For the input of our system, the Data Acquisition Toolbox in MATLAB was chosen to capture audio data. The Data Acquisition Toolbox, is not a fully real-time input acquisition system. It was not designed to support real-time operation, however, it does have some limited real-time capabilities. When used as a part of our system, music can be transcribed into a musical staff-like format with delays due to the inefficiencies that exist within MATLAB. The data is acquired through the following steps:

1. Data is acquired from an audio CD to a PC sound card
2. The Data Acquisition Toolbox handles the data
3. The acquired data are stored in the hardware's FIFO (First In First Out) buffer
4. Data are transferred from the FIFO buffer to system memory
5. The data are analyzed and information about notes is extracted
6. The music information is displayed on screen
7. Step 1 through 6 are repeated until the program is stopped



The sampling rate of the Data Acquisition Toolbox is set to 44.1 KHz. The timer function, along with a sampling trigger is used for signaling the system to extract the data at a rate of 2 Hz with 22050 samples per trigger. For our system, a single hardware channel is used to acquire the input sound in monophonic mode.