(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2004/0220488A1
`Vyshedskiy et al.
`(43) Pub. Date:
`Nov. 4, 2004
`
`US 2004O220488A1
`
`(54) METHOD AND APPARATUS FOR
`PHYSIOLOGICAL DATA ACQUISITION VIA
`SOUND INPUT PORT OF COMPUTING
`DEVICE
`(76) Inventors: Andrey Vyshedskiy, Boston, MA (US);
`William Kania, Westborough, MA
`(US); Raymond Murphy, Wellesley,
`MA (US)
`Correspondence Address:
`Andrey Vyshedskiy
`Suite 4990
`1153 Centre St.
`Boston, MA 02130 (US)
`(21) Appl. No.:
`10/694,910
`(22) Filed:
`Oct. 29, 2003
`Related U.S. Application Data
`(60) Provisional application No. 60/466.242, filed on Apr.
`29, 2003.
`
`Publication Classification
`
`(51) Int. Cl. ................................ A61B 5/04; A61 B 5/02
`
`(52) U.S. Cl. ............................. 600/513; 600/528; 381/67
`
`(57)
`
`ABSTRACT
`
`A Sound input port is ubiquitously present in many types of
`devices including PCS, PDAS, cellphones, land line phones,
`and Voice recorders thereafter referred to as "computing
`devices'. A Sound port allows data input into a computing
`device for further computation, Visualization and data trans
`mission. Unfortunately most computing devices only allow
`one channel of data acquisition via the Sound port. Further,
`the acquired data are highpass filtered. A method of extend
`ing the Signal range to very low frequencies and recording
`a plurality of data channels via a Single Sound port is
`disclosed here. This method uses amplitude modulation of
`carrier frequencies to create a composite Signal. The com
`posite Signal is then transmitted into the computing device
`either via wire or wirelessly. Demodulation occurs in the
`computing device. In the preferred embodiment the audio
`Signal from an electronic Stethoscope and the amplitude
`modulated EKG are transmitted into a computer via a single
`microphone port. In an alternative embodiment physiologi
`cal data from multiple Sensors are transmitted into a com
`puter via a single microphone port.
`
`204
`
`206
`
`207
`
`201
`
`203
`
`203
`
`203
`
`O
`
`
`
`Signal
`Conditioning
`and
`Modulation
`Circuit
`
`Microphone
`Input of
`Computing
`Device
`
`205
`
`APPLE 1005
`
`1
`
`

`

`Patent Application Publication Nov. 4, 2004 Sheet 1 of 8
`
`US 2004/0220488A1
`
`Figure lA.
`
`101
`
`102
`
`Amplifier
`1.
`
`103
`
`Lowpass
`Filter 1
`
`107
`
`108
`
`109
`
`1 10
`
`111
`
`
`
`Carrier
`Frequency
`
`Carrier
`Frequency
`N
`
`Carrier
`Frequency
`2
`
`Amplifier
`2
`
`Lowpass
`Filter 2
`
`Amplifier
`N
`
`Lowpass
`Filter N
`
`104
`
`105
`
`106
`
`Analog
`Multiplier 1
`
`Analog
`Multiplier 2
`
`Analog
`Multiplier N
`
`Summing
`Amplifier
`
`Composite
`Signal Output
`
`2
`
`

`

`Patent Application Publication Nov. 4, 2004 Sheet 2 of 8
`
`US 2004/0220488A1
`
`Figure 1B
`
`121
`
`
`
`Composite
`Signal from
`microphone
`port
`
`123
`
`124
`
`125
`
`126
`
`127
`
`Carrier
`Frequency
`1
`
`Carrier
`Frequency
`2
`
`Carrier
`Frequency
`N
`
`Digital
`Multiplier
`
`
`
`Digital
`Multiplier
`
`Digital
`Multiplier
`
`
`
`122
`
`128
`
`129
`
`/
`
`131
`
`132
`
`3
`
`

