SampleRate (Data Acquisition Toolbox)

SampleRate specifies the per-channel rate (in samples/second) that the analog input or analog output hardware can digitize data.

Data acquisition devices have a finite (though often large) number of valid sampling rates. To find out the range of sample rates supported by your board, you can use the propinfo function.

If you specify a sampling rate that does not match one of the valid device values, then the data acquisition engine automatically selects the closest supported sampling rate that is within 1% of the requested rate. If there is no valid sampling rate within this tolerance, the next highest value is selected. If a higher value is not available, then an error is returned.

Since SampleRate can be set to a value that differs from the one specified with the set function, you should return the actual sampling rate.

ActualRate = get(AI, 'SampleRate');

Alternatively, you can use the setverify function. This function sets the SampleRate value and then returns the actual value that is set.

ActualRate = setverify(AI, 'SampleRate', Value)

Note:
Whenever the SampleRate value is changed, the BufferingConfig values are recalculated by the engine.

Characteristics


Device Objects	AI, AO
Class	Common
Access	Read/write
Data Type	Double
Modify while Running	No

Values

The default value is obtained from the hardware driver.

Example

Suppose you create an analog input object AI for a sound card and add two channels to it.

AI = analoginput('winsound')
addchannel(AI, 1:2)

You can find out the range of valid sample rates with the propinfo function.

propinfo(AI,'SampleRate')

You can use the set command to set the sample rate to 8 kHz for each channel.

set(AI, 'SampleRate', 8000);

To find out what the actual sample rate is set to:

ActualRate = get(AI, 'SampleRate');

Alternatively, you can use the setverify function. This function sets the sample rate value and then returns the actual value that is set.

setverify(AI, 'SampleRate', 8000)