CORONARY ARTERY DISEASE DETECTION SIGNAL PROCESSING SYSTEM AND METHOD
An auscultatory sound signal acquired by a recording module is coupled through a high-pass filter having a cut-off frequency in the range of 3 to 15 Hz and subsequently filtered with a low-pass filter, and optionally subject to variable-gain amplification under external control—via a USB or wireless interface—of an associated docking system, responsive to the resulting processed auscultatory sound signal. A sound generator in the docking system generates an associated test signal having an integral number of wavelengths for each of a plurality of frequencies. The test signal is applied to a corresponding auscultatory sound-or-vibration sensor to test the integrity thereof. Resulting sound signals recorded by the recording module are analyzed using a Fourier Transform to determine sensor integrity.
The instant application claims the benefit of the U.S. Provisional Application Ser. No. 62/575,364 filed on 20 Oct. 2017, which is incorporated herein by reference in its entirety.
BRIEF DESCRIPTION OF THE DRAWINGSIn the accompanying drawings:
Referring to
As used herein, the terms “auscultatory sound” and “auscultatory sound or vibration” are each intended to mean a sound or vibration originating from inside a human or animal organism as a result of the biological functioning thereof, for example, as might be generated by action of the heart, lungs, other organs, or the associated vascular system; and is not intended to be limited to a particular range of frequencies—for example, not limited to a range of frequencies or sound/vibration intensities that would be audible to a human ear,—but could include frequencies above, below, and in the audible range, and sound/vibration intensities that are too faint to be audible to a human ear. Furthermore, the terms “auscultatory-sound sensor” and “auscultatory sound-or-vibration sensor” are each intended to mean a sound or vibration sensor that provides for transducing auscultatory sounds or vibrations into a corresponding electrical or optical signal that can be subsequently processed, and is not limited to a particular mode of transduction.
The auscultatory sound-or-vibration sensors 14, 14′ are operatively coupled—for example, by one or more cables or cable assemblies 30 between the auscultatory sound-or-vibration sensors 14, 14′ and a magnetically-secured electrical connector 32—to a recording module 34 that provides for preprocessing, and in some embodiments, locally storing, the auscultatory sound signals 36 that are transduced by the one or more auscultatory sound-or-vibration sensors 14, 14′. In some embodiments, the recording module 34 also provides for preprocessing, and in some embodiments, locally storing, an electrographic signal 38 generated by an associated ECG sensor 28, 28′, 28″. The magnetically-secured electrical connector 32 is removably attached to the recording module 34 by a magnetic attraction therebetween, with associated permanent magnets incorporated in one or both of the magnetically-secured electrical connector 32 or the recording module 34.
Referring also to
For example, referring to
and the second high-pass filter 44.2 comprises a second order Butterworth Sallen-Key filter, for which the associated cut-off frequency fc2 is given by:
The first high-pass filter 44.1 incorporates a balanced, differential input 52, each leg of which comprises a series, first R-C network 54 feeding a parallel, second RC network 56, the latter of which is in parallel with corresponding non-inverting 58.1 and inverting 58.2 inputs of an associated instrumentation amplifier 58 of the associated, below-described, first embodiment of the controllable gain amplifier 46, 46.1. The associated EMI protection circuit 42 comprises R-C network R86-C85.
Referring to
A differential measurement system—such as the high-pass filter 44, 44″ illustrated in
However, for the high-pass filter 44, 44″ illustrated in
Referring to
Accordingly, in one set of embodiments, the second embodiment of the high-pass filter 44, 44″ is used for receiving and filtering a corresponding auscultatory sound signal 36 from a corresponding auscultatory sound-or-vibration sensor 14, 14′, and the third embodiment of the high-pass filter 44, 44′″ is used for receiving and filtering a corresponding electrographic signal 38 from the ECG sensor 28, 28′, 28″. The body shielding ground 78 can be located anywhere on the skin 22 of the test subject 12. In one set of embodiments, the connection of the body shielding ground 78 is made via a conductive plate on the bottom side of the recording module 34, 34.1 that rests upon the skin 22 of the test subject 12 during the test. When measuring electrographic signals 38 from the ECG sensor 28, 28′, 28″, the body shielding ground 78 may be provided by an associated ground electrode 27° of the ECG sensor 28, 28′, 28″.
Referring again to
wherein RG is the effective resistance across the remaining two input terminals 58.3, 58.4 of the INA188 differential-input instrumentation amplifier 82. The controllable gain amplifier 46, 46.1 further comprises a fixed resister RG0 across input terminals 58.3, 58.4 of the INA188 differential-input instrumentation amplifier 82, and further comprises an array of N=4 selectable resistors RG1, RG2, RG3, RG4, each of which is in series with a corresponding respective controllable analog switch SW1, SW2, SW3, SW4 under control of a corresponding, respective logic bit control signal C1, C2, C3, C4, wherein each series combination is in parallel with the fixed resister RG0 across input terminals 58.3, 58.4 of the INA188 differential-input instrumentation amplifier 82. The resistance of each of the controllable analog switches SW1, SW2, SW3, SW4 in the ON state is negligible in comparison with the corresponding resistances of the associated selectable resistors RG1, RG2, RG3, RG4. The N=4 logic bit control signals C1, C2, C3, C4 provide for 16 different possible combinations, with a corresponding effective resistance across the input terminals 58.3, 58.4 of the INA188 differential-input instrumentation amplifier 82 ranging in value between RG0 and the parallel combination of all five resistors, i.e. RG0//RG1//RG2//RG3//RG4. In general, for N selectable resisters, there would be 2N different possible values of effective resistance RG. The resulting total effective gain of the controllable gain amplifier 46, 46.1 is then given by:
wherein the symbol “//R” means a parallel combination of that resistance with the remaining resistances if the corresponding controllable analog switch SW1, SW2, SW3, SW4 is activated, and means a parallel combination with an infinite resistance if the corresponding controllable analog switch SW1, SW2, SW3, SW4 is not activated.
