SoundImp: Data Acquisition using Sound Card

Below is a table of settings versus behavior of the SoundImp module-

To import from a sound card, select the sound-In Device, sample rate and record length.

The SoundImp module supports the graphical and programming user interfaces as explained below.

Graphical Interface

Ports

CH1 Left channel data output port. CH2 Right channel data output port.

Schematic Symbol

Settings

Sound-In Device [Dropbox]

This is a list of available sound recording devices in the PC. Select the device you want to use.

Sample Rate [Textbox]

This is the sound card sample rate in samples per second (SPS) or kilo samples per second (KSPS). Sound cards usually support 11.025 KSPS, 22.05 KSPS and 44.1 KSPS only. If you enter any other sample rate value and the sound card doesn't support it, then the sampling might not be accurate resulting in distorted sound recording.

Rec Length [Textbox]

Record length, i.e. number of samples to be acquired in one go. Be aware that entering a large value can increase the sweep time to very large values due to low sample rate of sound card.

Sweep Time [Textbox]

Time required to acquire the specified number of samples at the specified sample rate.

Freeze Signal [Checkbox]

Marking the Freeze Signal Checkbox freezes the output waveform and no new samples are acquired.

More [Checkbox]

Marking the More Checkbox shows more advanced options.

CHL Gain [Textbox]

Enter the gain for the left channel if you want to calibrate it.

CHL Offset [Textbox]

Enter the dc offset for the left channel

CHR Gain [Textbox]

Enter the gain for the right channel if you want to calibrate it.

CHR Offset [Textbox]

Enter the dc offset for the right channel

Horizontal Offset (s) [Textbox]

Enter horizontal offset in seconds. If Additive is unchecked, the entered horizontal offset is absolute and is the horizontal offset for the first point in the waveform, i.e. it overrides the horizontal offset inherent in the waveform. If Additive is checked, the entered horizontal offset is additive to any horizontal offset inherent in the waveform.

Additive [Checkbox]

Marking the Additive checkbox makes the entered horizontal offset as additive to the horizontal offset inherent in the waveform. Unmarking the Additive Checkbox makes the entered horizontal offset as absolute and is the horizontal offset for the first point in the waveform, i.e. it overrides the horizontal offset inherent in the waveform.

Mono [Option]

Selecting the mono option makes the sound card behave as a mono sound card. Refer the table at the top to see the sound card behavior when mono is selected.

Stereo [Option]

Selecting the stereo option lets you to use the sound card in stereo mode. Refer the table at the top to see the sound card behavior when stereo is selected.

Programming Interface

Settings

Record Length

Syntax	:reclen
Type	:long
Unit	:Points
Default	:1000

Number of data points to be acquired from the sound card.

Sample Rate

Syntax	:samplerate
Type	:long
Unit	:Samples/second
Default	:44100

Number of samples per second acquired by sound card. A higher number gives higher resolution. Most of the sound cards support sample rates of 11025, 22050 and 44100 samples/second.

Gain Calibration

Syntax	:chl.gain or chr.gain
Type	:double
Unit	:n/a
Default	:1

Used to calibrate sound card left or right channel gain. Specify a value that plots a 1 V signal as a 1 V signal.

Offset Calibration

Syntax	:chl.offset or chr.offset
Type	:double
Unit	:n/a
Default	:0

Used to calibrate sound card left or right channel offset. Specify this value to center an AC signal around 0 V.

Sound-In Device

Syntax	:device
Type	:long
Unit	:n/a
Default	:0

Selects the sound-in device to be used for data acquisition.

Mono/Stereo Mode

Syntax	:stereo
Type	:long
Unit	:n/a
Default	:0

Setting this setting to 1 enables stereo mode and setting it to 0 enables the mono mode. See the table at the top to see the module behavior for this setting.

Functions

Sound-In Device List

Detects sound input i.e. sound recording devices available and returns them in a comma separated list.

String devices()

Returns

:Comma separated list of sound input devices

Window Size

Changes the width and height of the GUI window.

void gui.size(float width, float height)

Returns	:None
width	:Window width in pixels
height	:Window height in pixels

Window Location

Moves GUI window to the specified location and optionally changes size.

void gui.move(float left, float top, float width, float height)

Returns	:None
left	:Horizontal coordinate for the left edge of the window in pixels.
top	:Vertical coordinate for the top edge of the window in pixels.
width	:Optional. Window width in pixels
height	:Optional. Window height in pixels

Ports

Left Channel Data Out

Syntax	:chl.out
Type	:Output

Left channel data output

Right Channel Data Out

Syntax	:chr.out
Type	:Output

Right channel data output