User manual

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2.14 Analog Filtering of the Signal Before Digitization
The waveform signal data should be filtered before being digitized with an analog filter set to half or less
of the digitization frequency. For example, if you are acquiring an AD sample at 50 µsec intervals (e.g. at
20 KHz sampling frequency), the analog filter should be set to at maximum 10 kHz (1/2 the sampling
frequency), or preferably to 5 kHz or lower (except if doing an Rs exponential fit, then keep it at 10 KHz).
If the analog filter is set to higher than half the sampling frequency (for example to 20 kHz in the above
example), mysterious things can begin to happen due to anti-aliasing such as loosing the capacitative
transients (e.g. the Rs measurement) that occur during the voltage clamp pulse when patch clamping.
2.15 Click the ‘MainProtocol’ Button to Start Stimulating and
Acquiring Data
In WinLTP, protocols are initiated either by clicking a Button, pressing a Function Key or by using the
RunMenu menu commands. To start the Main Protocol either click the ‘MainProtocol’ button or press the
F1 key, or pull down the Run menu and click on MainProtocol.
NOTE: If you want to change something (like the number of stimulus pulses, the Sweep Period, Delay
time etc, you have to do it at least 5 sec before the event starts. This is because in this version there is
substantial stimulus output buffering (3 sec in the Digidata board, and 2 sec in the WinLTP program. You
have to plan ahead a bit. (Eventually I would like to get it down to 2-3 seconds for the Digidata 132x
board, and 0.5-1 second for another board I have my eye on.) But this delay allows me to do multitasking
Continuous Acquisition and Capturing Spontaneous Events (not implemented yet), so I think its worth it.
2.16 Check that the Data Acquisition and Stimulation are Working
Correctly
Put in known amplitude and duration signals to check that WinLTP acquisition is working correctly,
and record WinLTP output on an oscilloscope to make sure the WinLTP stimulation is working correctly.
2.17 Use the Windows Task Manager to check CPU and Memory
Usage
In order to get an idea of how WinLTP is using your computer’s resources, primarily CPU usage and
memory usage you can use the Windows Task Manager. Press Ctrl-Alt-Del key combination to run the
Windows Task Manager.
Click on the Process tab (Fig. 2.17.1). Then use the menu command:
View -> Update Speed -> High
to update CPU usage as quick as possible.