Laser printer output of digitized EEG waveforms

A method is described for stripchart style output of multichannel EEG waveforms from a computerized data acquisition system using a laser printer optimized for the task. The printer formats the binary digitized data, transmitted from the host computer. Data transmission and page formatting parameters are specified by an initialization sequence sent to the printer ahead of the multipage stream data. Scaling and formatting are performed in real time by the laser printer controller using a fast line-drawing algorithm to connect the data points. Vector graphics and ASCII text can be overlaid on the waveform image for axes, grids, and labels. A typical 10-s page of 16-channel EEG data (13-b sample at 200 Hz) is printed at a rate of 15 'pages/min'. The resolution of 400 dots per inch (DPI) provides higher-quality traces than traditional pen recorders.<
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