1. A method for synchronization (SYNC) detection of a received serial offset quadrature pulse shaped waveform modulated by a predetermined SYNC sequence of symbols, the method comprising the steps of:
a) serially demodulating the received waveform into a serial baseband signal having the same predetermined SYNC sequence of symbols;
b) correlating the serial baseband signal with a plurality of segments of the SYNC sequence of symbols to form a plurality of parallel correlated output signals, the plurality of segments forming the predetermined SYNC sequence of symbols;
c) combining the parallel correlated output signals to form a combined correlation signal;
d) detecting SYNC using the combined correlation signal;
e) determining a peak of the combined correlation signal;
f) computing correlation strength estimates of each of the parallel correlated output signals;
g) adjusting a SYNC threshold level based upon the correlation strength estimates; and
h) comparing the peak of step (e) with the SYNC threshold level of step (g) to detect SYNC.
2. (canceled)
3. The method according to claim 1, wherein the received serial offset quadrature pulse shaped waveform includes one of minimum shift keying (MSK), Gaussian MSK, serial quasi-bandlimited-MSK (SQBL-MSK), binary phase shift keying (BPSK), filtered BPSK, offset quadrature PSK (OQPSK), intersymbol jitter free OQPSK (IJF-OQPSK), raised cosine filtered OQPSK (RC-OQPSK), continuous phase modulation (CPM), or tamed frequency modulation (TFM).
4. The method according to claim 1, wherein the received waveform has a symbol rate and step (a) includes:
demodulating the received waveform with a carrier frequency signal to form a baseband signal; and
sampling the baseband signal at a rate of twice the symbol rate.
5. The method according to claim 1, wherein step (a) includes forming in-phase (I) and quadrature (Q) baseband signals.
6. The method according to claim 1, wherein the received waveform has a symbol rate and step (a) includes:
demodulating the received waveform to form in-phase (I) and quadrature (Q) baseband signals, each of the I and Q baseband signals sampled at a rate of twice the symbol rate; and
phase-rotating each of the I and Q baseband signals to form serially demodulated I and Q baseband signals, each of the serial I and Q baseband signals having the same predetermined SYNC sequence of symbols.
7. The method according to claim 1, wherein a number of segments is 4 segments.
8. The method according to claim 1, wherein the SYNC sequence includes 128 symbols, divided into 4 segments each of 32 symbols.
9. The method according to claim 1, wherein step (b) includes:
aligning in time a first set of symbols of one segment of the SYNC sequence with a second set of symbols of another segment of the SYNC sequence; and
concurrently correlating the first set of symbols and the second set of symbols with the serial baseband signal to form the parallel correlated output signals.
10. The method according to claim 1, wherein step (b) includes:
sampling the serial baseband signal at a rate greater than or equal to twice a symbol rate of the SYNC sequence of symbols; and
correlating the serial baseband signal with one of the segments of the SYNC sequence of symbols by multiplying every other sample of the serial baseband signal with the SYNC sequence of symbols.
11. The method according to claim 1, wherein the parallel correlated output signals includes pairs of correlated in-phase (I) and quadrature (Q) signals, each pair corresponding to one of segments, and step (f) includes:
computing one of a magnitude signal or a squared magnitude for each of the pairs.
12. The method according to claim 11, wherein computing the squared magnitude includes:
computing a squared magnitude for each pair of the correlated I and Q output signals; and
combining the squared magnitude of each of the pairs to form the squared magnitude.
13. The method according to claim 12, wherein computing the magnitude includes computing a square root of the squared magnitude.
14. The method according to claim 1, wherein step (c) includes:
selectively delaying each of the parallel correlated output signals, so that the parallel correlated output signals are time aligned; and
combining the parallel correlated output signals after time alignment to form the combined correlation signal.
15. The method according to claim 4, further including correcting an error in the carrier frequency, after detecting SYNC.
16. The method according to claim 1, wherein step (e) includes comparing a value of a present correlation sample COR(k) in the combined correlation signal to a value of a past sample COR(k\u22121) and a value of a future sample COR(k+1), where k is an integer, and selecting a largest value as the peak.
17. The method according to claim 1 wherein step (g) includes:
selecting a maximum value from the correlation strength estimates to form a current value;
comparing the current value to a previously selected maximum value of a correlation strength estimate; and
adjusting the SYNC threshold level based on the comparison,
wherein the current value is selected as the SYNC threshold value when the current value is greater than the previously selected value.
18. The method according to claim 17, wherein the SYNC threshold level is lowpass filtered at a predetermined time constant.
19. The method according to claim 17, wherein the SYNC threshold level is adjusted by mapping the selected maximum value from the correlation strength estimates into the SYNC threshold level using a look up table (LUT) stored in a memory.
