Function Generator Comparison help please - Page 1
Forum section: electronics / testgear

author: Kaytrim
author_rank: Newbie
timestamp: August 04, 2013, 03:31:16 am
content: I am looking at two function generators on Amazon and trying to decide which one to buy. I am a current student at the local community college so finances are still quite tight. In the next semester I will be dealing with communication electronics and would like a decent FG to do some of the lab work at home. I do have a Tektronix dual channel scope TDS 1002B.Here are the two generators:GW-Instek-SFG-1013http://www.amazon.com/GW-Instek-SFG-1013-Generator-Frequency/dp/B0094JVT9O/ref=wl_it_dp_o_pC_S_nC?ie=UTF8&colid=2Z9RNVG1F0HEL&coliid=I1SYG96H8Y3L4M&psc=1B&K Precision 4005DDShttp://www.amazon.com/Precision-4005DDS-Function-Generator-Frequency/dp/B006PJD9KI/ref=wl_it_dp_o_pd_S_nC?ie=UTF8&colid=2Z9RNVG1F0HEL&coliid=I26OZ0REKKTKNFI am leaning towards the B&K as I was able to locate the data sheet for the device. The Amplitude goes down to 20mVp-p which is low enough for what we have dealt with in class so far. I wasn't so lucky in locating one for the Instek device. The only thing I could find on the Amplitude is 0 - 10Vp-p. The other thing to consider of course is the cost. The B&K is about twice the price of the Instek.One other option I was looking at more for grins and giggles is this little DIY kit generator...JYE Tech FG085http://www.amazon.com/Function-Generator-DIY-Tech-FG085/dp/B00C5UO8U6/ref=sr_1_2?s=industrial&ie=UTF8&qid=1375586892&sr=1-2&keywords=function+generator+kitAny advice or additional information on these generators would be helpful.Thank youKaytrim

author: rf-loop
author_rank: Super Contributor
timestamp: August 04, 2013, 06:15:11 am
content: If B&K Precision 4005DDS (USD 278) is still in your budget...you get much more for your money with example Siglent SDG1005.Totally different machine and quality is good, lot of features, 2 independent channels. If you want only simplest DDS func gen up to 5MHz do not pay nearly $300 for example this kind of B&K.If you want B&K you can also find Siglent there. B&K Precision, models 4052, 4053, 4054 and 4055They are renamed Siglent SDG1005, 1010, 1025 and 1050 All these have same features etc, differences are in maximum frequencies 5, 10, 25 and 50MHz. There is also 20MHz model SDG1020 in Siglent.SDG1000 series datasheet you can find here and downloadand on this forum you may find also quite lot of information about SDG1000 series, including some problems what factory have solved time ago. If you find some old opinions including these problems they are expired and it is better to first check if information is valid. Also some sellers frequently show obsolete or wrong datasheets/specs.

author: Kaytrim
author_rank: Newbie
timestamp: August 05, 2013, 11:43:53 pm
content: Thank you for the reply and info.Ok so the Siglent SDG1005 is now at the top of my list. After looking at the datasheet you linked I can see that it has a lot more bang for the buck than the B&K or the Instek. I just hope I can swing the funds for it. Just have to wait for my financial aid to pay out, see what I have left and where it needs to go. I almost want to look at the SDG1010 or SDG1020. The only real difference that I see is the max frequency. I question whether I need anything that high or not.

author: rf-loop
author_rank: Super Contributor
timestamp: August 06, 2013, 07:58:55 am
content: Quote from: Kaytrim on August 05, 2013, 11:43:53 pmSineSDG1005 5MHzSDG1010 10MHzSDG1020 20MHzSDG1025 25MHzSDG1050 50MHzSquareSDG1005 5MHzSDG1010 10MHzSDG1020 20MHzSDG1025 25MHz*SDG1050 25MHz*PulseSDG1005 5MHzSDG1010 10MHz*SDG1020 10MHz*SDG1025 10MHz*SDG1050 10MHz*Gaussian white noiseSDG1005 5MHzSDG1010 10MHzSDG1020 20MHzSDG1025 25MHzSDG1050 50MHzRampSDG1005 300kHz*SDG1010 300kHz*SDG1020 300kHz*SDG1025 300kHz*SDG1050 300kHz*ArbSDG1005 5MHz*SDG1010 5MHz*SDG1020 5MHz*SDG1025 5MHz*SDG1050 5MHz*SDG1005, 1010 No FanSDG1020, 1025, 1050 have FanFunctions, UI, and other things are same between models.There may be some differencies in some internal signal filtering etc things but in practiceI have not seen any markable differencies between SDG1010, 1020 and 1025 exept these named differencies in specs.SDG1020 some day I test using Arb and 10 cycle sine in one Arb waveform give 50MHz sinewave out.Note also very small difference between 1005 and 1010 prices.Be careful and avoid older versions!Least ask seller tell serial number SDG and next 8 digits. (it reads over original carton label so all sellers can tell it without even opening carton)

