Author Topic: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator  (Read 104436 times)

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Offline Apofview

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Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
« Reply #200 on: May 19, 2019, 02:10:39 pm »
Hi,
any experience with JDS6600 modulation.
In user manual there are modulation options sweep, pulse and burst.
I'm not able to find AM or FM modulation.
Other generator FY6800 seams to have AM modulation.
Does JDS6600 has AM modulation?
 

Offline Apofview

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Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
« Reply #201 on: May 19, 2019, 07:57:19 pm »
Sorry, just read all the messages in topic.
JDS is a miss, I should bought FY, difference in price is around 5USD on aliexpress.
There is no FM and AM modulation.
Didn't consult forum prior buy...
 

Offline KeepItSimpleStupid

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Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
« Reply #202 on: April 12, 2020, 01:16:30 am »
How that pesky 60 V show up.

Attached is a datasheet for an EMI filter.  f you don't earth the junction between C1 and C2 you end up with about 1/2 the line voltage at this point.
The filter leakage current is 0.25 mA.     If the capacitors are the same, they will likely have the same shunt impedance.

Release notes

The designer of the instrument is missing the "Release note" concept.  https://www.appcues.com/blog/release-notes-examples
Here https://www.appcues.com/blog/release-notes-examples are the release notes for Firefox

i think they add a layer of trust between the user and manufacturer.

I never saw any for Keithley products, but they had to exist.  They verified a really nasty hardware bug where an Electrometer would put 200 V spike at the input.   They did not believe me at first.  They responded with an immediate external fix that crippled the instrument in other ways and later a fix for the instrument.

With another company that we had a good relationship with, I called them up and asked why do you have a 10 Amp rectifier where a 50A rectifier should be?
That actually required a new upgraded transformer and rectifier for free.

The exchange of information can be very beneficial.  That was not the case with Apple.  They did not want to check or I could not get past the gatekeeper near when my warranty would be up to investigate:
If I send an email with ATH$ in it on a dial-up line, the modem will hang-up every time.

Six months later they issued a firmware fix for the modem.
I've never bought an Apple product since. They would not do the simple test.

 

Offline Ghanou

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  • Country: dz
Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
« Reply #203 on: July 24, 2020, 09:31:42 pm »
Btw, what's with the NOISE function of this device?
I connected it to an audio amp, and what comes out is nothing like white noise, it's some sort of buzzing sound, and you can actually set its frequency.
What is that good for? (maybe I am wrong to expect white noise here, but that pitched sound is not something I'd have in mind when someone says "noise")

EDIT:
I see, it's not an FPGA function or anything but also just a fixed table for DDS, and if I set it to 1 Hz, it does resemble noise with not very much high end. I guess it would be somewhat more useful if it had a lot more points in each table than those meager 2K.


it's an effect of the DAC (zero order hold) , white noise has a constant spectral density just like the delta impulse function, so what you're seeing is essentially the impulse response of the DAC at a given sampling frequency, you can see in this teardown video at 9:00 the usual frequency response of a sample and hold DAC:
https://youtu.be/b66nnWb3z54?t=521

EDIT: i bet its added just for marketing shit because its hardly any useful, you want your white noise to have a constant spectral density atleast to some higher frequencies so you can use it to view some filter's bode plot or some other system's frquency response.
« Last Edit: July 25, 2020, 03:11:57 am by Ghanou »
 


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