Referring to
Referring to
Referring again to
Referring also to
More particularly, referring to
The associated set of high-pass cut-off frequencies fc1H, fc2H of the fixed gain, full-differential band-pass filter 90, 90.2 are given by:
and the associated set of low-pass cut-off frequencies fc1L, fc2L of the fixed gain, full-differential band-pass filter 90, 90.2 given by:
The associated EMI protection circuit 42 comprises R-C network R3-C2.
Referring to
The component parameters of the circuit elements of the fixed gain, full-differential band-pass filter 90, 90.2 are adapted to the associated sensor that is the source of the signal being processed thereby. For example, in accordance with a first embodiment 90.2′, the fixed gain, full-differential band-pass filter 90, 90.2, 90.2′ is adapted to cooperate with a first aspect, passive, auscultatory sound-or-vibration sensor 14, 14′, with capacitors Cm or C4 and C8 each having a value of 1 microfarad, with capacitors CH2 or C5 having a value of 22 microfarads, and with the gain resistor RG or R10 having a value of 2 KOhm so as to provide for a fixed gain of 33 dB to satisfy the requirements of a particular first aspect, passive, auscultatory sound-or-vibration sensor 14, 14′, resulting in a 6 Hz cut-off frequency of the high-pass filter, so that the associated band-pass filter has a pass band of 6 Hz to 2 kHz. As another example, in accordance with a second embodiment 90.2″, the fixed gain, full-differential band-pass filter 90, 90.2, 90.2″ is adapted to cooperate with a microphone or background noise sensor 97 that provides for sensing the background sounds in the room in which the signals are gathered, so as to provide for prospectively compensating for a prospective adverse effect thereof on the auscultatory sound signals 36 that might otherwise interfere with the detection of cardiovascular disease, or might otherwise contribute to a false detection thereof. More particularly, for example, in one embodiment, the audio signal 97′ from the microphone or background noise sensor 97 is processed by a corresponding signal preprocessing channel 40, 40.8 of the fixed gain, full-differential band-pass filter 90, 90.2, 90.2″ for which the single-ended input (+) to which the microphone or background noise sensor 97 is connected to a +2 volt DC supply through a pull-up resistor RPULL, the remaining input (−) is connected to signal ground, with capacitors Cm or C4 having a value of 0.22 microfarads, with capacitors CH2 or C5 having a value of 2.2 microfarads, and with the gain resistor RG or R10 having a value of 2 KOhm so as to provide for a fixed gain of 33 dB to satisfy the requirements of the microphone or background noise sensor 97, resulting in a 70 Hz cut-off frequency of the high-pass filter, so that the associated band-pass filter has a pass band of 70 Hz to 2 kHz, which provides for filtering what can be relatively prevalent acoustic noise in frequencies below 70 Hz that are otherwise outside a range of interest.
As yet another example, in accordance with a third embodiment 90.2′″, the fixed gain, full-differential band-pass filter 90, 90.2, 90.2′″ is adapted to cooperate with a set of second aspect 14″, active auscultatory sound-or-vibration sensors 14, 14″, each of which requires power to operate, for example, each second aspect auscultatory sound-or-vibration sensor 14, 14″ comprising an accelerometer incorporating an integrated circuit that requires power to operate. More particularly, for example, in one embodiment, the associated corresponding signal preprocessing channel(s) 40, 40.1, 40.2, 40.3, 40.4, 40.5, 40.6 of the fixed gain, full-differential band-pass filter 90, 90.2, 90.2′″ each incorporate a 2 milliampere current source provided by an associated current regulator 98 powered from a +12.7 volt DC supply, with capacitors Cm or C4 and C8 having a value of 1 microfarad, with capacitors CH2 or C5 having a value of 22 microfarads, and with the gain resistor RG or R10 having a value of 4.99 KOhms so as to provide for a fixed gain of 26 dB to satisfy the requirements of a particular first aspect, passive, auscultatory sound-or-vibration sensor 14, 14′, resulting in a 4 Hz cut-off frequency of the high-pass filter, so that the associated band-pass filter has a pass band of 4 Hz to 2 kHz. Alternatively, in another embodiment, a gain resistor RG or R10 having a value of 14.3 KOhms so as to provide for a fixed gain of 7.5 dB to satisfy the requirements of a different first aspect, passive, auscultatory sound-or-vibration sensor 14, 14′, results in a 3 Hz cut-off frequency of the high-pass filter, so that the associated band-pass filter would have a pass band of 3 Hz to 2 kHz.
Compared to the fixed gain, full-differential band-pass filter 90, 90.2 illustrated in
Referring again to
Generally, the high-pass filters 44, 44′, 44″, 44″ or the input-stage second-order high-pass filter network 94 of the associated band-pass filters 90, 90.1, 90.2, 90.2′, 90.2″, 90.2′″ are configured with a 3 dB cut-off frequency in the range of 3 Hz to 15 Hz to process an auscultatory sound signal 36 from an auscultatory sound-or-vibration sensor 14, 14′, 14″, 1 Hz-3 Hz when used to process an electrographic signal 38 from an ECG sensor 28, 28′, 28″, and 65 Hz-75 Hz when used to process an audio signal 97′ from a microphone or background noise sensor 97; and the low-pass filters 48, 48′ or the output-stage second-order low-pass filter network 96 of the associated band-pass filters 90, 90.1, 90.2, 90.2′, 90.2″, 90.2′″ are configured with a 3 dB cut-off frequency in the range of 500 Hz to 2.5 kHz.
