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Audio Saving Module
Strašil, Ivo ; Kouřil, Jiří (referee) ; Říha, Kamil (advisor)
The aim of this thesis was to design and construct an autonomous, hardware voice recorder/player module. The device is made as a compact, built-in component for a motherboard of a target appliance. During recording, the incoming analog voice signal is converted to a digital stream by an ADC with 16 bits resolution and 24 kHz sample rate. Microcontroller LPC2103 (ARM7TDMI core) processes data, recalculates resolution and sample rate, encodes and converts to WAV format and save into a FAT/FAT32 filesystem on a Secure Digital memory card. At playback, the process is opposite: the microcontroller reads file from the memory card, decodes the stream and sends it to a DAC and then to a reconstruction filter. So there is an analog voice signal at the output again. The firmware allows control by logic inputs or by a serial bus, processing of uncompressed WAV files or WAV files with A-law or IMA ADPCM compression, continual recording including automatic freeing of card space by deleting the oldest records and a usage of a voice emphasis filter or of a signal dynamic compression circuit.
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Design of Portable Audio Recorder
Vávra, Marek ; Bukvald, Jiří (referee) ; Sládek, Josef (advisor)
The aim of this thesis was to design portable audio recorder for professionals and sound enthusiast. The important part of this bachelor thesis was to design simple controlled a endurable high quality device with simple and compact shape. Requirements of professional users were fullfilled by using modern technologies available in the sound industry.
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Design of Portable Audio Recorder
Vávra, Marek ; Bukvald, Jiří (referee) ; Sládek, Josef (advisor)
The aim of this thesis was to design portable audio recorder for professionals and sound enthusiast. The important part of this bachelor thesis was to design simple controlled a endurable high quality device with simple and compact shape. Requirements of professional users were fullfilled by using modern technologies available in the sound industry.
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Audio Saving Module
Strašil, Ivo ; Kouřil, Jiří (referee) ; Říha, Kamil (advisor)
The aim of this thesis was to design and construct an autonomous, hardware voice recorder/player module. The device is made as a compact, built-in component for a motherboard of a target appliance. During recording, the incoming analog voice signal is converted to a digital stream by an ADC with 16 bits resolution and 24 kHz sample rate. Microcontroller LPC2103 (ARM7TDMI core) processes data, recalculates resolution and sample rate, encodes and converts to WAV format and save into a FAT/FAT32 filesystem on a Secure Digital memory card. At playback, the process is opposite: the microcontroller reads file from the memory card, decodes the stream and sends it to a DAC and then to a reconstruction filter. So there is an analog voice signal at the output again. The firmware allows control by logic inputs or by a serial bus, processing of uncompressed WAV files or WAV files with A-law or IMA ADPCM compression, continual recording including automatic freeing of card space by deleting the oldest records and a usage of a voice emphasis filter or of a signal dynamic compression circuit.
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