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Products => Test Equipment => Topic started by: Lightages on December 26, 2014, 10:36:46 pm

Title: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: Lightages on December 26, 2014, 10:36:46 pm
I currently have an old analog 2Mhz function generator that has linear and log sweep functions. It is not very stable and the distortion adjustments drift quite a bit with temperature.

I am looking to improve on this and was looking at the latest hot topic on DDS AWG generators here, the Hantek HDG2002B or the old hot topic the Hantek DDS3X25. I don't see log sweep as part of the spec of the HDG2002B and I am not sure on the DDS 3X25 neither.

So I want something that does what these basically do but I do want log sweep. I would be happy with around 25MHz but of course more for the same money or a bit more is a good thing too. I also don't mind a USB only version as I have a computer on the bench.

So what is the current state of the DDS 3X25? Can it be hacked for higher frequency still? Does it have log sweep?
The HDG2002B? Log sweep?

Another possible option if anyone has experience with it:
http://www.ebay.com/itm/24Mhz-Dual-ch-DDS-Function-Arbitrary-Waveform-Signal-Generator-sweep-Software-/121496848485?pt=LH_DefaultDomain_0&hash=item1c49c6c865 (http://www.ebay.com/itm/24Mhz-Dual-ch-DDS-Function-Arbitrary-Waveform-Signal-Generator-sweep-Software-/121496848485?pt=LH_DefaultDomain_0&hash=item1c49c6c865)

Any other options in the $300 range that are known good buys?
Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: Lightages on December 27, 2014, 06:03:23 pm
I guess there aren't as many people interested in this as multimeters and scopes  :-//
Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: Syntax_Error on December 27, 2014, 06:26:36 pm
I wish I could contribute, but all I can say is that I, too am interested in reading the answers to your questions, as there is some overlap with my own. I hope your thread takes off soon.
Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: idpromnut on December 27, 2014, 06:50:20 pm
I can confirm that the HDG2002B only does linear sweeping (although there is an option that looks like you should be able to change it between linear and some other option(s) but I cannot change it's value in the firmware that I have).

Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: tautech on December 27, 2014, 06:57:58 pm
Siglent have recently released new firmware to get the Log Sweep correct in their SDG1000 series.
Quite a few here have these AWG's and seem to be content with them. Models to 50 MHz.
Dual output, 50 ohm or 1 M, 7 ns risetime in pulse mode.
http://www.siglent.com/ENs/pdxx.aspx?id=145&T=2&tid=16 (http://www.siglent.com/ENs/pdxx.aspx?id=145&T=2&tid=16)

AFAIK nobody has spent the time to attempt to hack these to higher BW's.
Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: toli on December 27, 2014, 07:04:28 pm
I was in the same spot as you are right now just a few months ago.

I've ended up purchasing a Siglent SDG1020 (20MHz model). I'm quite happy with it. It has dual output which is nice (but CH2 is limited in amplitude to 6Vpp or so), and the UI is easy enough to learn. I think overall its a solid performer, and it feels close enough to professional for my needs. It doesn't feel as cheap as it is. The latest fw did fix the log sweep option, so it can be used for Xfer function tracing much better now.
Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: Yago on December 27, 2014, 07:13:17 pm
I shopped for a budget FG for ages, jees was not fun.
Ebay auctions were screwed over by the same people, who never won an auction... but they managed to get everything out of my budget.
The older HP models, were just that, very old, I didn't fancy getting something so complex and possibly unreliable.

I actually forgot about the Hantek, even had it highlighted in a folder on PC! doh!

Ended up with a used Fluke/Philips PM5138, only 10Mhz, but there are a couple of models in the range.
Can't give you specifics(it does have log sweep in modulation, not used it), other than it works as expected so far, it does appear grainy on the scope, perhaps low bit depth(10bit?) and that may be something to consider.
In good condition and built like a tank (cast alloy case I think), was £100.
Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: radioFlash on December 28, 2014, 02:25:35 am
I have the Hantek DDS 3X25. It seems to function adequately, but I hate that it must be controlled from a PC, and the software that it comes with works, but it's not particularly good. I've been looking as well for a FG, but one with physical controls.
Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: apelly on December 28, 2014, 03:13:59 am
Can't remember how much my Rigol DG was, but it was pretty cheap from memory, and pretty damn flexible.

I guess you've seen Shahriar's recent review of the Siglent SDG5162 by now: http://thesignalpath.com/blogs/2014/12/08/review-comparison-and-teardown-of-siglent-sdg5162-and-rigol-dg4162-arbitary-waveform-generators/ (http://thesignalpath.com/blogs/2014/12/08/review-comparison-and-teardown-of-siglent-sdg5162-and-rigol-dg4162-arbitary-waveform-generators/)
Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: Lightages on December 28, 2014, 03:43:56 am
Thanks for the links guys. Unfortunately those AWGs reviewed by Shahriar are out of my price range.
Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: TMM on December 28, 2014, 03:45:32 am
Also consider the Rigol DG1022, though value for money is not quite as good as the others. It can only modulate/sweep on CH1 iirc.