20. A method for synchronization (SYNC) detection of a received serial offset quadrature pulse shaped waveform modulated by a predetermined SYNC sequence of symbols, the method comprising the steps of:
a) serially demodulating the received waveform into a serial baseband signal having the same predetermined SYNC sequence of symbols;
b) simultaneously correlating the entire serial baseband signal with each of a plurality of segments of the SYNC sequence of symbols to form a plurality of parallel correlated output signals, the plurality of segments forming the predetermined SYNC sequence of symbols;
c) computing correlation strength estimates of each of the parallel correlated output signals;
d) combining the correlation strength estimates to form a combined correlation signal; and
e) detecting SYNC using the combined correlation signal.
21. The method according to claim 20, further including the steps of:
f) determining a peak of the combined correlation signal;
g) adjusting a SYNC threshold level based upon the correlation strength estimates; and
h) comparing the peak of step (f) with the SYNC threshold level of step (g) to detect SYNC.
22. The method according to claim 20, wherein the received serial offset quadrature pulse shaped waveform includes one of minimum shift keying (MSK), Gaussian MSK, serial quasi-bandlimited-MSK (SQBL-MSK), binary phase shift keying (BPSK), filtered BPSK, offset quadrature PSK (OQPSK), intersymbol jitter free OQPSK (IJF-OQPSK), raised cosine filtered OQPSK (RC-OQPSK), continuous phase modulation (CPM), or tamed frequency modulation (TFM).
23. The method according to claim 20, wherein the received waveform has a symbol rate and step (a) includes:
demodulating the received waveform to form in-phase (I) and quadrature (Q) baseband signals, each of the I and Q baseband signals sampled at a rate of twice the symbol rate; and
phase-rotating each of the I and Q baseband signals to form serially demodulated I and Q baseband signals, each of the serial I and Q baseband signals having the same predetermined SYNC sequence of symbols.
24. The method according to claim 20, wherein step (b) includes:
aligning in time a first set of symbols of one segment of the SYNC sequence with a second set of symbols of another segment of the SYNC sequence; and
concurrently correlating the first set of symbols and the second set of symbols with the serial baseband signal to form the parallel correlated output signals.
25. The method according to claim 20, wherein step (d) includes:
selectively delaying each of the correlation strength estimates, so that the correlation strength estimates are time aligned; and
combining the correlation strength estimates after time alignment to form the combined correlation signal.
26. The method according to claim 21, wherein step (g) includes:
selecting a maximum value from the correlation strength estimates to form a current value;
comparing the current value to a previously selected maximum value of a correlation strength estimate; and
adjusting the SYNC threshold level based on the comparison,
wherein the current value is selected as the SYNC threshold value when the current value is greater than the previously selected value.
27. A receiver comprising:
a demodulator for serially demodulating a received waveform into a serial baseband signal, the serial baseband signal having a predetermined SYNC sequence of symbols;
a matched filter for correlating the serial baseband signal with a plurality of segments of the SYNC sequence of symbols to form a plurality of parallel correlated output signals, the plurality of segments forming the predetermined SYNC sequence of symbols; a correlation strength estimator for computing correlation strength estimates of each of the parallel correlated output signals;
a combiner for combining one of the correlation strength estimates or the parallel correlated output signals to form a combined correlation signal;
a peak detector for determining a peak in the combined correlation signal;
a threshold adjustor for adjusting a SYNC threshold level based upon the correlation strength estimates; and
a comparator for comparing the peak in the combined correlation signal with the SYNC threshold level to detect synchronization when the peak is greater than the SYNC threshold level.
28.-29. (canceled)
30. The receiver of claim 27, wherein the received waveform includes one of minimum shift keying (MSK), Gaussian MSK, serial quasi-bandlimited-MSK (SQBL-MSK), binary phase shift keying (BPSK), filtered BPSK offset quadrature PSK (OQPSK), intersymbol jitter free OQPSK (IJF-OQPSK), raised cosine filtered OQPSK (RC-OQPSK), bandwidth continuous phase modulation (CPM), or tamed frequency modulation (TFM).
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 improved late gadolinium enhancement (LGE) magnetic resonance imaging (MRI) sequence, wherein the LGE-MRI has a center modulation frequency, comprising:
shifting the center modulation frequency of the LGE-MRI sequence prior to collecting imaging information of the patient, wherein the shifting of center modulation frequency is achieved by using a wideband inversion pulse with a spectral bandwidth of 1 kHz or larger.
