Patent Description:
Ultrasound imaging systems are often used for medical imaging. An ultrasound imaging system typically includes a transducer probe as well as a main processing system. The transducer probe may include an array of ultrasound transducer elements. The ultrasound transducer elements send acoustic waves through a patient's body and generate signals as the acoustic waves are reflected back by tissues and/or organs within the patient's body. In traditional ultrasound applications, the timing and/or strength of the echo signals may correspond to the size, shape, and mass of the tissues, organs, or other features of the patient and images depicting the measured tissues, organs, or other features may be displayed to a user of the ultrasound system. Some ultrasound applications additionally employ continuous wave (CW) Doppler imaging methods to measure velocities within a patient, such as velocities of fluids (e.g. blood flow). Analog ultrasound echo signals corresponding to each ultrasound transducer element may be passed through a cable from the transducer probe to the main processing system. For CW Doppler applications, the processing system may display a graphical representation of velocities within the patient.

To transmit analog ultrasound echo signals from the probe to the main processing system, the connecting cable may include many conductors and, in some instances, may require a conductor or set of conductors for each receiving ultrasound transducer element, making the cable very thick, unwieldy, complex, and cumbersome. Due to the many conductors within the cable, the cost of the cable can also be the costliest component in an ultrasound imaging system. The cable may also have a high failure rate.

One approach to overcoming the limitations of transmitting analog ultrasound signals from the probe to the processing system is to include low-power analog-to-digital converters (ADCs) in the transducer probe, perform full or partial beamforming and/or multiplexing, and then transmit digital signals via a reduced number of conductors. This method may significantly reduce the cost, diameter, and overall maneuverability of the cable connecting the ultrasound imaging probe and the main processing system. However, due to the high dynamic range of CW Doppler ultrasound signals, in some embodiments, this approach may be unsuitable for ultrasound systems with a CW Doppler path. In particular, the low-power ADCs used to convert analog signals to digital signals may not have sufficient dynamic range to convert analog signals associated with CW Doppler imaging and maintain high signal quality.

"<NPL>), presents some results in the design of a pulsed Doppler ultrasound system that aims to detect alterations of diabetic foot cataloged as "high risk" associated with the processes that lead to occlusion of blood vessels.

In "<NPL>), it is presented a proof-of-concept system-on-a-chip prototype for a guidewire ultrasound imaging system that includes interface electronics for ultrasound Tx/Rx and a quadrature sampler on-chip.

<CIT> relates to a system for ultrasound beamforming, including a sampled analog beamformer, an array of ultrasound transducers, and a high voltage amplifier coupled to the sampled analog beamformer and the array of ultrasound transducers. The sampled analog beamformer includes a sampled analog filter for filtering an incoming analog signal and adding a fractional delay, and for transmitting a filtered analog ultrasound signal. The array of ultrasound transducers further transmits the filtered analog ultrasound signal. The high voltage amplifier drives transducers in the array of ultrasound transducers.

Embodiments of the present disclosure are systems, devices, and methods for continuous wave (CW) Doppler ultrasound imaging. An ultrasound system can include a host, a probe, and a connecting cable between the host and the probe. The ultrasound imaging probe includes an array of ultrasound transducers which transmit ultrasound waves toward an anatomy and receive waves reflected from the anatomy. The received ultrasound waves may be used for CW Doppler imaging of velocities within the patient's anatomy. An example of such a velocity is the velocity of blood flow, e.g., between chambers of the heart (e.g., between an atrium and a ventricle). For CW Doppler imaging, some ultrasound imaging systems may transmit analog signals from each transducer element to the host via separate conductors requiring a connecting cable with many conductors. However, embodiments of the present disclosure perform some processing steps at the probe. According to the invention, analog signals may be summed and are mixed via in-phase and quadrature (I/Q) mixers within the probe. In some embodiments, CW Doppler signals may also be partially or completely beamformed and/or otherwise combined within the probe before or after I/Q mixing. Mixed CW Doppler signals are transmitted to the host via the connecting cable. Because signals are summed and mixed at the probe, the number of conductors in the connecting cable may be significantly reduced. In turn, the cost of the cable may also be significantly decreased. The cable may also become less cumbersome. While reducing the number of necessary conductors in the connecting cable, the present invention may additionally preserve the analog nature of CW Doppler signals sent to the processing system.

Embodiments of the present disclosure may additionally include processing components within the host system. The host system may receive digital B-mode ultrasound signals and generate an image of the patient's anatomy with various processing components or circuitry. The host system may receive analog CW signals and perform further processing to generate a graphical representation of velocity within the anatomy (e.g., blood flow).

In an exemplary aspect, an ultrasound probe in communication with an ultrasound system is provided. The ultrasound probe includes a transducer array configured to generate analog ultrasound signals; analog in-phase/quadrature (I/Q) mixers disposed within a housing of the ultrasound probe and in communication with the transducer array, wherein the analog I/Q mixers are configured to generate analog continuous wave (CW) Doppler signals based on the analog ultrasound signals; and a cable coupled to the housing, wherein the cable is configured to transmit the analog CW Doppler signals from the ultrasound probe to the ultrasound system.

In some aspects, the ultrasound probe further includes an analog-to-digital converter (ADC) disposed within the housing and in communication with the transducer array, wherein the ADC is configured to convert the analog ultrasound signals to digital ultrasound signals, and wherein the cable is configured to transmit the digital ultrasound signals to the ultrasound system. In some aspects, the ultrasound probe further includes at least one of a digital beamformer or a multiplexor in communication with the ADC. In some aspects, the cable comprises a first plurality of conductors configured to transmit the digital ultrasound signals. In some aspects, the cable comprises a second plurality of conductors configured to transmit the analog CW Doppler signals. In some aspects, the analog CW Doppler signals comprise I signals and Q signals, and the second plurality of conductors comprises: a first conductor configured to transmit the I signals; and a second conductor configured to transmit the Q signals. In some aspects, the ultrasound probe further includes a plurality of analog I/Q mixers disposed within the housing, wherein the plurality of analog I/Q mixers respectively correspond to a plurality of receive elements of the transducer array. In some aspects, the first conductor and the second conductor are electrically coupled to the plurality of analog I/Q mixers in parallel. In some aspects, respective outputs of the plurality of analog I/Q mixers are summed such that the first conductor and the second conductor transmit summed outputs of analog I/Q mixers. In some aspects, the ultrasound probe further includes a quadrature clock generator disposed within the housing and in communication with the analog I/Q mixers. In some aspects, the ultrasound probe further includes a plurality of conductors configured to transmit power, clock and control signals from the ultrasound system to the quadrature clock generator. In some aspects, the ultrasound probe further includes an analog beamformer disposed within the housing and in communication with the transducer array.

