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DSO4072c AFG AM modulation frequencies

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Post time 2020-4-27 21:05:09 | Show all posts |Read mode
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

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Use magic Report

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Post time 2020-4-28 02:18:50 | Show all posts
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.



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 Author| Post time 2020-4-28 15:38:27 | Show all posts
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

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Post time 2020-4-28 17:36:49 | Show all posts
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.





Куда уплыла несущая?
Что это? Это генератор?


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





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.



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


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Post time 2020-5-2 17:07:10 | Show all posts
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?

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Post time 2020-5-12 10:31:38 | Show all posts



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

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Post time 2020-5-12 14:14:55 | Show all posts
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!



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Post time 2020-5-21 11:42:37 | Show all posts
Please use this firmware to do measurement.
https://fil.email/PmZozBWb

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Post time 2020-5-21 16:32:05 | Show all posts
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.

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Post time 2020-5-23 14:44:06 | Show all posts
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

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