Black Box IEEE 1284 Uživatelská příručka stáhnout pdf (Strana 30)

Page 30 of 98 The Black Box Toolkit

• RSVP

Test

In the RSVP test two bitmaps are alternately displayed with the chosen

frequency. One bitmap has a 32x32 white block on the left, with a black

block on the right whereas the other bitmap has the reverse. One opto-

detector should be positioned over the left and right block. The central

white blocks are displayed on every frame.

Alternating activity between opto-detectors should be seen as alternate

bitmaps are displayed at the chosen frequency. In the screen shot above

we can see the simulated effect of two images being presented at very

high speed. Where the first daytime woodland scene is replaced by a

similar scene at sunset with a blurring effect.

• Video

Test

In the video test a black and white block has been superimposed onto the

lower right hand corner of a video stimulus. An opto-detector can be

positioned over the block. In this case when a cyclist with a white jumper

rides past the block will change from black to white and a tone will sound.

In your own paradigms you could use the block to indicate the onset and

duration of a stimulus. This could be picked-up by an opto-detector and

responses could be detected using the optional toolkit response pad. This

would ensure that you knew with absolute certainty where the stimulus

occurred in the video relative to the response.

Before you test the timing of your own paradigm you are advised to make use of the toolkit

software to benchmark the sensor check utility to ensure you’ve correctly setup the

sensors and adjusted the thresholds accordingly. You should bear in mind that the

presentation timing of our utility may not be exact on your specific hardware.

7.3.2. Tutorial 2: Setting-up microphones for monitoring auditory stimuli

The sensor check utility can be used to produce tones of various durations. These will be

played through the default audio device on the remote PC. This is useful when adjusting

the sensitivity of the toolkits digital microphone(s). You should begin by positioning one or

more microphones next to the speakers or headphones of the remote PC. Next select one

of the tone schedules from the “Microphone” menu.

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Black Box IEEE 1284 Uživatelská příručka Strana 30