`

`Patent Application Publication Nov. 4, 2004 Sheet 3 of 8
`
`US 2004/0220488A1
`
`Figure 2.
`
`201
`
`203
`
`2O3
`
`204
`
`206
`
`207
`
`203
`
`O
`
`
`
`Signal
`Conditioning
`and
`Modulation
`Circuit
`
`Microphone
`Input of
`Computing
`Device
`
`205
`
`4
`
`

`

`Patent Application Publication Nov. 4, 2004 Sheet 4 of 8
`
`US 2004/0220488A1
`
`Audio Input
`
`Audio
`Amplifier
`
`308
`
`309
`
`Lowpass Filter
`
`310
`
`Figure 3
`
`301
`
`EKG Input
`
`302
`
`EKG
`Amplifier
`
`307
`
`Carrier
`Frequency
`
`304
`
`305
`
`306
`
`Analog
`Multiplier
`
`Summing
`Amplifier
`
`Composite
`Signal Output
`
`5
`
`

`

`Patent Application Publication Nov. 4, 2004 Sheet 5 of 8
`
`US 2004/0220488A1
`
`Figure 4.
`
`404
`
`
`
`6
`
`

`

`Patent Application Publication Nov. 4, 2004 Sheet 6 of 8
`
`US 2004/0220488A1
`
`Figure 5.
`
`
`
`,
`
`
`
`501
`
`'''''
`
`502
`
`150 sects 1800
`
`18,
`
`7
`
`

`

`Patent Application Publication Nov. 4, 2004 Sheet 7 of 8
`
`US 2004/0220488A1
`
`Figure 6.
`
`
`
`2000
`
`8
`
`

`

`Patent Application Publication Nov. 4, 2004 Sheet 8 of 8
`
`US 2004/0220488A1
`
`Figure 7.
`
`
`
`s
`
`so
`
`17
`
`seconds 18,000
`
`18
`
`1so
`
`1950
`
`2000
`
`9
`
`

