Need Signal Generator - Page 1
Forum section: electronics / testgear

author: rpschultz13
author_rank: Contributor
timestamp: August 19, 2025, 09:59:33 pm
content: Hi,I'm looking for a signal generator, low frequency audio range. I'd like it to do white (or better yet pink) noise. Pink noise seems much harder to find.The OWON DGE1030 seems good for $100, 1 channel and it does white noise. 125 MSa/s, probably not that important in the audio range?https://www.amazon.com/dp/B0CYSBZBNQ?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1What are other units in the $100-150 price range?

author: shabaz
author_rank: Frequent Contributor
timestamp: August 19, 2025, 10:34:59 pm
content: Hi,The built-in noise capability is very limited for that; the only settings are amplitude and offset. However, it's possible to add a custom arbitrary waveform, which could look like noise, although the amount of sample memory is limited (8 ksamples), so it will repeat extremely frequently.Other than that, the DGE1030 is very usable (has a few other minor annoyances, like no dBm setting, but that's not relevant for audio). At that price range, it's probably as reasonable as any other basic signal generator, but bear in mind it's a general-purpose instrument, not audio-specific, so you won't have (say) balanced output capability directly from the instrument, and so on. It may be worth buying a small audio transformer too.Alternatively you could use a sound card to generate audio signals, but you'd need to verify signal levels with a 'scope or other instrument, since sometimes the PC's software sound pipeline can adjust levels unexpectedly with typical consumer sound cards.

author: rpschultz13
author_rank: Contributor
timestamp: August 19, 2025, 11:41:31 pm
content: I'm fairly new to the EE hobby of designing audio circuits. Last fall I bought a Siglent SDS804XHD from Saelig, fantastic unit that I'm still learning how to utilize. When looking for a waveform generator of the Siglent/Rigol family, the price jumps a a lot over the $100 Owon. Saelig has FUNCTION generators and ARBITRARY generators, what's the difference? Cheapest one in all of those is a Siglent SDG800 for $275. I don't think I want to spend that much, just wondering what would be best for my audio needs.Koolertron has a 15Mhz version for $118.https://www.amazon.com/dp/B07211YWMK/?coliid=I2O57QZ8UL22HY&colid=1HESTW5KSW54&ref_=list_c_wl_lv_ov_lig_dp_it&th=1This UNI-T UTG962E *might* be middle of the road for $180.https://www.amazon.com/UTG962E-Function-Arbitrary-Generator-Frequency/dp/B0BZVDFDD5?ref_=pd_ci_mcx_mh_pe_im_d1_hxwPPE_sspa_dk_det_cai_p_33_1&pd_rd_i=B0BZVDFDD5&pd_rd_w=gPYE3&content-id=amzn1.sym.12ce0654-ac91-4fa7-a6f7-4f4b7e1b273b&pf_rd_p=12ce0654-ac91-4fa7-a6f7-4f4b7e1b273b&pf_rd_r=GY8CF80YPKQBW90TT1KW&pd_rd_wg=ffms9&pd_rd_r=c721c003-04ec-4447-83b0-6cd1d9ace50e

author: KungFuJosh
author_rank: Super Contributor
timestamp: August 20, 2025, 12:25:16 am
content: Quote from: rpschultz13 on August 19, 2025, 11:41:31 pmFor audio needs you probably want better quality output than the models you're looking at. I'd try to find a used SDG2042X or the new SDG1000X Plus series (both series are 16 bit). You can do Bode plots using your Siglent scope with any Siglent AWG, but you're better off with the models that have an X.While you can trick some other AWGs into working with Siglent Bode plots, it's easier if you can budget the Siglent AWG.

author: shabaz
author_rank: Frequent Contributor
timestamp: August 20, 2025, 12:37:58 am
content: Hi,I don't know much about these other signal generators, but from a quick glance the Uni-T has half the sample length, although it's very useful to have two channels. The Koolertron model has a quarter of the sample length capability of the Owon.The SDG800 also supports white noise from what I can tell, but at least you can adjust the standard deviation, and has twice the sample memory for arb waveforms. There is also a SAG1021I which is compatible with your 'scope, and then it's easier to perform frequency response analysis (FRA) using the 'scope (this is possible, but not as straightforward to do with a standalone signal generator). FRA is very useful for applying stimulus to audio amplifiers for instance, and observing the output amplitude and phase, at a range of frequencies, and charting it.A compromise will be needed, i.e. pick a general-purpose signal generator (probably not the Koolertron though, it sounds like a very obscure manufacturer, so you may be on your own if you experience issues) for general electronics and a load of typical audio electronics, and switch to sound card if you cannot generate your desired output for specific audio tests.

author: themadhippy
author_rank: Super Contributor
timestamp: August 20, 2025, 12:56:03 am
content: ya could always build a white and pink noise generator, for examplehttps://sound-au.com/project11.htm

author: rpschultz13
author_rank: Contributor
timestamp: August 20, 2025, 12:57:15 am
content: Don’t think I can justify $300+.The Owon dge2035 is 2ch and 35mhz for $150, not sure if that’s better than the $100 version. It’s probably more on par with the UNI-T.https://a.co/d/3q2mC21

author: tautech
author_rank: Super Contributor
timestamp: August 20, 2025, 01:05:08 am
content: Quote from: rpschultz13 on August 20, 2025, 12:57:15 amWhen fully conversant with the scope you now have and learn how powerful its Bode plot is you might see things different.

