US5437281A — Direct demodulation in ultrasound instruments

Claim 1

Independent Claim 93 words

A digital demodulator for use in an ultrasonic imaging system having a front end for generating an ultrasound passband signal and display for displaying an ultrasound image, said demodulator comprising: compensation means for performing phase and frequency compensation on said ultrasound passband signal signal, wherein said compensation means comprises a Hilbert transformer to convert the ultrasound passband signal to an analytic baseband signal, such that the ultrasound passband signal is converted to said analytic baseband signal that is phase and frequency compensated without affecting the phase, Doppler information and magnitude information contained therein.

Claim 2

Dependent Claim 93 words

A digital demodulator for use in an ultrasonic imaging system having a front end for generating an ultrasound passband signal and display for displaying an ultrasound image, said demodulator comprising: compensation means for performing phase and frequency compensation on said ultrasound passband signal signal, wherein said compensation means comprises a Hilbert transformer to convert the ultrasound passband signal to an analytic baseband signal, such that the ultrasound passband signal is converted to said analytic baseband signal that is phase and frequency compensated without affecting the phase, Doppler information and magnitude information contained therein.

Claim 3

Dependent Claim 103 words

A digital demodulator for use in a real-time ultrasonic imaging system having a front end for generating an ultrasound passband signal and a display for displaying an ultrasound image, said digital demodulator comprising: transform means for receiving said ultrasound passband signal and generating an analytic baseband signal in response to said ultrasound signal; and digital sampling mixer means for performing mixing by sampling of said analytic baseband signal to compensate the frequency and phase of said analytic baseband signal digitally, such that the ultrasound passband signal is converted to said analytic baseband signal without affecting the phase, Doppler information and magnitude contained therein.

Claim 4

Dependent Claim 103 words

A digital demodulator for use in a real-time ultrasonic imaging system having a front end for generating an ultrasound passband signal and a display for displaying an ultrasound image, said digital demodulator comprising: transform means for receiving said ultrasound passband signal and generating an analytic baseband signal in response to said ultrasound signal; and digital sampling mixer means for performing mixing by sampling of said analytic baseband signal to compensate the frequency and phase of said analytic baseband signal digitally, such that the ultrasound passband signal is converted to said analytic baseband signal without affecting the phase, Doppler information and magnitude contained therein.

Claim 5

Dependent Claim 16 words

The digital demodulator as defined in claim 2 wherein said transform means comprises a Hilbert transform.

Claim 6

Dependent Claim 54 words

The digital demodulator as defined in claim 2 wherein said sampling mixer means comprises: mixer means for shifting said analytic signal to an analytic baseband signal; and rotation means coupled to said mixer means and responsive to said analytic baseband signal, said rotation means for arbitrarily shifting the frequency of said analytic baseband signal.

Claim 7

Dependent Claim 97 words

A digital demodulator for use in a real-time ultrasonic imaging system having a front end for generating an ultrasound signal and display for displaying an ultrasound image, said demodulator comprising: transform means for receiving said signal and generating an analytic signal in response to said ultrasound signal; sampling mixer means for performing mixing by sampling of said analytic signal, such that the frequency and phase of said analytic signal is compensated; and coordinate transform means for translating said analytic signal to polar coordinates, such that the magnitude information and phase information of said analytic signal are produced.

Claim 8

Dependent Claim 97 words

A digital demodulator for use in a real-time ultrasonic imaging system having a front end for generating an ultrasound signal and display for displaying an ultrasound image, said demodulator comprising: transform means for receiving said signal and generating an analytic signal in response to said ultrasound signal; sampling mixer means for performing mixing by sampling of said analytic signal, such that the frequency and phase of said analytic signal is compensated; and coordinate transform means for translating said analytic signal to polar coordinates, such that the magnitude information and phase information of said analytic signal are produced.