`

`US 2004/0220488 A1
`
`Nov. 4, 2004
`
`METHOD AND APPARATUS FOR
`PHYSIOLOGICAL DATA ACQUISITION VIA
`SOUND INPUT PORT OF COMPUTING DEVICE
`0001
`Priority is claimed by provisional application No.
`60/466.242 filed on Apr. 29, 2003 entitled Method of data
`acquisition via microphone port of a computer.
`
`FIELD OF THE INVENTION
`0002 The invention relates to systems used for physi
`ological data acquisition. It also relates to diagnostic Sys
`temS.
`
`BACKGROUND OF THE INVENTION
`0.003 A Sound input port is ubiquitously present in many
`types of devices including PCs, PDAs, cellphones, land line
`phones, Voice recorders, etc., hereafter referred to as com
`puting devices. This Sound input port can be primarily of 3
`types: 1) a microphone port, 2) a line port, and 3) a wireless
`port (e.g. Bluetooth Headset). These ports are similar in their
`frequency characteristics with two notable differences. A
`line port is designed for Stronger "line-level” Signals with
`peak-to-peak amplitude of approximately 10V. Furthermore
`a line port does not Supply bias DC voltage. A microphone
`port is designed to receive Smaller Signals with peak-to-peak
`amplitude of approximately 100 mV. In addition, a micro
`phone port normally provides a bias DC voltage. Micro
`phones lacking their own power Supply rely on bias DC
`voltage for their power source. The invention disclosed
`herein can be used with either line, microphone, or wireleSS
`ports. Consequently, all Sound input ports are hereafter
`referred to as “a microphone port” or “a sound port'.
`0004. A microphone port allows analog data input into
`computing devices for further computation, Visualization
`and data transmission. Unfortunately most computing
`devices only allow one channel of data acquisition via a
`microphone port. Standard multiplexing methods for trans
`mitting a plurality of data channels via a single channel do
`not work Since the microphone port has a hardware lowpass
`filter. The invention disclosed herein does not use a multi
`plexing method. Rather, the invention uses amplitude modu
`lation of a plurality of data channels to transmit the com
`posite Signal into a microphone port of a computing device.
`All Signals can be demodulated in the computing device
`with no loss of data.
`0005 Devices for concurrent recording of two or more
`channels of physiological data are well known. U.S. Pat.
`Nos. 5,165,417, 5,844,997, 6,139,505, 6,394.967 to Ray
`mond Murphy, the inventor herein, disclose multichannel
`Sound recording System based on a multichannel A/D board.
`0006 U.S. Pat. No. 4,053,951, to Hudspeth, et al. entitled
`Data acquisition, Storage and display System discloses the
`device for medical data acquisition including temperature,
`respiration rate and pulse rate are measured and Stored in an
`acquisition unit incorporating a circulating register for Stor
`ing data covering many patients.
`0007 U.S. Pat. No. 5,701,904 to Simmons, et al., entitled
`Telemedicine instrumentation pack discloses a portable
`medical diagnostic apparatus which includes three types of
`data-gathering instruments: (1) visual instruments (e.g., oto
`Scope, ophthalmoscope, rhino-laryngoscope, macro lens and
`fundus camera); (2) an audio instrument (e.g., electronic
`
`Stethoscope); and (3) data-gathering instruments (eg, pulse
`Oximeter and ECG monitor). The signals are transmitted to
`a remote site for analysis by medical perSonnel.
`0008 Although these devices fulfill the purpose of mul
`tichannel data acquisition they all rely on Special data
`acquisition hardware which makes them expensive and
`cumberSome. Recording two or more channels of data via
`the ubiquitous microphone port is advantageous for many
`reasons. The multichannel Sound recording System disclosed
`herein is based on the existing microphone port and conse
`quently does not require an addition of data acquisition
`hardware resulting in a cheaper and leSS cumberSome Sys
`tem.
`0009 Further, a highpass filter on the input of the micro
`phone port prevents recording of data below 20 Hz. Many
`physiological Signals below 20 HZ are of great importance,
`for example EKG and Seismocardiogram. The invention
`disclosed herein uses amplitude modulation of a carrier
`frequency. The particular carrier frequencies are chosen
`from frequency range that is unaffected by the microphone
`port hardware filters. This allows recording of low frequency
`Signals, that is signals below 20 HZ, Via the microphone port
`of the computing device.
`BRIEF SUMMARY OF THE INVENTION
`0010. The invention disclosed herein extends the record
`ing frequency range of a microphone port to very low
`frequencies and allows a plurality of data channels to be
`transmitted into a computing device via the microphone port
`using multiple frequency bands. Briefly, amplitude modu
`lation occurs in the hardware using a set of carrier frequen
`cies. The resulting amplitude modulated Signals are Summed
`into a composite signal which is transmitted into the micro
`phone port of the computing device. Demodulation occurs in
`the Software. The composite signal can be transmitted to the
`computing device by wires, by wireleSS data communica
`tions, by a network of computing devices or by a combina
`tion of these means.
`0011. The stethoscopes are widely used by medical per
`Sonnel to listen to body sounds. Unfortunately the stetho
`Scopes do not allow recording or Visualization of Sounds, nor
`do they allow to easily relate heart sounds to the events of
`the heart cycle apparent on the EKG. In the preferred
`embodiment, referred thereafter as “EKG Stethoscope', the
`disclosed method is used to Simultaneously transmit the
`audio signal from an electronic Stethoscope and the corre
`sponding electrical EKG signal into a computing device via
`the microphone port of the computing device. In other
`words, the EKG Stethoscope allows the medical practitioner
`to perform auscultation and obtain electrocardiogram at the
`Same time. The recording/visualization device could be a
`personal computer, a PDA, a mobile phone, a land line
`phone or a voice recorder. The data can be transmitted via
`wire or wirelessly (for example using Bluetooth technol
`ogy).
`0012. The EKG Stethoscope has the following advan
`tages:
`0013 A phonocardiogram can be visualized simul
`taneously with an electrocardiogram.
`0014 Auscultation of heart sounds is greatly facili
`tated by knowing the event of the heart cycle Visu
`alized on the EKG.
`
`10
`
`