author: Kaytrim
author_rank: Newbie
timestamp: August 08, 2013, 12:18:27 am
content: Quote from: rf-loop on August 06, 2013, 07:58:55 amHow would I know if the serial number is an old one or an updated one? Also is there a way to update the firmware on these?Thanks,Kaytrim

author: Electro Fan
author_rank: Super Contributor
timestamp: August 08, 2013, 02:25:15 am
content: http://www.amazon.com/Siglent-SDG1020-Function-Arbitrary-Generator/dp/B00DF3P6SU/ref=sr_1_7?ie=UTF8&qid=1375928507&sr=8-7&keywords=siglent+sdgThis place has the 1020 priced for a little less than the 1010.And less than the 1005 from this place:http://www.amazon.com/Siglent-SDG1005-Function-Arbitrary-Generator/dp/B00DF0ZGIS/ref=sr_1_1?ie=UTF8&qid=1375928779&sr=8-1&keywords=siglent+sdg1005

author: rf-loop
author_rank: Super Contributor
timestamp: August 08, 2013, 06:53:42 am
content: Quote from: Kaytrim on August 08, 2013, 12:18:27 amOf course FW can update.It all reads in public available User Manual.Go tohttp://www.siglent.com/en/server/download.aspx?nodecode=119004002001There is user manuals. Go to Download center you find also FW:s, Service manuals etc.Note: In User manual pictures all TFT images are wrong colors.Service manual have better (year 2011 made user manual some pictures have these terrible "candy shop colors" what have been in guite first firmwares)Chapter "2.13. Edition Information" page 81 in User manual.User manual (2011 edition) pages 81 - 82:(also it tell about HW version. No need know more but very last version is starting with numbers 02- (not today 00 or 0f)From manual:Serial No:Bit 1-6 represent maker and series of the product. Bit 7-10 representproduction date. Bit 11-14 represent serial number of product.For example: SDG00002110008 represents the eighth generator made bySIGLENT in the second quarter of 2011.So today SDG0000213xxxx or laterFrom manual:2.14. Updating FirmwareUsing USB flash drive update firmwareThe software of the generator can be updated directly via USB flash drive.This process takes about two minutes. Follow the next steps:1. Insert USB flash drive with firmware procedure to USB host interface onthe front panel of the generator.2. Press the Utility button to enter the ‘Utility Menu’.3. Press ‘1/2?’ option button to enter the second page of ‘Utility Menu’.4. Press the ‘Update’ option button.5. Press ‘Brower’ option button to select ‘Directory’, then select the ‘USBDevice (A:)’ through direction key.6. Press ‘Brower’ option button to select ‘File’, then select the ‘XXXX.ADS’file by direction key.7. Press the ‘Recall’ option button to updating.8. After accomplish update, restart the generator.Today current FW version twolast digits are 27,

author: Kaytrim
author_rank: Newbie
timestamp: August 08, 2013, 09:54:02 pm
content: Quote from: Electro Fan on August 08, 2013, 02:25:15 amWhile that seems to be a good price, look at the shipping cost. I always figure in the shipping for anything. Sometimes it makes a good deal turn sour. I found a better overall price on e-bay, since I am in the USA I look for suppliers/sellers from here, it saves on the up front shipping cost normally.rf-loop, thank you for all your information it has been very helpful.

author: MasterOfNone
author_rank: Regular Contributor
timestamp: August 08, 2013, 10:09:03 pm
content: rf-loop is always helpful but, but I’m not sure if it was made clear that some of the issues in the older SDG models cannot be fixed by updating the firmware. These issues are related to using the Square wave output, and in most cases you can avoid the issues by using the Pulse Wave (instead of square) if you happen to get a model that has the problems.

author: Kaytrim
author_rank: Newbie
timestamp: August 09, 2013, 12:13:37 am
content: Quote from: MasterOfNone on August 08, 2013, 10:09:03 pmIf a firmware update doesn't fix the issue then I had best make sure I get a more recent build. Thanks for the clarification.

author: rf-loop
author_rank: Super Contributor
timestamp: August 09, 2013, 06:17:58 am
content: Quote from: Kaytrim on August 09, 2013, 12:13:37 amIt is also handled here.On older units and in some manufacture lots there have been problem with Square wave quality.This is pure HW problem and it have solved by Siglent time ago.In these units if want repair it, it need small modification in circuit.Allways with low frequancies Pulse give much better signal than Square. This problem in square wave do not affect Pulse function at all.

author: Kaytrim
author_rank: Newbie
timestamp: August 09, 2013, 10:37:42 pm
content: Quote from: rf-loop on August 09, 2013, 06:17:58 amSo if I am reading those forums right the problem with the Square Wave can be mostly fixed by replacing R87 & R82 with a 12k-15k resistor (size 0603) on the board. I should have no problem with that as I can get those from work and have a good setup at home.Kaytrim

author: nctnico
author_rank: Super Contributor
timestamp: August 09, 2013, 11:31:17 pm
content: Could someone create a topic with the final fix for the older SDG1000 hardware? I'm not sure what needs to be changed.