Claim 9

Dependent Claim 71 words

The digital demodulator as defined in claim 5 further comprising: differential phase generator means responsive to said phase information and for generating a phase signal, said phase signal representing the phase difference between successive samples along the path of said analytic baseband signal; and magnitude compression means responsive to said magnitude for compressing said magnitude of said analytic signal, said magnitude compression means generating said analytic signal having a compressed magnitude.

Claim 10

Dependent Claim 60 words

The digital demodulator as defined in claim 6 further comprising switching means for receiving said phase signal and said compressed magnitude signal, said switching means sending said phase signal to said display means when send switching means is in a first position and sending said compressed magnitude to said display means when said switching means is in a second position.

Claim 11

Dependent Claim 40 words

The digital demodulator as defined in claim 6 further comprising phase compression means responsive to said compressed magnitude signal, said phase compression means for compressing said phase signal when said magnitude of said analytic signal is below a predetermined level.

Claim 12

Dependent Claim 74 words

The digital demodulator as defined in claim 5 further comprising: differential phase generator means responsive to said phase information and for generating a phase signal, said phase signal representing the phase difference between successive samples along the path of said analytic baseband signal; and phase compression means responsive to said compressed magnitude signal, said phase compression means for compressing said phase signal when said magnitude of said analytic signal is below a predetermined level.

Claim 13

Dependent Claim 116 words

A digital demodulator :for use in a real-time ultrasonic imaging system having a front end for generating an ultrasound signal and a display for displaying an ultrasound image, said demodulator comprising: a Hilbert transformer for converting said ultrasound signal into an analytic signal; a complex mixer coupled to said Hilbert transformer for shifting said analytic signal to baseband and to compensate for attenuated signals, such that a shifted analytic signal is generated; a magnitude and differential phase generator responsive to said shifted analytic Signal to generate phase information and magnitude information for display; and a Doppler preprocessor responsive to said shifted analytic baseband signal to extract Doppler data from said shifted analytic baseband signal for display.

Claim 14

Dependent Claim 116 words

A digital demodulator :for use in a real-time ultrasonic imaging system having a front end for generating an ultrasound signal and a display for displaying an ultrasound image, said demodulator comprising: a Hilbert transformer for converting said ultrasound signal into an analytic signal; a complex mixer coupled to said Hilbert transformer for shifting said analytic signal to baseband and to compensate for attenuated signals, such that a shifted analytic signal is generated; a magnitude and differential phase generator responsive to said shifted analytic Signal to generate phase information and magnitude information for display; and a Doppler preprocessor responsive to said shifted analytic baseband signal to extract Doppler data from said shifted analytic baseband signal for display.

Claim 15

Independent Claim 42 words

A method for demodulating a signal from the front end of an ultrasound imaging apparatus comprising the steps of: compensating the frequency and phase of said signal; detecting the phase information along the path of said signal; and displaying said phase information.

Claim 16

Independent Claim 42 words

A method for demodulating a signal from the front end of an ultrasound imaging apparatus comprising the steps of: compensating the frequency and phase of said signal; detecting the phase information along the path of said signal; and displaying said phase information.

Claim 17

Dependent Claim 122 words

A digital demodulator for use in a real-time ultrasonic imaging system having a front end for generating an ultrasound signal and display for displaying an ultrasound image, said demodulator comprising: transform means for receiving said signal and generating an analytic signal in response to said ultrasound signal using a Hilbert transform; and sampling mixer means for performing mixing by sampling of said analytic signal, wherein said sampling mixer means comprises mixer means for shifting said analytic signal to an analytic baseband signal; and rotation means coupled to said mixer means and responsive to said analytic baseband signal, said rotation means for arbitrarily shifting the frequency of said analytic baseband signal, such that the phase and frequency of said analytic signal are compensated.

Claim 18

Dependent Claim 122 words

A digital demodulator for use in a real-time ultrasonic imaging system having a front end for generating an ultrasound signal and display for displaying an ultrasound image, said demodulator comprising: transform means for receiving said signal and generating an analytic signal in response to said ultrasound signal using a Hilbert transform; and sampling mixer means for performing mixing by sampling of said analytic signal, wherein said sampling mixer means comprises mixer means for shifting said analytic signal to an analytic baseband signal; and rotation means coupled to said mixer means and responsive to said analytic baseband signal, said rotation means for arbitrarily shifting the frequency of said analytic baseband signal, such that the phase and frequency of said analytic signal are compensated.