I guess you've seen Shahriar's recent review of the Siglent SDG5162 by now: http://thesignalpath.com/blogs/2014/12/08/review-comparison-and-teardown-of-siglent-sdg5162-and-rigol-dg4162-arbitary-waveform-generators/ (http://thesignalpath.com/blogs/2014/12/08/review-comparison-and-teardown-of-siglent-sdg5162-and-rigol-dg4162-arbitary-waveform-generators/)
Too bad they are about 4 times the OP's budget.
Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: LaurentR on December 28, 2014, 05:00:42 am
Also consider the Rigol DG1022, though value for money is not quite as good as the others. It can only modulate/sweep on CH1 iirc.

I second that. Not nearly the incredible bargain a DS1054Z is, but a reasonable performer for the price. It's a bit dated, but that also means it can be found occasionally used on EBay for <$300, otherwise, they seem to sell really well on TEquipment (best selling function gen - $356 after discount), so you wouldn't be the only owner out there :-)
Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: MartyD on December 28, 2014, 12:28:53 pm
Siglent have recently released new firmware to get the Log Sweep correct in their SDG1000 series.
Quite a few here have these AWG's and seem to be content with them. Models to 50 MHz.
Dual output, 50 ohm or 1 M, 7 ns risetime in pulse mode.
http://www.siglent.com/ENs/pdxx.aspx?id=145&T=2&tid=16 (http://www.siglent.com/ENs/pdxx.aspx?id=145&T=2&tid=16)

AFAIK nobody has spent the time to attempt to hack these to higher BW's.

In opposite to Rigol there seem to be hardware differences between the various Siglent 1000 series generators. In other peoples teardowns I could spot minor differences on the main boards, also the units >20MHz have a cooling fan. So I'm not sure they can simply be hacked to a higher bandwidth without performance impacts in the higher frequency ranges.

However, I think they offer the best bang for the buck at the moment in the entry level segment. It looks and feels like a quality product and I have been through quite a few entry level generators before I settled with the SDG. Now that the firmware has matured there's no more argument against it. If you want/need higher stability, just drop in a $25 TCXO from ebay.

If you want "hackability" you're probably better off with a Rigol product. Though I'm not too keen on that...

Marty
Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: Howardlong on December 28, 2014, 04:46:54 pm
Be aware that the HDG2002B is incredibly buggy, especially for anything more complex that your standard non-complex waveforms: in general as a test instrument it can't really be trusted, I frequently double check the output signal with a scope to make sure it's doing what it should be. It seems they spent a reasonable amount of time on the hardware but the software team went to the pub for lunch and never came back.

Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: Lightages on December 30, 2014, 03:24:41 am
Another question: Does the Rigol DG1022 have the option to just take recorded waveforms from the DS1052E or DS1054Z and play them back? Is it easier to do so Rigol to Rigol than from the Rigol scope to Siglent AWG?

Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: ivan747 on December 30, 2014, 03:59:16 am
Another question: Does the Rigol DG1022 have the option to just take recorded waveforms from the DS1052E or DS1054Z and play them back? Is it easier to do so Rigol to Rigol than from the Rigol scope to Siglent AWG?

As an owner of a DS1102E and a SDG1010, it's nightmarish  |O
My workflow is the following:
-Export a CSV file from the Rigol scope, not full memory depth because it takes ages and cannot be taken advantage of by the AWG
-Edit the waveform with a DECENT waveform software, Tektronix ArbExpress (this shouldn't be done, the license forbids it, but I always have my Tek scope when opening arb express, you know  ;) ;)  -I'm looking for alternatives here). Editing, in my case, is clipping the waveform, editing its amplitude, sampling rate (ArbExpress can compress a waveform using frequency-limited interpolation) etc.
-Export from ArbExpress. The CSV format is the format used on Tektronix scopes (the CSV used for AWGs is very different and confuses Siglent's EasyWave).
-Import that into EasyWave
-Export into AWG

The main problem is shuffling around file format, as you see.

*I am not entirely sure it's going to be better from rigol to rigol*. Why? Well, in theory (I haven't checked, sorry), the formats are compatible, but, you still need to clip the waveforms, change the sample rate and such, don't you? As far as I know, this is not practical to do inside the Rigol generator (and I'm sure of that because I have seen how low resolution that grayscale display is). So you still need the computer. You save maybe 2 or 3 steps out of 7.

As a brand, I trust Rigol more than Siglent, but the Siglent is giving me twice the sampling memory and 4 times the resolution (12bit vs 14 bit).