Referring again to
In one set of embodiments, for example, incorporating a wireless interface 102, the recording module 34, 34.1, 34.2 is powered by a battery 110, for example, a nominally 3.7 V lithium-ion battery 110′, the charge of which is under control of a battery management and monitoring system 112 responsive to current, voltage and temperature, for example, by an STC3100 integrated circuit from STMicroelectronics, as described in STMicroelectronics, “STC3100 Battery monitor IC with Coulomb counter/gas gauge,” January 2009, 21 pages, the latter of which is incorporated herein by reference in its entirety. The battery management and monitoring system 112 is programmable, and readable, through an I2C interface. Alternatively, the battery management and monitoring system 112 may be integrated with the battery 110, for example, using an RRC1120 Li-ion Semi-Smart Battery Pack from RRC Power Solutions. The battery 110 is charged by an associated battery charger 114 from an external +5V power supply via an associated power jack 116. Power from the battery 110 is provided through a power switch 118 under control of the battery management and monitoring system 112, to one or more DC-DC power supplies 120 that provide power to the electronics of the recording module 34, 34.1, 34.2, wherein the recording module 34, 34.1, 34.2 is automatically powered down if the voltage of the of the battery 110, 110′ is less than a threshold, for example, less than 3.3 V.
Alternatively, in another set of embodiments, for example, incorporating a USB interface 104, the recording module 34, 34.1, 34.2 is powered directly from the +5 volt power supply of the USB interface 104, thereby precluding a need for a battery 110, 110′, battery management and monitoring system 112, or battery charger 114, which may be therefore be excluded embodiments that are connected to the docking system 100, 100.1, 100.2 exclusively via a USB interface 104. For example, in some hospital environments, a wireless interface 102 would not be suitable because of interference with other wireless-based systems. In systems incorporating both wireless 102 and USB 104 interfaces, a battery bypass switch 121 provides for switching from battery power to USB power when the USB interface 104 is active.
Referring again to
Referring to
For example, the COM Express Compact Module 122, 122′ performs high-speed functions of the docking system 100, 100.2, for example, including control of, or communication with: 1) USB ports for the recording module 34, 34.1, 34.2, WIFI or Bluetooth® adapter 138, a wireless access point, etc.; 2) Gigabit Ethernet; 3) Audio codec that supports sensor integrity test signal output, input from a microphone or background noise sensor 97, and headphone output; 4) HDMI and DP interfaces for LCD monitors; 5) high performance processor for GUI and DAA; 6) SSD for storage of the operating system, application software and recorded test subject data; and 7) communication with an associated Microprocessor Control Unit (MCU) 140 via a UART port for hardware control and status. The Microprocessor Control Unit (MCU) 140 performs low-speed functions of the docking system 100, 100.2, for example, including the following monitoring, control and communication activities: 1) monitoring all voltage and current of various voltage regulators; 2) monitoring the board temperature; 3) controlling the LCD backlight brightness; 4) detecting the open or close status of the lid of the docking system 100, 100.2; 5) controlling the LED indictor for system status; 6) monitoring the power button status; 7) controlling and monitoring the fan speed; 8) accessing an optional EEPROM memory chip; 9) communicating with the COM Express Compact Module 122, 122′ via a UART port for hardware control and status; and 10) accessing an ID chip 141 for the serial number, wherein the ID chip 141 provides a unique, factory-lasered 64-bit serial number that can be used to identify the hardware and system in the associated data that is captured by the docking system 100, 100.2 form the recording module 34, 34.1, 34.2.
Referring to
Referring to
For example, in accordance with one set of embodiments, each of the plurality of sound generators 146 of the array 145 comprises a piezoelectric sound generator 146, 146′ similar in construction to the piezoelectric sensor disk of the auscultatory sound-or-vibration sensors 14, as described in U.S. Provisional Application No. 62/568,155 incorporated herein by reference, but with an AC signal applied across the associated piezoelectric material, which causes the piezoelectric sensor disk to vibrate, and causes the associated metallic diaphragm disk substrate to act as a speaker to generate sound. Each piezoelectric sound generator 146, 146′ is located at the base of a well 148 that is sized to receive a corresponding auscultatory sound-or-vibration sensor 14 to be tested and align each auscultatory sound-or-vibration sensor 14 with a corresponding sound generator 146, 146′, with the metallic diaphragm disk substrate of the piezoelectric sound generator 146, 146′ facing upwards so as to abut the polyester film layer covering the piezoelectric sensor disk of the corresponding auscultatory sound-or-vibration sensor 14 when the latter is placed in the corresponding well 148 when performing an integrity-test thereof.
In accordance with one set of embodiments, the piezoelectric sound generators 146, 146′ are picked as a batch of transducers with similar frequency response (+−5 dB from median) within the frequency range of 0 to 2 kHz.
For example, referring to
In accordance with the second aspect 100.2 of the docking system 100, 100.2, the piezoelectric sound generators 146, 146′ are driven either by an amplified analog signal 150′ from an audio amplifier 152 that is driven by an analog signal 150 from an audio CODEC 154, or directly from the audio CODEC 154 the latter of which is driven by a digital signal 156 from the COM Express Compact Module 122, 122′ based upon an associated test signal that is stored on a file, for example, on the associated solid-state disk 139, responsive to an associated integrity-test software application running on the COM Express Compact Module 122, 122′. In accordance with the third aspect 100.3 of the docking system 100, 100.3, the piezoelectric sound generators 146, 146′ are driven from an audio signal generator card 158 by an amplified analog signal 160′ from an audio amplifier 152 driven by an analog signal 160 from a digital-to-analog converter 162 driven by a micro-controller 164 either responsive to a digital signal waveform 166 stored on flash memory 168, or generated in real time by the micro-controller 164, responsive to a stored program on EEPROM 170. For example, in accordance with one set of embodiments, the associated amplified analog signal 150′, 160′ from the audio amplifier 152 is applied in parallel to each of the piezoelectric sound generators 146, 146′ of the array 145. In one set of embodiments, the audio signal generator card 158 is powered from an AC-powered 19 VDC power supply 172, wherein the power therefrom is also coupled to the panel PC 142. In one set of embodiments, the panel PC 142 is grounded to earth ground 174 by connection to the audio signal generator card 158. Alternatively, if another source of earth ground 174 is established for the panel PC 142, or if the panel PC 142 is configured so as to not require an earth ground 174, then the 19 VDC power supply 172 could be connected directly to the panel PC 142, rather than via the audio signal generator card 158. Furthermore, the second USB interface 142.3 on the panel PC 142 may be used to provide +5 VDC to the audio signal generator card 158 by connection to a USB port 176 on the audio signal generator card 158, the latter of which can also be used to receive associated control signals from the panel PC 142 that provide for initiating the sensor integrity test.
