Test and Measurement Software

LOADING in the following WAV file formats has been added:
PCM WAV 16 bit (Integer format)
PCM WAV 24 bit (Integer format)
PCM WAV 32 bit (Integer format)
IEEE WAV 32 bit (Floating Point format)
IEEE WAV 64 bit (Floating Point format)

SAVING in the following WAV file formats has been added:
PCM WAV 16 bit (Integer format)
PCM WAV 32 bit (Integer format)
IEEE WAV 32 bit (Floating Point format)
IEEE WAV 64 bit (Floating Point format)

Time data (of both Impulse Response or Scope buffers) can be now imported/exported also in the above WAV formats.

Some normalization options concerning WAV files LOAD and SAVE have been added in Settings/File Options window.

Example: a PCM 16 bit WAV file can handle integer data between +/-32767. A measured impulse response has a peak value of 0.254 mPascal. If it is saved as PCM 16 bit WAV without normalization, the resulting WAV file will contain only zero values.

The same happens when saving as PCM 32 bit WAV, that can handle integer data between +/-2147483647.

The IEEE floating point WAV format does not have this problem since can handle floating point data. A normalization to "1" is available anyway for giving the better compatibility with other software.

The normalization feature can be disabled setting the normalization peak value to "0".

When LOADING a WAV file (that can be classified as Scope or Impulse Response by the Load WAV file as setting), another option is available:

Impulse Responses: the peak can be optionally normalized to "1"

Scope data: the current amplitude calibration can be optionally applied.

- FRD files LOAD/SAVE

FRD files are an ASCII stadard format for frequency response exchange between different software systems. More info are here.

This is an FRD file format example:

* Frequency Data exported from SampleChampion
* DeltaF (Hz) = 5.85937500
* FFT Length = 8192
* Data (from f=0 to f=24000.00000000 Hz):
* FREQUENCY -------- SPL --------------PHASE -------
5.859375000 -6.6413279209929422 161.172205576833990
11.71875000 -6.2717003153797555 142.893539456514790
17.57812500 -5.7170485135652076 125.547620204225055
23.43750000 -5.0415376898741889 109.294398830669541
29.29687500 -4.3013566780912727 94.1163743150220921
35.15625000 -3.5376477339700959 79.8990622262171842
41.01562500 -2.7771475142395961 66.4949803316312349
46.87500000 -2.0357062995903430 53.7595379304933006
52.73437500 -1.3218866288923240 41.5660817383207405
...

Sample Champion can now save and load frequency data also in this format. In order to have the better results, the current FFT size setting in Sample Champion must be the same of the loaded FRD file.

FRD spectra saving feature has been added also inside the Enhanced View plugin, in order to save Minimum Phase data.

To save frequency data from Enhanced View plugin the Phase View must be selected.

Some basic editing functions on the phase have been added in the Enhanced View plugin: Add and Shrink.

- New THD and THD+N computation mode

It is now possible to select a different computation formula of THD and THD+N.

In RTA window is available the THD Mode option.

Enabling the THD Mode option, THD will be computed by means of the following formula:

and THD+N will be computed by means of the following formula:

Refer to Application note # 8 for more information.

- Increased accuracy and displayed digits in Correlation Meter

- Additional Audio Settings options

When one audio input format parameter is changed, the output format will be changed accordingly. Also a Buffer Length change will cause the automatic selection of an MLS signal with the right length.

Output parameters and MLS signal settings can still be changed manually.

- Average mode new option

It's possible to let the software ignore the first sampled buffer when in Average Mode. When the option is enabled the first buffer will not be averaged.
This can be useful for some soundcards or in specific measurements settings (for having a stationary sound field, for example).

- Other small changes and bug fixed:

- Fixed the "Right Bank" error when the FFT button was pressed and the Time window was maximized.

- Changed the IFT button in spectrum window

The IFT button also automatically opens a time window with the result of the Inverse Fourier Transform.

- Now the LOAD dialog remembers the last file type.

- Shortcuts to the Plugins have been added in the right bar

- Fixed the Flashing save window bug in Windows 2000

- Manual Amplitude calibration

A new method for the amplitude calibration procedure has been added. The amplitude calibration can be performed in real-time using a pure tone source (external or internal) or off-line by means of a manual setting.

In the Setting / Calibration window a new section is present:

The manual procedure allows to set a dB (Peak) calibration without a real measurement. The user can assign to a time peak value (Scope window, raw sampled data) a dB (Peak) power level by pressing the SET button.

In the example above a peak value of 32767 in Scope window has been assigned to 0 dB. In this way a 16 bit WAV file with a sine signal between +/- 32767 will show a spectrum with a peak of 0 dB. With this same calibration a WAV file with a sine between +/-327 will show a peak in the spectrum of about -40 dB.