`

`US 2004/0220488 A1
`
`Nov. 4, 2004
`
`0015 Automatic, that is computer based, heart
`Sound analysis is facilitated by identification of
`events on the electrocardiogram.
`0016. The EKG Stethoscope system uses the fact that
`neither the EKG nor the audio signal requires the full
`bandwidth of the microphone port (which is 20 Hz to 44,100
`Hz). Normally the EKG signal is between 0.5 Hz and 300
`HZ, and body sounds are between 20 Hz and 2000 Hz.
`Therefore, there is Sufficient bandwidth to transmit both
`EKG and Sound into the microphone port of the computing
`device.
`0.017. In an alternative embodiment physiological data
`from multiple Sensors, Such as acoustic pick-up Sensors, are
`transmitted into the computing device via a Single micro
`phone port. Similarly, body sounds are limited in bandwidth
`to 2000 Hz. Therefore, theoretically, up to 11 channels can
`be modulated and concurrently transmitted into a micro
`phone port with bandwidth of 44,000 Hz.
`
`BRIEF DESCRIPTION OF THE DRAWING
`FIG. 1A is a flow chart of a system for implement
`0.018
`ing data acquisition from a plurality of data channels via a
`Single microphone port of a computing device;
`0019 FIG. 1B is a flow chart of a system for implement
`ing demodulation of a composite Signal of FIG. 1A,
`0020 FIG. 2 is a block diagram of a system for imple
`menting a preferred embodiment of the present invention;
`0021 FIG. 3 is a flow chart of the steps performed in
`Signal Conditioning and Modulation Circuit of FIG. 2.
`0022 FIG. 4 shows overall design of the EKG Stetho
`scope with EKG electrodes embedded into the chest piece as
`viewed from the bottom.
`0023 FIG. 5 is a data plot of the composite signal (top)
`separated by filtering into modulated EKG (middle) and
`audio signal (bottom).
`0024 FIG. 6 is a data plot of the amplitude modulated
`EKG (top), the EKG multiplied by carrier signal (middle)
`and the EKG lowpass filtered with a cutoff frequency equal
`to 25 Hz resulting in a clean EKG signal (bottom).
`0025 FIG. 7 is a data plot of the composite signal (top)
`and the recovered signals. The EKG signal is shown in the
`middle and heart Sound is shown in the bottom.
`
`DETAILED DESCRIPTION OF THE
`INVENTION
`FIG. 1A is a flow chart of a system for implement
`0.026
`ing data acquisition from a plurality of data channels via a
`microphone port of a computing device. Input 1101 is first
`amplified by an Amplifier 102 and then is filtered by a
`Lowpass Filter 103 with cutoff frequency of f. Further
`the resulting Signal is multiplied by the carrier frequency
`f
`107 in an Analog Multiplier 104. The resulting modu
`lated input 1 signal is moved up on the frequency Scale to
`occupy the interval from f.
`f
`f
`carrier cutoff tO carrier'feutoff
`0027) A plurality of inputs from Input 2108 to Input N
`110 can be modulated by the corresponding carrier frequen
`cies 109, 111. All modulated signals are summed by a
`Summing Amplifier 105 to derive a composite Signal output
`
`106. The composite signal can be then transmitted into the
`microphone port of the computing device via wire or wire
`lessly.
`0028 Consider an 8 channel data acquisition system
`transmitting data into a Standard computer Sound card with
`sampling rate of 44,100 Hz. Each input channel of the 8
