GB2162644A

GB2162644A - Separating heartbeat sources

Info

Publication number: GB2162644A
Application number: GB08516405A
Authority: GB
Inventors: Walter Campbell Peaston
Original assignee: Individual
Current assignee: Individual
Priority date: 1984-06-29
Filing date: 1985-06-28
Publication date: 1986-02-05
Also published as: GB8516405D0

Abstract

To separate heartbeat sources, heartbeat pulse signals 3 and 4 are recorded and the time intervals between a series of successive pulses are analysed statistically to determine the number of individual heartbeat sources in the original heartbeat pulse signals. The technique has particular application in determining the number of foetuses being carried by a pregnant ewe. This allows more efficient feeding of the ewes to be carried out. Pulse signals 3 and 4 and noise signals 5 and 6 from microphone 1, electrodes or laser interferometer are filtered at 7 to pick out pulse peaks 3a and 3b. The pulse intervals are timed at 9 and the frequency distribution is produced by a computer 10 which also determines the most probable number of sources. <IMAGE>

Description

SPECIFICATION Apparatus for and a method of separating heartbeat sources This invention relates to apparatus for and a method of separating heartbeat sources.

In the management of sheep during pregnancy it is important to know how many foetuses each ewe is carrying as this allows the proper feeding and treatment of the ewes thus increasing the efficiency of the management of the flock. Indeed, the correct feeding and care of the ewes, according to the number of lambs being carried, increases the profitability on a flock to the extent that the cost of employing specialist contractors to assess each ewe in a flock can be justified. However, such assessments do involve substantial costs and a great deal of inconvenience.

It is an object of the present invention to provide a simple technique for ascertaining the number of foetuses being carried by a pregnant ewe.

According to the present invention there is provided a method of separating heartbeat sources comprising detecting heartbeat pulse signals, measuring the time interval between each successive pulse to produce pulse interval data and analysing the pulse interval data to calculate the number of individual heartbeat sources in the original heartbeat signals.

Preferably, the heartbeat pulse signals are filtered to remove background noise.

The heartbeat pulse signals may then be shaped and conditioned to produce suitable signals for pulse counting and pulse interval timing.

Further according to the present invention there is provided apparatus for separating heartbeat sources comprising means for detecting heartbeat pulse signals, means for amplifying said heartbeat pulse signals, means for counting said heartbeat pulse signals and for recording time intervals between said pulse signals and microprocessor means for analysing the pulse time intervals over a plurality of said pulse time intervals so as to calculate the number of individual heartbeat sources producing the original heartbeat pulse signals.

The means for detecting the heartbeat pulse signals may be in the form of a sound transducer, for example a microphone. Alternatively, electrocardiograph or similar surface potential electrodes or laser interferometer techniques may be used.

Preferably, filter means are included for removing background noise from the heartbeat pulse signals.

Preferably also, the means for counting said heartbeat pulse signals is a binary counter.

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a block schematic diagram illustrating the method of separating heartbeat sources in accordance with the present invention; Figure 2 is a block schematic diagram of one embodiment of apparatus for use in a method of separating heartbeat sources in accordance with the present invention; and Figure 3 is a block schematic diagram of a second embodiment of apparatus for use in a method of separating heartbeat sources in accordance with the present invention.

Referring now to Figure 1 of the drawings, a method of separating heartbeat sources comprises detecting heartbeat pulse signals with a sound transducer 1. The signal detected by the transducer 1 is a combined signal 2 made up of, in the case illustrated, two separate heartbeat pulses 3 and 4, low frequency noise 5 and high frequency noise 6.

This combined signal is then applied to a signal conditioning circuit 7 which amplifies the signal and filters out the low frequency noise 5 and high frequency noise 6 to produce an output signal 8 which contains only pulse signals 3a and 4a representing the peaks of the two heartbeat pulses 3 and 4.

These pulses 3a and 4a are then timed by an electronic counter circuit 9 to produce data relating to the pulse intervals, this data is then analysed by a microprocessor 10 which determines by statistical methods the parameters relating to the number of separate heartbeat pulse sources contained in the original combined signal 2.

The times between each pulse are summed forward over a suitable range so that repetitive times of the regular periods occur more frequently than the irregular periods due to the asynchronism of the various sources. A frequency distribution can thus be produced to show the number of sources present.

Figure 2 of the drawings illustrates in block schematic form one embodiment of apparatus for use in carrying out the method of Figure 1.

A combined signal consisting of heartbeats and unwanted noise is detected by a microphone 11.

