BSL PRO Software Guide - Biopac

Recording Data 49Chapter 3Selecting a waveform / channelAlthough multiple waveforms can be displayed,only one waveform at a time is considered“active.” Most software functions only apply to theactive waveform, which is also referred to as theselected channel. Selecting a channel allows you tohighlight all or part of that waveform, and enablesyou to perform transformations on a given channel.In the upper left corner of the graph window there is aseries of numbered boxes that represent each channel ofdata. The numbers in the boxes correspond to thechannel used to acquire the data (the specifics of settingup channels are discussed on page 645).In the sample file, ECG is on channels 1 and 2, withrespiration is on channel 3 and blood pressure is onchannel 4.Analysis BasicsTo select a channel, position the cursor over the channel box thatcorresponds to the desired channel and click the mouse button or position thecursor on the waveform of interest and click the mouse button. Note that theselected channel box appears depressed and the channel label to the right of thechannel boxes changes to correspond to the selected channel. Additionally, thechannel label in the display (on the left edge of the track) will be highlightedfor the active channel.Channel LabelsEach channel has a label on the left edge of the track to identify the contents of the channel. When achannel is active, its label is highlighted and also appears by the channel boxes.To change the label for a given channel, double-click the track label. A dialog will be generated so you can changethe text. You can also change the Label entry in the MP UNIT > Setup Channel dialog. When you change theLabel this way, the change will not take effect until you start an acquisition.Hide a channelYou can “hide” a waveform display without changing the data file.To hide a channel, hold down the Ctrl key and click in the channelbox. When a channel is hidden, the channel box will have a slashthrough it. You may view a hidden channel by holding down theCtrl key and clicking in the channel box again. Channels 2 and 4are hidden in the following display.When the active channel is hidden in Chart or Scope Mode, thefirst channel (of the remaining enabled channels) becomes the new(default) active channel and its Horizontal and Vertical Scales aredisplayed.The hide/show function should only be used after acquisition, not during. The entire Graph window will berefreshed when channels are shown or hidden during an acquisition. For large acquisitions, the refresh may interferewith the acquisition and generate an “Acquisition buffer overflow” and stop acquisition.