`channel data acquisition System records data from a Sensor
`with a bandwidth of 0 Hz to 1,000 Hz. All eight lowpass
`filters can be chosen to have cutoff frequency equal to 1,000
`HZ. Eight carrier frequencies can be chosen as follows:
`f1=2,500 Hz, f2=5,000 Hz, f3=7.500 Hz, f4=10,000 Hz,
`f5=12,500 Hz, fö=15,000 Hz, f7=17,500 Hz, fs=20,000 Hz.
`Amplitude modulation allows to distribute 8 data channels
`over the frequency range of the Sound card. The carrier f1
`modulated by input 1 occupies interval from 1,500 Hz to
`3,500 Hz, the carrier f2 modulated by input 2 occupies
`interval from 4,000 Hz to 6,000 Hz, . . . , the carrier f8
`modulated by input 8 occupies interval from 19,000 Hz to
`21,000 Hz. The Summing amplifier then sums eight ampli
`tude modulated carrier frequencies into a composite signal.
`0029. The composite signal is then transmitted into the
`microphone port of the computing device via wire or wire
`lessly.
`0030) Inside the computing device the composite signal is
`demodulated. AS long as intervals occupied by modulated
`Signals in the frequency domain are Separated, it is possible
`to recover original Signals with no loSS. The demodulation
`flow chart is shown in FIG. 11B. The composite signal 121
`is digitized by the computing device Sound card. A digital
`bandpass filter 1122 is used to Separate the frequency band
`around the carrier frequency 1123 from f
`-fcutoff to
`faie-fir. The resulting Signal is multiplied by a digitally
`generated carrier frequency 1123 in a digital multiplier 128.
`The resulting signal is filtered by a Digital Lowpass Filter
`129. AS long as the carrier frequency 123 is equal to the
`carrier frequency 107 of FIG. 1A, the resulting Output
`signal 1130 is equal to the Input 1101 of FIG. 1A.
`0031 Similarly, the composite signal 121 can be broken
`down into a plurality of frequency bands by digital bandpass
`filters 2124 through N 126. Each band is multiplied by the
`corresponding carrier frequency 125 through 127 and con
`Sequently filtered with lowpass filters. The resulting
`demodulated output signals 2131 through N 132 are indis
`tinguishable from the corresponding inputs 108 through 110.
`These outputs can now be recorded, Visualized, and ana
`lyzed by the computing device.
`0032. In the example of the eight channel data acquisition
`System mentioned above the digital bandpass filter 1 can be
`a Hamming bandpass filter with 512 taps and pass band from
`1,500 Hz to 3,500 Hz; the digital bandpass filter 2 can be a
`Hamming bandpass filter with 512 taps and pass band from
`4,000 Hz to 6,000 Hz; . . . ; the digital bandpass filter 8 can
`be a Hamming Window bandpass filter with 512 taps and
`pass band from 19,000 Hz to 21,000 Hz. Further each
`channel is digitally multiplied by the corresponding carrier
`frequency. The output of the digital bandpass filter 1 is
`multiplied by the carrier frequency 1 equal to 2,500 Hz; the
`output of the digital bandpass filter 2 is multiplied by the
`carrier frequency 2 equal to 5,000 Hz, . . . ; the output of the
`digital bandpass filter 8 is multiplied by the carrier fre
`quency 8 equal to 20,000 Hz. Further the result of multi
`plication is filtered by a digital lowpass filter. All digital
`
`carrier cuto
`
`11
`
`

