Electronic Engineer Discuss

Title: DSO4072c AFG AM modulation frequencies [Print this page]

Author: FSC Time: 2020-4-27 21:05
Title: DSO4072c AFG AM modulation frequencies
Hi,
I tried to set up an AM on my DSO4072C.
- I pressed the GEN/DSO-Button
- I set Wave with F1/F2-key to AM/FM
- I set Type to AM
- I set Freq to 1000Hz
- I set F0 to 10.00kHz
The rest is a default. In the display the proper signal is displayed. But when I mesuare the signal it does not look right. It semms that modulation frequency and carrier frequency are swapped (this is prooved by the FFT.
When I then set Frequency to 10kHz and F0 to 1kHz the signal looks correct but that is different to the documentation and to the common understanding that F0 is the carrier frequency.
Is it possible, that there is a bug?
Also it is not clear to me when the data is aclnowledged by the scope. sometime you have to change to another field and sometimes a cahnge of value is applied directly. Alos it is not clear to me when the number pad appeares and when the field is only highlighted to be modified by the V0 turn button.

FW is the latest from the homepage:
- [sw] 3.50.0(191123.0)
- [hw] 1020xffffa000

Thanks an best regards
Florian

Author: pavlenkoa Time: 2020-4-28 02:18
Edited by pavlenkoa at 2020-4-28 02:20

I believe that everything is correct in the device, and the error is contained in the instruction, where F0 was erroneously called the carrier frequency. Look - everything is logical on the first page of the generator we set the carrier frequency of the generator, and the second - the type of modulation, and then either the modulation frequency or the deviation frequency. It would be strange to first select the modulation frequency on the first page. They really messed up the names. On the first page, the carrier really needs to be called F0, and on the second page, Fmod and Fdev, respectively. Let them fix it. There are still many shortcomings in the generator. Later I want to describe those that I found.
DSO4102c.

Author: FSC Time: 2020-4-28 15:38
I agree that it might "only" be a documentation/naming issue. But what really bugs me is that the displayed signal is not what the output is. I set the parameters according to "common" understandig (and the documentation), hope that the values are applied and get a signal displayed that looks correct but the output differs...
Similar issues apply (as you said) to the FM.

Best regards
Florian

Author: pavlenkoa Time: 2020-4-28 17:36
Edited by pavlenkoa at 2020-4-28 20:33

FSC replied at 2020-4-28 15:38
I agree that it might "only" be a documentation/naming issue. But what really bugs me is that the di ...

What kind of correspondence are you talking about ?! THIS IS NOT ALLOWED TO BE USED! Compare the set carrier frequency and the spectrum readings on the first two frames. Then I added modulation. I wish I didn’t! New laws of radio technology.

[attach]3542[/attach]

[attach]3543[/attach]

Куда уплыла несущая?
Что это? Это генератор?

Where did the carrier go?
What is it? Is this a generator?

[attach]3544[/attach]

[attach]3545[/attach]

IN THIS TYPE IT IS IMPOSSIBLE TO SELL. PLEASE READ THE TIME WHICH IT IS PERFORMING!
DSO4102c

p.s.
By the way, here's how an external generator FY6900 works with the same parameters. Pay attention to the carrier frequency - it does not move anywhere and is equal to exactly 20 kHz.
See the difference !!!!!
Although I have DSO4102c, but I think the generator we wrote the same programmer. (He was in a hurry somewhere and did not check much that he wrote - there are still bugs for several posts).
There is no time for jokes.
They sell an appliance that cannot be used.
I really ask the developers to respond and fix all the errors, although it costs us nerves.

[attach]3547[/attach]

Model: DSO4102C
sw version: 3.50.0(200410.0)
hw version: 1020xffffa000

Author: pavlenkoa Time: 2020-5-2 17:07
Do the developer representatives see our comments?
5 days have passed - no reaction.
We did not write about impressions about the oscilloscope - we wrote about a really idle generator sold to us under the guise of working!
Where are the answers?

Author: wangshuang Time: 2020-5-12 10:31

The manual is wrong, F0 is the modulation frequency, Freq is the carrier frequency, and MaximFreq is the FM deviation.

Author: pavlenkoa Time: 2020-5-12 14:14
Edited by pavlenkoa at 2020-5-12 14:20

wangshuang replied at 2020-5-12 10:31
The manual is wrong, F0 is the modulation frequency, Freq is the carrier frequency, and MaximFreq ...

Good afternoon! The error in the manual was understandable even earlier, but how do you explain the discrepancy between the output signal and the values set in the menu?
As you can see above, I set the carrier frequency to 20 kHz. Modulation frequency 1 kHz. And what do we see at the output of the generator? The carrier frequency decreased by half and shifted by the magnitude of the modulation frequency. She became equal to 11 kHz !!!f I set the modulation frequency to 0, then the carrier frequency at the output is half the set frequency, namely 10 kHz.

Below I posted a picture from another external generator with the same signal parameters - everything is fine there!

Author: wangshuang Time: 2020-5-21 11:42
Please use this firmware to do measurement.
https://fil.email/PmZozBWb

Author: pavlenkoa Time: 2020-5-21 16:32

wangshuang replied at 2020-5-21 11:42
Please use this firmware to do measurement.
https://fil.email/PmZozBWb

Please give and on dso4102c .........
The problem is the same.

Author: wangshuang Time: 2020-5-23 14:44

pavlenkoa replied at 2020-5-21 16:32
Please give and on dso4102c .........
The problem is the same.

