WO1995000935A1

WO1995000935A1 - Gradual audio defiltering

Info

Publication number: WO1995000935A1
Application number: PCT/FR1994/000738
Authority: WO
Inventors: Raphaël ROBERT
Original assignee: Robert Raphael
Priority date: 1993-06-17
Filing date: 1994-06-17
Publication date: 1995-01-05
Also published as: EP0704083A1; FR2706657B1; FR2706657A1

Abstract

A device for waking up a sleeping or drowsy person by creating an audio signal sound spectrum extending from high-pitched to low-pitched sounds in accordance with an adjustable time scale and until 'normal' or audible levels are reached. Several techniques may be used for this purpose, including the one set out in the claims which uses a switched-capacity variable high-pass filter (1) dependent on the frequency of a clock (3) obtained from an oscillator (2) of other filters for rejecting interference signals. This gradual audio signal source defiltering system is primarily designed for use in manufacturing timepieces, particularly clock radios.

Description

Progressive audio filtering.

The device of the invention is intended to extract a subject or a natural person from a state of sleep or drowsiness to an awake state. The prior techniques relating to this subject have the drawback in their uses of provoking in return psychosomatic resistance. The accompanying drawings illustrate the invention:

Fig.l: Progressive filtering of an audio signal Fig.2: Relaxation curve - X = voltage

Y = time X '= listening Y' = time

T = latency time Fig. 3: Energy efficiency curve

X = signal-to-noise ratio

Y = time

X '= energy efficiency

Y '= listening T = latency

Fig. 4: Opening of the sound spectrum Fig. 5: Electronic device

The solution to this problem is: a) to avoid psychosomatic resistance by preserving the relaxation of the physical subject (XY - Fig. 2) and his availability of nervous circuit, motivation, vigilance, etc. (see listening X 'Y' Fig. 2).

b) in return ensuring a cortical load generating energy (X ′ Y ′ Fig. 3) by soliciting the subject by acute so-called load sounds. The principle of defiltration lowers the signal / noise ratio (X Y Fig.3) which accentuates the profitability of the cortical load (energy efficiency X 'Y' Fig.3).

The principle used in this field is the opening of a sound spectrum of audio signal, from high to low, on a given time scale until the so-called normal air hearing, even social. Fig.l.

When the "ringing" system is triggered, an imperceptible sound begins in the treble. Gradually, the frequency spectrum contains more low tones until the rest of the spectral integrity is restored. The diagram in Fig. 4 gives the curve for the reproduction of the sound intensity as a function of the frequencies for different times in time. The right part of the curve remains fixed up to 8000 Hertz (the slope is 12 DB / octave) (5). The left part of the curve gradually slides towards low frequencies up to 300 Hertz (36 DB / octave) (6) to reinforce the perceptual phenomenon.

Said progressive filtering system of the audio signal is provided by an electronic device, (block diagram Fig.5). The functionality of the system is based on the use of a variable high pass filter (1) Fig. 5 whose characteristics change over time: the cut-off frequencies vary progressively between 8 Khz and 300 Hertz in a variable time on demand preferably ranging from 10 seconds to several minutes. This high-pass filter with switched capacity depends on the clock frequency (3) Fig. 5. This variable clock frequency is obtained from a voltage controlled oscillator (voltage / frequency converter (2) Fig.5). Other filters provide rejection of parasitic clock signals.

Said progressive sound defiltration system has an application in fields such as automobile, rail, air transport, in order to stop the drowsiness effect. It also has a possible application for apartment doorbells, telephone rings, alarm systems, this in order to avoid the effects of auditory shock or stress. Application also possible for decompression stops during scuba diving. Another possible application in resuscitation services in hospitals.

Claims

1) Device making it possible to extract a person from a state of sleep or drowsiness to an awake state, characterized in that it comprises means of progressive filtering of the sound of an audio signal (opening of the sound spectrum) up to in so-called normal, or even social, aerial hearing, the so-called means being constituted by a variable high pass filter (1) whose cut-off frequencies vary progressively from high to low (from 8 kHz to 300 Hz) in variable time on demand.

2) Device according to claim 1 characterized in that it comprises a variable high pass filter with switched capacity (1).

These characteristics change over time and it depends on the frequency of the clock (3).

3) Device according to any one of the preceding claims characterized in that it comprises the clock frequency which is obtained from a voltage controlled oscillator (2) (voltage / frequency converter). Other filters provide rejection of parasitic clock signals.

4) Device according to any one of the preceding claims, characterized in that it comprises a restitution of the sound intensity as a function of the frequencies for different instants in time. A diagram shows us the right part of the fixed curve up to 8000 Hertz according to a slope of 12 DB / octave (5), the left part of the curve sliding progressively towards low frequencies according to a slope of 36 DB / octave ( 6).