`

`US 2004/0220488 A1
`
`Nov. 4, 2004
`
`lowpass filters can be Hamming Window lowpass filters
`with 512 taps and pass band between 0 Hz and 1000 Hz.
`0.033
`FIG. 2 shows a block diagram of a system for
`implementing a preferred embodiment of the present inven
`tion, the EKG Stethoscope. The chest piece 201 picks up an
`acoustic Signal from the body, converts the acoustic energy
`into an electrical Signal and than transmits the Signal via wire
`or wirelessly 204 into a Signal Conditioning and Modulation
`Box 206. Further the electrocardiographic signal from the
`patient's skin is picked up by EKG electrodes 203 and
`transmitted via wire or wirelessly 205 into a Signal Condi
`tioning and Modulation Box 206. The composite signal from
`the Signal Conditioning and Modulation Box 206 is trans
`mitted to the Microphone Port of the computing device 207.
`0034 FIG. 3 describes the flow chart of the steps per
`formed in the Signal Conditioning and Modulation Box 206
`of FIG. 2. The EKG input 301 from EKG electrodes placed
`on patient's skin is amplified by a Standard EKG amplifier
`302 with a gain of 1 V/mV. Further it is filtered by a bandpass
`filter 0.5 to 120 Hz and 60 Hz, notch filter (-23 dB). The
`resulting amplified and filtered EKG is multiplied by the
`carrier signal 307 with frequency 3,000 Hz in the Analog
`Multiplier 304. Note that the resulting modulated EKG
`Signal is located in the frequency band centered around the
`carrier frequency, that is between 2,700 Hz and 3,300 Hz.
`0035. The audio input 308 from sound pickup placed on
`the patient's skin is amplified by the Audio Amplifier 309
`and filtered by a Lowpass Filter 310 with a cutoff frequency
`of 2,000 Hz. The modulated EKG signal is then Summed
`with the amplified and filtered audio signal by the Summing
`amplifier 305. The resulting composite signal output 306 is
`transmitted via wire or wirelessly into the computing device.
`0036 FIG. 4 shows the overall design of the EKG
`Stethoscope with three EKG electrodes 403 mounted on the
`chest piece 401 around the diaphragm 402. The physician
`can move chest piece around the chest to collect data at
`different sites. The Suitable EKG electrodes can be made of
`electroconductive material and have an area of 1 cm. The
`Sound amplification can be either electronic via wire or
`acoustic via tubing 404. The suitable microphone for the
`electronic Sound amplification can be omnidirectional elec
`tret microphone embedded into the chest piece. The EKG
`StethoScope allows a medical practitioner to avoid applica
`tion of separate EKG electrodes. The result is a faster and
`leSS cumberSome procedure.
`0037. The computing device of the EKG Stethoscope can
`be a PDA such as Compaq iPAQ5450 Pocket PC. The
`composite signal 306 of FIG. 3 is transmitted to the PDA's
`microphone input port. The transmission can be via the wire
`connected to an external 3.5 mm microphone jack or wire
`lessly via bluetooth headset protocol. No modification or
`special hardware is required with iPAQ5450. The PDA can
`be programmed to conduct the demodulation of the com
`posite signal. The PDA can display the results of demodu
`lation on its Screen and Store the data for later retrieval/
`transfer. Also, the PDA can be programmed to perform the
`automatic analysis of the EKG and acoustic Signals.
`0.038. Inside the computing device the composite signal
`306 of FIG. 3 is demodulated into an EKG and audio signals
`for further recording, visualization, and analysis. FIG. 5 is
`a data plot of a composite signal 501 recorded from a
`
`subject. The composite signal 501 is first filtered by a
`lowpass filter with cutoff frequency of 2000 Hz. The result
`ing signal is a pure audio signal 503, FIG. 5. Further, the
`composite signal 501 is filtered by a bandpass filter with
`cutoff frequencies of 2700 Hz and 3300 Hz. The resulting
`signal is the modulated EKG signal 502.
`0039 FIG. 6 shows the process of demodulation of the
`EKG signal 502 of FIG. 5. The modulated EKG signal 601
`is multiplied by the carrier frequency. The result of digital
`multiplication is the Signal marked 602. Further, the Signal
`602 is filtered by a lowpass filter with a cutoff frequency of
`25 Hz. The resulting signal is a clean EKG signal 603.
`0040 FIG. 7 is a data plot of the composite signal 701,
`same as 501 of FIG. 5, and the demodulated EKG 702, same
`as 603 of FIG. 6, and sound signal 703, same as 503 of FIG.
`5, shown in the stack mode.
`
`We claim:
`1. A method of wired or wireleSS physiological data
`acquisition via Sound input port of a computing device using
`amplitude modulation of data with one or more carrier
`frequencies.
`2. The computing device of claim 1 Selected from a group
`consisting of a desktop computer, a notebook, a tablet PC, a
`PDA, a mobile phone, a land line phone, a tape recorder, and
`a digital voice recorder.
`3. The computing device of claim 1 transmitting data to a
`Secondary computing device, Such as a Server either via wire
`or wirelessly.
`4. The data of claim 1 including a plurality of channels
`modulated by multiple carrier frequencies.
`5. The carrier frequencies of claim 1 distributed over the
`permissible Sound port frequency range in Such a manner
`that neither frequency band overlaps with any other fre
`quency band.
`6. The carrier frequencies of claim 1 Supplied by the audio
`output of the computing device or generated by circuitry
`outside of the computing device.
`7. The Sound input port of claim 1 wherein sound input
`port is a microphone port, a line port, or the wireleSS Sound
`port of a computing device.
`8. The wireless Sound port of claim 7 wherein wireless
`protocol Selected from a group consisting of a bluetooth
`protocol and a Wi-Fi protocol.
`9. The bluetooth protocol of claim 8 wherein a headset
`profile is used to transmit data to and from the computing
`device.
`10. The physiological data acquisition System using Said
`amplitude modulation method of claim 1 to transmit mul
`tiple cannels of physiological data to Said microphone port
`of Said computing device.
`11. The computing device of claim 1 wherein the demodu
`lation of the composite Signal by Software occurs in real
`time.
`12. The EKG Stethoscope using said amplitude modula
`tion method of claim 1 comprised of
`(a) a stethoscope,
`(b) an electrocardiograph, and
`(c) EKG electrodes,
`whereby a medical practitioner is enabled perform
`Simultaneous auscultation and electrocardiography.
`
`12
`
`