If I was doing arbitrary waveforms all the time, then I would personally get the Rigol to keep me sane, but since I was already stretching my budget by quite a bit looking for a decent analog or DDS FG, and I wasn't originally looking for an AWG, I thought "well, I'm getting the AWG and the color LCD, that's a pretty nice bonus".

I'm still looking for a way to open the CSV (or whatever format) directly on the SDG1010 via a USB drive. If anyone can help me out, I would be thankful.

By the way, here's my review for the Siglent, if you're interested:
http://www.tequipment.net/Siglent/SDG1010/Fully-usable-AWG-at-a-very-low-price/c629c3f1890b4/ (http://www.tequipment.net/Siglent/SDG1010/Fully-usable-AWG-at-a-very-low-price/c629c3f1890b4/)
Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: Lightages on December 30, 2014, 04:41:18 am
Thanks for the information on using Rigol waveforms with the Siglent.
Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: rf-loop on December 30, 2014, 09:30:07 am

I'm still looking for a way to open the CSV (or whatever format) directly on the SDG1010 via a USB drive. If anyone can help me out, I would be thankful.

By the way, here's my review for the Siglent, if you're interested:
http://www.tequipment.net/Siglent/SDG1010/Fully-usable-AWG-at-a-very-low-price/c629c3f1890b4/ (http://www.tequipment.net/Siglent/SDG1010/Fully-usable-AWG-at-a-very-low-price/c629c3f1890b4/)

In rewiev: AM modulation only 1kHz.
This is not true. Internal AM modulation freq range is 2mHz to 20kHz (but of course user need also know basic fundamentals about modulations.)

CSV (Comma Separated Values) from USB stick to SDG. Of course it can. It is made for this.

You can write acceptable CSV even with windows notepad.

This is simply example.
(also it is good to note that in practice offset and vertical  value etc is not so much meaning (it automatically scale it but when you turn it on, these values are "default" values. Front panel you set freq, level and offset (as for all arbs))

Attached: Sine1.csv.txt
Just remove .txt save it to USB and read it with SDG1000 and use it.
If you want other waveform, just edit its data area xpos (arb memory "address") range is 0 - 16383 and nothing else.

If you manually want edit it, take care that not add any hidden control etc characters to file due to text editor.

Siglent scope CSV is compatible. Other brand waveform CSV may need modification before it can read in SDG.  (copy paste 16384 vertical values to "value" column)

I do not have now any SDG1000 what I can use for test but if I remember right it also automatically scale csv values to arb memory so that max and min values match full level in arb memory.


NOTE: in file "header" part, there is "data lenth,16384"
(it is not my mistake!  Siglent produce it.  I can not now test (not available SDG1000 for testing) what happend if repair this error in file so best keep it as it is)


Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: ivan747 on December 30, 2014, 01:57:40 pm
Well, thanks for the info. I'm still figuring out a reliable way to clip the waveforms (change their sampling rate too) and maybe adjust their amplitude to use the full resolution of the DAC.
Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: rf-loop on December 30, 2014, 06:32:51 pm
I did some short test with oscilloscope and SDG5082.
Result was surprise. Due to very limited time visit in lab I do not have enough data at all for proof anything. Also I do not have SDG1000 what I can use for testing.

Surprise start after I made mistake and load wrong .CSV to  SDG5082 arb memory.
SDG5000 CH1 arb memory is exactly same as SDG1000 (16k)
My accidentally loaded CSV was made with oscilloscope and with 280kpoints waveform where also vertical was  not at all full display.

SDG5000 read it without any err message. Then I store it to CH1 16k arb and agen, not any err message.

Ok, then I start run this and look with scope what is coming out. Surprise (Also at this time I can see that this was not wavefform what I think I load to SDG5000, instead it was this 280kpoints CSV): It was vertically rescaled up (p-p to match full scale) but more surprise. It was also horizontally scaled to match this memory and waveform was horizontally just same what is was on the scope screen before save it as CSV.  It was not cutted, it was scaled to 16k memory.

Due to this surprise I did other. I take sinewave and oscilloscope adjusted so that display (wfm lenght) just one cycle and now 14k memory. Then save it as CSV to USB.   Then USB to SDG5000 and there to CH1 16k memory. It read it just without err message. Result same. Run it back to scope and vertical was agen up scaled and horizontally output was just same full cycle of sine.

Only what I now think is that this "feeature" need really test and document better. Also I hope I can do same with SDG1000 later.

Also, when I look these oscilloscope produced CSV files, there header information is different.
Previously this attachment .CSV was made with EasyWave software.

I have not seen any good documents how SDG1000 and SDG5000 really handle .CSV waveform files.
If it really can aautomatically adjust lenght and height of waveform it may be useful feature, specially if it is documented how and what it really do in SDG1000 and in SDG5000.