Referring to
More particularly, referring to
Looking ahead, for each auscultatory sound-or-vibration sensor 14, a sample of NFFT samples of the associated acoustic signal 36′—generated responsive to an acoustic stimulus by the piezoelectric sound generators 146, 146′ responsive to the sensor test acoustic-frequency waveform W, and sampled at a sampling frequency of FS Hz, for example, 24 kHz—are transformed from the time domain to the frequency domain by a Short Time Fourier Transform (STFT) process, wherein specific frequency components in the frequency domain output are then analyzed to assess the integrity of the auscultatory sound-or-vibration sensors 14. Accordingly, in order to mitigate against spectral leakage by an associated non-windowed NFFT-point Fast Fourier Transform (FFT) algorithm, the actual test frequencies FA, FB, FC, FD underlying the corresponding NFFT-point time-domain sensor test acoustic-frequency waveform W are adapted so that each has an integral number of associated cycles therewithin, or equivalently, so that each test frequency FA, FB, FC, FD is an integral multiple of the sampling frequency FS divided by the number of samples NFFT in the time-domain sensor test acoustic-frequency waveform W, i.e., an integral multiple of FS/NFFT. Accordingly, in step (2204), this condition may be satisfied by the following test frequencies FA, FB, FC, FD that are relatively close to the nominal test frequencies F′A, F′B, F′C, F′D:
Accordingly, for the nominal test frequencies F′A=500 Hz, F′B=650 Hz, F′C=800 Hz and F′D=1100 Hz, and for NFFT=4096 points, the corresponding resulting actual test frequencies (and number of cycles in the sensor test acoustic-frequency waveform W auscultatory sound-or-vibration sensors 14) are respectively, FA=498.046875 Hz (85 cycles), FB=650.390625 Hz (111 cycles), FC=802.734375 Hz (137 cycles) and FD=1101.5625 Hz (188 cycles), wherein each test frequency FA, FB, FC, FD is evenly divisible by FS/NFFT=5.859375 Hz
Then, in step (2206), the result of which is illustrated in
Then, in step (2208), the resulting sensor test acoustic-frequency waveform W—or, equivalently, the associated set of parameters by which it is generated—is stored in the docking system 100, 100.1, 100.2, 100.3 for subsequent use in driving the plurality of sound generators 146 during the auscultatory-sensor integrity-test procedure 2400.
Referring to
Then, in step (2404), the docking system 100, 100.1, 100.2, 100.3 causes the recording module 34, 34.1, 34.2 to preprocess and record ΔTTEST seconds of acoustic signals 36′, for example, a duration of about five seconds, sufficient to span a plurality of NFFT-point frames of the acoustic signals 36′, each recorded at a sampling rated of Ns Hz, resulting in a total of NS×ΔTTEST samples. Then, in step 2406, the recorded acoustic signals 36′ of a time-series A—containing NS×ΔTTEST samples—are transferred to the docking system 100, 100.1, 100.2, 100.3, for example, via either a wireless 102 or USB 104 interface.
Then, in step 2408, the acoustic signals 36′ from each of the plurality of auscultatory sound-or-vibration sensors 14 are processed, beginning with step (2410), by initializing a pointer i0 to point to the beginning of the first NFFT-point frame of the acoustic signal 36′ to be processed—i.e. the acoustic data 36′—, and by initializing a frame counter k to a value of zero. Then, in step (2412), a pointer iMAX is set to point to the last sample of the corresponding NFFT-point frame of the acoustic signal 36′ to be processed, i.e. to a value of i0±NFFT−1. Then, in step (2414), if the end of time-series A has not been reached, or less than TMAX seconds of data has been processed, for example, in one set of embodiments, less than three seconds, then in step (2416), a Short Term Fourier Transform (STFT) of the NFFT-point frame of acoustic data 36′ is calculated, i.e. an NFFT-point Fast Fourier Transform (FFT) of one NFFT-point frame subset of the entire acoustic signal 36′ time series, and the values of the resulting series are each squared and logarithmically expressed in dB to give a spectral series PA providing a measure of the power of the acoustic data 36′ as a function of frequency. Since the FFT of a real signal is conjugate symmetric, only the first NFF/2+1 values are returned in the spectral series PA, covering the frequency range 0 to FS/2. The Short Term Fourier Transform (STFT) provides for resolutions in both time and frequency, with a time resolution of NFF/FS, and a frequency resolution of FS/NFF, which for NFF=4096 and FS=24 kHz, are 0.17 sec and 5.86 Hz, respectively. For example,
Then, in step (2418), the power of each of the test frequencies FA, FB, FC, FD is stored as the kth value in a corresponding test-frequency-power array PA, PB, PC, PD, i.e.:
Then, in step (2420), the frame counter k is incremented, and in step (2422), the pointer i0 is updated to point to the beginning of the next NFFT-point frame of acoustic data 36′ in the acoustic signal 36′ to be processed, adjacent in time to the just-processed previous NFFT-point frame of acoustic data 36′, after which the process of step (2408) repeats, beginning with step (2412) until the condition of step (2414) is satisfied, after which the total number of frames NFrame is set equal to the last value of the frame counter k, and, from step (2426), the test-frequency-power arrays PA, PB, PC, PD are analyzed in a second phase 2600 of the auscultatory-sensor integrity-test procedure 2400, to determine whether or not any of the auscultatory sound-or-vibration sensors 14 might be defective.
