QPSK, and 8PSK.
25. The method of claim 23 wherein the QAM modulation types are selected from the group consisting of 16-QAM, 64-QAM, and 256-QAM.
26. The method of claim 15 wherein the auto-cumulant of the known waveform is obtained from a database.
27. The method of claim 15 wherein the auto-cumulant of the known waveform is obtained from a lookup table.
28. A method for characterizing a received waveform comprising the steps of:
(a) sampling the received waveform to thereby obtain a predetermined number of samples of an attribute of the received waveform;
(b) estimating a multidimensional higher-order nonzero-lag auto-cumulant of the received waveform attribute samples; and
(c) comparing the estimated auto-cumulant of the received waveform attribute samples with a multidimensional higher-order nonzero-lag auto-cumulant of a known waveform to thereby characterize the received waveform.
29. The method of claim 28 wherein the attribute is a random process.
30. The method of claim 29 wherein the random process is stationary with statistical properties up to order N1 that are invariant to a shift in the origin over the sample observations for a fingerprint of dimension N.
31. The method of claim 29 wherein the random process is zero-mean.
32. The method of claim 29 wherein the attribute is selected from the group consisting of phase, frequency, amplitude, power spectral density, symbol rate, symbol energy, bandwidth, modulation, phase jitter, timing jitter, pulse shape, signal constellation, and frequency offset.
33. The method of claim 28 wherein the auto-cumulant is a fourth order cumulant.
34. The method of claim 28 wherein the auto-cumulant is determined as a function of three lags.
35. The method of claim 28 wherein the known waveform is idealized so that the samples of the attribute do not contain anomalous variations.
36. The method of claim 35 wherein the received waveform is characterized by anomalous variations of the attribute in the samples as determined by the difference between the estimated auto-cumulant of the received waveform and the auto-cumulant of the idealized known waveform.
37. The method of claim 28 wherein the auto-cumulant of the known waveform is obtained from a database.
38. The method of claim 28 wherein the auto-cumulant of the known waveform is obtained from a lookup table.
39. A method for identifying a received waveform comprising the steps of:
(a) sampling the received waveform to thereby obtain a predetermined number of samples of an attribute of the received waveform;
(b) estimating a multidimensional higher-order nonzero-lag auto-cumulant of the received waveform attribute samples; and
(c) comparing the estimated auto-cumulant of the received waveform attribute samples with a multidimensional higher-order nonzero-lag auto-cumulant of a known waveform to thereby identify the received waveform.
40. The method of claim 39 wherein the attribute is a random process.
41. The method of claim 40 wherein the random process is stationary with statistical properties up to order N1 that are invariant to a shift in the origin over the sample observations for a fingerprint of dimension N.
42. The method of claim 40 wherein the random process is zero-mean.
43. The method of claim 40 wherein the attribute is selected from the group consisting of phase, frequency, amplitude, power spectral density, symbol rate, symbol energy, bandwidth, modulation, phase jitter, timing jitter, pulse shape, signal constellation, and frequency offset.
44. The method of claim 40 wherein the auto-cumulant is a fourth order cumulant.
45. The method of claim 40 wherein the auto-cumulant is determined as a function of three lags.
46. The method of claim 40 wherein the auto-cumulant of the known waveform is obtained from a database.
47. The method of claim 40 wherein the auto-cumulant of the known waveform is obtained from a lookup table.
48. A method for intercepting a received waveform comprising the steps of:
(a) sampling the received waveform to thereby obtain a predetermined number of samples of an attribute of the received waveform;
(b) estimating a multidimensional higher-order nonzero-lag auto-cumulant of the received waveform attribute samples;
(c) comparing the estimated auto-cumulant of the received waveform attribute samples with a multidimensional higher-order nonzero-lag auto-cumulant of a known waveform to thereby determine the modulation of the received waveform; and
(d) processing the received waveform using the determined modulation to thereby intercept the received waveform.
49. The method of claim 48 wherein the attribute is a random process.
50. The method of claim 49 wherein the random process is stationary with statistical properties up to order N1 that are invariant to a shift in the origin over the sample observations for a fingerprint of dimension N.
51. The method of claim 49 wherein the random process is zero-mean.
52. The method of claim 49 wherein the attribute is selected from the group consisting of phase, frequency, amplitude, power spectral density, symbol rate, symbol energy, bandwidth, modulation, phase jitter, timing jitter, pulse shape, signal constellation, and frequency offset.
53. The method of claim 48 wherein the auto-cumulant is a fourth order cumulant.
54. The method of claim 48 wherein the auto-cumulant is determined as a function of three lags.
55. The method of claim 48 wherein the auto-cumulant of the known waveform is obtained from a database.
56. The method of claim 48 wherein the auto-cumulant of the known waveform is obtained from a lookup table.
57. In a method for classifying a received signal from an unknown emitter using characteristics of the waveform of the received signal, the improvement comprising the steps of:
(a) determining for the received signal variations of 4th-order cumulant multidimensional features over a plurality of lag combinations; and
(b) comparing the 4th-order cumulant multidimensional features of the received signal with the variations of similar 4th-order cumulant multidimensional features of a known reference signal to thereby classify the received signal.