Add: 16k waveform Arb. .CSV data points can be what ever from 2 points to full 16k (16384). What ever amount of points SDG5000 play it as one Arb cycle. (btw, if Arb cycle have 10 cycle of sine then 10MHz Arb freq setting give 100MHz out and so on).  With today some more tests it is clear that SDG1000 and SDG5000  .CSV file things need investigate more or get detailed information from Siglent.

Later I will try with Rigol DS1000Z waveform .CSV if it is possible



Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: dom0 on December 30, 2014, 08:26:16 pm
Ended up with a used Fluke/Philips PM5138, only 10Mhz, but there are a couple of models in the range.
Can't give you specifics(it does have log sweep in modulation, not used it), other than it works as expected so far, it does appear grainy on the scope, perhaps low bit depth(10bit?) and that may be something to consider.
In good condition and built like a tank (cast alloy case I think), was £100.

The PM5138 has quite a few sister models. The lowest endish thing has 2 MHz max and the highest one goes to 20 or 25. These are good generators generally, nice to use. 10 bit is correct, I think.

Shameless self-quote from another thread:

I wouldn't focus on the very-well known function gens on the used market, since they are popular they are more expensive.

Look for not so well known models.  For example, HP 3312a, HP 3324A, Philips/Fluke generators (e.g. pm5138, pm5139, pm5136), there are also always some Wavetek generators around, but I found it hard to get solid specs on them and skipped them. That's a very long list.

Patience pays, I bought my fg (50 MHz Philips) for c. 150 $ (excluding shipping etc.), but I had to wait a few months for a good offer... OTOH it might be hard to get spare parts for "unpopular" generators. But then again, spare parts are usually rather expensive... especially for HP, Tek, ... devices.

When doing audio stuff it might be worth to look for an additional sine oscillator or some fg with lower distortion numbers than general-purpose fun-gens, since those usually have rather high distortion (most synthesized fgs from the 80s-90s are in the 0.1-0.5 % ballpark). Building a good, solid, low distortion sine oscillator is btw. a nice project to do. I recommend it.

Be careful with the HP 3325A as only the sine and square go to an appreciable frequency.  The triangles and ramps only go up to something like 11 kHz.

This is a common limitation of all early synthesized generators I am aware of. Generally, always fetch and read the specs for gear if you are about to spend an appreciable amount of money.

There is also the 8112A/8116A series. But they're not overly good generators IMHO. They're based on some very tricky analog oscillators, controlled by DACs, and have rather poor stability and precision. In this regard they are not better than analog generators.

There is also the 8165A, a very early synthesizer. I don't know anything more about it.
Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: Lightages on December 30, 2014, 08:49:01 pm
Thanks for all the replies. It looks like if I want to play it safe and get something modern, the Siglent SDG1025 would be a good buy for me. Higher frequency output on square and other waveforms than the Rigol DG and good build quality.

If I want to take a chance and take one for the team to see what is like there is this still:
http://www.ebay.com/itm/24Mhz-Dual-ch-DDS-Function-Arbitrary-Waveform-Signal-Generator-sweep-Software-/121478483178?pt=LH_DefaultDomain_0&hash=item1c48ae8cea&autorefresh=true (http://www.ebay.com/itm/24Mhz-Dual-ch-DDS-Function-Arbitrary-Waveform-Signal-Generator-sweep-Software-/121478483178?pt=LH_DefaultDomain_0&hash=item1c48ae8cea&autorefresh=true)
It could be OK, or real bad.

I would also still consider the Hantek DDS3X25 but there seems to be no recent activity on it here so I am not sure of its status.
Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: rf-loop on December 31, 2014, 07:59:22 am
Thanks for all the replies. It looks like if I want to play it safe and get something modern, the Siglent SDG1025 would be a good buy for me. Higher frequency output on square and other waveforms than the Rigol DG and good build quality.



Siglent frequency limits by different models are mainly in Sinewave.  In square wave function it still also internally works producing sinewave what is now not coming out. (limited in 1050 model to 25MHz, in other models same max as sine). It is used internally to produce square wave using comparator method (very common method  in many old and also new function generators). It have advantages and disadvantages.  With higher frequencies it give less time jitter.

Pulse, what can also use mostly as square wave, is produced  by DAC's as also other waveforms.

When sinewave is limited to 10, 20, 25MHs (1025 model 25MHz) there still can produce 50MHz (and over) sinewave (quality is not as perfect what it is with sinewave function). It can simply do with math equation using Arb. (Equation draw with EasyWave)
10 cycles sine with arb. Setting Arb then for 5MHz and output is 50MHz.  here 5 cycles:
10*(sin(5*x))     here ten is for 20V pp range (-10 to +10V) (property setting 20Vpp)

Or something other, example this: 10*(sin(2*(sin(2*(sin(3*x))))))
(yes it is (simplified version) how square wave looks when we reduce amount of harmonics.  There is 3 cycles )  Just open EasyWave and write equation (draw --> Equation draw) and it draw it for you and save file (.csv) to USB stick and run with SDG.