In an exemplary aspect, an apparatus is provided. The apparatus includes an ultrasound probe and an ultrasound system, wherein the ultrasound system is spaced from the ultrasound probe such that the cable extends between the ultrasound probe and the ultrasound system.

In some aspects, the ultrasound system comprises a processor circuit configured to: generate a graphical representation of a distribution of blood flow velocities based on the analog CW Doppler signals; and output the graphical representation to a display in communication with the processor circuit. In some aspects, the ultrasound probe is configured to convert the analog ultrasound signals to digital ultrasound signals, the cable is configured to transmit the digital ultrasound signals from the ultrasound probe to the ultrasound system, and the processor circuit is configured to: generate an ultrasound image of a heart based on the digital ultrasound signals; and output the ultrasound image to the display.

In an exemplary aspect, a method is provided. The method includes generating analog ultrasound signals with a transducer array of an ultrasound probe; generating analog CW Doppler signals based on the analog ultrasound signals with analog in-phase/quadrature (I/Q) mixers disposed within a housing of the ultrasound probe; transmitting the analog CW Doppler signals from the ultrasound probe to an ultrasound system spaced from the ultrasound probe by a cable coupled to the housing; generating, with a processor circuit of the ultrasound system, a graphical representation of blood flow velocities based on the analog CW Doppler signals; and outputting the graphical representation to a display in communication with the processor circuit.

It is nevertheless understood that no limitation to the scope of the appended claims is intended.

<FIG> is a schematic diagram of an ultrasound imaging system <NUM>, according to aspects of the present disclosure. The system <NUM> may be used for scanning a region, area, or volume of a patient's body. The system <NUM> can be referred to as an apparatus in some instances. The system <NUM> includes an ultrasound imaging probe <NUM> in communication with a host <NUM> over a communication interface or link <NUM>. At a high level, the probe <NUM> emits ultrasound waves towards an anatomical object <NUM> (e.g., a patient's body) and receives ultrasound echoes that are reflected from the object <NUM>. The probe <NUM> transmits electrical signals representative of the received echoes over the link <NUM> to the host <NUM> for processing and image display. The probe <NUM> may be in any suitable form for imaging various body parts of a patient while positioned inside or outside of the patient's body. For example, the probe <NUM> may be in the form of a handheld ultrasound scanner or a patch-based ultrasound device. In some embodiments, the probe <NUM> can be an intra-body probe, such as a catheter, a transesophageal echocardiography (TEE) probe, and/or any other suitable an endo-cavity probe. The probe <NUM> includes a transducer array <NUM>, various circuitry <NUM>, and a communication interface <NUM>.

The transducer array <NUM> emits ultrasound signals towards the object <NUM> and receives echo signals reflected from the object <NUM> back to the transducer array <NUM>. The transducer array <NUM> may include acoustic elements arranged in a one-dimensional (1D) array, a <NUM>. X-dimensional array, or a two-dimensional (2D) array. The acoustic elements may be referred to as transducer elements. Each transducer element can emit ultrasound waves towards the object <NUM> and can receive echoes as the ultrasound waves are reflected back from the object <NUM>. For example, the transducer array <NUM> can include M transducer elements producing M analog ultrasound echo signals <NUM>. In some embodiments, M can be about <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and/or other suitable values both larger and smaller.

Circuitry <NUM> positioned within the probe <NUM> may be any of any suitable type and may serve several functions. For example, circuity <NUM> may include resistors, capacitors, transistors, inductors, relays, clocks, timers, or any other suitable electrical component that may be integrated in an integrated circuit. In addition, circuitry <NUM> may be configured to support analog signals and/or digital signals transmitted to or from the transducer array <NUM> and/or the probe <NUM>. In some embodiments, circuitry <NUM> may include analog frontends (AFEs), analog-to-digital converters (ADCs), multiplexers (MUXs), and encoders, among other components. The circuitry <NUM> can include hardware components, software components, and/or a combination of hardware and software components.

The communication interface <NUM> is coupled to the circuitry <NUM> via L signal lines. In some embodiments, circuitry <NUM> may reduce the number of required lines from M signal lines to L signal lines. This may be accomplished by any suitable method using any suitable component. For example, MUXs, beamformers, or other components may be used to reduce the required signal lines M from the transducer array <NUM> to L signal lines <NUM>. In the embodiment of <FIG>, L is less than M. The communication interface <NUM> may be configured to transmit the L signals <NUM> to the host <NUM> via the communication link <NUM>. The communication link <NUM> may include L data lanes for transferring the digital signals <NUM> to the host <NUM>, as described in greater detail herein. The communication interface <NUM> may include hardware components, software components, or a combination of hardware components and software components configured to generate signals <NUM>, carrying the information from the L signals <NUM>, for transmission over the communication link <NUM>. The signals <NUM> can be digital signals, analog signals, or a combination of digital signals and analog signals.

The host <NUM> may be any suitable computing and display device, such as a workstation, a personal computer (PC), a laptop, a tablet, a mobile phone, or a patient monitor. The host <NUM> can be referred to as an ultrasound system or an ultrasound host system. In some embodiments, the host <NUM> may be located on a moveable cart. At the host <NUM>, the communication interface <NUM> may receive the digital and/or analog signals <NUM> from the communication link <NUM>. The communication interface <NUM> may include hardware components, software components, or a combination of hardware components and software components. The communication interface may be substantially similar to the communication interface <NUM> in the probe <NUM>.

Circuitry <NUM> positioned within host <NUM> may be any of any suitable type and may serve any suitable function. For example, circuity <NUM> may include resistors, capacitors, transistors, inductors, relays, clocks, timers, processing components, memory components, or any other suitable electrical component that may be integrated in an integrated circuit. In addition, circuitry <NUM> may be configured to support analog signals and/or digital signals transmitted to or from the probe <NUM>. Circuitry <NUM> may be configured to process signals <NUM> received from the probe <NUM>. For example, circuitry <NUM> may expand L signal lines received from the probe <NUM> to the original M signal lines corresponding to specific transducer elements or groups/patches of transducer elements within the transducer array <NUM>. Circuitry <NUM> may additionally include a central processing unit (CPU), a digital signal processor (DSP), a graphical processing unit (GPU), an application-specific integrated circuit (ASIC), a controller, a field-programmable gate array (FPGA), another hardware device, a firmware device, or any combination thereof. Circuitry <NUM> may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a GPU and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. Circuitry <NUM> can be configured to generate image signals <NUM> for display to a user and/or perform image processing and image analysis for various diagnostic modalities or ultrasound types (B-mode, CW Doppler, etc.). For example, the circuitry <NUM> may be configured to process received digital ultrasound signals and generate an ultrasound image of the patient anatomy (e.g. a heart) and output the ultrasound image to the display <NUM>. The circuitry <NUM> can include hardware components, software components, and/or a combination of hardware and software components.