Claim 19

Dependent Claim 16 words

The digital demodulator as defined in claim 12 wherein said transform means comprises a Hilbert transform.

Claim 20

Dependent Claim 92 words

A digital demodulator for use in a real-time ultrasonic imaging system having a front end for generating an ultrasound signal and display for displaying an ultrasound image, said demodulator comprising: transform means for receiving said signal and generating an analytic signal in response to said ultrasound signal; and sampling mixer means for performing mixing by sampling of said analytic signal, such that the frequency of said analytic signal is compensated; and coordinate transform means for translating said analytic signal to polar coordinates, such that the magnitude of said analytic signal is obtained.

Claim 21

Dependent Claim 92 words

A digital demodulator for use in a real-time ultrasonic imaging system having a front end for generating an ultrasound signal and display for displaying an ultrasound image, said demodulator comprising: transform means for receiving said signal and generating an analytic signal in response to said ultrasound signal; and sampling mixer means for performing mixing by sampling of said analytic signal, such that the frequency of said analytic signal is compensated; and coordinate transform means for translating said analytic signal to polar coordinates, such that the magnitude of said analytic signal is obtained.

Claim 22

Dependent Claim 37 words

The digital demodulator as defined in claim 14 further comprising: magnitude compression means responsive to said magnitude for compressing said magnitude of said analytic signal, said magnitude compression means generating said analytic signal having a compressed magnitude.

Claim 23

Dependent Claim 118 words

A digital demodulator for use in a real-time ultrasonic imaging system having a front end for generating an ultrasound signal and a display for displaying an ultrasound image, said demodulator comprising: a Hilbert transformer for converting said signal into an analytic signal; a complex mixer for shifting said analytic signal to said baseband and further shifting said analytic signal to compensate for attenuation in said signal; magnitude generation means responsive to said shifted analytic baseband for generating the magnitude information signal and the magnitude of said signal for said display; and Doppler preprocessing means responsive to said shifted analytic baseband signal and for extracting Doppler data from said shifted analytic baseband signal, said display displays said Doppler data.

Claim 24

Dependent Claim 118 words

A digital demodulator for use in a real-time ultrasonic imaging system having a front end for generating an ultrasound signal and a display for displaying an ultrasound image, said demodulator comprising: a Hilbert transformer for converting said signal into an analytic signal; a complex mixer for shifting said analytic signal to said baseband and further shifting said analytic signal to compensate for attenuation in said signal; magnitude generation means responsive to said shifted analytic baseband for generating the magnitude information signal and the magnitude of said signal for said display; and Doppler preprocessing means responsive to said shifted analytic baseband signal and for extracting Doppler data from said shifted analytic baseband signal, said display displays said Doppler data.

Claim 25

Dependent Claim 123 words

A digital demodulator for use in a real-time ultrasonic imaging system having a front end for generating an ultrasound signal and a display for displaying an ultrasound image, said demodulator comprising: a baseband demodulator producing an analytic baseband signal in response to the ultrasound signal, wherein the baseband demodulator comprises a Hilbert transformer converting said ultrasound signal into a first analytic signal; a complex mixer coupled to the Hilbert transformer, wherein the complex mixer performs phase and frequency equalization by shifting said first analytic signal to baseband and moving a peak of said first analytic signal, thereby creating the analytic baseband signal; and a generator coupled to the baseband demodulator, wherein the generator derives phase and amplitude information from said analytic baseband signal.