The signal is then amplified by an amplifier 12 and passed through a band pass filter 13 which removes unwanted low and high frequency noise from the signal leaving only the sharp pulse components of the heartbeats.

These pulse components are then shaped and conditioned to produce suitable gating signals for peak-counter/timer circuits 14 which comprises a peak detector 14a, binary counter 14b and clock 14c. Each pulse is detected by the peak detector 14a the output signals of which are applied to a binary counter 14b. Each pulse which arrives at the counter 14b causes the clock 14c count since the previous pulse to be output as pulse time count 15.

Thus each pulse which arrives at the counter/ timer 14 causes the count so far, that is the time since the last pulse, to be inputed into a microprocessor 16 and the timer to be reset. Thus, a series of the pulse time counts 15 is built up for analysis by the microprocessor 16.

The microprocessor 16 sums these times forward over a suitable range such that repetitive times of the regular periods occur more frequently than the irregular times due to asynchronism of the various sources.

Summed times outside of a suitably chosen range are discarded, and the remaining times are accumulated into a frequency distribution, where the monotonic regular periods show a higher frequency of occurrence than the chance times collected.

The probability of any measured period emanating from two independent sources is calculated and used to calculate the probability of the number of separate sources in the original signal. The calculated number of sources is then displayed on an L.E.D. 17 and other derived information is recorded by a recording device 18.

In addition to calculating the number of separate heartbeat sources the apparatus can carry out further analysis to calculate the various rates of the measured heartbeats and record how consistent they are.

A typical application of this technique is in the management of sheep during pregnancy when knowledge of how many foetuses a ewe is carrying allows proper feeding and treatment of the ewes.

The present method and apparatus makes it simple for ewes to be assessed and separated into single, twin, triplet, etc. lamb-bearing groups for appropriate feeding and care.

Figure 3 of the drawings illustrates in block schematic form a second embodiment of apparatus for use in carrying out the method of Figure 1.

In this embodiment the heartbeat signal is detected by a pair of electrodes 20. An impedance detector 21 and contact indicator 22 provide an indication that the electrodes 20 are correctly in place for signal detection. The detected signal is amplified by an amplifier 23 and has unwanted noise removed by a 50Hz notch 24 and low pass filter circuit 25. The heartbeat pulse signal is then amplified by a further amplifier 26 to provide a suitable input signal for a peak detector counter circuit 27. Information from the counter circuit 27 is then inputed to a microprocessor 28 which analyses the information and then displays the calculated number of heartbeat sources on a display device 29.

Modifications and improvements may be incorporated without departing from the scope of the invention.

Claims

1. A method of separating heartbeat sources comprising detecting heartbeat pulse signals, measuring the time interval between each successive pulse to produce pulse interval data and analysing the pulse interval data to calculate the number of individual heartbeat sources in the original heartbeat signals.

2. A method of separating heartbeat sources according to Claim 1, wherein the heartbeat pulse signals are filtered to remove background noise.

3. A method of separating heartbeat sources according to Claim 1 or Claim 2, wherein the heartbeat pulse signals are shaped to produce signals for pulse counting and pulse interval timing.

4. Apparatus for separating heartbeat sources comprising means for detecting heartbeat pulse signals, means for amplifying said heartbeat pulse signals, means for counting said heartbeat pulse signals and for recording time intervals between said pulse signals and microprocessor means for analysing the pulse time intervals over a plurality of said pulse time intervals so as to calculate the number of individual heartbeat sources producing the original heartbeat pulse signals.

5. Apparatus as claimed in Claim 4, wherein the means for detecting the heartbeat pulse signal is a sound transducer.

6. Apparatus as claimed in Claim 5, wherein the sound transducer is a microphone.

7. Apparatus as claimed in Claim 4, wherein the means for detecting the heartbeat pulse signal are surface potential electrodes.

8. Apparatus as claimed in Claim 4, wherein the means for detecting the heartbeat pulse signals is a laser interferometer.

9. Apparatus as claimed in any one of Claims 4 to 8, wherein means are included for removing background noise from said heartbeat pulse signals.

10. Apparatus as claimed in Claim 9, wherein the means for removing background noise from the heartbeat pulse signals is a filter means.

11. Apparatus as claimed in any one of Claims 4 to 10, wherein the means for counting said heartbeat pulse signals is a binary counter.

12. A method of separating heartbeat sources substantially as hereinbefore described with reference to the accompanying drawings.

13. Apparatus for separating heartbeat sources substantially as hereinbefore described with reference to the accompanying drawings.