Tips regarding SW5012 Software (ID #259)
The following explanations complete the manual and deal with frequently asked questions.
1.1 The current service pack for NT must be installed if "Windows NT4.0" is in use.
1.2 Laptop PCs sometimes cause problems with the serial interface (PC). The Laptop producer can only eliminate such problems.
Known difficulties are output levels sometimes too low at the PC interface, as well as data overflow.
1.3 After a new start, the last settings in SW5012 are present only if it was closed last time by "Exit" in pull down menu "Data".
1.4 Measurement results and/or parameter settings are stored in database format (*.mdb). On condition that Microsoft Access is installed, this program can be used to edit data. The possibility of data import in other programs such as Excel etc., depends on the availability of data conversion programs; please ask your software dealer or Microsoft.
1.5 The logarithmic frequency scale (X direction) is available only if at least one decade is present (scan or stop-/startfrequency dependent) i.e. 1MHz to 10MHz.
1.6 The level scale is set automatically, depending on the highest level captured during measurement and can not be set manually. If the scale does not change in spite of wide signal level changes (no signal / -50dBm), the zero peak at 0Hz may be the reason. In this case the center frequency should be changed slightly, so that 0Hz is no longer within the measurement range.
1.7 Only the graphic window can be changed in position and size. All other windows can be changed in position only.
1.8 The PC graphic resolution should be set to minimum 1024x768, to avoid windows having to be minimized for better graphic reading.
2. Normal Mode
2.1 Center frequency and reference level setting changes ("Measurement" window) must be carried out in the following way: Highlight the present value by the aid of the mouse, press delete, enter the new value (keyboard) and confirm it by pressing the ENTER (RETURN) button. Click on Set/Read to send the new value(s) to the Spectrum Analyzer (Set function). Afterwards the PC receives the measurement results (Read function) made under the new settig(s).
2.2 The "Toolbox" button will be displayed after "Read" is performed. This function is intended for measurement under "Mode" > "Normal" and enables monitoring a specified frequency range (center frequency and span) with reference to signal levels. The level setting can be performed by shifting the "A" cursor line using the mouse to a suitable position within the present graphic window. Clicking the "Cursor A ->" button confirms this setting and causes the "Triggervalue" display to show the new value. Should the trigger value be set to a value that is not available in the graphic window, highlight the "Triggervalue" (mouse) and input the new value (keyboard).
"Start" activates monitoring and sets the "Read / View" sector within the "Display Mode" window to display "Memory B" only. The selected frequency range will now be constantly monitored until the trigger value is exceeded. Then the monitoring is stopped. The measured data will be stored in the Spectrum Analyzer`s memory "B", transmitted to the PC and displayed in the graphic window. If the "Print after trigger and wait for trigger" was activated before starting, the results will also be printed by the PC printer. For a new monitor procedure click "Start" again. Monitoring can be stopped at any time with "Stop". It is recommended to select "Memory Off" and activate "Sample" after the "Toolbox" has been switched off.
The input of "Freq. Steps" serves for the ease of operation regarding the center frequency setting. If the center frequency is set to 200MHz and a 50MHz signal is applied, the center frequency can easily be changed to harmonics and sub harmonics using the "+" and "-" buttons, if the step size is set to 50MHz.
3. EMC Mode
1. The application of facilities offered in EMC mode requires a good knowledge of EMC standards. Due to extent, country specific differences and complexity of these standards, their application is not considered in the manual.
2. The following explanations refer to EMC mode, called via the pull down menu "Mode" > "EMC". Both the graphic window and the "EMC" window must be displayed on the PC monitor. All hints are related to one of the measurement examples "50081-1 Conducted 150kHz - 30MHz" and "50081-1 Radiated Emission 200-1000MHz", which are included in SW5012.
3.1 The "Test Settings" window is called by "View settings" (EMC window). If changes are made by keyboard input (i.e. Stopfrequency), the ENTER/RETURN keyboard button must be pressed for confirmation. All other settings become active by closing the window with a mouse click on " X ". Thereafter the measurement can be started by clicking "START" (EMC window).
3.2 EMC measurement can be carried out in "Sweep + Step" or in "Step" mode. The selection can be made in the "Test Settings" window, after "Mode" > "EMC" > "View settings" has been called. Do not forget to close the "Test Settings" window.
In contrast to "Step" mode, where measurement takes place in fixed frequency steps even if there is no signal, "Sweep + Step" mode offers the advantage to save time. The following explanations are related to "Sweep + Step" operation.
At the beginning, a pre measurement is started in "Sweep" mode. An IF bandwidth (RBW) of 120kHz is used, if the " 50081-1 Conducted 150kHz - 30MHz" is in use and a bandwidth of 9kHz (conforming to the standard) has been activated in the "Test Settings" window. In the frequency range from 30MHz to 1GHz ("50081-1 Radiated Emission 200-1000MHz") the pre measurement is performed with an IF bandwidth of 400kHz if 120kHz (standard) has been selected in the "Test Settings" window.
During the measurement in "Sweep" mode, all frequencies and the accompanying levels are stored. If no level reached or exceeded the "Limit distance" value, the measurement finishes and the result is displayed in the graphic window.
If the "Limit distance" has been reached or exceeded on some frequencies, "Step" measurement is performed on these frequencies with the selected IF bandwidth. Then the measurement is finished and the result is displayed.
The "Limit distance" is displayed in "Test Settings" window. It is related to the standard dependent limits (i.e. 30dBµV/m from 30MHz to 230MHz). A keyboard input of " - 6 " (Enter/Return) sets the "Limit distance" to i.e. 30dbµV/m - 6dB = 24dBµV/m. The "Limit distance" value can also be input unsigned (i.e. 20) to be added to the standard limit (i.e. 30dBµV/m + 20dB = 50dBµV/m); in this case a post measurement in "Step" condition requires a minimum level of 50dBµV/m.
3.3 "EMC window". Two configurations are available in this window:
1. "50081-1 Conducted 150kHz - 30MHz" does not contain any limit and correction values for frequencies > 30MHz.
2. "50081-1 Radiated Emission 200-1000MHz" without limit and correction values < 30MHz.
The missing values (standard dependent) can cause problems, explained in the following example:
If the configuration "50081-1 Radiated Emission 200-1000MHz" is present in the "EMC" window and a measurement is started, although the "Test Settings" window (closed before starting) had shown a "Startfrequency" of 4.5MHz and a "Stopfrequency" of 5.5MHz, there will be no "Step" measurement in "Sweep + Step" mode despite a signal level at the input which is exceeding the "Limit distance". Only a "Sweep" measurement from 4.5 to 5.5MHz will be performed. The reason is that no limit values exist for frequencies < 30MHz at "50081-1 Radiated Emission 200-1000MHz". Consequently no limit or the limit related "Limit distance" can be exceeded. The result is that no "Step" measurement is performed.
3.4 After "START" was activated in the "EMC" window, the "Select Measurement" window is displayed. Input the filename for the following measurement.
3.5 "Ambient" in the "Test Settings" window enables the comparison of device under test off (where ambient signals are measured) and on condition. After the "START" the first measurement takes place under DUT off condition, after that in DUT on condition (please note the remarks in the windows). The display of both measurements enables evaluation of ambient distortions.
3.6 "Limit distance" and "Meas. time" settings ("Test Settings" window) are effective only during "Sweep" measurement. Hence the settings are displayed in gray if "Step" mode is selected. In "Step" mode all frequencies are measured with a fixed measuring time of 1 second.