Claim 26

Dependent Claim 123 words

A digital demodulator for use in a real-time ultrasonic imaging system having a front end for generating an ultrasound signal and a display for displaying an ultrasound image, said demodulator comprising: a baseband demodulator producing an analytic baseband signal in response to the ultrasound signal, wherein the baseband demodulator comprises a Hilbert transformer converting said ultrasound signal into a first analytic signal; a complex mixer coupled to the Hilbert transformer, wherein the complex mixer performs phase and frequency equalization by shifting said first analytic signal to baseband and moving a peak of said first analytic signal, thereby creating the analytic baseband signal; and a generator coupled to the baseband demodulator, wherein the generator derives phase and amplitude information from said analytic baseband signal.

Claim 27

Dependent Claim 15 words

The digital demodulator defined in claim 17 wherein the complex mixer comprises a digital mixer.

Claim 28

Dependent Claim 28 words

The digital demodulator defined in claim 17 wherein the complex mixer shifts the first analytic signal to the baseband and then moves its peak to the center frequency.

Claim 29

Dependent Claim 28 words

The digital demodulator defined in claim 17 wherein the baseband demodulator produces the analytic baseband signal without affecting the phase, Doppler or magnitude information in the ultrasound signal.

Claim 30

Dependent Claim 22 words

The digital demodulator defined in claim 17 wherein the generator determines phase differences between successive samples of the said analytic baseband signal.

Claim 31

Dependent Claim 42 words

The digital demodulator defined in claim 17 wherein the generator comprises a magnitude generator generating a signal indicative of magnitude in the analytic baseband signal; and a differential generator determining a phase difference between successive samples of the said analytic baseband signal.

Claim 32

Dependent Claim 26 words

The digital demodulator defined in claim 17 wherein the generator further comprises a transform for transforming the analytic baseband signal from rectangular coordinates to polar coordinates.

Claim 33

Dependent Claim 98 words

The digital demodulator defined in claim 17 wherein the generator comprises a transform for transforming the analytic baseband signal from rectangular coordinates to polar coordinates having a magnitude (R) component and a phase component; a magnitude generator coupled to the transform to generate a signal indicative of magnitude in response to the magnitude (R) component of the analytic baseband signal in polar coordinates; and a differential generator coupled to the transform to determine a phase difference between successive samples of the said analytic baseband signal in response to the phase component of the analytic signal in polar coordinates.

Claim 34

Dependent Claim 33 words

The digital demodulator defined in claim 24 further comprising phase compression for preventing output of information indicative of the phase difference in response to the magnitude (R) component being below a predetermined threshold.

Claim 35

Dependent Claim 36 words

The digital demodulator defined in claim 17 further comprising a Doppler preprocessor responsive to said shifted analytic baseband signal and for extracting Doppler data from said shifted analytic baseband signal, said display displays said Doppler data.

Claim 36

Dependent Claim 19 words

The digital demodulator defined in claim 26 wherein the Doppler preprocessor evaluates phase change for a specific sample volume.

Claim 37

Dependent Claim 17 words

The digital demodulator defined in claim 17 wherein the Hilbert transformer comprises a finite impulse response filter.

Claim 38

Dependent Claim 42 words

The digital demodulator defined in claim 17 wherein the front end includes at least one transducer having a center frequency and wherein the Hilbert transformer comprises a complex bandpass filter with a sample rate that is a multiple of the center frequency.

Claim 39

Dependent Claim 15 words

The digital demodulator defined in claim 17 wherein the baseband demodulator further comprises a decimator.

Claim 40

Dependent Claim 62 words

The digital demodulator defined in claim 17 wherein the complex mixer comprises a mixer coupled to receive the first analytic signal to shift the first analytic signal to create a second analytic signal centered on zero frequency; and a rotator coupled to receive the second analytic signal from the mixer to compensate for attenuation of high frequency components of the ultrasound signal.

Claim 41

Dependent Claim 20 words

The digital demodulator defined in claim 31 wherein the baseband demodulator further comprises a look-up table (LUT) coupled to rotator.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1998-07-31	1999-01-30	1999-08-01	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2002-07-31	2003-01-30	2003-08-01	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2006-07-31	2007-01-30	2007-08-01	$7700.00	Window Closed / Lapsed

Direct demodulation in ultrasound instruments

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