Patent No. 3576185 Sleep-inducing method and arrangement using modulated sound and light
Patent No. 3576185 Sleep-inducing method and arrangement using modulated sound and light (Schultz et al., Apr 27, 1971)
Abstract
A tone or a blue light are modulated slowly between a perceivable maximum d a perceivable minimum with a perceivable period. Both the light and the tone are switched in after a time delay past the energization of the carrier and modulating signal generators used in the generation of the modulated light and tone, so that no transient effects are visible to the patient. The switch-out process is similarly effected in gradual stages to reduce transient effects.
Notes:
The effectiveness of the sleep-inducing
effect is increased considerably when the frequency of the sine tones emitted
by both speakers differ by approximately 0.5 to 2 Hz. This causes additional
beat frequencies to appear. This method is particularly effective when the modulation
periods of the two acoustic signals are slightly different. This improvement
may probably be traced to the fact that the acoustic center of the emitted sound
moves from one of these signal sources to the other during the treatment period
because of the differences in modulation frequency.
While the invention has been illustrated and described as embodied in particular
circuit arrangements, it is not intended to be limited to the details shown,
since various modifications and structural and circuit changes may be made without
departing in any way from the spirit of the present invention.
Without further analysis, the foregoing will so fully reveal the gist of the
present invention that others can by applying current knowledge readily adapt
it for various applications without omitting features that, from the standpoint
of prior art, fairly constitute essential characteristics of the generic or
specific aspects of this invention and, therefore, such adaptations should and
are intended to be comprehended within the meaning and range of equivalence
of the following claims.
What is claimed as new and desired to be protected by Letters Patent is set
forth in the appended claims.
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