Just found a SW bug regarding the modulation with noise:
1) Set carrier, eg 40MHz
2) turn on AM modulation, 100% depth, sine wave, set AM frequency to x Mhz (I used x=1, but tested others too)
At this point the correct AM modulated waveform is generated
3) Change modulation "shape" to noise
instead of noise being modulated, an infinite number of sub-carriers spaced x Mhz apart are generated
Can I ask, which model? 40, 80 or 120 MHz unit.
Edit.
Got a PM from MasterTech and his is a improved SDG2042X. <wink>
We'll attempt to replicate this bug with a new unit and if proven will be notified to Siglent next week.
Following on from the bug MasterTech revealed above....
Is a Noise type of modulation even required? ![Confused :-//](https://www.eevblog.com/forum/Smileys/default/confused0024.gif.pagespeed.ce.5xOqKkq0Co.gif)
Why? Real use example please.
Do other AWG's provide Noise modulation of waveforms?
Makes? Models?
Take one SW radio and turn it on. Start searching some transmission.
What you hear. You hear enormous amount of natural and human made noise and somewhere inside this are also many kind of signals. In lab when we test example wireless data transmission we need signal + noise for emulate natural situation. (yes it can do also other ways) Some times overall noise level is far over wanted signal level and we need build equipments what can catch this signal from deep under noise level.
(Least I solve this problem with mixixing noise source and signal)
But overall, noise is very important tool for many many things and usefulness of noise is many times underestimated or even misunderstooded. Pity that these AWG software made noises are mostly far from ideal random gaussian noise.
How you characterize filter. Whos is using sweep generator. Other and very good way is use just noise. Input wide BW random (white or nearly white or bit pink) noise to filter and look what come out, thats it and so simple.
Even if you transmit RS232 over cable between equipments, how uoy know it work in real word if you have tested only with ideal "school book" signal. No, it need test in natural worst caase environment or you need simulate this situation, noise is one good tool for it. So, modulate your pulse queye with noise and know more how it work.
If we use signal generator only connected to oscilloscope and we want look nice images on the scope screen... we want clean signal many times. But for real testings we need also dirty or very dirty signals and so that all parameters are in "worst case" position, including levels, freq tolerances, noises and mismatching ringing etc. These can simulate with good tools. Going to natural worst case real world testing is next phase but this IS expensive. One test may cost more that couple of equipments.
![Wink ;)](https://www.eevblog.com/forum/Smileys/default/xwink.gif.pagespeed.ic.cldandycH0.png)
(I have not tested SDG2000X noise modulation but SDG5000 I have tested and if talk seriously. It is NOT true gaussian random noise. It is some kind of "looks like random but not at all random" fake noise.
One example here. I can ask. is this random gaussian noise. No, it is far away. (yes there is trick and note also scale but... if look this with spectrum... it is fun)