Or of course also some complex things.

SDG1000 models sinewave quality is also quite good in this price class. Here can find some tests with spectrum analyzer.  (http://siglent.freeforums.org/tests-updated-siglent-sdg1000-function-arbitrary-wfm-gen-t5.html)

It need also note that today product versions do not have old time square wave glitch issue.

Newest FW give also:

- Channels can lock so that slave channel follow when master channel frequency is adjusted (ser select which one is master). There can also set offset frequency between channels.

- Ouput impedance (better say Load impedance setting, because output itself is always 50ohm)
Old version have selections Hi-Z and 50ohm (for display right level dependent if load is 50ohm or Hi-Z. 
Now there can set also other loads.  Example if signal is going to 600ohm input, just set output for  600ohm and agen it display right signal level. (load impedance can set wide range. If some amplifier input is 10k then just set 10k...etc )

(LOG sweep up/down is finally also repaired, now it works right. (old works right only for 1 decade start stop range.)








Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: ivan747 on January 02, 2015, 03:24:05 pm
RF-loop. I will be experimenting with this on the SDG1000
Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: dom0 on January 02, 2015, 03:32:36 pm
(load impedance can set wide range. If some amplifier input is 10k then just set 10k...etc )

I doubt the amplitude accuracy of most generators is high enough that such a high impedance load matters... ;)
Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: ivan747 on January 02, 2015, 03:35:18 pm
If I want to take a chance and take one for the team to see what is like there is this still:
http://www.ebay.com/itm/24Mhz-Dual-ch-DDS-Function-Arbitrary-Waveform-Signal-Generator-sweep-Software-/121478483178?pt=LH_DefaultDomain_0&hash=item1c48ae8cea&autorefresh=true (http://www.ebay.com/itm/24Mhz-Dual-ch-DDS-Function-Arbitrary-Waveform-Signal-Generator-sweep-Software-/121478483178?pt=LH_DefaultDomain_0&hash=item1c48ae8cea&autorefresh=true)
It could be OK, or real bad.

That look's like some student's university project, honestly. Unless you wan a toy to play with (and that looks like an expensive toy), I would run away.

If you really wanted something out of ebay, for bargain price (and you know it's going to be low performance, but you're not paying much) you could look for something like this:
http://www.ebay.com/itm/DDS-Function-Signal-Generator-Sine-Square-Sawtooth-Triangle-Wave-Digital-LCD-DDS-/261603309142?pt=LH_DefaultDomain_0&hash=item3ce8c5b656 (http://www.ebay.com/itm/DDS-Function-Signal-Generator-Sine-Square-Sawtooth-Triangle-Wave-Digital-LCD-DDS-/261603309142?pt=LH_DefaultDomain_0&hash=item3ce8c5b656)

http://www.ebay.com/itm/DDS-Function-Signal-Generator-Module-Sine-Square-Sawtooth-Triangle-Wave-US-/311240598773?pt=LH_DefaultDomain_0&hash=item487762a4f5 (http://www.ebay.com/itm/DDS-Function-Signal-Generator-Module-Sine-Square-Sawtooth-Triangle-Wave-US-/311240598773?pt=LH_DefaultDomain_0&hash=item487762a4f5)



There's no problem in buying cheap stuff, you just have to know that you won't get the same performance and/or quality.

I'm afraid that, what you linked might be that same circuit board inside a pretty enclosure with a transformer and some buttons.
I even found the same function generator you linked, at 1/3 of the price. I can't find a difference:
http://www.ebay.com/itm/2MHz-Dual-Channel-DDS-Function-Signal-Generator-Sine-Square-Wave-Sweep-Counter-/111407197529?pt=LH_DefaultDomain_0&hash=item19f062ed59 (http://www.ebay.com/itm/2MHz-Dual-Channel-DDS-Function-Signal-Generator-Sine-Square-Wave-Sweep-Counter-/111407197529?pt=LH_DefaultDomain_0&hash=item19f062ed59)
Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: kwass on January 02, 2015, 04:09:57 pm
Thanks for all the replies. It looks like if I want to play it safe and get something modern, the Siglent SDG1025 would be a good buy for me. Higher frequency output on square and other waveforms than the Rigol DG and good build quality.


If you do buy a SDG1025 there are two or three useful mods that I've done and recommend.

1)  Change the fan to a quieter one.  I also used a series resistor to slow it down.  The SDG1025 needs very little cooling if any, the lower speed models don't even have a fan.