The Scope data info button searches minimum and maximum values of the current data in Scope buffer (loaded from a file or measured in real-time). The uncalibrated maximum data (Left and Right channels) are automatically written in the LEFT and RIGHT fields of manual calibration.

In this way the manual calibration is very simple: after pressing the Scope data info button, the user can write the desired dB value for LEFT and RIGHT channels (only LEFT for mono) and press SET.

In the above example a 100 dB value has been set. The LEFT and RIGHT values (7976 and 7912) are the raw (uncalibrated) max values found in the Scope window, written automatically after pressing the Scope data info button.

Sample Champion Release 3.6

- Auto-sync function

This option allows a very robust synchronization of your soundcard and avoids all errors due to data sync loss. It allows extremely accurate measurements when used in the Average mode.

When the auto-sync function is active, the time latency calibration (that depends on many factors: soundcard hardware and drivers, operating system, etc..) will be automatically compensated.

It can be enabled in the Settings/General window:

or in the Settings/Calibration window:

When this option is enabled, the soundcard Channel 2 INPUT must be connected directly to Channel 2 OUTPUT (Loopback).

Example of connection:

Adjust input and output levels of Channel 2 in order to obtain a low input peak level. Usually a value of 1% or 2% of the peak level is enough to activate the sync function.

The microphone (or any other input device) can be connected to Channel 1 INPUT. The power amplifier and loudspeaker can be connected to Channel 1 OUTPUT.

When this option is active, the saving window consents to optionally save only the impulse response channel 1 data (channel 2 contains only sync information).

- New method for the evaluation of the Noise Floor

A new method for the evaluation of the Noise Floor value in the SNR computation has been added and can be accessed in the RTA window.

It is now possible to select 3 options:

1- computation of the Noise Floor level as logarithmic sum of narrow band power levels in a frequency range selected by the user. This option can be used for estimating the Noise Floor WITHOUT the harmonics due to distortion; it is, for instance, possible to select the band 100..800 Hz when a 1 kHz tone is used as signal generator.

2- manual: this option allows to set manually the Noise Floor value. It can be measured, for example, recording the background noise in absence of input signals.

3- computation of the Noise Floor level as logarithmic sum of narrow band power levels on the whole bandwidth from 20 to 20000 Hz.

A yellow line corresponding to the Noise Floor level and a blue line under the frequency range selected by the user for the computation can be optionally visualized on the plot.

If the pure tone used for the measure falls inside the frequency range selected by the user, it is automatically excluded from the computation.

The Noise Floor value used for THD+N computation is not influenced by this option and is computed on the whole bandwidth; all harmonics generated by the 2 pure tones are also automatically excluded.

IMD computation is not influenced by this option.

- Load and Save Spectra in RTA window

Buttons for saving and loading the spectra measured in RTA window (narrow band, 1/1 or 1/3 octave) have been added. Now functions (Transfer function, Cross-Spectrum, Coherence, Auto-Correlation, Cross-Correlation) can be computed in post-processing mode on loaded data.

Left channel and right channel FFT banks can be saved and loaded independently.

- Clear all data buffers

A function (Post-Processing menu) for clearing all data currently in memory buffers (impulse response, scope, FFT, etc..) has been added.

- The "Remove offset from sampled data" function (Settings/Advanced), time window autoscale and zoom out functions have been improved.

Sample Champion Release 3.4

- Room Acoustics Plugin: Improved computation accuracy. Added an option for selecting comma or dot as decimal separator in the exported Excel files.

Fixed a visualization bug in Excel export window.

- Smooth Spectrum: Added a post-processing function for smoothing spectra. The number of cycles can be selected, to obtain a more deep effect.

The smoothing is obtained performing a moving average on the frequency data. The spectrum, after the smoothing, will have only Real data (the Imaginary part is set to 0). The original (unsmoothed) spectrum can be restored by pressing F5 (refresh).

- Custom Plot Label: The label of frequency plots can be customized.

This option allows to the user the personalization of the title label of the frequency plot, adapting it to the kind of data analyzed and to current settings.

Sample Champion Release 3.2

- Room Acoustics Plugin: Now the computed acoustical parameters (1/1 and 1/3 octave) can be exported directly as Excel file (.XLS).

- Manual Data windowing and additional Information: The windowing of the Impulse Response (Selection A and B) can now be done also manually. Moreover some very useful information computed from the current data window are shown.

The microphone-loudspeaker distance can be easily computed from the current data window, just placing the beginning of data window at t=0 and the end of data window at the peak position.
Other distance computations can be easily done moving the start and end of the data window. This can help to find and verify the true anechoical part of an Impulse Response and isolate the first floor or walls reflections.