More particularly, referring to
Then, if, in step (2604), any of the average spectral power values
The auscultatory-sensor integrity-test procedure 2400 is performed both prior to placing the array 18 of auscultatory sound-or-vibration sensors 14 on the thorax 26 of the test subject 12, and after collection of auscultatory sound signals 36 has been completed for a given test of the test subject 12 by the coronary-artery-disease (CAD) detection system 10.
The auscultatory-sensor integrity-test procedure 2400 is performed with each auscultatory sound-or-vibration sensors 14 of the array 18 seated in a corresponding well 148 in the docking system 100, 100.1, 100.2, 100.3, abutting a corresponding sound generator 146, 146′ of the associated array 145 of sound generators 146, 146′.
Referring to
Referring to
In accordance with a first aspect, all of the data communicated between the recording module 34, 34.1, 34.2 and the docking system 100, 100.1, 100.2 is via the WIFI communication link 180.
Alternatively, referring to
Yet further alternatively, referring to
Yet further alternatively, referring to
Referring to
Referring to
Referring to
Referring to
While specific embodiments have been described in detail in the foregoing detailed description and illustrated in the accompanying drawings, those with ordinary skill in the art will appreciate that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. It should be understood, that any reference herein to the term “or” is intended to mean an “inclusive or” or what is also known as a “logical OR”, wherein when used as a logic statement, the expression “A or B” is true if either A or B is true, or if both A and B are true, and when used as a list of elements, the expression “A, B or C” is intended to include all combinations of the elements recited in the expression, for example, any of the elements selected from the group consisting of A, B, C, (A, B), (A, C), (B, C), and (A, B, C); and so on if additional elements are listed. Furthermore, it should also be understood that the indefinite articles “a” or “an”, and the corresponding associated definite articles “the’ or “said”, are each intended to mean one or more unless otherwise stated, implied, or physically impossible. Yet further, it should be understood that the expressions “at least one of A and B, etc.”, “at least one of A or B, etc.”, “selected from A and B, etc.” and “selected from A or B, etc.” are each intended to mean either any recited element individually or any combination of two or more elements, for example, any of the elements from the group consisting of “A”, “B”, and “A AND B together”, etc. Yet further, it should be understood that the expressions “one of A and B, etc.” and “one of A or B, etc.” are each intended to mean any of the recited elements individually alone, for example, either A alone or B alone, etc., but not A AND B together. Furthermore, it should also be understood that unless indicated otherwise or unless physically impossible, that the above-described embodiments and aspects can be used in combination with one another and are not mutually exclusive. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of the invention, which is to be given the full breadth of any claims that are supportable by the specification and drawings, and any and all equivalents thereof.
Claims
1. A recording module for processing at least one electronic auscultatory sound signal from a corresponding at least one auscultatory sound-or-vibration sensor operatively coupled to a portion of the skin of a test subject, comprising:
- a. a corresponding auscultatory sound-signal processing channel in correspondence with the at least one electronic auscultatory sound signal of said at least one electronic auscultatory sound signal, wherein said corresponding auscultatory sound-signal processing channel provides for receiving said at least one electronic auscultatory sound signal from the corresponding at least one auscultatory sound-or-vibration sensor of said at least one auscultatory sound-or-vibration sensor, and each said corresponding auscultatory sound-signal processing channel comprises: i. a high-pass filter portion comprising either a first electronic differential-input high-pass filter having a 3 dB cut-off frequency in the range of 3 Hz to 15 Hz, or a first differential-input high-pass filter portion of an electronic band-pass filter having a 3 dB cut-off frequency in the range of 3 Hz to 15 Hz, wherein said at least one electronic auscultatory sound signal is operatively coupled to either a differential input of said first electronic differential-input high-pass filter or a differential input of said first differential-input high-pass filter portion of said electronic band-pass filter; ii. an amplifier portion comprising an electronic differential-input amplifier associated with either said first electronic differential-input high-pass filter or said first differential-input high-pass filter portion of said electronic band-pass filter; iii. a low-pass filter portion comprising either an electronic low-pass filter, or a low-pass filter portion of said electronic band-pass filter, wherein said electronic low-pass filter or said low-pass filter portion of said electronic band-pass filter is operatively coupled to an output of said electronic differential-input amplifier; and iv. an analog-to-digital converter portion operatively coupled to an output of either said electronic low-pass filter or said electronic band-pass filter, wherein said analog-to-digital converter portion provides for converting said output of either said electronic low-pass filter or said electronic band-pass filter to digital form; and
- b. a communications interface operatively coupled to an output of said analog-to-digital converter portion, wherein said communications interface provides for transmitting at least one digital signal generated by said analog-to-digital converter portion to a device external of said recording module.
2. A recording module for processing at least one electronic auscultatory sound signal from a corresponding at least one auscultatory sound-or-vibration sensor operatively coupled to a portion of the skin of a test subject as recited in claim 1, wherein said high-pass filter portion comprises a pair of first high-pass filter input circuits in cooperation with a pair of inputs of said electronic differential-input amplifier, said electronic differential-input amplifier comprises either a common first operational amplifier or a corresponding pair of first operational amplifiers, each first high-pass filter input circuit of said pair of first high-pass filter input circuits comprises a first capacitor and a first resistor, a first terminal of said first capacitor is operatively coupled to said at least one electronic auscultatory sound signal, a second terminal of said first capacitor is operatively coupled to a node that is operatively coupled to a corresponding input of said electronic differential-input amplifier, a first terminal of said first resistor is operatively coupled to said node, and a second terminal of said first resistor is operatively coupled to a circuit ground.