The display unit <NUM> is coupled to circuitry <NUM>. The display unit <NUM> may include a monitor, a touch-screen, or any suitable display. The display unit <NUM> is configured to display images and/or diagnostic results processed by circuitry <NUM>. The host <NUM> may further include a keyboard, a mouse, a touchscreen or any suitable user-input components configured to receive user inputs for controlling the system <NUM>.

While <FIG> is described in the context of transmitting digital ultrasound echo signals from the probe <NUM> to the host <NUM> for display, the host <NUM> can generate signals for transmitting to the probe <NUM>. For example, power signals, signals for controlling the probe <NUM> (e.g., exciting the transducer elements at the transducer array <NUM> to emit energy) can be transmitted by the host <NUM> to the probe <NUM> over the communication link <NUM>.

<FIG> is a schematic diagram of a processor circuit <NUM>, according to aspects of the present disclosure. The processor circuit <NUM> may be implemented in the probe <NUM>, the host system <NUM> of <FIG>, or any other suitable location. One or more processor circuits <NUM> can be configured to perform the operations described herein. The processor circuit <NUM> can include additional circuitry or electronic components, such as those described herein. In an example, the processor circuit <NUM> may be in communication with the transducer array <NUM>, circuitry <NUM>, the communication interface <NUM>, the communication interface <NUM>, circuitry <NUM>, and/or the display <NUM>, as well as any other suitable component or circuit within the ultrasound system <NUM>. In some embodiments, one or more components of the processor circuit <NUM> form at least a portion of the circuitry <NUM> or the circuitry <NUM>. In some embodiments, one or more components of the circuitry <NUM> or the circuitry <NUM> form at least a portion of the processor circuit <NUM>. In some instances, a distinct processor circuit <NUM> is implemented in the probe <NUM> and a distinct processor circuit <NUM> is implemented in the host <NUM>. As shown, the processor circuit <NUM> may include a processor <NUM>, a memory <NUM>, and a communication module <NUM>. These elements may be in direct or indirect communication with each other, for example via one or more buses.

The processor <NUM> may include a CPU, a GPU, a DSP, an application-specific integrated circuit (ASIC), a controller, an FPGA, another hardware device, a firmware device, or any combination thereof configured to perform the operations described herein.

The memory <NUM> may include a cache memory (e.g., a cache memory of the processor <NUM>), random access memory (RAM), magnetoresistive RAM (MRAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read only memory (EPROM), electrically erasable programmable read only memory (EEPROM), flash memory, solid state memory device, hard disk drives, other forms of volatile and non-volatile memory, or a combination of different types of memory. In an embodiment, the memory <NUM> includes a non-transitory computer-readable medium. The instructions <NUM> may include instructions that, when executed by the processor <NUM>, cause the processor <NUM> to perform the operations described herein with reference to the probe <NUM> and/or the host <NUM> (<FIG>). Instructions <NUM> may also be referred to as code. The terms "instructions" and "code" should be interpreted broadly to include any type of computer-readable statement(s). For example, the terms "instructions" and "code" may refer to one or more programs, routines, sub-routines, functions, procedures, etc. "Instructions" and "code" may include a single computer-readable statement or many computer-readable statements.

The communication module <NUM> can include any electronic circuitry and/or logic circuitry to facilitate direct or indirect communication of data between the processor circuit <NUM>, the probe <NUM>, and/or the display <NUM> and/or the display <NUM>. In that regard, the communication module <NUM> can be an input/output (I/O) device. In some instances, the communication module <NUM> facilitates direct or indirect communication between various elements of the processor circuit <NUM> and/or the probe <NUM> (<FIG>) and/or the host <NUM> (<FIG>).

<FIG> is a schematic diagram illustrating example circuitry of an ultrasound imaging probe, according to aspects of the present disclosure. <FIG> provides a more detailed view of the probe <NUM> of the system <NUM> including transmission paths from the probe <NUM> to the host <NUM> and from the host <NUM> to the probe <NUM>.

As shown in <FIG>, the probe <NUM> further includes a housing <NUM>, an optional analog beamformer <NUM>, L circuitry blocks <NUM> (including, e.g., L transmit/receive switches (T/R switches) <NUM>, transmit pulsers <NUM>, preamplifiers <NUM>, analog-to-digital converters (ADCs) <NUM>, a quadrature clock generator <NUM>, in-phase/quadrature mixers <NUM>, <NUM>), a combiner <NUM>, and/or a serializer and high speed current mode logic (CML) <NUM>. The probe <NUM> includes a plurality of circuitry blocks <NUM>, each corresponding to a different signal channel associated with a group or sub-array of transducer elements of the transducer array <NUM>. A connecting cable <NUM> is positioned between the probe <NUM> and the host <NUM> to establish signal communication. In that regard, the probe <NUM> and the host <NUM> can be spaced from one another. The connecting cable <NUM> extends between the probe <NUM> and the host <NUM>. Circuitry within the host <NUM> can transmit signals to circuitry within the probe <NUM> via the cable <NUM>. Circuitry within the probe <NUM> can transmit signals to circuitry within host <NUM> the via the cable <NUM>. The cable <NUM> may include multiple signal lines including conductors, twisted pairs, coaxial cable, twin-axial cables, and/or any other suitable communication pathway for transferring data. The cable <NUM> can include a power conductor <NUM> for transmitting power from the host <NUM> to the probe <NUM>. The cable <NUM> also includes a control signal line <NUM> and a clock line <NUM> for transmitting control and clock signals, respectively, from the host <NUM> to the probe <NUM>. The cable <NUM> can also include one or more digital signal lines <NUM> for transmitting digital ultrasound signals from the probe <NUM> to the host <NUM>, and I/Q signal lines <NUM>, <NUM> for transmitting analog CW Doppler signals from the probe <NUM> to the host <NUM>. The housing <NUM> may be any suitable enclosure of any suitable material and may house any or all of the components described herein. The cable <NUM> may be coupled to the housing <NUM>.

The transmission path from the probe <NUM> to the host <NUM> may begin at the transducer array <NUM> shown in <FIG>. The transducer array <NUM> may be coupled to the housing <NUM>. The transducer array <NUM> may include M transducer elements. As previously stated, in some embodiments, M can be any suitable number and the transducer elements may be of any suitable type and in any suitable arrangement. The transducer array <NUM> generates analog ultrasound signals, or analog electrical signals representative of ultrasound echoes received at one or more transducer elements for any suitable imaging type (e.g., B-mode imaging, CW Doppler imaging, etc.). For CW Doppler imaging, one or more elements of the transducer array <NUM> are continuously emitting ultrasound energy simultaneously as one or more other elements of the transducer array <NUM> are continuously receiving ultrasound echoes (based on the emitted ultrasound energy). For example, half of the acoustic elements in the transducer array <NUM> can be transmitting while half of the acoustic elements in the transducer array <NUM> can be receiving.