- Quick Spectrum: A shortcut to the Frequency Analysis window of selected data is now available (Selection A and B).

- Excel export of Time Data: Time Data (Scope or Impulse Response) can be exported directly as Excel file (.XLS).

The Time Data export button is located inside the Time domain View Values window.

- Excel export of Frequency Data: Frequency Data can be exported directly as Excel file (.XLS).

The Frequency Data export button is located inside the Frequency domain View Values window.

- Adapt to Large Fonts: Now Sample Champion can work correctly also when Large Fonts are in use in Windows. Since the Windows appearance, with Large Fonts in use, is different in different Windows versions, the user can select the better Mode, for an optimal setting.

The toolbar will be shown correctly when the optimal Mode is selected.
The Adapt to Large Fonts function is enabled or disabled automatically when the user changes the Font setting in windows, but can be also enabled or disabled manually.

The Large/Small Fonts setting in Windows can be found in Screen/Properties/Settings/Advanced: Large Fonts (120 dpi) or Small Fonts (96 dpi). The Small Fonts setting is anyway recommended.

- Impedance Calibration Plugin: Improved the Impedance Calibration accuracy. Now it is no more dependent from Peak/RMS Setting in main program. Check here

- File Operations: Fixed a visualization bug in the list of processed files in File Operations log window.

Sample Champion Release 3.0

- Program optimization: Sample Champion uses now considerably reduced system resources. It is thus much easier to use the program while other software are running. The "Low system resources" alert message should now appear only rarely.

- Size and position of the main program window are saved and restored.

- Support of sample rates up to 192 kHz. The support must be enabled in Settings/Hardware window. Note that some old soundcards give an error when a sample rate not allowed is used or tested.

- The frequency plots in the main program have now a lower limit of 1 Hz (in registered version).

- A spectrum normalization function has been added. This function is available also in the RTA window.

- The graphical user interface can be adapted under the XP operating system.

- A rarely occurring bug in the Enhanced View plugin when plotting ETC graph has been fixed.

- In Impedance and T/S Plugin some new features have been added: higher and lower frequency computation can be set; calibration with external resistor accuracy has been highly improved; some other minor bugs have been eliminated.

Sample Champion Release 2.8

REAL TIME ANALYSIS FUNCTIONS (Major upgrade)

A completely new bunch of functions have been added to Sample Champion. It's now possible to analyze simultaneously in real-time the 2 oscilloscope input channels and perform some DSP functions on them.

The RTA functions display can be opened by pressing the button:

placed on the remote bar.

In order to operate properly, the RTA window requires that:

- Number of input channels = 2
- INPUT BUFFER LENGTH = FFT LENGTH

For example, for a buffer of 16K samples, the settings are the following:

All the frequency windows in the main program must be closed when RTA functions are used.

In the SIGNAL ANALYSIS FUNCTIONS window, the FFTs of one or both input channels can be plotted simultaneously, using different graph options. Note that, in some cases, when the FFTs of both channels are plotted, it could be necessary to use the line plotting option, to prevent the masking of one channel by the other.

Also 1/3 Octave and 1/1 Octave plot of both channels or of a single one are available:

It is possible to optionally write the Octave or 1/3 Octave value and frequency directly on the plot.

From the FFT data of the 2 input channels it's possible to perform in real-time and plot the following DSP functions:

- Transfer function [L(1)] / [R(2)] (Frequency Domain)
- Transfer function [R(2)] / [L(1)] (Frequency Domain)
- Cross-Spectrum [L(1)] * [R(2)] (Frequency Domain)
- Cross-Spectrum [R(2)] * [L(1)] (Frequency Domain)
- Coherence (Frequency Domain)
- Auto-Correlation [L(1)] (Time Domain)
- Auto-Correlation [R(2)] (Time Domain)
- Cross-Correlation (Time Domain)
- Correlation Meter
- Stereo Check

Transfer function

This function performs the complex FFT operation of channel 1 divided by the FFT of channel 2 (L/R) or the FFT of channel 2 divided by the FFT of channel 1 (R/L).

When measuring a transfer function, it's recommended to use a wide band signal (MLS) to obtain information on the entire audio band up to half the sample rate. In some cases it could be useful to make some averages to improve the measures.

IMPORTANT NOTE: when using the RTA functions, ONLY the complex average is available and NOT the power average. In other words, the average is done on the complex FFT data and when average option is enabled IT'S RECOMMENDED to use ALWAYS the internal signal generator to maintain the synchronism between each block of time data sampled and perform thus correctly the average.

