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Colour Noise Generator
Křivánek, Tomáš ; Rajmic, Pavel (referee) ; Frenštátský, Petr (advisor)
The main purpose of this bachelor thesis is explanation of „colored noise“, such as pink, brown, blue and more. There are completely subscribed coloured noises in this work, includig their importance and use for measurement in electroacustic and sound technology. Practical part of this thesis is focused on generating colored noises in Matlab, where we mainly work with model frequency spekter, frequency response and FIR filters.
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Standard baffle - laboratory device
Hodinka, Tomáš ; Říha, Kamil (referee) ; Balík, Miroslav (advisor)
The purpose of this project is the design and the construction of a laboratory preparation for loudspeaker measurements, a standard baffle. Standard baffle is a rectangular panel with a loudspeaker placed eccentrically. Measurements with this baffle are then done in an anechoic chamber. The main purpose of a standard baffle is the ability to measure loudspeakers without the effect, that is caused by the pressure properties of a closed baffle and without an acoustic short circuit. The standard baffle is designed, so that it is self-supporting, transferable by 2 people, easy to be stored, modular and able to support loudspeakers that are up to 12 inches in diameter. The designed baffle is detachable into 3 parts. The base, the panel, and the inserts. The base is a big, heavy board with a key on the upper side. This key fits into a key groove in the panel and that allows the two parts to assemble. The plane is made of four layers of different types of plywood. That allows the design to make a compromise between the toughness and weight. The inserts are designed, so that the replacement and manipulation of loudspeakers during measurement are as past and as simple as possible. During measurement the loudspeakers are mounted in their respective inserts, which can be mounted and dismounted from the standard baffle without any tools. The test measurements demonstrated that the standard baffle is unsuitable for reference measurements. Resonance of the plane, reflections from the base, refractions from the outer edges of the baffle and potentially different causes unduly distort the results of measurements. These distortions are displayed with a considerable consistency even between different loudspeakers. This indicates that these distortions could be filtered oud by, for example, using a specialized software.
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Acoustic stimulation of Slow wave sleep and its influence on consolidation of declarative memory in insomnia
Orendáčová, Mária ; Kopřivová, Jana (advisor) ; Kelemen, Eduard (referee)
Slow-wave sleep plays an important role in consolidation of declarative memory. From electrophysiological point of view, this process is dependent on a common occurrence and mutual integration of neocortical slow oscillations (< 1 Hz), hippocampal sharp-wave ripples (150-250 Hz) and thalamo-cortical sleep spindles (10-15 Hz). Previous studies demonstrated that periodic acoustic stimulation by pink noise pulses applied at frequency of sleep slow oscillation during slow wave sleep leads to prolongation of slow wave sleep and to enhancement in declarative memory performance in normal sleepers. Our study investigated this kind of periodic acoustic stimulation in its relation to sleep architecture and declarative memory of people suffering from insomnia due to which there often comes to a reduction in slow wave sleep which positively correlates with worsening of declarative memory performance. Our aim was to investigate if this kind of comparatively non-invasive brain stimulation has a potential to increase a total length of slow wave sleep and enhance declarative memory performance in insomnia. Our study revealed acoustic stimulation neither improved declarative memory performance nor it increased total length of slow-wave sleep. No positive association was found between level of declarative memory...
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Standard baffle - laboratory device
Hodinka, Tomáš ; Říha, Kamil (referee) ; Balík, Miroslav (advisor)
The purpose of this project is the design and the construction of a laboratory preparation for loudspeaker measurements, a standard baffle. Standard baffle is a rectangular panel with a loudspeaker placed eccentrically. Measurements with this baffle are then done in an anechoic chamber. The main purpose of a standard baffle is the ability to measure loudspeakers without the effect, that is caused by the pressure properties of a closed baffle and without an acoustic short circuit. The standard baffle is designed, so that it is self-supporting, transferable by 2 people, easy to be stored, modular and able to support loudspeakers that are up to 12 inches in diameter. The designed baffle is detachable into 3 parts. The base, the panel, and the inserts. The base is a big, heavy board with a key on the upper side. This key fits into a key groove in the panel and that allows the two parts to assemble. The plane is made of four layers of different types of plywood. That allows the design to make a compromise between the toughness and weight. The inserts are designed, so that the replacement and manipulation of loudspeakers during measurement are as past and as simple as possible. During measurement the loudspeakers are mounted in their respective inserts, which can be mounted and dismounted from the standard baffle without any tools. The test measurements demonstrated that the standard baffle is unsuitable for reference measurements. Resonance of the plane, reflections from the base, refractions from the outer edges of the baffle and potentially different causes unduly distort the results of measurements. These distortions are displayed with a considerable consistency even between different loudspeakers. This indicates that these distortions could be filtered oud by, for example, using a specialized software.
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Acoustic stimulation of Slow wave sleep and its influence on consolidation of declarative memory in insomnia
Orendáčová, Mária ; Kopřivová, Jana (advisor) ; Kelemen, Eduard (referee)
Slow-wave sleep plays an important role in consolidation of declarative memory. From electrophysiological point of view, this process is dependent on a common occurrence and mutual integration of neocortical slow oscillations (< 1 Hz), hippocampal sharp-wave ripples (150-250 Hz) and thalamo-cortical sleep spindles (10-15 Hz). Previous studies demonstrated that periodic acoustic stimulation by pink noise pulses applied at frequency of sleep slow oscillation during slow wave sleep leads to prolongation of slow wave sleep and to enhancement in declarative memory performance in normal sleepers. Our study investigated this kind of periodic acoustic stimulation in its relation to sleep architecture and declarative memory of people suffering from insomnia due to which there often comes to a reduction in slow wave sleep which positively correlates with worsening of declarative memory performance. Our aim was to investigate if this kind of comparatively non-invasive brain stimulation has a potential to increase a total length of slow wave sleep and enhance declarative memory performance in insomnia. Our study revealed acoustic stimulation neither improved declarative memory performance nor it increased total length of slow-wave sleep. No positive association was found between level of declarative memory...
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Colour Noise Generator
Křivánek, Tomáš ; Rajmic, Pavel (referee) ; Frenštátský, Petr (advisor)
The main purpose of this bachelor thesis is explanation of „colored noise“, such as pink, brown, blue and more. There are completely subscribed coloured noises in this work, includig their importance and use for measurement in electroacustic and sound technology. Practical part of this thesis is focused on generating colored noises in Matlab, where we mainly work with model frequency spekter, frequency response and FIR filters.
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