The transducer array <NUM> may be in communication with the analog beamformer <NUM> via M signal lines. The analog beamformer <NUM> may be used to reduce the signal lines from the transducer array <NUM> to the rest of the circuitry <NUM> (<FIG>) within the probe <NUM>. For example, in some embodiments, the analog beamformer <NUM> may delay and sum the signals received from the transducer array <NUM> to create a smaller subset. The analog beamformer <NUM> may be a receive beamformer and/or a transmit beamformer. In embodiments in which the analog beamformer is a transmit beamformer, the analog beamformer <NUM> may include or be in communication with high voltage pulse generation circuitry. In other embodiments, for example, in embodiments where the transducer array <NUM> is a one-dimensional array of transducer elements or the number of transducer elements is otherwise reduced, the analog beamformer <NUM> may not be necessary or included within the probe <NUM>. In some embodiments where the transducer array <NUM> is a one-dimensional array or the number of transducer elements is otherwise reduced, the analog beamformer <NUM> may still be included within the probe <NUM>.

The analog beamformer <NUM> may be in communication with multiple T/R switches <NUM> via a reduced number of signal lines (e.g., L signal lines). The probe <NUM> can include one T/R switch <NUM> for every transducer element of the array <NUM> or for every group/patch of transducer elements. The T/R switches <NUM> may be configured to switch positions between different transmit and receive signal paths. For example, in a position for the transmit path, T/R switch <NUM> may transmit a high voltage activation signal from the pulser <NUM> to one or more elements of the transducer array <NUM> to activate one or more elements of the transducer array <NUM> to emit ultrasound energy. In receive mode, the T/R switch <NUM> may transmit receive signals corresponding to reflected waves received by the one or more transducer elements of the transducer array <NUM> to the preamplifier <NUM>. The T/R switches <NUM> may be in communication with the host <NUM> via the control line <NUM> and may receive instructions regarding switching between various signal paths through the control line <NUM>. The T/R switches <NUM> may also be in communication with the host <NUM> through any other suitable conductor or method.

The probe <NUM> may additionally include transmit pulsers <NUM>. The transmit pulsers <NUM> may receive a command signal generated by the host <NUM>. In response to the command signal, the transmit pulsers <NUM> generate electrical excitation pulses timed to cause the transducer array <NUM> to produce an acoustic transmit wave-front with any desired or specified focal characteristics.

The probe <NUM> may include L preamplifiers <NUM>. The preamplifiers <NUM> may amplify signals received from the T/R switches <NUM> to improve the quality of received signals by, for example, reducing a noise floor. In some embodiments, the number of transmit pulsers <NUM> may be equal to the number of the transmit pulsers <NUM> and the number of T/R switches <NUM>. For example, each T/R switch <NUM> may be configured to receive data from one pulser <NUM> and transmit data from the transducer array <NUM> to one preamplifier <NUM>.

The receive signal path can be the same for CW Doppler imaging data and other imaging data (e.g., B-mode imaging data) from the transducer array to the preamplifiers <NUM>. At the preamplifiers <NUM>, the receive signal path diverges within the probe <NUM> to include different, parallel paths for CW Doppler imaging data and other imaging data. In the signal path for other imaging data, such as B-mode imaging data, each preamplifier <NUM> may be in communication with an ADC <NUM>. The ADCs <NUM> may be configured to convert analog ultrasound echo signals into digital ultrasound echo signals. In that regard, the ultrasound probe <NUM> can generate digital ultrasound signals from the analog ultrasound signals and transmit the digital ultrasound signal to the host <NUM>. For example, the ADCs <NUM> may receive analog ultrasound echo signals from the transducer array <NUM> via the T/R switches <NUM> and preamplifiers <NUM> and convert them into digital ultrasound echo signals. Digital ultrasound echo signals may include digital samples representing the waveforms of corresponding analog ultrasound echo signals. The ADCs <NUM> may employ a successive approximation ADC architecture to provide high-performance and lower-power consumption, and thus may keep total power dissipation of the probe <NUM> to be within a thermal budget of the probe <NUM>. However, any suitable ADC architecture may be used for the ADCs <NUM>.

Each ADC <NUM> may be in communication with the combiner <NUM>. The combiner <NUM> is representative of circuitry that can reduce the total signal lines received from the ADCs <NUM> and reduce the number of required signal lines for transmitting data to the host <NUM>. The combiner <NUM> may reduce the number of signal lines by any suitable method. In some embodiments, the combiner <NUM> may include a summing node. The combiner <NUM>, as well as any other suitable component or circuitry within the system <NUM> may include features similar to those described in <CIT> and/or <CIT>. The combiner <NUM> may be a multiplexor and/or a digital beamformer. In some embodiments, the combiner <NUM> may be a multiplexor or may multiplex data received from the ADCs <NUM> into high-speed serial links and then send the data to the host <NUM> to be processed. In some embodiments, the combiner <NUM> may be a digital beamformer that performs a second stage of beamforming (delaying and summing of signals) after the first stage of beamforming is completed by the analog beamformer <NUM>. The combiner <NUM> may be in communication with the serializer and high speed current mode logic (CML) <NUM>. The serializer/CML <NUM> may rearrange lines received from the combiner <NUM> and/or the ADC's <NUM> into a high rate serial data stream. In some embodiments, the serializer/CML <NUM> may run at a higher data rate than other circuitry within the probe <NUM>. For example, the serial data stream may run at <NUM> whereas other circuitry within the ultrasound signal path may run at <NUM>. The serializer/CML <NUM> may operate in a similar manner to the serializer disclosed in <CIT>. Accordingly, in one of the signals paths of the probe <NUM>, digital ultrasound data (e.g., B-mode data) can be transmitted from the probe <NUM> to the host <NUM> via the conductors <NUM>. The conductors <NUM> may be a twisted pairs of conductors, coaxial cables, twin-axial cables, and/or any other suitable signal pathway. In general, one or a plurality of conductors can transmit the digital ultrasound signals from the probe <NUM> to the host <NUM>.