2) Add a TCXO for accuracy.  This makes a huge difference in accuracy:

https://www.youtube.com/watch?v=RxCDfNCLj08#ws (https://www.youtube.com/watch?v=RxCDfNCLj08#ws)

3) If you don't have the latest firmware installed, make sure you get it.  Version  1.01.01.36R1 fixes several significant bugs and adds some features.

Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: Lightages on January 02, 2015, 08:00:08 pm
Thanks again all for the information. SDG1025 it is!
Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: DJ on January 02, 2015, 10:03:30 pm
Thanks for all the replies. It looks like if I want to play it safe and get something modern, the Siglent SDG1025 would be a good buy for me. Higher frequency output on square and other waveforms than the Rigol DG and good build quality.


If you do buy a SDG1025 there are two or three useful mods that I've done and recommend.

1)  Change the fan to a quieter one.  I also used a series resistor to slow it down.  The SDG1025 needs very little cooling if any, the lower speed models don't even have a fan.

2) Add a TCXO for accuracy.  This makes a huge difference in accuracy:

https://www.youtube.com/watch?v=RxCDfNCLj08#ws (https://www.youtube.com/watch?v=RxCDfNCLj08#ws)

3) If you don't have the latest firmware installed, make sure you get it.  Version  1.01.01.36R1 fixes several significant bugs and adds some features.

I seem to recall the SDG5162 had an unpopulated TCXO spot, can anyone confirm?
Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: BloodyCactus on January 02, 2015, 10:13:02 pm
I have a rigol 1035Z thats pretty nice for pumping out waveforms.
Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: pickle9000 on January 02, 2015, 10:23:22 pm
I have an SDG1020 and have had no issues at all. I purchased it based only on the specs and no disappointment there. I was slightly confused by the menu (for about 15 seconds) and in reality it's very intuitive.
Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: Electro Fan on January 03, 2015, 12:24:54 am
I have a rigol 1035Z thats pretty nice for pumping out waveforms.

Is that a 1032Z?  Thx
Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: drakke on January 21, 2015, 02:37:37 am

If you do buy a SDG1025 there are two or three useful mods that I've done and recommend.

1)  Change the fan to a quieter one.  I also used a series resistor to slow it down.  The SDG1025 needs very little cooling if any, the lower speed models don't even have a fan.

2) Add a TCXO for accuracy.  This makes a huge difference in accuracy:


I'm a beginner and my SDG1025 arrived yesterday and it does look nice. The fan noise is noticeable but I would not call it loud.

In what situations will the added accuracy from the TCXO be required?
Can you elaborate further?




Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: tautech on January 21, 2015, 03:02:34 am

If you do buy a SDG1025 there are two or three useful mods that I've done and recommend.

1)  Change the fan to a quieter one.  I also used a series resistor to slow it down.  The SDG1025 needs very little cooling if any, the lower speed models don't even have a fan.

2) Add a TCXO for accuracy.  This makes a huge difference in accuracy:


I'm a beginner and my SDG1025 arrived yesterday and it does look nice. The fan noise is noticeable but I would not call it loud.

In what situations will the added accuracy from the TCXO be required?
Can you elaborate further?
Few.
I'm sure there are more details in the links in this thread.
https://www.eevblog.com/forum/testgear/the-sdg1000-and-sdg800-thread/ (https://www.eevblog.com/forum/testgear/the-sdg1000-and-sdg800-thread/)
Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: kwass on February 27, 2015, 07:47:12 am

In what situations will the added accuracy from the TCXO be required?
Can you elaborate further?

The advantage to using a TCXO is for applications where you need absolute accuracy and/or in applications where you need limited drift.  If you're using the generator to calibrate a radio receiver for example.  The recommended TCXO is also adjustable so that you can adjust it's absolute accuracy as it will change over time.  You can not do this with the stock crystal oscillator.  For about $20 and an hour of time it's a very useful upgrade.
Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: Lightages on February 27, 2015, 07:51:11 am
I would agree with the TCXO modification. It was worthwhile to me. My SDG1025 improved quite a bit. And thanks to all for the help me decide which to get.
Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: skyjumper on April 10, 2015, 06:29:40 am
I realize the OP made his choice, but I'm in the same boat now but don't want to spend > $300.00. I don't need anything fancy, but the ability to not need a PC in an inexpensive FG would be very nice. What about this one:

http://www.ebay.com/itm/251169054479?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT (http://www.ebay.com/itm/251169054479?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT)

And what was the issue with this one? I don't understand why it was rejected out of hand:

http://www.ebay.com/itm/251169054479?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT (http://www.ebay.com/itm/251169054479?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT)

Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: tautech on April 10, 2015, 08:04:21 am
And what was the issue with this one? I don't understand why it was rejected out of hand:
5V P-P is very poor capability.

