RIGOL ds1054z - help getting signals to show properly - Page 1
Forum section: electronics / testgear

author: mapleLC
author_rank: Frequent Contributor
timestamp: April 01, 2022, 11:36:19 am
content: New to this oscilloscope.I have an input audio signal on one channel, and an output on the other. The output should either be amplified or attenuated.I need to compare both signals on the scope, and understand them. It's too many buttons right now, so if anyone understands what I need to do, give me a hand.What settings do I need to see both audio signals, either overlayed or not, and what do I look for to get a clear understanding of the measures between them?

author: Fungus
author_rank: Super Contributor
timestamp: April 01, 2022, 11:42:53 am
content: Try pressing "auto".

author: mapleLC
author_rank: Frequent Contributor
timestamp: April 01, 2022, 12:56:14 pm
content: I did.My question stands.

author: Fungus
author_rank: Super Contributor
timestamp: April 01, 2022, 01:15:21 pm
content: Quote from: mapleLC on April 01, 2022, 12:56:14 pmWhat happened? My crystal ball is broken, I can't see from here.

author: mapleLC
author_rank: Frequent Contributor
timestamp: April 01, 2022, 02:00:21 pm
content: I'm not the best to practice your generic jokes on.

author: Fungus
author_rank: Super Contributor
timestamp: April 01, 2022, 02:26:32 pm
content: My question stands.

author: Bicurico
author_rank: Super Contributor
timestamp: April 01, 2022, 04:16:53 pm
content: Connect Input on Channel One and amplified Output on Channel Two.Start audio on your amplifier.Now press the AUTO button on your scope. It should recognise the signals and show them both, each with the colour of the respective input channel.

author: mapleLC
author_rank: Frequent Contributor
timestamp: April 01, 2022, 05:43:17 pm
content: Quote from: Bicurico on April 01, 2022, 04:16:53 pmI'm seeing two signals when I do this, "auto" focuses them both, but this is where I get a bit stuck... what am I looking at now? I tried several settings and YT vids without success.I need to see if the amplitude of the output signal is correct, and I need to see if the wave is clean and undistorted. Is this enough detail to frame what I would like to see from the scope?

author: Martin72
author_rank: Super Contributor
timestamp: April 01, 2022, 06:10:33 pm
content: Hi,Show your actual test setup...

author: darkspr1te
author_rank: Frequent Contributor
timestamp: April 01, 2022, 07:14:37 pm
content: Quote from: mapleLC on April 01, 2022, 05:43:17 pmthis video might help,https://youtu.be/FONXhQHoDxcwhen you have you auto done and seeing the two signals, press the blue "Menu" button on the left of the screen to switch to "Vertical" ,you will have some options, Vmax, vpp might help, note this will only display data for last channel selected, to add the same data from the other channel just press it's button and the colour will change reflecting that channel.On the right hand side is a dial with Level written above, normally this is triggering of channel 1 and turning the dial can allow you to set the point at which the sample triggers,you should be able to compare the Vmax,vpp voltage for both to see if you are amplifying and the signal displayed should be the same as input.Your choice of input signal is also important as the amp system work between certain frequencies so inject a 5hz or 50mkhz signal may produce odd results, normal signals start around 20hz to 22khz,when you have all the above setup and see some values then pressing "Single" will freezeframe the data, press the red run/stop to return to prior mode. Again the signal type (square wave, sine, sawtooth, music audio) will have a effect on what you see, a example is Music audio will have too much information in it for you to narrow down issues quickly at the start , Square & sawtooth also wont always produce the correct feed to reproduce crossover delay for example but can be used to trace fast clipping issues from leaky caps. Sine wave is the normal goto start injected signal as output should be identical to input just higher VPP (Voltage Peak to Peak) and VMAX (Voltage Max).Take care also when choosing the HIGH side (amped side) ground connection as some amps the Negative terminal to speaker is at much higher voltage potential than that of the Input ground and your scope's grounds are connected together , dave does a good video on how not to blow up your scope and potential difference is discussed there to in more detail.this video describes the usage of the FFT "Math" function to visualize the signal spectrum , depending on the input signal type you will see spikes/gaps/troughs here that could indicate audio noise.!!but dont do this on a power supply , see video above!! just use the video to learn which buttons to push for FFT,EEVBlog has many videos on using/reading scopes for many task's and it's a case of the more you watch the more you will understand what you are seeing and which button/knob to push/turn to get the information you want.hope these help.darkspr1te

author: mapleLC
author_rank: Frequent Contributor
timestamp: April 01, 2022, 09:14:29 pm
content: Quote from: darkspr1te on April 01, 2022, 07:14:37 pmThank you. Let me churn thru this and see if the results starts to look like what I expect. This helps a lot.

author: Martin72
author_rank: Super Contributor
timestamp: April 02, 2022, 11:06:59 am
content: Quote from: Martin72 on April 01, 2022, 06:10:33 pmNo?

author: mapleLC
author_rank: Frequent Contributor
timestamp: April 02, 2022, 11:16:17 am
content: Quote from: Martin72 on April 02, 2022, 11:06:59 amPerhaps, but can you elaborate on what you are asking for?

author: Martin72
author_rank: Super Contributor
timestamp: April 02, 2022, 11:05:40 pm
content: Hi,Quote.......You want help, we can help - but we can help only when the whole situation is clear.Here a list:- Describe the situation you stuck into.- Describe what you want to measure- Describe the setup: Source - DUT - Measure points- Source: What signal, waveform, amplitude- DUT : Amplifier, filter ??- Measure Points : Output of the Source ? Output of the DUT ?- Actual setup: Post pics of what you had done, what the scope showsExample: Feeding in a 1khz sinewave with 500mVrms amplitude into an audio amp, increasing the amplification until the output of the amp got 10Vrms.Using channel 1 of the scope for the output of the sinewave generator, channel 2 of the scope connected to the output of the amplifier.On both channels of the scope you should see the sinewave, only difference between the two channels are the amplitude and maybe the phase (180 degrees inverted).But you should see a sinewave in every case.If not, incerase/decrease timebase and/or voltage on the scope.When you want to see distortions of the amplifier, activate the fft function, in this case of channel 2.Maybe now you got a clue, why showing the test setup and showing what your scope is showing are helpful for others.

author: ledtester
author_rank: Super Contributor
timestamp: April 03, 2022, 03:49:53 am
content: As a sanity check, try the following:1. Connect your two probes to the probe compensation signal output.2. Press "Auto"You should see that the oscilloscope has positioned the two signals like this:If this isn't happening, upload a pic of what your scope display looks like.

author: james_s
author_rank: Super Contributor
timestamp: April 03, 2022, 07:35:50 am
content: What are you using as a source signal? If you're using something like music then a scope is not really going to show you much of any use, it will just look like noise. If you want to take meaningful measurements you have to use an appropriate test signal, something like a 1kHz sine wave would be a good place to start. I'm not really clear on what you're trying to measure though, can you define that more clearly?