2. The LGE-MRI sequence of claim 1, wherein the wideband inversion pulse is a wideband adiabatic inversion pulse.
3. The LGE-MRI sequence of claim 1, wherein the wideband inversion pulse has a spectral bandwidth selected from the group consisting of 1.5 kHz or larger, 2 kHz or larger, 2.5 kHz or larger, 3 kHz or larger, and 3.5 kHz or larger.
4. The LGE-MRI sequence of claim 1, wherein the wideband inversion pulse has a spectral bandwidth of 3.8 kHz.
5. The LGE-MRI sequence of claim 1, wherein the wideband inversion pulse has a specific absorption rate (SAR) of 0.07 Wkg or lower.
6. The LGE-MRI sequence of claim 1, wherein the center frequency shift is between the range of zero Hz to 2500 Hz or higher.
7. The LGE-MRI sequence of claim 1, wherein the center frequency shift is selected from the group consisting of 50 Hz or higher, 100 Hz or higher, 150 Hz or higher, 200 Hz or higher, 250 Hz or higher, 300 Hz or higher, 350 Hz or higher, 400 Hz or higher, 450 Hz or higher, 500 Hz or higher, 550 Hz or higher, 600 Hz or higher, 650 Hz or higher, 700 Hz or higher, 750 Hz or higher, 800 Hz or higher, 850 Hz or higher, 900 Hz or higher, 950 Hz or higher, 1000 Hz or higher, 1050 Hz or higher, 1100 Hz or higher, 1150 Hz or higher, 1200 Hz or higher, 1250 Hz or higher, 1300 Hz or higher, 1350 Hz or higher, 1400 Hz or higher, 1450 Hz or higher, 1500 Hz or higher, 1550 Hz or higher, 1600 Hz or higher, 1650 Hz or higher, 1700 Hz or higher, 1750 Hz or higher, 1800 Hz or higher, 1850 Hz or higher, 1900 Hz or higher, 1950 Hz or higher, 2000 Hz or higher, 2050 Hz or higher, 2100 Hz or higher, 2150 Hz or higher, 2200 Hz or higher, 2250 Hz or higher, 2300 Hz or higher, 2350 Hz or higher, 2400 Hz or higher, 2450 Hz or higher, and 2500 Hz or higher.
8. The LGE-MRI sequence of claim 1, wherein the center frequency shift is 800 Hz or larger or 1000 Hz or larger.
9. A method for improved late gadolinium enhancement (LGE) magnetic resonance imaging (MRI) for assessing myocardial viability for a patient with a metal-containing device, comprising:
collecting imaging information of the patient using a traditional LGE-MRI sequence;
shifting the center modulation frequency of the traditional LGE-MRI sequence; and
repeating the collecting step to collect additional imaging information of the patient,
wherein the shifting of center modulation frequency is achieved by using a wideband inversion pulse with a spectral bandwidth of 1 kHz or larger.
10. The method of claim 9, wherein the metal-containing device is selected from the group consisting of an implanted cardiac device, a cardiac pacemaker, an implantable cardiac defibrillator (ICD), a catheter, and a balloon.
11. The method of claim 9, wherein the wideband inversion pulse is a wideband adiabatic inversion pulse.
12. The method of claim 9, wherein the wideband inversion pulse has a spectral bandwidth selected from the group consisting of 1.5 kHz or larger, 2 kHz or larger, 2.5 kHz or larger, 3 kHz or larger, and 3.5 kHz or larger.
13. The method of claim 9, wherein the wideband inversion pulse has a spectral bandwidth of 3.8 kHz.
14. The method of claim 9, wherein the center modulation frequency is shifted by a frequency selected from the group consisting of 750 Hz or higher, 800 Hz or higher, 850 Hz or higher, 900 Hz or higher, 950 Hz or higher, 1000 Hz or higher, 1050 Hz or higher, 1100 Hz or higher, 1150 Hz or higher, 1200 Hz or higher, 1250 Hz or higher, 1300 Hz or higher, 1350 Hz or higher, 1400 Hz or higher, 1450 Hz or higher, and 1500 Hz or higher.
15. The method of claim 9, wherein the center modulation frequency shift is 800 Hz or larger.
16. The method of claim 9, wherein the center modulation frequency shift is 1000 Hz or larger.
17. The method of claim 9, further comprising:
determining an LGE MRI image, wherein the LGE MRI image comprises measurements of a scar area within the patient.
18. The method of claim 17, wherein the scar area is selected from the group consisting of an endocardial scar area, epicardial scar area, and a transmural scar area.
19. The method of claim 9, further comprising:
correlating an LGE MRI image with an electroanatomical map of the same patient, wherein the correlation is based on measurements of a scar area.
20. The method of claim 19, wherein the scar area is selected from the group consisting of an endocardial scar area, epicardial scar area, and a transmural scar area.