In the parallel CW Doppler imaging path, the ultrasound probe <NUM> generates analog CW Doppler signals from the analog ultrasound signals and transmit the analog CW Doppler signals to the host <NUM>. The circuitry block <NUM> of the ultrasound probe <NUM> includes quadrature clock generators <NUM>. Each quadrature clock generator <NUM> may be in communication with analog I/Q mixers <NUM>, <NUM>. The analog I/Q mixers <NUM>, <NUM> may be disposed within the housing <NUM> and in communication with the transducer array <NUM>. The I/Q mixers <NUM>, <NUM> generate analog CW Doppler signals within the probe <NUM>, which are then transmitted to the host <NUM>. In particular, the I/Q mixers <NUM>, <NUM> generate analog baseband quadrature outputs. <FIG> depicts the I mixers <NUM>, the Q mixers <NUM>, and the quadrature clock generators <NUM> positioned within the probe <NUM>. For each circuitry block <NUM> or ultrasound channel, the respective I/Q mixers generate CW Doppler signals for the ultrasound data corresponding to the associated group or sub-array of acoustic element. The CW Doppler signals from each circuitry block <NUM> may be converted to baseband and summed prior to being transmitted to the host <NUM>. This reduces the number of conductors required to transmit the CW Doppler signal data, compared to if a different conductor was required for each ultrasound channel or circuitry block <NUM>. In some embodiments, the analog CW Doppler signals are transmitted from the probe <NUM> to the host <NUM> via <NUM> signal lines: an I signal line <NUM> corresponding to the output of summed I mixers <NUM> and a Q signal line <NUM> corresponding to the output of summed Q mixers <NUM>. Stated differently, the outputs of the I mixers <NUM> and the Q mixers <NUM>, respectively, are electrically connected in parallel so as to create two signal lines: the I signal line <NUM> and the Q signal line <NUM>. In this way, the I signal line <NUM> carries the summed outputs of the I mixers <NUM> within the housing <NUM> and the Q signal line <NUM> carried the summed outputs of the Q mixers <NUM> within the housing <NUM>.

The quadrature clock generator <NUM> may include two outputs, one of which is in communication with an I mixer <NUM> and the other is in communication with a Q mixer <NUM>. The quadrature clock generator <NUM> may produce a delay difference between the output of the I mixer <NUM> and the output of the Q mixer <NUM>. The delay difference of the Q mixer <NUM> may be equal to one-quarter of a clock phase from the clock signal of the I mixer <NUM> such that the I mixer <NUM> produces an in-phase signal and the Q mixer <NUM> produces a quadrature signal. In some embodiments, the quadrature clock generator <NUM> may generate a signal that is substantially similar to a square wave. The quadrature clock generator <NUM> may include any suitable electrical components to generate the phase difference between the I mixer <NUM> and the Q mixer <NUM>. For example, the quadrature clock generator <NUM> may include one or more edge triggered D flip-flops or any other suitable flip-flops, inverters such as tri-state inverters, or any other suitable electrical component. The quadrature clock generator <NUM> receives power, clock and control signals from the host <NUM> through connections <NUM>, <NUM>, and <NUM>, respectively.

The I mixers <NUM> are positioned within the probe <NUM> with one I mixer <NUM> for each circuitry block <NUM>. In some embodiments, the I mixers <NUM> may be multiplying mixers. In other embodiments, the I mixers <NUM> may be any suitable mixers of any particular type. An I mixer <NUM> may include two inputs. One input may be in communication with the output of the preamplifier <NUM> within a circuitry block <NUM> and may receive ultrasound signals. The other input may be in communication with the output of the quadrature clock generator <NUM>. The I mixer <NUM> may multiply the signal received by the transducer array <NUM> with the signal received from the quadrature clock generator <NUM> and output the result. The output signal from the I mixer <NUM> may therefore correspond to a sum and a difference of the two input signals.

Similar to the I mixer <NUM>, the Q mixers <NUM> are also positioned within the probe <NUM> with one Q mixer <NUM> for each circuitry block <NUM>. The Q mixer <NUM> may also be a multiplying mixer or any other suitable type of mixer. The Q mixer <NUM> may be substantially similar to the I mixer <NUM>. However, the Q mixer <NUM> may differ from the I mixer <NUM> in that it receives a phase shifted signal from the quadrature clock generator <NUM>. However, like the I mixer <NUM>, the Q mixer <NUM> may also multiply two inputs, one corresponding to the output of the preamplifier <NUM> (the electrical signals generated by the transducer array <NUM> in response to the received echoes) and the other in communication with the output of the quadrature clock generator <NUM>. Like the I mixer <NUM>, the Q mixer <NUM> may also reduce the CW Doppler signal content received from the transducer array <NUM> to baseband prior to transmitting to the host <NUM>.

As previously stated, multiple I mixers <NUM> and Q mixers <NUM> are positioned within the probe <NUM>. In some embodiments, an I mixer <NUM> may be present on each circuitry block <NUM> and a Q mixer <NUM> may be present on each circuitry block <NUM>. In some embodiments, the outputs from each I mixer <NUM> and each Q mixer <NUM> may be transmitted via a twisted pair, a coaxial cable, a twin-axial cable, and/or other suitable conductor from the probe <NUM> to the host <NUM>. In other embodiments, and as shown in <FIG>, the outputs of all I mixers <NUM> within the probe <NUM> may be summed together into a single twisted pair <NUM>, coaxial cable, twin-axial cable, or other wire type, corresponding to the I mixer output signal before transmitting to the host <NUM>. In general, one or a plurality of conductors can transmit the I signal from the probe <NUM> to the host <NUM>. Similarly, the outputs of all the Q mixers <NUM> within the probe <NUM> may be summed together into a single twisted pair <NUM>, coaxial cable, twin-axial cable, or other wire type, corresponding to the Q mixer output signal before transmitting to the host <NUM>. In general, one or a plurality of conductors can transmit the Q signal from the probe <NUM> to the host <NUM>. The I signal line <NUM> may be a twisted pair or any other suitable conductor, such as a coaxial cable or twin-axial cable. The Q signal line <NUM> may be substantially similar to the I signal line <NUM>. Because the I/Q outputs, respectively, are connected in parallel, only one signal pathway (e.g., twisted pair, coaxial cable, twin-axial cable, and/or any suitable conductor) is needed to carry the summed I signal on the I signal line <NUM> and only one signal pathway (e.g., twisted pair, coaxial cable, twin-axial cable, and/or any suitable conductor) is needed to carry the summed Q signal on the Q signal line <NUM>. Advantageously, this reduces the quantity of analog CW Doppler signal carrying lines in the cable <NUM>. For example, a CW Doppler signal line for each ultrasound channel (each circuit block <NUM>) is advantageously avoided, as this would add undesired bulk and expense for the cable <NUM>.