3. A recording module for processing at least one electronic auscultatory sound signal from a corresponding at least one auscultatory sound-or-vibration sensor operatively coupled to a portion of the skin of a test subject as recited in claim 2, wherein said high-pass filter portion further comprises a second resistor and a second capacitor, said second resistor is in series with said first capacitor, and said second capacitor is in parallel with said first resistor.
4. A recording module for processing at least one electronic auscultatory sound signal from a corresponding at least one auscultatory sound-or-vibration sensor operatively coupled to a portion of the skin of a test subject as recited in claim 2, wherein said high-pass filter portion further comprises a second high pass filter circuit in cooperation with a second operational amplifier,
5. A recording module for processing at least one electronic auscultatory sound signal from a corresponding at least one auscultatory sound-or-vibration sensor operatively coupled to a portion of the skin of a test subject as recited in claim 4, wherein an input of said second operational amplifier is operatively coupled to an output of said electronic differential-input amplifier. and said circuit ground is operatively coupled to the skin of the test subject via a series RC network.
6. A recording module for processing at least one electronic auscultatory sound signal from a corresponding at least one auscultatory sound-or-vibration sensor operatively coupled to a portion of the skin of a test subject as recited in claim 5, wherein said circuit ground is operatively coupled to the skin of the test subject via a ground conductor on a surface of said recording module in contact with said skin of said test subject.
7. A recording module for processing at least one electronic auscultatory sound signal from a corresponding at least one auscultatory sound-or-vibration sensor operatively coupled to a portion of the skin of a test subject as recited in claim 1, wherein said electronic differential-input amplifier is configured with a variable gain, and said variable gain is responsive to an external signal from said device external of said recording module, responsive to said at least one digital signal generated by said recording module.
8. A recording module for processing at least one electronic auscultatory sound signal from a corresponding at least one auscultatory sound-or-vibration sensor operatively coupled to a portion of the skin of a test subject as recited in claim 7, further comprising a plurality of resistors and a corresponding plurality of electronically-controllable analog switches, wherein each electronically-controllable analog switch of said plurality of electronically-controllable analog switches provides for controlling an operative coupling a corresponding resistor to a pair of nodes operatively coupled to said electronic differential-input amplifier, wherein when said electronically-controllable analog switch is activated responsive to said external signal, said corresponding resistor is connected electrically in parallel with said pair of nodes, and when said electronically-controllable analog switch is deactivated responsive to said external signal, the resistance across said pair of nodes is unaffected by said corresponding resistor.
9. A recording module for processing at least one electronic auscultatory sound signal from a corresponding at least one auscultatory sound-or-vibration sensor operatively coupled to a portion of the skin of a test subject as recited in claim 1, wherein said analog-to-digital converter portion incorporates a variable-gain amplifier, and a gain of said variable-gain amplifier is responsive to an external signal from said device external of said recording module, responsive to said at least one digital signal generated by said recording module.
10. A recording module for processing at least one electronic auscultatory sound signal from a corresponding at least one auscultatory sound-or-vibration sensor operatively coupled to a portion of the skin of a test subject as recited in claim 1, wherein said communications interface comprises a USB interface, wherein said recording module is powered from said USB interface.
11. A recording module for processing at least one electronic auscultatory sound signal from a corresponding at least one auscultatory sound-or-vibration sensor operatively coupled to a portion of the skin of a test subject as recited in claim 1, wherein said communications interface comprises a wireless interface, further comprising a battery that provides for powering said recording module.
12. A recording module for processing at least one electronic auscultatory sound signal from a corresponding at least one auscultatory sound-or-vibration sensor operatively coupled to a portion of the skin of a test subject as recited in claim 1, wherein said at least one auscultatory sound-or-vibration sensor is powered by said recording module.
13. A recording module for processing at least one electronic auscultatory sound signal from a corresponding at least one auscultatory sound-or-vibration sensor operatively coupled to a portion of the skin of a test subject as recited in claim 1, wherein said electronic low-pass filter, or said low-pass filter portion of said electronic band-pass filter, of each said corresponding auscultatory-sound-signal-processing channel has a 3 dB cut-off frequency in the range of 500 Hz to 2.5 KHz.
14. A recording module for processing at least one electronic auscultatory sound signal from a corresponding at least one auscultatory sound-or-vibration sensor operatively coupled to a portion of the skin of a test subject as recited in claim 13, wherein said electronic low-pass filter, or said low-pass filter portion of said electronic band-pass filter, of each said corresponding auscultatory-sound-signal-processing channel has a 3 dB cut-off frequency in the range of 1 kHz to 2.5 KHz.
