Signal data received from the A/D device is for SIGVIEW only a series of samples with different
numeric values. For example, each sample from the sound card has usually a value between -32767 and 32767 (16-bit resolution). Of course, these values have no physical meaning. To
transfer these values into meaningful physical values like Volt, meter, Celsius, etc., you have to
tell SIGVIEW how to convert generic numeric values into real word units. This complete
transformation is described in a ‘calibration file’. You can create as many calibration files you
want, and use them for different data acquisitions.
Each calibration file can contain calibration data for multiple channels. You can choose the
number of channels in the combo-box in the upper part of the dialog. To switch between channels
during editing, use '<' and '>' buttons on the right side of the dialog.
By choosing Data acquisition/Sound card calibration option from the main menu, you will open a
calibration dialog where you can create a calibration file through 6 simple steps:
1. Use Data acquisition menu option to record constant signal with known amplitude (for
example 5V) from your DAQ device. Use only "default.cal" calibration file for this
2. Measure the average value of the signal recorded by SIGVIEW during first step and
enter it in ‘Recorded input level’ field.
3. Enter the actual amplitude level in physical units which corresponds to the signal
recorded during first step in ‘Input level in physical units’ field. You can also define if
this value should be considered as peak or RMS value.
4. Enter the description of your physical units (for example V or Volt) in field ‘Physical
5. You can also define offset to be added to recorded values (in physical units).
6. Save your calibration file and use it later for data acquisition in Data acquisition
All calibration files should be saved in the “Calibration” folder located in the SIGVIEW's application data directory (usually C:\Documents and Settings\<UserName>\Application
Data\Sigview\). Each of these calibration files can be used later for data acquisition.
There is one special data acquisition file, “default.cal”, which is distributed with SIGVIEW and
used by default. It leaves recorded data from the DAQ device just as they are, without any
conversion. You should not change the content of this file.