The probe <NUM> transmits digital ultrasound data via conductors <NUM> and analog CW Doppler signals via the conductors <NUM> and <NUM>. An advantage of the present disclosure includes maintaining the analog nature of the CW Doppler signals transmitted from the probe <NUM> to the host <NUM>. Transmitting analog CW Doppler signals to the host <NUM> may prevent artefacts in the data inherent in some digital conversion processes. As a result, analog CW Doppler signals may retain original signal quality and lead to better quality images and/or fluid velocity measurements. In addition, analog CW Doppler signals may be processed using similar components or techniques within the host as extant systems, which results in reduced cost of implementation.

<FIG> is a schematic diagram illustrating example circuitry of an ultrasound imaging host system <NUM>, according to aspects of the present disclosure. <FIG> provides a more detailed view of the host <NUM> of the system <NUM> including transmission paths from the probe <NUM> to the host <NUM> and from the host <NUM> to the probe <NUM>. As shown in <FIG>, the host <NUM> may include a controller <NUM>, power supply <NUM>, a B-mode processing circuit block <NUM>, a CW Doppler processing circuit block <NUM>, a fast Fourier transform (FFT) processing block <NUM>, a conditioning block <NUM>, and a display <NUM>.

The controller <NUM> within the host <NUM> may control the operations of any number of components within the probe <NUM> and/or the host <NUM>. For example, the controller <NUM> may control the combiner <NUM> and/or the serializer/CML <NUM> (<FIG>). The controller <NUM> may generate control data for operating the transducer elements at the transducer array <NUM>, for example, for ultrasound wave emissions. The controller <NUM> may further control the analog beamformer <NUM>, the T/R switches <NUM>, the pulsers <NUM>, the preamplifiers <NUM>, and the quadrature clock generators <NUM> (<FIG>). The controller may also be in communication with components within the B-mode processing circuitry block <NUM> and/or the CW Doppler processing circuitry block <NUM>, including an encoder, serializing and/or de-serializing components, transmitters, or any other suitable components within the host <NUM>. In some embodiments, the controller <NUM> could be a processor circuit or could be a part of a processor circuit. The controller <NUM> could be part of the processor circuit <NUM> shown in <FIG>. The control line <NUM> may be in communication with the controller <NUM> within the host <NUM> and may provide signals for controlling components within the probe <NUM>. In some embodiments, the control line <NUM> and/or the clock line <NUM> may be a twisted pair. In other embodiments, the control line <NUM> and/or the clock line <NUM> may be a conductor, coaxial cable, twin-axial cable, and/o any other suitable signal communication pathway for transmitting data signals. In some embodiments, data transmitted via the control line <NUM> may be 800Mbs data, or data of any suitable frequency or type. Signals transmitted from the host <NUM> to the probe <NUM> via control line <NUM> and/or clock line <NUM> may be analog or digital signals. When digital command signals are transmitted, the data may be transmitted via the data line <NUM> at any suitable bit rate, such as between <NUM> Mbit/s and 8Gbit/s, including values such as <NUM>. 4Gbit/s and/or other suitable values both larger and smaller.

The power supply <NUM> may provide power to the host <NUM> and to the probe <NUM> (e.g., any suitable components within the probe <NUM> or the host <NUM>). The power line <NUM> may be in communication with a power supply <NUM> within the host <NUM> or at any suitable location in relation to other components. The power line <NUM> may provide electrical power to various components within the probe <NUM>.

The processing circuit block <NUM> may receive digital ultrasound signals via the signal lines <NUM>. The processing circuit block <NUM> may include any suitable components used for processing digital ultrasound data, generating an ultrasound image, and outputting display data for display to a user of the ultrasound system <NUM> on the display <NUM>. In that regard, the processing circuit block <NUM> can be implemented as hardware components, software components, and/or a combination of hardware and software components. For example, the circuit block <NUM> may include encoders, serializing components, de-serializing components, transmitters, decoders, multiplexors, de-multiplexors, beamformers, or any other suitable components. The circuit block <NUM> may also include signal processing components, scan converter components, controllers, or other components. The circuit block <NUM> may be configured to display to a user a depiction of tissues, organs, or other structures within a patient anatomy. The processing circuit block <NUM> can be used for processing digital B-mode ultrasound imaging signals. In other embodiments, the processing circuit block <NUM> is representative of the circuitry used for may be processing circuitry for any suitable ultrasound imaging type (e.g., B-mode imaging, 3D/4D imaging, M-mode imaging, color flow Doppler imaging, or any other suitable form or type of ultrasound imaging).

The CW Doppler processing circuit block <NUM> receives analog CW Doppler signals via the signal lines <NUM>, <NUM>. The CW Doppler processing circuit block <NUM> may include a plurality of high pass filters (HPFs) <NUM>, anti-aliasing low pass filters (LPFs) <NUM>, and analog-to-digital converters (ADCs) <NUM>. In that regard, the CW Doppler processing circuit block <NUM> can include HPF <NUM>, LPF <NUM>, and ADC <NUM> for each of the I signal pathway and the Q signal pathway. The HPFs <NUM> can be referred to as wall filters. The HPFs <NUM> and the LPFs <NUM> can be analog components.

In the illustrated embodiment, the HPFs or wall filters <NUM> operate on the analog CW Doppler signals. The HPFs <NUM> may be positioned either within the probe <NUM> or the host <NUM> as shown in <FIG>. One HPF <NUM> may be in communication with the summed output of I mixers <NUM> via I signal line <NUM> and an additional HPF <NUM> may be in communication with the summed output of Q mixers <NUM> via Q signal line <NUM>. The wall filters <NUM> may include additional circuitry within the host <NUM>. The wall filters <NUM> may also include op amps. The HPFs <NUM> may filter out low Doppler signals corresponding to arterial walls or any other static tissue within a patient. The HPF <NUM> may additionally filter high amplitude low frequency content from movement within a patient from, for example, heart beats, general patient or probe movement, or other movement. In some embodiments, the HPF <NUM> may be an aggressive filter.

After signals are processed through the HPF <NUM>, a LPF <NUM> may be used to remove high frequency energy that would otherwise be aliased into the pass band by the sampling function of analog to digital convertor <NUM>. In that regard, CW Doppler ultrasound signals are obtained when a high frequency ultrasound energy is emitted by the transducer array <NUM> and propagates into the anatomy of a patient. Ultrasound echoes, based on the emitted ultrasound energy, that are received at the transducer array <NUM> may be of a slightly higher or lower frequency compared to the emitted ultrasound energy and correspond to moving liquids such as blood flow. The relevant information for CW Doppler imaging to be extracted from the ultrasound signal is then the difference between the transmitted and received ultrasound energy. The output of the I mixer <NUM> corresponding to the sum and difference between the inputs of the I mixer <NUM> may then be filtered by LPF <NUM> to remove the high frequency content corresponding to the sum, leaving only the lower audio-level frequencies or baseband frequencies for additional processing. This filtering may be performed within the probe <NUM>, within the circuitry block <NUM>, or within the host <NUM> after signals have been transmitted to the host <NUM>. The output of the Q mixer <NUM> may also be filtered by LPF <NUM> like the I mixer <NUM>. This filtering may be performed within the probe <NUM>, within circuitry block <NUM>, or within the host <NUM> after signals have been transmitted to the host <NUM>.

