Troubleshooting of R&S EPL1000

EPL1000 determines that the click has failed, but according to the upper and lower limit rules (upper limit and lower limit) of CISPR 14-1, the device may actually be qualified.

Principle clarification:

CISPR 14-1 adopts the "N_limit" rule for intermittent interference: when the number of clicks per unit time exceeds the specified value and the click amplitude exceeds the limit, it is judged as FAIL. EPL1000 will display the "Clicks above limit" count and "Decision" for each channel in the "Result Summary". But some users mistakenly treat instantaneous exceeding as FAIL.

Correct interpretation steps:

Open the 'Result Details' window and view the:

Total clicks

The number of clicks exceeding the upper limit

The number of clicks exceeding the lower limit but not exceeding the upper limit

The N_limit value applied to this channel (depending on the number of switch operations)

According to the standard, FAIL is only judged when the number of severe clicks (exceeding the upper limit) exceeds N_limit. Exceeding the lower limit does not constitute failure.

Using the "Flow Chart" visual interface, EPL1000 will draw a logical tree from measurement to decision, helping users understand the basis of the decision.

If there are still doubts, the original measurement data can be exported to Excel and manually calculated according to the CISPR 14-1 formula.

Optimization measures:

If FAIL is caused by a few abnormally high clicks and the clicks come from external interference (such as other devices in the same laboratory), the "Exclude spikes" filter can be enabled in the "Click Rate" setting, or the majority decision can be taken by repeating the measurement three times.

Spectrum diagram and real-time spectrum diagram mode failure

5.1 There is a time gap in the standard spectrum diagram, and transient signals are missing

Fault phenomenon:

In the conventional spectrogram mode, although signal strength changes over time can be observed, some fast transients (such as<1ms) are not displayed.

Reason explanation:

In standard spectrogram mode, the level values within each row (time slice) may come from multiple non continuous acquisition cycles, and there are also time gaps between rows. This means that very narrow pulses may fall into the gap and be missed.

Switch to real-time spectrum:

EPL1000 offers optional R&S ® EPL1-K55E， After enabling, you can select "Real time mode" in the "Spectrogram" settings. This mode forces the use of gapless data collection to ensure continuous and uninterrupted frequency range and measurement time. Enabling steps:

Ensure that the K55E option is installed.

Press the MEAS key and select "Spectrogram".

In the "Config" menu, change the "Mode" from "Normal" to "Real time".

The system will automatically adjust parameters such as RBW and measurement time to meet the seamless condition. Users cannot modify these parameters arbitrarily, otherwise the mode will revert back to standard mode.

Starting the measurement, the screen will draw a real-time spectrum line by line, with color depth representing the level. The circular buffer can store up to the last 100000 rows and can be replayed for analysis even if measured continuously for several hours.

Application Scenario:

Check for intermittent stray emissions from wireless products such as Bluetooth and Wi Fi, or observe the response at the moment of filter insertion during electromagnetic compatibility rectification. Real time spectrograms can capture every detail.

5.2 Insufficient color contrast in the spectrogram, making it difficult to identify weak signals

Fault phenomenon:

The default rainbow color map displays levels close to the noise base as dark blue, making it difficult to distinguish from areas without signal.

Adjustment method:

Enter the "Color Map" settings and select the "High Contrast" or "Thermal" color palette.

Manually set the reference level and display dynamic range. For example, if Reference is set to 60dB μ V and Range is set to 100dB, the noise floor (such as 20dB μ V) will be mapped to the bottom of the color scale and clearly visible.

Enable the "Marker" function, click on the suspicious time-frequency point, and EPL1000 will pop up the precise amplitude value and frequency of the point, avoiding relying on visual judgment.

Automated measurement and report generation failures

6.1 Scan Table execution sequence error or repeated measurement of the same frequency band

Fault phenomenon:

Multiple frequency bands were defined (e.g. Band A: 9kHz~150kHz, Band B: 150kHz~30MHz), but only Band B was measured during execution, or two bands were alternately confused.

Configuration correction:

Enter the "Scan Table" editor and check that the "Start Freq" and "Stop Freq" of each entry do not overlap. Suggest arranging them in ascending order of frequency.

Each entry can independently set RBW, detector, measurement time, etc. Confirm that the 'Enabled' checkbox for each entry is checked.