15. A recording module for processing at least one electronic auscultatory sound signal from a corresponding at least one auscultatory sound-or-vibration sensor operatively coupled to a portion of the skin of a test subject as recited in claim 1, wherein said recording module further provides for processing an electrographic signal from a corresponding ECG sensor operatively coupled to a corresponding portion of said skin of said test subject, further comprising a corresponding electrographic-signal-processing channel in correspondence with said ECG sensor, wherein said corresponding electrographic-signal-processing channel provides for receiving said electrographic signal from said ECG sensor, and said corresponding electrographic-signal-processing channel comprises:
- a. a high-pass filter portion comprising either a first electronic differential-input high-pass filter having a 3 dB cut-off frequency in the range of 1 Hz to 3 Hz, or a first differential-input high-pass filter portion of an electronic band-pass filter having a 3 dB cut-off frequency in the range of 1 Hz to 3 Hz, wherein said electrographic signal is operatively coupled to either a differential input of said first electronic differential-input high-pass filter or a differential input of said first differential-input high-pass filter portion of said electronic band-pass filter;
- b. an amplifier portion comprising an electronic differential-input amplifier associated with either said first electronic differential-input high-pass filter or said first differential-input high-pass filter portion of said electronic band-pass filter;
- c. a low-pass filter portion comprising either an electronic low-pass filter, or a low-pass filter portion of said electronic band-pass filter, wherein said electronic band-pass filter or said low-pass filter portion of said electronic band-pass filter is operatively coupled to an output of said electronic differential-input amplifier; and
- d. an analog-to-digital converter portion operatively coupled to an output of either said electronic low-pass filter or said electronic band-pass filter, wherein said analog-to-digital converter portion provides for converting said output of either said electronic low-pass filter or said electronic band-pass filter to digital form, wherein said communications interface operatively coupled to an output of said analog-to-digital converter portion.
16. A recording module for processing at least one electronic auscultatory sound signal from a corresponding at least one auscultatory sound-or-vibration sensor operatively coupled to a portion of the skin of a test subject as recited in claim 15, wherein said high-pass filter portion comprises a pair of first high-pass filter input circuits in cooperation with a pair of inputs of said electronic differential-input amplifier, said electronic differential-input amplifier comprises either a common first operational amplifier or a corresponding pair of first operational amplifiers, each first high-pass filter input circuit of said pair of first high-pass filter input circuits comprises a first capacitor and a first resistor, a first terminal of said first capacitor is operatively coupled to said electrographic signal, a second terminal of said first capacitor is operatively coupled to a node that is operatively coupled to a corresponding input of said electronic differential-input amplifier, a first terminal of said first resistor is operatively coupled to said node, a second terminal of said first resistor is operatively coupled to a circuit ground, and said circuit ground is operatively coupled to a ground electrode of said ECG sensor applied to the skin of the test subject, via a series RC network.
17. A recording module for processing at least one electronic auscultatory sound signal from a corresponding at least one auscultatory sound-or-vibration sensor operatively coupled to a portion of the skin of a test subject as recited in claim 15, wherein said electronic low-pass filter, or said low-pass filter portion of said electronic band-pass filter, of said corresponding electrographic-signal-processing channel has a 3 dB cut-off frequency in the range of 500 Hz to 2.5 KHz.
18. A recording module for processing at least one electronic auscultatory sound signal from a corresponding at least one auscultatory sound-or-vibration sensor operatively coupled to a portion of the skin of a test subject as recited in claim 17, wherein said electronic low-pass filter, or said low-pass filter portion of said electronic band-pass filter, of said corresponding electrographic-signal-processing channel has a 3 dB cut-off frequency in the range of 1 kHz to 2.5 KHz.
19. A recording module for processing at least one electronic auscultatory sound signal from a corresponding at least one auscultatory sound-or-vibration sensor operatively coupled to a portion of the skin of a test subject as recited in claim 1, wherein said recording module further provides for processing a background sound signal from a corresponding microphone, further comprising a corresponding background-sound-signal-signal-processing channel in correspondence with said microphone, wherein said corresponding background-sound-signal-signal-processing channel provides for receiving said background sound signal from said microphone, and said corresponding background-sound-signal-signal-processing channel comprises:
- a. a high-pass filter portion comprising either a first electronic differential-input high-pass filter having a 3 dB cut-off frequency in the range of 65 Hz to 75 Hz, or a first differential-input high-pass filter portion of an electronic band-pass filter having a 3 dB cut-off frequency in the range of 65 Hz to 75 Hz, wherein said background sound signal is operatively coupled to either a differential input of said first electronic differential-input high-pass filter or a differential input of said first differential-input high-pass filter portion of said electronic band-pass filter;
- b. an amplifier portion comprising an electronic differential-input amplifier associated with either said first electronic differential-input high-pass filter or said first differential-input high-pass filter portion of said electronic band-pass filter;
- c. a low-pass filter portion comprising either an electronic low-pass filter, or a low-pass filter portion of said electronic band-pass filter, wherein said electronic band-pass filter or said low-pass filter portion of said electronic band-pass filter is operatively coupled to an output of said electronic differential-input amplifier; and
- d. an analog-to-digital converter portion operatively coupled to an output of either said electronic low-pass filter or said electronic band-pass filter, wherein said analog-to-digital converter portion provides for converting said output of either said electronic low-pass filter or said electronic band-pass filter to digital form, wherein said communications interface operatively coupled to an output of said analog-to-digital converter portion.
20. A recording module for processing at least one electronic auscultatory sound signal from a corresponding at least one auscultatory sound-or-vibration sensor operatively coupled to a portion of the skin of a test subject as recited in claim 19, wherein said electronic low-pass filter, or said low-pass filter portion of said electronic band-pass filter, of said corresponding background-sound-signal-signal-processing channel has a 3 dB cut-off frequency in the range of 500 Hz to 2.5 KHz.
21. A recording module for processing at least one electronic auscultatory sound signal from a corresponding at least one auscultatory sound-or-vibration sensor operatively coupled to a portion of the skin of a test subject as recited in claim 20, wherein said electronic low-pass filter, or said low-pass filter portion of said electronic band-pass filter, of said corresponding background-sound-signal-signal-processing channel has a 3 dB cut-off frequency in the range of 1 kHz to 2.5 KHz.