Following the LPF <NUM>, one or more analog-to-digital converters (ADCs) <NUM> may be utilized to convert analog CW Doppler signals to digital CW Doppler signals. In some embodiments, the ADCs <NUM> could be positioned after the LPF <NUM> and before the FFT <NUM>. However, in other embodiments, the ADCs <NUM> may be positioned at any other location within the host <NUM> along the signal chain. For example, the ADCs <NUM> could be positioned before the HPFs <NUM>, between the HPFs <NUM> and the LPF <NUM> or at any other suitable location. All circuitry after the position of the ADCs <NUM> may therefore be of a digital implementation or could be implemented via software and/or hardware circuitry, while processing circuits before the positions of the ADC's <NUM> in the signal chain may be of an analog implementation. Thus, in the illustrated embodiment of <FIG>, the HPF <NUM> and the LPF <NUM> can be analog components. In other embodiment, the HPF <NUM> and the LPF <NUM> could be digital components.

The fast Fourier transform (FFT) <NUM> may be applied to the signal data output from the CW Doppler processing circuitry block <NUM> to create a Doppler spectrum associated with velocity of movement within a patient. Following the FFT <NUM>, the signal data may be further processed at conditioning <NUM> and then output for display to a user via display <NUM>. In that regard, for CW Doppler imaging, a graphical representation of distribution of blood flow velocities is output via the display <NUM>. It is fully contemplated that any suitable form of data processing may be applied to the signal data at this or any stage in the circuitry of the present invention. For example, the host <NUM> may apply additional data processing techniques to enhance the quality of the signal data, identify or emphasize various characteristics or aspects of the signal data, etc..

<FIG> additionally depicts the connecting cable <NUM> positioned between the probe <NUM> and the host <NUM>. The cable <NUM> may include multiple signal lines including conductors, twisted pairs, coaxial cables, twin-axial cables, or any other suitable communication pathway of transferring data. In some embodiments, the cable can be replaced with an optical or a wireless interface. For example, the cable <NUM> may include the control line <NUM>, the power line <NUM>, the clock line <NUM>, and multiple signal lines <NUM> previously discussed. Multiple signal lines <NUM> may correspond to a reduced number of signal lines output from the combiner <NUM> and/or the serializer/CML <NUM>. In some embodiments, the signal lines <NUM> may include only a single signal line. In other embodiments, the signal lines <NUM> may include more than one. The cable <NUM>, and any corresponding cables enclosed within the cable <NUM> such as the control line <NUM>, the clock line <NUM>, the signal lines <NUM>, the power line <NUM>, and/or the I mixer line <NUM> and the Q mixer line <NUM> may be of any suitable length and/or may be a flexible elongate member. For example, the cable <NUM> and all associated conductors may be <NUM> meter, <NUM> meters, <NUM> meters in length, or more, or any suitable length therebetween.

In some embodiments, the B processing circuitry block <NUM> and the CW Doppler processing circuitry block <NUM> are composed of separate components and separate signal paths. In some embodiments, components or sets of components within the processing circuitry block <NUM> may be shared with the CW Doppler processing circuitry block <NUM> or any other circuitry or components within the host <NUM>.

In some embodiments, the B-mode processing circuitry block <NUM> could be a processor circuit or could be a part of a processor circuit. The B-mode processing circuitry block <NUM> could be part of the processor circuit <NUM> shown in <FIG>. The B-mode processing circuitry block <NUM> could include any sort of suitable processing circuit including one or more of any components of the processor circuit <NUM>. Similarly, the CW Doppler processing circuitry block <NUM> could be a processor circuit or could be a part of a processor circuit or could be part of the processor circuit <NUM> shown in <FIG>. The CW Doppler processing circuitry block <NUM> could also include any sort of suitable processing circuit including one or more of any component of processor circuit <NUM>.

<FIG> is a schematic diagram illustrating an example ultrasound transducer array <NUM>, according to aspects of the present disclosure. The ultrasound transducer array <NUM> includes multiple ultrasound transducers <NUM> arranged into sub-arrays <NUM>.

The transducer array <NUM> shown in <FIG> may be a <NUM>. X-dimensional or two-dimensional matrix of ultrasound elements <NUM>. The transducer array <NUM> may be substantially similar to the transducer array <NUM> of <FIG> and/or <FIG>. In other embodiments, the transducer array <NUM> may also be a <NUM>-dimensional linear array, or any other suitable type of array. As previously mentioned in regards to the transducer array <NUM>, the transducer array <NUM> may include any suitable number of transducer elements <NUM>. The transducer elements <NUM> may be arranged within the transducer array <NUM> in multiple sub-arrays <NUM>. The sub-arrays <NUM> may additionally be referred to as groups or patches, among other suitable terms. Each sub-array <NUM> may include four transducer elements <NUM>, or any other suitable number of transducer elements <NUM>. For example, the sub-array <NUM> may comprise <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or more transducer elements <NUM> as well as any suitable number therebetween. In addition, in some embodiments, each sub-array <NUM> need not include the same number of transducer elements <NUM>, but each could vary according to any suitable arrangement or pattern. It is noted that the spacing between the sub-arrays <NUM> shown in <FIG> does not necessarily indicate physical spacing or separation within the array <NUM>. For example, each of the transducer elements <NUM> in the array can have the same space with each adjacent element (whether or not that element is part of the same sub-array <NUM>). Rather, the spacing shown in <FIG> can be illustrative of the sub-array groupings.

<FIG> is a schematic diagram illustrating example circuitry of an analog beamformer <NUM>, according to aspects of the present disclosure. The analog beamformer <NUM> may be substantially similar to the analog beamformer <NUM> of <FIG>. <FIG> provides a more detailed view of the analog beamformer <NUM>, which may be implemented within the ultrasound probe. The analog beamformer <NUM> includes multiple transmit pulsers <NUM>, preamplifiers <NUM>, delay circuits <NUM>, a summation component <NUM>, and conductors <NUM> providing power, clock, and/or control signals to any of these components. <FIG> additionally depicts one sub-array <NUM> including multiple ultrasound transducer elements <NUM>. The sub-array <NUM> shown in <FIG> may be one of the sub-arrays <NUM> shown in <FIG> or may be a different sub-array.