author: rf-loop
author_rank: Super Contributor
timestamp: August 10, 2013, 07:31:48 am
content: Quote from: nctnico on August 09, 2013, 11:31:17 pmIt depends what is problem and what is HW etc.1. Square wave and same glitches in both channel and IF there is factory installed around 40k R87&R82 (PECL comparator hyster setting resistors)This can reduce changing PECL comparator hysteresis window - IF it is too narrow.Perhaps best and most "safe" compromise is change R87 and R82 to 20k (19-21k but so that they are equal). More radical values are 12-15k BUT if use these it need carefully test they do not affect too much Duty % accuracy. Also too wide hysteresis window (smaller resistance) may work still good with 50% duty but some problems may rise if use other than 50% duty if hysteresis is too wide. It is easy understand if look "theory" how this circuit work.2. There may be situation where CH1 and CH2 have big difference in square (jitter/glitch) In this case Bad Channel may help with small capacitor what filters internal sinewave what is coming to PECL. (there is 50 ohm line terminator resistor just before PECL. Small capacitor parallel with this resistor may help.)3. If there is wrong amplifier in CH2 AND if it produce parasitic oscillations using some levels and specially mismatched output loading. This amplifier need change. (this is quite rare problem - in some lot factory have installed other manufacturer pin compatible amplifier. Right amplifier in CH2 is EL5166. and afaik, only this.If there is this problem, it affects ALL waveforms in CH2. (knowing this may help diagnose without opening case)Ch1 do NOT have this problem!First need carefully investigate what is problem exactly (or if there is not problem) and then think what is solution just for this case. If gliches level is well under 10% of square level and if 1kHz timing jitter (period time error related to ideal time ) is around 0.1% or less it tells it is ok and no need repair. (If want improve it better than specs, it is other case)Always, also after repair, Square wave time jitter is quite high. (but around inside specifications)If need Square wave, and if need less jitter and if frequency is under some hundred kiloherz and if need much much less jitter below 10kHz Square wave. Just do it using Pulse function. Nearly it can recommend to use Square wave only if some reason Pulse function can not use for producing needes square wave. But with higher frequencies (over 5MHz) Pulse can not use. And Square jitter is less than Pulse jitter but I do not remember now numbers. It becouse Pulse have always 8ns system jitter independent of frequency (exept with these "golden" frequencies what can produce without 8ns timing jitter for keep (short time average) frequency right)Thumb rule: Use Pulse function for Square wave.1kHz Square wave have 1000000ns cycle time. If timing jitter is 0.1% from cycle it is still 1000ns.1kHz Square wave made with Pulse function have only this around 8ns jitter.And what best, Pulse do not have glitches before rising edge and falling edge.Pulse is made directly by main DAC.Square is made by PECL comparator from internal sinewave (made by DAC,s of course)But, it is good to know that becouse this, with higher frequencies, Square wave time jitter is very low (and also with high frequencies clitches level is very low or no clitches)These some problems have been mainly in last year and partially 1Q2013.Perhaps later these all are ok from factory.Also example SDG1010 what I have normally get from factory and produced 1Q2013 did not have any problems.And as can see in last phasenoise test with unit just as from factory box, they have very good Sinewave if look phasenoise/noise floor sidebands from carrier.

author: Kaytrim
author_rank: Newbie
timestamp: September 02, 2013, 02:49:24 am
content: I finally got my financial aid from school. I ordered the Siglent SDG1025 from Amazon as I had $160 in credit from selling back a few books. I think that this was the best bang for my buck for what was available in the Siglent line and it was free shipping. It should arrive with a few other things I ordered on Wednesday. I'll let you know what I find as far as the date code. Hopefully it is a newer one so I don't have to do the modification to the board. Though I feel confident that I can swap the resistors if need be.

author: Kaytrim
author_rank: Newbie
timestamp: September 04, 2013, 11:57:46 pm
content: It Has Arrived!!!And it is a brand new model!!!From the EditInfo ScreenBoot Strap Number:1Software Version: 1.01.01.27Hardware Version: 02-00-00-21-24Model: SDG1025S/N SDG00003130007So according to the information posted this should be good to go right out of the box.I should be set now for classes and my own projects now and in the future.Thank you everyone for your help and input,Kaytrim

author: eurofox
author_rank: Unknown
timestamp: September 05, 2013, 10:25:00 am
content: I got my SDG1050 last week direct from China.Bright display, loaded with last firmware and all function look OKNice toy for my bencheurofox

author: paul
author_rank: Contributor
timestamp: September 13, 2013, 10:41:17 pm
content: Just got a new SDG1020 and checking everything is ok.It all looks good except, does the rotary knob do any thing when you push it ?Mine clicks but wont select any thing, or even beep when its pushed.Is this normal or is mine duff ?I keep pressing it to select menu items etc as its the obvious thing to do but nothing happens and it seems to be a strange thing to leave out of the software.It had a bit of a rough journey on its way to me and I am wondering if the switch is damaged ?ThanksPaul.