Audio memory HLM-491
The module is designed for recording and playback of high quality monophonic sound (bandwidth 30 Hz – 10 kHz, S/N ratio 80 dB). Recording is performed on a standard SD memory card; the length of recording is limited only by the capacity of the card (for the standard 1 GB card it is 5.5 hours, in the special version it is possible to record up to a week of continuous recording even in a “circular” version, where the oldest part of the recording is overwritten by a new recording). The SD card stores files in RAW or WAV format (depending on the module version) in the standard FAT file system, if necessary, the sounds on the card can be edited using common Windows audio editing programs or the cards can be copied or backed up using common procedures, for example in Explorer.
The recording module has one line input to connect a signal source, one line output for the NF amplifier and a simple parallel control interface that accepts TTL levels (four signals to select a total of 16 messages, signals to start recording, start reading and indicate module operation).
Alternatively, a version with serial bus or I2C line control can be ordered; using these interfaces, it is possible to use an almost unlimited number of records, the module’s internal real-time clock, volume control and other functions.