The transmit pulsers <NUM> may be substantially similar to the pulsers <NUM> of <FIG>. Specifically, the transmit pulsers <NUM> may receive command signals from the host and in response to these command signals, transmit high-voltage pulses to activate the ultrasound elements <NUM> to emit ultrasound energy that propagates into a patient's anatomy. Each ultrasound element <NUM> may therefore correspond to and/or be in communication with a transmit pulser <NUM>.

Multiple preamplifiers <NUM> are additionally depicted in <FIG>. The preamplifiers <NUM> may be substantially similar to the preamplifiers <NUM> of <FIG>. The preamplifiers <NUM> may amplify signals received from the ultrasound elements <NUM> to improve the quality of received signals by, for example, reducing a noise floor.

Multiple delay circuits <NUM> may be in communication with the preamplifiers <NUM> within the analog beamformer <NUM>. The delay circuits <NUM> may be of any suitable type. For example, the delay circuits <NUM> may include analog delay circuitry for the analog beamformer <NUM>. The delay circuits <NUM> may apply a delay profile to signals received from the ultrasound transducers <NUM> so as to perform beamforming in relation to all elements within a sub-array <NUM> or partial beamforming. Such delay profiles may be provided to the delay circuits <NUM> via any suitable method. For example, in some embodiments, a conductor corresponding to control or clock data within the conductors <NUM> may be in communication with the delay circuits <NUM> and may dictate delay profiles for the delay circuits <NUM>.

<FIG> additionally depicts a summation component <NUM>. The summation component <NUM> may be an analog adder circuit, summing mixer, or any suitable electronic component for summing signals. The summation component <NUM> is in communication with the respective outputs of the delay circuits <NUM>. In such a configuration, the signals output from each delay circuit <NUM> may be summed in an analog fashion. In other embodiments, the summation component <NUM> may comprise any suitable circuitry or configuration to otherwise combine signals from the outputs of the delay circuits <NUM>. The output of the summation component <NUM> may then be in communication with one or more T/R switches <NUM> from <FIG> and the signals combined by the analog beamformer <NUM> may be further processed and/or combined within the probe <NUM> and/or the host <NUM> as has been described or in any other suitable way.

<FIG> is a flow diagram of an ultrasound imaging method <NUM>, according to aspects of the present disclosure. As illustrated, the method <NUM> includes a number of enumerated steps, but embodiments of the method <NUM> may include additional steps before, after, or in between the enumerated steps. In some embodiments, one or more of the enumerated steps may be performed concurrently. The steps of the method <NUM> can be carried out by any suitable component within ultrasound imaging system <NUM> and all steps need not be carried out by the same component. In some embodiments, one or more steps of the method <NUM> can be performed by, or at the direction of, a processor circuit of the ultrasound imaging system <NUM>, including, e.g., the processor <NUM> (<FIG>) or any other component.

At step <NUM>, the method <NUM> includes generating analog ultrasound signals. Command signals may be generated at the host <NUM> and transmitted to the probe <NUM> via the signal line <NUM>. The pulsers <NUM> may consequently generate a signal to excite the transducer elements of the transducer array <NUM> to generate ultrasound waves (<FIG>). The transducer array <NUM> may then also receive echo signals reflected from features in the patient's anatomy and generate analog electrical signals representative of the ultrasound echoes. The generated analog ultrasound signals may then be transmitted to the circuitry block(s) <NUM> (<FIG>).

At step <NUM>, the method <NUM> includes generating, based on the analog ultrasound signals, analog continuous wave (CW) Doppler signals with in-phase/quadrature (I/Q) mixers within the ultrasound probe <NUM>. The CW Doppler signals may be generated using multiple I mixers <NUM> and Q mixers <NUM> (<FIG>). The I mixers <NUM> and Q mixers <NUM> may include multiplying mixers or any other suitable type of mixer. The probe <NUM> may include one or more quadrature clock generators <NUM> (<FIG>) which may provide an additional input to the I mixers <NUM> and the Q mixers <NUM> to reduce analog ultrasound signals to baseband frequencies and create an appropriate phase shift between the output of the I mixers <NUM> and the output of the Q mixers <NUM>.

At step <NUM>, the method <NUM> includes transmitting the analog CW Doppler signals to a processor circuit within the host <NUM>. The CW Doppler signals may be transmitted to the host <NUM> via the cable <NUM>, conductors, twisted pairs, coaxial cables, twin-axial cables, or any other appropriate signal line within the cable <NUM>, or via any suitable method.

At step <NUM>, the method <NUM> includes processing the analog CW Doppler signals. Processing of the analog CW Doppler signals may include any suitable data processing component or procedure, including filtering via low pass filters, high pass filters or any suitable type of filter. Data processing may additional include windowing, summations, averaging, smoothing, transformations from one domain to another, such as with fast Fourier transforms, and any other suitable conditioning to improve the overall data quality, clarity, or presentation. Signal processing may additionally include converting analog CW Doppler signals to digital CW Doppler signals. In such an embodiment, signal processing may also be performed digitally, via a standard personal computer and/or processor, in software form, or with hardware, such as physical circuitry within the host <NUM> or via any other suitable method or form.

At step <NUM>, method <NUM> includes generating graphical representations of blood flow velocities over one or multiple cardiac cycles. Graphical representations may include any suitable data presentation. For example, graphical representations may include simple lists of data including time, velocities, dimensions, or data relating to the location of an imaged object within a patient's anatomy. Graphical representations may additionally include a Doppler spectrum or other applicable spectrum, plot, or other graphical representation. Graphical representations may also include any suitable plots, pictures, or depictions which may convey to a user information regarding the health or physical state of a patient. Graphical representations of the distribution of blood flow velocities, or other fluid velocities, may be output to a display <NUM> (<FIG>) in communication with the processor circuit <NUM> (<FIG>) or any other suitable processor described herein.

Claim 1:
An ultrasound probe (<NUM>) adapted to communicate with an ultrasound system (<NUM>), the ultrasound probe comprising:
a transducer array (<NUM>) configured to generate analog ultrasound signals (<NUM>);
analog in-phase/quadrature (I/Q) mixers (<NUM>, <NUM>) disposed within a housing (<NUM>) of the ultrasound probe and in communication with the transducer array, wherein the analog I/Q mixers are configured to generate analog continuous wave (CW) Doppler signals based on the analog ultrasound signals; and
a cable (<NUM>) coupled to the housing, wherein the cable is configured to transmit the analog CW Doppler signals from the ultrasound probe to the ultrasound system.