New firmware has been released, you can download corresponding file in Hantek website:
http://hantek.com/en/ProductDetail_3_4163.html

Author: pavlenkoa Time: 2020-5-24 19:29

wangshuang replied at 2020-5-23 14:44
New firmware has been released, you can download corresponding file in Hantek website:
http://hant ...

Good afternoon!
On this topic, the new firmware practically did not fix anything. The only thing that is fixed is that the carrier frequency is now not divided in half.
Below are screenshots that show that the carrier frequency is shifted relative to the frequency deviation set by the value. I ask developers to finally study what the spectrum of the FM signal looks like! Why are we doing this here? This is a school? Why are they relentlessly releasing a product unsuitable for work ?! I was hoping that a couple of frames in the previous posts would be enough to understand what was going on.
[attach]3605[/attach]

[attach]3606[/attach]

[attach]3607[/attach]

[attach]3608[/attach]

This is what the spectrum of the fm signal should look like.
This is how it looks on my oscilloscope DSO4102c , but from an external generator.

[attach]3610[/attach]

And further. I wrote in a neighboring post about the terrible color scheme of the themes of this device. No one answered me. Can you really make out the line at the bottom of the screen? I assure you - on the screen it reads even worse than this screenshot. Perhaps this gives joy to the developers so, I’m not afraid of it, to mock buyers?
Give us the opportunity to redefine the colors in the theme ourselves! It's horrible! Is it really not visible ?!

[attach]3609[/attach]

I want to apologize to those who may have offended my words, but I can no longer tolerate. I purchased your device for work, but I'm starting to regret it .....

Author: pavlenkoa Time: 2020-6-9 18:29
Edited by pavlenkoa at 2020-6-9 18:35

Why is there no answer?
I want to use your device, but I can’t. It does not work as stated in the specifications! Please correct your flaws. Why am I forced to ask for this? Aren't you ashamed of your professionalism?

Imagine that you bought a car that turns anywhere, just not right! In addition, his speedometer is made purple, and on it are pink numbers that you can only see if you stop! What would you say about the manufacturers of this device? But they can’t, but you can produce such devices ?! I’m already thinking about buying an additional external generator, since my work must be done, and your car, even after repair (updating), has not learned how to drive to the right. And judging by the speed of your response to comments, he will never go.

Author: wangshuang Time: 2020-6-12 10:01
Sorry for the late reply, the product engineer is already revising, and then release a new version, I will inform you in time.

Author: pavlenkoa Time: 2020-7-5 15:08
Hello! There is no answer for a very long time. A month has passed. The oscilloscope generator in modulation mode cannot be used. Please speed up the development of the software.

Author: wangshuang Time: 2020-7-6 09:57

pavlenkoa replied at 2020-7-5 15:08
Hello! There is no answer for a very long time. A month has passed. The oscilloscope generator in mo ...

Sorry. A new version will be released next week.

Author: pavlenkoa Time: 2020-7-21 20:58

wangshuang replied at 2020-7-6 09:57
Sorry. A new version will be released next week.

Good afternoon, a long time has passed and the problem has not been resolved. The update from 06/11/20 did not touch on this topic - everything remained the same. DS4102c

Author: wangshuang Time: 2020-7-22 18:14

pavlenkoa replied at 2020-7-21 20:58
Good afternoon, a long time has passed and the problem has not been resolved. The update from 06/1 ...

Hantek has released the latest firmware.
http://hantek.com.cn/products/detail/4163

Author: pavlenkoa Time: 2020-8-2 19:19
I installed the latest firmware. The problem is not solved!!!!!!!!!!! I'm tired of sending you screenshots! Are your engineers having trouble identifying and fixing the problem on their own? Check out what we have been doing here since winter! I am sending a description of the same error - you write to me to download the latest firmware, I download it and see that the problem is not solved. I am sending screenshots again. It will go on forever. I want to hear the answer from your management - will a problem be solved that is not a problem for other manufacturers at all? Or is it beyond the power of your engineers? Write about it on the first page of your site! "WE CAN'T RELEASE PRODUCTS WORKING CORRECTLY!"

Author: pavlenkoa Time: 2020-9-5 00:18
Good day! I'm afraid to seem too persistent, but I want to ask: will anyone make a workable generator in DSO4102c? Is the topic of a non-working generator, for the purchase of which many paid, no longer interests anyone?

Author: FSC Time: 2020-11-4 16:50
Hi pavlenkoa,
no I still have also the same issue and as I am a developer of embedded software and implement DSP software for measuring devices, I don't think it should be that hard to fix THAT problem!
The problem is that the calculation of the FM/AM waveform is in my opinion- just not done in the correct way. F0 should indicate a carrier which is then modified by the modulation frequency. Not that hard... There are a lot of formulas on the net how to do it.
And also a lot of other hickups like the failing limitation of the values when turning the dials and erratic behavior of the increments when changing values.
And also the problem with the trigger position is in my opinion not fixed...

I did not have time to work a lot with the device in the last months and also got a personal reply about the questions I asked directly to the support in the spring. But I will try to follow up on that a little.

The problem is that this is very tiring and I don't see it as my duty to identify their bugs in a product I paid money for. And if they can't fix it I am open for a new device they can sent me and I will gladly use that as a beta tester and help them make it better but not when paying money for it!

cu
FSC

Welcome to Electronic Engineer Discuss (https://www.eediscuss.com/)