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Class guinea.logic.TAFCTest

java.lang.Object
   |
   +----guinea.logic.Test
           |
           +----guinea.logic.GenericTest
                   |
                   +----guinea.logic.GenericABCTest
                           |
                           +----guinea.logic.TAFCTest

public class TAFCTest
extends GenericABCTest
implements PropertyLoader
In an TAFC (Two alternatives forced choice) Test two samples are compared. Two samples are played altering some parameter until the subject can no longer hear the difference between the samples.

The test uses the procedures and terms described in

Levitt H. (1971) Transformed Up-Down Methods in Psychoacoustics

See Also:
TAFCRule

Variable Index

· answerName
The question ID used to log the answer.
· buttonPressed
Did the subject press a button (indicates heard a difference, etc.) within given time between TAFC trials.
· initialLevel
Initial level for signal B at the start of test item's test procedure.
· logTrial
Whether to log the trials list of this item.
· maxRuns
The maximum number of runs for this TAFC test.
· pauseLength
Length of pause (in milliseconds) between TAFC trials.
· rule
The TAFC rule object for this test.
· ruleType
The rule type number.
· sampleB
The sample for signal B.
· sampleRef
The reference sample the sample B is compared with.
· stepSize
The step size of a step in a TAFC test.
· trialAnswerName
The question ID used to log the trial list (if trials logging is enabled via logTrial variable.

Constructor Index

· TAFCTest()
Construct a new TAFC test object.

Method Index

· endItem()
Add the result of the TAFC procedure to the subject.
· getRule(int)
Get a TAFC rule object.
· initItemSamples_base()
Initialize samples for this item.
· initTest()
Initialize the TAFC rule object for use in this test.
· propertyLoad(Properties, String)
Read parameters for this test from the properties.
· runSequence()
Run the TAFC procedure for this item.
· runSequence2()
Play the sample sequence.

Variables

· sampleB
 protected transient Sample sampleB
The sample for signal B. Sample B's level is controlled by the current TAFC rule.

· sampleRef
 protected transient Sample sampleRef
The reference sample the sample B is compared with.

· initialLevel
 protected Volume initialLevel
Initial level for signal B at the start of test item's test procedure. Default level is +0.0dB (1.0 linear).

· stepSize
 protected Volume stepSize
The step size of a step in a TAFC test. Default is 3.0dB.

· maxRuns
 protected int maxRuns
The maximum number of runs for this TAFC test.

· rule
 protected TAFCRule rule
The TAFC rule object for this test.

· ruleType
 protected int ruleType
The rule type number.

· buttonPressed
 protected boolean buttonPressed
Did the subject press a button (indicates heard a difference, etc.) within given time between TAFC trials.

· pauseLength
 protected long pauseLength
Length of pause (in milliseconds) between TAFC trials. Default is 2000ms (2 seconds).

· answerName
 protected String answerName
The question ID used to log the answer.

· logTrial
 protected boolean logTrial
Whether to log the trials list of this item. Default is false.

· trialAnswerName
 protected String trialAnswerName
The question ID used to log the trial list (if trials logging is enabled via logTrial variable.

Constructors

· TAFCTest
 public TAFCTest()
Construct a new TAFC test object.

Methods

· initTest
 public void initTest() throws Exception
Initialize the TAFC rule object for use in this test. It calls super-classes initTest() method to do default stuff. In addition it creates and initializes a TAFC rule object for the test.

Throws: Exception
an exception is thrown if player initialization fails for some reason.
Overrides:
initTest in class Test
· getRule
 protected TAFCRule getRule(int type)
Get a TAFC rule object.

Parameters:
type - Type of rule. Only rule 1 is currently implemented.
Returns:
A TAFC rule object.
See Also:
TAFCRule1
· runSequence
 protected void runSequence() throws InterruptedException
Run the TAFC procedure for this item. It plays the selected fixed sample sequence and waits for answer for a period. Then the TAFC rule is called to record the result. Then rule decides whether TAFC procedure should continue or finish.

Throws: InterruptedException
an exception is thrown if sequence was interrupted for some reason .
Overrides:
runSequence in class GenericTest
See Also:
rule, TAFCRule
· runSequence2
 protected void runSequence2() throws InterruptedException
Play the sample sequence. This is essentially the same as superclasses runSequence() method. It has some minor tuning for TAFC test.

Throws: InterruptedException
an exception is thrown if sequence was interrupted for some reason .
See Also:
runSequence
· initItemSamples_base
 protected void initItemSamples_base() throws Exception
Initialize samples for this item.

Throws: Exception
an exception is thrown if item samples initialization fails for some reason.
Overrides:
initItemSamples_base in class GenericABCTest
· endItem
 protected void endItem()
Add the result of the TAFC procedure to the subject. It is done this way because there is no actual UI components that could give this kind of answer directly. The answer is calculated based of a series of answers from the subject. Optionally, the procedure's trial list can also be logged.

Overrides:
endItem in class Test
· propertyLoad
 public void propertyLoad(Properties p,
                          String name) throws IllegalArgumentException
Read parameters for this test from the properties.

Parameters:
p - the properties.
name - the name of this object (not usually used)
Throws: IllegalArgumentException
thrown if parameters are wrong.
Overrides:
propertyLoad in class GenericABCTest

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