When a noisy signal is measured, the influence of the noise can be eliminated by averaging several measurements. The noise component(s) will disappear and the actual signal remains.

Averaging can be switched on by selecting the item Perform averaging of from the Measure menu. In the next menu a number of measurements can be selected that have to be averaged. The item 1 measurement will switch off averaging. Averaging can also be switched on or off by pressing the Averaging button.

When averaging is set to e.g. 20 measurements and the oscilloscope is set to Pause, pressing the One-shot button will result in taking 20 measurements which are averaged.

Averaging is reset each time when the setting of the instrument hardware changes (sensitivity, coupling, sampling frequency, record length etc.) and when the pre-defined reset number is reached.

The TiePie engineering Windows software provides the possibility to use cursors to perform measurements on measured data. When the cursors are accurately positioned, the desired data can be read from the Cursor readout table.

To enable the cursors, choose either Large cursors or Small cursors from the Cursors menu. Large cursors consist of a pair of two intersecting lines, whereas the small cursors consist of a pair of crosses.

Positioning the cursors can be done by dragging and dropping the intersected lines or crosses. When a cursor has been positioned, the position of that cursor will be displayed in the time axis as two vertical red lines. This way the cursors can easily be located. When the cursor has disappeared from the display, move your mouse to the edge of the signal display at which the cursor is currently located and the mouse pointer changes shape. Now you can drag the cursor back in the display.

In addition to the standard cursor options, there is also a possibility to perform other measurements on the measured data using the cursor function. These functions can be called by clicking on the c button on top of the Cursor readout table. All the functions that are available in the voltmeter, are also available in the Voltmeter measurements submenu of the Cursor readout table. A few of the measurements that are possible:

• Time related: Rise time, sample time, cursor frequency
• Voltage related: Voltage left/right/difference
• Slew rate: slew rate left/right
• Phase difference: Degrees, Radials, cos()

When a signal is monitored and a glitch is expected, envelope mode can be switched on to be sure to see a glitch. In envelope mode, for each sample in the record a highest value and a lowest value is stored. Each measurement is checked whether the new value lies between the previous highest and lowest or not. If not, the highest or lowest value is changed to the new value. Then a vertical line is drawn between the lowest and highest value. So a glitch is always captured.

Envelope mode is reset each time when the setting of the instrument changes (sensitivity, offset, record length etc.), when the window size changes and when the pre-defined reset number is reached. To set the reset number, enter the Envelope mode, which can be found in the Measure menu or by clicking the right mouse button on the Envelope mode button. Select the item Reset envelope after and a menu with the possible options pops up. When the choice 32 measurements is selected, envelope mode will be reset after 32 measurements. When the choice infinite measurements is slected, envelope mode will not be reset automatically, only by changes in the instrument settings or by a window size change.

The horizontal axis in the oscilloscope, the transient recorder and the spectrum analyzer displays time-related information regarding the measured signal. Right-clicking on this axis results in the ability to control all the time-related settings.

The Sample frequency menu controls the speed at which the instrument will take samples of the input signal that is present on any of the channels. Depending on the instrument that is used, the menu will display a list of the available sample frequencies. In the menu is, besides the sample frequency, also the maximum total measure time given. The value of the total measure time that is given is calculated from the current record length and a 0% pre trigger value. A user defined value can also be entered, providing that the hardware is capable of this sample frequency. In case a sample frequency is entered that is not valid, the closest valid sample frequency will be generated. The Record length menu can set the number of samples the measurement instrument takes to display the measured data in the display window. The higher the record length, the more detailed the horizontal resolution. There are a number of pre-defined record lenghts, but it's also possible to specify your own record lenght, by choosing the User defined.... This record length obviously has to be supported by the hardware. For the spectrum analyzer, there is small difference in the record lenght; the record lenght has to be a number that is a power of 2. The record lenght is therefore selectable between 25 and 215 frequency components. Another function that is solely available in the horizontal axis menu of the spectrum analyzer is the choice of Axis type, which can be set between linear, logarithmic, octave bands and 1/3 octave bands. In the oscilloscope and the transient recorder, the Record view gain option in the menu changes the horizontal display gain, which is basically a zoom method to display only that part of the measured signal you're interested in. This value can also be adjusted by adjusting the lenght of the light gray scrollbar under the horizontal axis.