Compare it against the specs of the SDG800 series:
http://www.siglentamerica.com/pdxx.aspx?id=71&T=2&tid=16 (http://www.siglentamerica.com/pdxx.aspx?id=71&T=2&tid=16)

Plenty more info here: https://www.eevblog.com/forum/testgear/the-sdg1000-and-sdg800-thread/ (https://www.eevblog.com/forum/testgear/the-sdg1000-and-sdg800-thread/)
All documentation:
http://www.siglentamerica.com/prodcut-wd.aspx?id=71&tid=16&T=2 (http://www.siglentamerica.com/prodcut-wd.aspx?id=71&tid=16&T=2)

In fact rf_loop has found some SDG800 capabilities that exceed the SDG1000 series, it's big brother.
Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: Lightages on April 10, 2015, 01:26:01 pm
I realize the OP made his choice, but I'm in the same boat now but don't want to spend > $300.00. I don't need anything fancy, but the ability to not need a PC in an inexpensive FG would be very nice. What about this one:

http://www.ebay.com/itm/251169054479?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT (http://www.ebay.com/itm/251169054479?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT)

And what was the issue with this one? I don't understand why it was rejected out of hand:

Simply for me, it was an unknown and it was lacking a real company to back it up. It takes me months to get things here and it is even worse to send things back if there is a problem. This is also a kit, and didn't want to spend the time to build a kit from an unknown company. It could be fine for its purpose and price, but not what I wanted.
Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: skyjumper on April 10, 2015, 02:46:17 pm
Thanks for the replies and for explaining. For me, the Ebay kit would be fine, I mostly just want to fool around with the new oscilloscope and play with some filters. That said, the SDG800 series looks like a great value, with the 805 going to 5MHz for $250 delivered. Of course I might go to the SDG830 for $332 delivered, because I just seem to do that.

In my post I made an error, I pasted the wrong link for the one that was dismissed out of hand. The one I meant to ask about was this one for $140:

http://www.ebay.com/itm/121478483178?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT (http://www.ebay.com/itm/121478483178?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT)

This one goes to 20MHz for the sine wave and claims 20Vp-p.
 
Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: Lightages on April 10, 2015, 03:46:00 pm
I also considered that one. When I asked about it as an alternative, there seemed to be very little experience and answers about it. I didn't feel like being the test rat for it, so I decided on the much more capable SDG1025. It does look like a good buy, IF it works as described, has good frequency stability, has good distortion, and the UI isn't crap.
Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: skyjumper on April 10, 2015, 04:53:48 pm
I also considered that one. When I asked about it as an alternative, there seemed to be very little experience and answers about it. I didn't feel like being the test rat for it, so I decided on the much more capable SDG1025. It does look like a good buy, IF it works as described, has good frequency stability, has good distortion, and the UI isn't crap.

I can't find much info about it either, so let me suggest this, if you and others are agreeable. I just got a Rigol 1054z, but I don't have a spectrum analyzer. If you and others are willing to help me (I'm relatively new at this analog stuff) I'll do a bunch of tests and post a review. I'll do as much as I can given the tools I have.
Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: Lightages on April 10, 2015, 05:00:58 pm
Sure, buy one and review it. I will help with my knowledge and I am sure there are others with more knowledge than I have who will help too. If you really want to measure the distortion figures, the FFT in the DS1054Z is not very good. It will give you some idea but will do no better than its noise floor, around -45dB to -55dB. A better way to measure the distortion and noise levels, in the audio range, is with the sound card of your computer. There are many free programs to do real audio analysis.

Edit:
I just checked. It looks like the FFT on the DS1054Z can do -47db to -50db at best.
Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: nctnico on April 10, 2015, 05:19:33 pm
It looks interesting. The 20Vpp output amplitude on both channels is very nice and an area where the SDG1000 comes up short (only 10Vpp on one channel and 6Vpp on the other). I wouldn't expect it to be free of high frequency harmonics though but good enough to send a tone through a circuit or just generate some pulses. Maybe I'll get one.
Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: rf-loop on April 10, 2015, 05:42:51 pm
It looks interesting. The 20Vpp output amplitude on both channels is very nice and an area where the SDG1000 comes up short (only 10Vpp on one channel and 6Vpp on the other). I wouldn't expect it to be free of high frequency harmonics though but good enough to send a tone through a circuit or just generate some pulses. Maybe I'll get one.