Cross-Spectrum

This is computed by multiplying one complex spectrum by the complex conjugate of a second spectrum. It gives information about the power common to 2 signals.

In the figure above a Cross-Spectrum example is shown. The spectrum of channel 1 is plotted in green, the spectrum of channel 2 in red and the Cross-Spectrum in yellow. The frequency axis is linear. Also the MAX values of the spectrums are shown on the plot .

Note that the Cross-Spectrum of ch.1*ch.2 can be different from the Cross-Spectrum of ch.2*ch.1!

The spectra of the 2 input channels can be plotted on the same plot as the the selected function (in the frequency domain). The input spectrum can be plotted also in 1/3 octave mode, like in the example below (frequency axis logarithmic):

Coherence

This function is the ratio of the squared magnitude of the Cross-Spectrum and the spectrum of channel 1 multiplied by the spectrum of channel 2. It gives information about the mutual linearity of the channels.
The example below shows the coherence of a signal before (ch.1) and after (ch.2) a digital reverb effect.

Cross-Correlation and Auto-Correlation

These Time domain functions give information about the mutual correlation of 2 signals (or the same signal in case of Auto-Correlation). It is very useful for finding, for example, echo or delays in time data. In the example below a signal has been passed through a digital echo effect; the peaks correspond to the delays (with feedback) set on the effect machine.

To perform this test, a pulse signal has been used. It can be downloaded here and loaded in Sample Champion as shown below:

Correlation Meter

This function offers a quick and easy way to check the correlation between the 2 input channels. This measurement can be performed by pressing only REC (red) button (no signal generator) for measuring, for example, a stereo musical signal. In other cases it is possible to use the signal generator.

A single number is given:

+1 = LEFT and RIGHT signals are identical
0 = LEFT and RIGHT signals are not correlated
-1 = LEFT and RIGHT signals are exactly out of phase (180 degrees)

Stereo Check

This function plots the LEFT channel versus the RIGHT channel. It's easy, in this way, to obtain information about the 2 channels.

- Example of a stereo musical signal:

- Example of a mono musical signal. The amplitude of the 2 signals are exactly the same since the slope of the line is exactly 45 degrees:

- Example of a signal present only on the right channel:

Audio Quality functions

Now the computation of SNR, THD, THD+N and IMD can be performed in the RTA window. See the documentation of Audio Quality plugin about these parameters.

A data box containing all details about the parameters computation can be shown inside the data box.

Data of scope spectrum or functions can be exported as TXT files (with options set in Settings/File Options) and the graph can be saved as BMP image.

POINTS TO REMEMBER WHEN USING RTA FUNCTIONS:

- THE AVERAGE IS COMPUTED ONLY IN COMPLEX MODE

- ONLY THE INTERNAL SIGNAL GENERATOR MUST BE USED

- IF THE YELLOW LABEL "BUFFER OK" ON THE REMOTE BAR IS NOT VISIBLE EVERY SAMPLING CYCLE, THE STEP VALUE MUST BE INCREASED TO AVOID LOSS OF DATA

- IF THE SYSTEM DOES NOT RESPOND (STEP VALUE TOO LOW!), THE SAMPLING CAN BE STOPPED BY PRESSING THE "BREAK" KEY OF THE KEYBOARD (WAIT THEN FOR THE STOP)

RESOURCE MONITOR

A global system resource monitor has been now integrated in Sample Champion.

It is located on the remote bar. When system resources are too low, a warning window is opened, and some actions are suggested :

This function can be enabled only in Windows 95, 98 and Me.

AUTOPLACE OF PEAK AT X=100

This option (Processing menu) can be useful for avoiding to move, in some cases, the position of the data windowing cursors.

Some bugs concerning saving and loading of WAV files and the use of Microphone compensation function with low sampling frequencies has been fixed.

Sample Champion Release 2.6 and above.

SPECTRA MERGE function.

This function is very useful for merging Nearfield with Farfield measurements. This function can be activated from the Processing menu.

This is an example concerning the use of this function (with 2 of the spectrum files in the setup package):
- Open SC and select in the processing menu "Spectra merge"
- Load as File 1 "Lower_QC.spe"
- Load as File 2 "Upper_QC.spe"
- Select "Combine file 1 and 2" and press Refresh (set Top Plot value around -42 dB for plotting the spectrum)
- Now you can "attach" the first spectrum to the second at the split point (or vice versa) and save the result of the operation

Now the total power value of each measurement cycle is shown in the Info window.
The Log History of the Info window can be now saved in a file or copied to the Windows Clipboard.

What's new in version 2.8.0.0 (this page)
What's new in version 1.2.0.10 to 2.8 (previous update)
What's new in version 1.0.2.204 (previous update)