RadCon 1.1 Conducted-Immunity
Test Definition, Frequencies
This is the test definition form. All of the parameters for testing a product are here. Above, the "Frequency" tab has been selected. The start and stop frequencies of 1 and 230 MHz have been selected. In this case, only the frequencies in the list file "peugeot bci.lst" that are between the start/stop frequencies will be tested with a dwell time of 2 seconds. Clicking on the "Create List" button will pull up a frequency list form that allows easy editing of the frequency list. If testing harmonics, only the fundamental and the number of harmonics needs to be entered. Frequencies can be added to the list from other files, such as Bellcore standard frequencies. Even though the calibration file and list file can have frequencies outside the range of the test, the test will only include frequencies between the "from/to" frequencies. (back to top)
Test Definition, Modulation
The "Modulation" tab is where the modulation type and levels are selected. Some of the automotive specs (which follow closely to Mil Std testing) call for a constant-peak amplitude modulation, where the peak of the modulation envelope is equal to the cw calibration level. This software can perform this, and automatically adjusts the output level based on the specified modulation level. If leveling to forward or net-power (with a true average power sensor) the power measurement is properly compensated for by the software. If not using a true average power sensor, the modulation may be turned off between frequencies to allow proper measurement of the test level. (back to top)
Clicking on the "Browse" button allows selection of the calibration file to use for the test. All of the information about the calibration file is displayed here to allow the test operator to be sure the same equipment is used for the test that was used for the calibration. If the calibration is performed at one level, the same calibration can be used for all lower levels by using the "adjust test level by" option, and entering a number in the text box representing the level reduction in dB. (Only a negative number can be used). This saves time since only one calibration level per device needs to be performed. (back to top)
Test Definition, Test Level
The "Test Level" tab tells the program how to level at each frequency. If forward and reverse power levels were recorded during the calibration, then the test can be run several ways. Leveling to the recorded signal generator levels is possible, or leveling to the recorded forward power, or leveling to the recorded "net" power (as per most automotive and Mil Std tests) is possible. The leveling can also be controlled by measuring the actual induced current level, with the level ramping halted based on a margin to the limit (plus or negative).
The "Initial Level Offset" specifies how much to lower the signal generator between each frequency. The program will use a certain amount of intelligence to implement this. For instance, given the above settings, if leveling using forward power, and the forward power is reached but the signal generator is 0.5 dB below the level recorded in the calibration file, then the next frequency will start 6.5 dB below the calibration signal generator level. Basically, the program will always err on the side of the lowest signal generator level before starting to ramp up again. (back to top)
Running a Test
This is the heart of the program. The screen shot above shows an actual test in progress. The test is presently at 2.852449 MHz. The signal generator output is -16.0 dBm. The level ramping halted on the forward power level (denoted by the power level being red in color), which is 326 mW or 25.1 dBm. The test level achieved is 3.0 volts, or 129.5 dBuv. The program is dwelling, with 29.2 seconds left at the present frequency. The progress bar at the bottom shows how far the test has run.
During a test, the "Run Test" form will always be on top. Even if another program receives the focus, this small form will stay on top. Clicking on this form will bring the main program form back to the foreground.
Clicking on the "manual" button will allow the test operator to manually cruise up and down in frequency so as to determine the failure threshold of the product being tested. Not only can the frequency be varied, a level offset can be selected as well. (The signal generator level will be set automatically according to the calibration data and the offset value.) All of this can be done by using the left/right arrow keys (frequency) and up/down arrow keys (level), which means it can be done without having to look away from the test setup to see where to click the mouse. Once the failure threshold is determined, the operator can type in a comment which will be stored in the grid along with the frequency and level offset information associated with the failure.
The grid is a scrolling display of the test run data. The grid displays all information that is available from the instrumentation selected. If leveling to forward or net power, then the power levels are displayed and recorded. If using a feedback probe, then the actual induced level is displayed and recorded. At the end of a test run, the data can be saved to a file for inclusion in a test report.
For tests that include leveling to forward power levels, and/or measuring the induced current, Radcon uses some intelligence to help speed up the test process. Whenever possible, the measurements will take place during the required dwell period, instead of measuring and dwelling seperately. This can mean an improvement of almost 50% compared to other software.