A device is provided for acoustically reproducing the respiratory function for a respirator, with a patient respiration circuit. The device has a noise generator, a volume flow sensor device, which determines the volume flow in the patient respiration circuit and generates an electric signal representing the volume flow, and a volume flow evaluating unit, which is set up to pick up the volume flow signal and to generate a control signal for the noise generator as a function of this in such a way that an acoustic signal with a loudness rising (falling) with rising (falling) volume flow is generated. To optimize the loudness of the acoustic signal, a microphone and an evaluating unit connected thereto are provided, which said evaluating unit is set up to generate at least a first measure for the instantaneous ambient noise level on the basis of the microphone signal by averaging over at least one period of time and to increase (reduce) the loudness of the acoustic signal with rising (falling) ambient noise level as a preset monotonic function of the at least one measure.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1, is a block diagram of the device according to the invention.
Claims
1. A device for acoustically reproducing the respiratory function for a respirator, with a patient respiration circuit, the device comprising:
a noise generator;a volume flow sensor device, which determines the volume flow in the patient respiration circuit and generates an electric signal representing the volume flow;a volume flow evaluating unit, which is set up to pick up the volume flow signal and to generate, as a function of the volume flow signal, a control signal for the noise generator in such a way that an acoustic signal with a loudness rising or falling with a rising or falling volume flow is generated;a microphone; andan evaluating unit connected to said microphone, said evaluating unit generating a measure for an instantaneous ambient noise level on the basis of a microphone signal by averaging over at least one period of time and to increase or reduce the loudness of the acoustic signal with rising or falling ambient noise level as a preset monotonic function of said measure.
2. A device in accordance with claim 1, wherein said evaluating unit generates, on the basis of the microphone signal, said measure by averaging over a first period of time and generates another measure for the instantaneous ambient noise level by averaging over a second period of time that is different from said first period of time and selects the smaller of the first and second measures and varies the control signal as a preset monotonic function of the selected measure, so that the loudness of the acoustic signal rises or falls with a rising or falling ambient noise level.
3. A device in accordance with claim 1, wherein said evaluating unit varies the control signal in proportion to the measure.
4. A device in accordance with claim 1, wherein said noise generator has a noise generator, which is designed to simulate breath sounds like those audible with a stethoscope.
5. A device in accordance with claim 1, wherein a low-pass filter is provided as a filter circuit following said noise generator, said volume flow sensor device and a trigger evaluating circuit cooperating to provide a direction of volume flow for distinguishing the phase of inspiration from the phase of expiration and controlling the low-pass filter in accordance with the direction of flow such that the noise passing through during inspiration sounds differently and/or is distinguishable from the noise passing through during expiration.
6. A device in accordance with claim 1, wherein the noise passing through during inspiration sounds higher in pitch from the noise passing through during expiration.
7. A device in accordance with claim 1, wherein said evaluating unit evaluates a microphone signal, for generating a measure for the ambient noise level, only during periods of time during which no acoustic signal is generated by said noise generator or during periods of time during which no acoustic alarm is signaled.
8. A device in accordance with claim 1, wherein said evaluating unit compensates for a contribution to the microphone signal, which contribution is generated by said noise generator based on a correction, which is generated as a preset function of the control signal for said noise generator, in order to obtain the measure for the ambient noise level as a result.
9. A device in accordance with claim 1, wherein an input device is present to enable the basic loudness of the acoustic signal generated to be selected manually.
10. A device in accordance with claim 8, wherein said input device is designed such that the loudness cannot drop below a preset minimal basic loudness for safety-relevant acoustic indicators.
11. A device in accordance with claim 1, wherein said evaluating unit suppresses increased ambient noise levels, which do not exceed a preset maximum duration.
12. A device in accordance with claim 1, further comprising a sensor unit detecting a type of the respiratory activity as spontaneous, spontaneous supported or mandatory and that is set up, furthermore, to acoustically reproduce the type of the respiratory activity.
13. A device in accordance with claim 12, wherein said sensor unit detecting a type of the respiratory activity cooperates with a trigger evaluating circuit to vary the acoustic breathing signal in accordance with the detected type of respiratory activity.
14. A device in accordance with claim 12, wherein said trigger evaluating circuit varies the frequencies of the acoustic breathing signal generated in accordance with the detected type of respiratory activity by actuating a filter circuit.
15. A device in accordance with claim 12, wherein said trigger evaluating circuit generates a separate characteristic tone signal via a signal generator for each detected type of respiratory activity.
16. A device in accordance with claim 1, further comprising a band-pass filter to detect the ambient noise level only in a preset frequency range.
17. A device in accordance with claim 1, wherein the respirator is an intensive care respirator, an emergency respirator or anesthesia apparatus.
18. A combination respirator with device for acoustically reproducing the respiratory function, the combination comprising:
a patient respiration circuit;a volume flow sensor determining a volume flow in said patient respiration circuit and generating an electric signal representing the volume flow;a noise generator;a volume flow evaluating unit for receiving said volume flow signal and generating, as a function of said volume flow signal, a control signal for the noise generator;a microphone; andan evaluating unit connected to said microphone, said evaluating unit generating an instantaneous ambient noise level value on the basis of a microphone signal by averaging over at east one period of time and increasing or decreasing a loudness of the output of said noise generator.
19. A device in accordance with claim 18, wherein said evaluating unit generates, on the basis of the microphone signal, said noise level value by averaging over a first period of time and generates another noise level value for the instantaneous ambient noise level by averaging over a second period of time that is different from said first period of time and selects the smaller of the first and second noise level value and varies the control signal as a function of the selected noise level value such that the loudness of an acoustic signal based on the output of the noise generator rises or falls with a rising or falling ambient noise level.
20. A device in accordance with claim 18, further comprising a low-pass filter following said noise generator, said volume flow sensor device and a trigger evaluating circuit cooperating to provide a direction of volume flow for distinguishing the phase of inspiration from the phase of expiration and controlling the low-pass filter in accordance with the direction of flow such that the noise passing through during inspiration sounds differently and/or is distinguishable from the noise passing through during expiration.
21. A device for acoustically reproducing the respiratory function for a respirator, with a patient respiration circuit, the device comprising:
a noise generator;a volume flow sensor device, which determines the volume flow in the patient respiration circuit and generates an electric signal representing the volume flow;a volume flow evaluating unit, which is set up to pick up the volume flow signal and to generate, as a function of the volume flow signal, a control signal for the noise generator in such a way that an acoustic signal with a loudness rising or falling with a rising or falling volume flow is generated;a microphone;an evaluating unit connected to said microphone, said evaluating unit generating a measure for an instantaneous ambient noise level on the basis of a microphone signal by averaging over at least one period of time and to increase or reduce the loudness of the acoustic signal with rising or falling ambient noise level as a preset monotonic function of said measure; anda mixing stage for mixing ambient noise from said microphone with said acoustic signal to form a mixed signal.
22. A device in accordance with claim 21, further comprising an amplifier receiving an ambient noise signal from said microphone to provide an amplified ambient noise signal, said mixing stage receiving said acoustic signal and said amplified ambient noise signal to form said mixed signal.
23. A device in accordance with claim 22, further comprising headphones for providing a audible output based on said mixed signal.
Patent Application
20070208267