FY3200S
20Vp-p  No load

Just for fun from specs:
Square wave rise and fall time 100ns !  But then they tell Square  max freq 6MHz







Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: nctnico on April 10, 2015, 06:00:35 pm
It looks interesting. The 20Vpp output amplitude on both channels is very nice and an area where the SDG1000 comes up short (only 10Vpp on one channel and 6Vpp on the other). I wouldn't expect it to be free of high frequency harmonics though but good enough to send a tone through a circuit or just generate some pulses. Maybe I'll get one.
20Vp-p  No load
Which means 20Vpp into a high impedance load. Because the output impedance is 50 Ohm you'll still get 19Vpp into a load of 1kOhm. Way more than the SDG1000 series can do. And yes I ran into that limitation recently when I needed two 5V signals to drive some logic inputs.
Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: rf-loop on April 10, 2015, 07:03:58 pm
It looks interesting. The 20Vpp output amplitude on both channels is very nice and an area where the SDG1000 comes up short (only 10Vpp on one channel and 6Vpp on the other). I wouldn't expect it to be free of high frequency harmonics though but good enough to send a tone through a circuit or just generate some pulses. Maybe I'll get one.
20Vp-p  No load
Which means 20Vpp into a high impedance load. Because the output impedance is 50 Ohm you'll still get 19Vpp into a load of 1kOhm. Way more than the SDG1000 series can do. And yes I ran into that limitation recently when I needed two 5V signals to drive some logic inputs.

CH1
Hi-Z ("no load")
SDG1000 20Vpp  but limited to 10MHz  (FY3200 rectangle waves limited to 6MHz so can not get any level)
Over 10MHz  10Vpp what still give 0-5V for "no load"

(CH2 limited to 6Vpp  for Hi-Z)

So is do not know how to read this "way more"

But so or so, FY3200S give more level. But then for logic, typically I thyink we use rectangle waves. FY3200S is limited to 6MHz with 100ns rise and fall. So you do not get even 10MHz rectangle wave for any kind of level for some logic circuit.

Up to 10MHz SDG1000 CH1 give same. 

To 5V logic  FY3200 100ns risetime is nice.. really nice.



Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: nctnico on April 10, 2015, 07:37:12 pm
I think the 100ns is a typo. Probably the real number is 10ns (BW=35MHz). How would they get 25MHz from the generator otherwise and how about the 5th harmonic of a 6MHz square wave? And why would I need more than 6MHz to drive logic? In my case I needed signals of less than one Hz.

I've bid on a different generator in an auction but if I don't get that I'll get a FY3200 just for fun...
Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: Lightages on April 10, 2015, 07:55:22 pm
I would have purchased the FY model if there was any real experience here from knowledgeable people. As it was, the SDG1025 was a safe bet.
Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: skyjumper on April 10, 2015, 09:05:06 pm
It looks interesting. The 20Vpp output amplitude on both channels is very nice and an area where the SDG1000 comes up short (only 10Vpp on one channel and 6Vpp on the other). I wouldn't expect it to be free of high frequency harmonics though but good enough to send a tone through a circuit or just generate some pulses. Maybe I'll get one.

FY3200S
20Vp-p  No load

Just for fun from specs:
Square wave rise and fall time 100ns !  But then they tell Square  max freq 6MHz

What would be good specs?
Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: nctnico on April 10, 2015, 09:54:00 pm
Whatever your wallet can afford  >:D Seriously: a good tool is adequate for the job so there is no way to tell what are good specs without knowing what is piece of equipment is used for.
Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: skyjumper on April 10, 2015, 11:17:47 pm
Fair enough,  and truthfully,  my primary motivation is to just have one to play with, which means I can't justify much money out of my wallet at all. Most of the work I do is digital.

So I could convince myself to order one of these. I like ten kit but it's only about $30 less and this thong, if it works, does so much more.

But the feedback, wow, a small percentage of negative items bit a high number.  I'll decide this weekend.  If I buy one today it will be here in about 2.5 weeks,  assuming it gets shipped as promised.

Inbthe meantime I can breadboard something up with an arduino or something
..
Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: kazik70 on September 07, 2019, 10:34:27 am
ET12 - Siglent SDG1025 0.1ppm TCXO Hack - YouTube
https://www.youtube.com/watch?v=T9uLUM9DZ9A (https://www.youtube.com/watch?v=T9uLUM9DZ9A)
Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: colorado.rob on September 07, 2019, 08:47:54 pm
Necro-posting to a thread that has been dormant for 4 years is considered rather rude.  There is no reason this could not have been posted to a new thread?  And in particular, this post belongs in the repair forum (https://www.eevblog.com/forum/repair/ (https://www.eevblog.com/forum/repair/)), not here.

Mods, can we lock this down somehow?
Title: Re: Looking for reasonable DDS or AWG or function gererator, need opinions please
Post by: tautech on September 07, 2019, 08:54:58 pm
Necro-posting to a thread that has been dormant for 4 years is considered rather rude.  There is no reason this could not have been posted to a new thread? 
Unnecessary.
Actually it would have been better posted here:
https://www.eevblog.com/forum/testgear/the-sdg1000-and-sdg800-thread/ (https://www.eevblog.com/forum/testgear/the-sdg1000-and-sdg800-thread/)

I'll quote it into that thread.