New experience in measuring modulation wave, power ripple and power-on timing

 Why can't the power ripple be captured directly with one click when using an oscilloscope, why is it so troublesome to analyze and compare the timing of multiple power-on channels, and why is the waveform contrast so poor when analyzing modulated signals? In fact, every user experience is an invisible improvement space for the product. For the above three questions, here I would like to share with you new methods and new experiences of measuring with ZDS3000/4000 series oscilloscopes. Let's learn about the relevant content with the test and measurement editor.

1. Automatic capture of power ripple

Experienced engineers know that when measuring power supply ripple, it is not possible to automatically capture the ripple through the [AutoSetup] function (as shown in Figure 1). This is very painful for engineers and production line testers who are not familiar with oscilloscopes.

The ZDS3000/4000 series oscilloscope is different in that it can automatically capture ripples, as shown in Figure 2.

Figure 1 Traditional capture mode

Figure 2 Latest capture method

(1) Basic settings

During the normal test, after the waveform is captured with one click, the [Channel Coupling] defaults to "DC" coupling, which is not suitable for power ripples that require AC coupling. Therefore, the oscilloscope needs to be set before measurement. The automatic capture of power ripple only requires setting one parameter and can be used continuously afterwards without repeated settings.

Figure 3 Automatic capture parameter settings

"DC" means [Auto Setup], all channels use DC coupling to sample and identify waveforms.

"Keep" means [Auto Setup], all channels keep sampling and identifying waveforms in the current channel coupling mode.

(2) Example test

1. Use the ZDS4054 Plus oscilloscope to measure the 3.3V power supply ripple of the Demo board, as shown in Figure 4 below. Note that the spring ground is used for grounding and the X1 position is used.

Figure 4 Wiring diagram

2. Select the input channel (here is channel [1]) and select "AC" for [Channel Coupling].

3. Click [Utility] to enter the system settings interface, click [System] and then click [Auto Capture]. At this time, you can select channel coupling as "Keep".

4. Click [Auto Setup] to capture the power ripple with one click, as shown in Figure 2.

5. Subsequent power pattern test capture can be achieved by simply pressing [Auto Setup].

2. One-click temporary storage of multi-channel waveforms

When performing a 4-channel power-on timing waveform comparison test, the traditional multi-channel temporary waveform user needs to enter the Ref menu to set up temporary storage one by one. It takes at least 13 steps to save 4 waveforms as shown in Figure 5. The operation is cumbersome and time-consuming.

The ZDS3000/4000 series oscilloscopes only require one step: click the [Trace] button to temporarily store multiple channel reference waveforms at the same time.

Figure 5 Traditional temporary storage method

As shown in Figure 6, it is a power-on timing diagram. The signal is captured under single sampling [Single], and multiple reference waveforms are temporarily stored through one-key traces. The changes in the power-on timings before and after can be compared, and the stability of the power-on can be quickly analyzed.

Figure 6: Power-on sequence comparison before and after

(1) Basic settings

One-click [Trace] to temporarily save waveforms. You can temporarily save the waveforms of all open channels at the same time, or you can temporarily save the waveform of only one channel. The specific settings are as follows:

1. Click [Utility] and then click [System Settings] to enter the system settings interface, where you can see the parameters shown in Figure 7.

Figure 7 Temporary waveform settings

2. [Trace Type] includes "Current Channel" and "All Channels".

Current channel: only save the last channel trace to Trace;

All channels: Save all channel traces to REF1, REF2, REF3, and REF4 respectively.

Note: When [Trace Type] selects "All Channels", after pressing [Trace], the original reference waveforms stored in REF1~4 will be overwritten.

3. Waveform brightness can be adjusted separately

The waveform brightness (percentage) of each channel of a traditional oscilloscope is adjusted synchronously, and the contrast between channels is similar, which is not conducive to signal observation, comparison and analysis. The ZDS3000/4000 series oscilloscope supports independent adjustment of channel brightness, with a step accuracy of up to 1%. It is particularly suitable for the observation of modulation signals (AM, FM, PM, FSK, PSK, ASK, PWM) in the communication test industry.

Figure 8 Waveform brightness adjustment

Features: Creates good visual effects, relieves visual fatigue, and is suitable for testing positions that require long-term use of oscilloscopes.

Test examples

FIG9 shows a test example of a modulated (FM) signal. The waveform brightness in the figure is all 50%. It can be seen that the waveform brightness contrast between channels is similar, the visual effect is poor, and observation is difficult, especially for production line test engineers who observe for a long time and their eyes are easily fatigued.

Note: CH2 (green waveform) is the original signal before modulation, and CH1 (yellow waveform) is the signal after modulation.

Figure 9 Two-channel waveform

In order to achieve a good visual effect, we can increase the brightness of CH2 (green waveform) and reduce the brightness of CH1 (yellow waveform) to form a higher contrast.

As shown in the waveform in Figure 10, the overall interface waveform has a comfortable brightness, the channel signals are clearly distinguished, and it is not easy to cause visual fatigue even if observed for a long time.

Figure 10 Waveform brightness adjustment

Adjust settings

Press the [Intensity] button on the key panel to pop up the adjustment interface. Press [Intensity] twice in a row to enter the waveform CH1 and CH2 brightness adjustment interface. Click it three times in a row to enter the waveform CH3 and CH4 brightness adjustment interface.

This time, use CH1 and CH2 channels. Turn knob A to lower the brightness of CH1, and turn knob B to increase the brightness of CH2, as shown in Figure 11.

Figure 11 Waveform brightness adjustment interface switching

The above is an introduction to the new experience of modulation wave, power supply ripple and power-on timing measurement in test and measurement. If you want to know more related information, please pay more attention to eeworld. eeworld Electronic Engineering will provide you with more complete, detailed and updated information.