The vertical axis in the oscilloscope, the transient recorder and the spectrum analyzer represents the amplitude of the channel that is selected. A right-click on the vertical axis therefore pops up a menu that provides access to all amplitude related settings, like input sensitivity, signal coupling or the signal offset. To set the input sensitivity, select the Sensitivity submenu and pick the input sensitivity that you prefer, or let the software decide on the best sensitivity by choosing Autoranging. The signal coupling can be selected through the corresponding menu and can be set to either DC or AC. Sometimes it may be necassary to adjust the vertical position of a channel. This can be done through the same menu as well. Depending on the hardware that is used for the measurement, there are different methods available. The vertical position can be adjusted by either adding a DC voltage before the sampling takes place or afterwards, by applying a software offset. However, there is a big difference between the two, so pay attention to which setting is chosen. If a signal is clipped with the current sensitivity setting, adding a DC voltage might bring the signal back into the screen without distortion. This can be done because the DC voltage is added before the sampling takes place. On the other hand, if a software offset alone is used to bring the signal in the screen, the signal will still be distorted. In this case, use a different input sensitivity setting.

The software offset can be set either through the menu by right-clicking on the vertical axis and selecting the Software offset... submenu or by dragging the cdentre of the vertical axis up or down. Another useful feature of the software is the possibility to magnify the measured values; if two different channels have to be compared, yet their size isn't the same, the Software gain... submenu provides a perfect solution to scale the measurements. The offset can also be controlled by dragging the top label or bottom label of the vertical axis up or down to scale the signals. Inverting the axis is also possible, allowing for easy inverting of polarity. In the menu, choose Invert and tick your choice. Units of measure provides the means to setup the vertical axis to a unit of measure other than voltage. This is particularly useful when you're actually interested in the amplitude of a measurement which is voltage related, but is not the unit of measure you're interested in. For example, a temperature measurement. The Units gain... and Units offset... submenus provide further control over these measurements where the axis has to be corrected. The Mouse sensitivity vertical axis menu sets the sensitivity for the mouse when the vertical axis is being adjusted by means of dragging. Finally, in the spectrum analyzer there is one more option where the axis type can be set; either linear or logarithmic.

The resolution that is used during the measurement determines the accuracy of the amplitude of the measured signal. Usually the TiePie engineering measuring instruments are capable of using a few different resolutions, so it might be necassary to setup the resolution that is appropriate for the measurement at hand. This can be done in an instant through the instrument taskbar by clicking on the setup button. The menu which appears next allows for setup of both the program settings of the software or the instrument settings. On the Hardware tab of the Program settings menu, the resolution of the instrument can be selected. This is offcourse hardware dependent, so the resolutions that are not supported by your measuring instrument do not appear in the Instrument resolution drop-down menu. If the resolution is changed during a measurement, sometimes the frequency axis has to be set up again, so it is advised to change the resolution prior to a measurement.

The trigger system is a powerful tool for displaying the measured data in a convenient way or even for scheduling the start of an entire measurement! The setup menu for the trigger system can be brought up by right-clicking on the trigger symbol, right of the vertical axis.

Basic operation

Advanced operation

Pre- and post-trigger

The spectrum analyzer has a function that applies only to FFT data. A quick introduction...

FFT treats the FFT-block like it is one period of a periodic signal. If the sampled signal is not periodic, harmonic distortion can arise, since the periodic waveform, 'created by the FFT', can have sharp discontinuities. See also the following illustration. These discontinuities are also known as calculation errors. This means that because of the calculation errors extra frequency components are generated around the true frequency. Because of this 'smearing' the amplitude of the true frequency decreases, since the area under the curve remains the same. The smearing, caused by the calculation errors, can be decreased by placing a window on the FFT-block samples, in such a way that the ends of the FFT-block are smoothly tampered to zero and discontinuities do not occur when the FFT treats the windowed block as one period of a periodic signal. Each sample of the FFT-block is therefore multiplied by a factor, whose size is dependent on the position of the sample in the FFT-block.

The following window modes are supported by the TiePie engineering Windows software:

• rectangular
• Blackman-Harris
• Blackman
• Hanning
• Hamming
• Bartlett
• Parzen
• Welch