`

`US 2004/0220488 A1
`
`Nov. 4, 2004
`
`13. The EKG Stethoscope of claim 12 wherein the EKG
`is modulated by a carrier frequency and added to an audio
`Signal resulting in a composite Signal that is transmitted to
`the Sound port of a computing device.
`14. The EKG Stethoscope of claim 12 visualizing both
`phonocardiogram and EKG concurrently on the Screen of
`the computing device in the Stack mode or Superimposed.
`15. The EKG electrodes of claim 12 located on the chest
`piece to Simplify application of Said EKG StethoScope on
`patients.
`16. The EKG electrodes of claim 12 attached to the
`subject's skin connected to the said EKG Stethoscope via
`standard wired EKG leads.
`17. The EKG Stethoscope of claim 12 having means for
`Visualizing the EKG and audio waveform on a read-out
`display located on the chest piece.
`18. The EKG Stethoscope of claim 12 having means to
`Signal the operator events of the EKG cycle, whereby said
`event will include the QRS complex, which corresponds to
`
`the start of systole, the P-wave, which corresponds to the
`Start of atrial depolarization, and T-wave, which corresponds
`to the start of diastole.
`19. The EKG Stethoscope of claim 12 having means for
`transmitting Sounds from the chest piece to the operators
`CS.
`20. The EKG Stethoscope of claim 12 having the chest
`piece mounted on a computing device, Such as a PDA.
`21. The EKG Stethoscope of claim 12 incorporating
`means for automatic identification of respiratory cycle,
`automatic identification of events on EKG, and automatic
`identification of heart Sounds components.
`22. The physiological data acquisition System using Said
`amplitude modulation method of claim 1 to transmit Sound
`recordings from 2 or more Sound pick-up Sensors into Said
`Sound input port of the computing device whereby each
`channel is modulated by its own carrier frequency.
`
`k
`
`k
`
`k
`
`k
`
`k
`
`13
`
`