22. A method of acquiring signals from a test subject to be used for assessing the cardiovascular health of the test subject, comprising:
- a. providing for operatively coupling at least one auscultatory sound signal from a corresponding at least one auscultatory sound-or-vibration sensor to a corresponding at least one auscultatory sound signal-processing channel of a recording module, wherein said at least one auscultatory sound signal-processing channel provides for transforming said at least one auscultatory sound signal to a corresponding at least one processed auscultatory sound signal through a method comprising: i. operatively coupling said at least one auscultatory sound signal to a differential input of either a corresponding high-pass filter having a 3 dB cut-off frequency in the range of 3 Hz to 15 Hz, or a corresponding high-pass filter portion of a band-pass filter having a 3 dB cut-off frequency in the range of 3 Hz to 15 Hz; ii. filtering said at least one auscultatory sound signal with either said corresponding high-pass filter or said corresponding high-pass filter portion of said band-pass filter; iii. amplifying said at least one auscultatory sound signal with a corresponding amplifier having an amplification gain; iv. filtering said at least one auscultatory sound signal with a corresponding low-pass filter, or a corresponding low-pass filter portion of said band-pass filter; and v. converting an output of said at least one auscultatory sound signal-processing channel to digital form so as to generate a corresponding digital-output signal; and
- b. transferring at least one said corresponding digital-output signal to a device external of the recording module.
23. A method of acquiring signals from a test subject to be used for assessing the cardiovascular health of the test subject as recited in claim 22, wherein said corresponding low-pass filter, or said corresponding low-pass filter portion of said band-pass filter, used to filter said at least one auscultatory sound signal has a 3 dB cut-off frequency in the range of 500 Hz to 2 KHz.
24. A method of acquiring signals from a test subject to be used for assessing the cardiovascular health of the test subject as recited in claim 23, wherein said corresponding low-pass filter, or said corresponding low-pass filter portion of said band-pass filter, used to filter said at least one auscultatory sound signal has a 3 dB cut-off frequency in the range of 1 kHz to 2 KHz.
25. A method of acquiring signals from a test subject to be used for assessing the cardiovascular health of the test subject as recited in claim 22, further comprising:
- a. providing for operatively coupling an electrographic signal from an ECG sensor operatively coupled to the test subject to a corresponding electrographic signal-processing channel of said recording module, wherein said electrographic signal-processing channel provides for transforming said electrographic signal to a corresponding processed electrographic signal through a method comprising: i. operatively coupling said electrographic signal to a differential input of either a corresponding high-pass filter having a 3 dB cut-off frequency in the range of 1 Hz to 3 Hz, or a corresponding high-pass filter portion of a band-pass filter having a 3 dB cut-off frequency in the range of 1 Hz to 3 Hz; ii. filtering said electrographic signal with either said corresponding high-pass filter or said corresponding high-pass filter portion of said band-pass filter; iii. amplifying said electrographic signal with a corresponding amplifier having an amplification gain; iv. filtering said electrographic signal with a corresponding low-pass filter, or a corresponding low-pass filter portion of said band-pass filter; and v. converting an output of said electrographic signal-processing channel to digital form so as to generate a corresponding digital-output signal; and
- b. transferring at least one said corresponding digital-output signal to said device external of said recording module.
26. A method of acquiring signals from a test subject to be used for assessing the cardiovascular health of the test subject as recited in claim 25, wherein said corresponding low-pass filter, or said corresponding low-pass filter portion of said band-pass filter, used to filter said electrographic signal has a 3 dB cut-off frequency in the range of 500 Hz to 2 KHz.
27. A method of acquiring signals from a test subject to be used for assessing the cardiovascular health of the test subject as recited in claim 26, wherein said corresponding low-pass filter, or said corresponding low-pass filter portion of said band-pass filter, used to filter said electrographic signal has a 3 dB cut-off frequency in the range of 1 kHz to 2 KHz.
28. A method of acquiring signals from a test subject to be used for assessing the cardiovascular health of the test subject as recited in claim 22, further comprising:
- a. providing for operatively coupling a background sound signal from a microphone located in a same room as the test subject to a corresponding background-sound signal-processing channel of said recording module, wherein said background-sound signal-processing channel provides for transforming said background sound signal to a corresponding processed background sound signal through a method comprising: i. operatively coupling said background sound signal to a differential input of either a corresponding high-pass filter having a 3 dB cut-off frequency in the range of 65 Hz to 75 Hz, or a corresponding high-pass filter portion of a band-pass filter having a 3 dB cut-off frequency in the range of 65 Hz to 75 Hz; ii. filtering said background sound signal with either said corresponding high-pass filter or said corresponding high-pass filter portion of said band-pass filter; iii. amplifying said background sound signal with a corresponding amplifier having an amplification gain; iv. filtering said background sound signal with a corresponding low-pass filter, or a corresponding low-pass filter portion of said band-pass filter; and v. converting an output of said background-sound signal-processing channel to digital form so as to generate a corresponding digital-output signal; and
- b. transferring at least one said corresponding digital-output signal to said device external of said recording module.
29. A method of acquiring signals from a test subject to be used for assessing the cardiovascular health of the test subject as recited in claim 28, wherein said corresponding low-pass filter, or said corresponding low-pass filter portion of said band-pass filter, used to filter said background sound signal has a 3 dB cut-off frequency in the range of 500 Hz to 2 KHz.
30. A method of acquiring signals from a test subject to be used for assessing the cardiovascular health of the test subject as recited in claim 29, wherein said corresponding low-pass filter, or said corresponding low-pass filter portion of said band-pass filter, used to filter said background sound signal has a 3 dB cut-off frequency in the range of 1 kHz to 2 KHz.
Type: Application
Filed: Oct 21, 2018
Publication Date: Apr 25, 2019
Inventors: Jikang ZENG (Kanata), Md Shahidul ISLAM (Ottawa), Jun ZHOU (Kanata), Daniel LABONTÉ (Ottawa), Simon MARTIN (Gatineau), Brady LASKA (Arnprior), Sergey A. TELENKOV (Ottawa)
Application Number: 16/166,104