author: rpschultz13
author_rank: Contributor
timestamp: August 20, 2025, 01:10:58 am
content: Yes I create bode plots in spice.So you’re saying if I get the $300 generator, I could create bode plots on my scope, from the response through my circuits I’m designing?Generator > my circuit > scope

author: tautech
author_rank: Super Contributor
timestamp: August 20, 2025, 01:30:24 am
content: Quote from: rpschultz13 on August 20, 2025, 01:10:58 amYup but even better, you can prove your designs.

author: rpschultz13
author_rank: Contributor
timestamp: August 20, 2025, 01:35:23 am
content: So what can a siglent generator do that the Owon can’t?

author: themadhippy
author_rank: Super Contributor
timestamp: August 20, 2025, 01:47:15 am
content: Quotewith a bit of fiddling most dual channel signal generators can be used with a scope to produce a bode plot,1 channel for the frequency sweep and the second to trigger the scope

author: tautech
author_rank: Super Contributor
timestamp: August 20, 2025, 01:51:49 am
content: Quote from: rpschultz13 on August 20, 2025, 01:35:23 amInterface directly with your scope which takes control of the AWG when in Bode plot mode.Just Plug and Play.

author: KungFuJosh
author_rank: Super Contributor
timestamp: August 20, 2025, 02:04:50 am
content: And I already made a pink noise waveform that works on the SDG2042X, and I think I posted it in its thread.

author: rpschultz13
author_rank: Contributor
timestamp: August 20, 2025, 02:24:08 am
content: Ok I’m convinced. So the question is will the SDG810 for $275 do what I need for audio design? Or do I need the SDG1022X+ for $424?A quick AI probe suggests I might need a 2 channel AWG.This siglent application note suggests the sdg800 1ch will work to create a bode plot connected via USB.https://siglentna.com/application-note/bode-plot-filter-oscilloscope-generator/

author: rpschultz13
author_rank: Contributor
timestamp: August 20, 2025, 03:02:16 am
content: I’ll probably save my Penny’s and spring for the SDG1022x+.One of my questions, in testing my guitar preamp pedal… the input impedance is 1M, while output impedance is less, maybe 10-100k. Do I need some sort of impedance between my DUT and my AWG or scope?

author: tautech
author_rank: Super Contributor
timestamp: August 20, 2025, 06:17:19 am
content: Quote from: rpschultz13 on August 20, 2025, 03:02:16 amGood choice.For some examples what Bode plot can offer see these old posts using SDS1000X-E but the 800X HD is more refined.https://www.eevblog.com/forum/testgear/siglent-sds1204x-e-released-for-domestic-markets-in-china/msg1435854/#msg1435854https://www.eevblog.com/forum/testgear/siglent-sds1204x-e-released-for-domestic-markets-in-china/msg1436912/#msg1436912For levels to be correct impedance adjustments need be made. and you have those options.

author: egonotto
author_rank: Super Contributor
timestamp: August 20, 2025, 06:18:35 am
content: Quote from: rpschultz13 on August 20, 2025, 01:35:23 amHello,Siglent has 16 bits, while Owon only has 14 bits.With Siglent and your SDS804XHD, you can use Bode Plot.The Siglent SDG1022X Plus has 8 Mpts of memory for True Arb Mode.This allows you to generate many waveforms, including pink noise or guitar sounds.Many generators, including Owon and Siglent, have an output impedance of 50 ohms.Since cables have a capacitance, the input impedance forms a filter. This should be taken into account.There is a good YouTube channel in German that might still be of interest to you:https://www.youtube.com/@physik-der-elektrogitarreBest regardsegonotto

author: rusoaie
author_rank: Contributor
timestamp: August 20, 2025, 07:05:12 am
content: Hello, just putting a few "multi-purpose" or "jack of all trades" of sig-gen+scope combo on the table:- USB audio interface- Digilent Analog Discovery (newer "3" model, or second-hand older versions)- if you don't own an oscilloscope yet and you want to skip a few "upgrades", you can check out 12bit oscilloscopes with included 1CH or 2CH signal generator: Rigol DHO900s, Rigol MHO2000, Siglent SDS2000X etc.- any signal generator that has arbitrary waveform can do noise or pink noise, you just need to create the signal yourselfSome benefits of and USB audio interface over a dedicated sig-gen+scope if you are ONLY doing audio design/repairs:- lower noise-floor- lower distortion levels- wider dynamic range, typical 10's of uV to 10's of volts (-100dBu to +21dBu or even +24dBu)- differential outputs (can be also used as single-ended)- differential inputs (can be also used as single-ended)- multiple inputs and multiple outputs: can be used either as a mixer or to generate or measure more than 2/4 signals at the same time- included headphone amplifier- extended frequency response to 96kHz using 192k sampling rate makes it also useful for sensor experiments and much more- High-gain (60-80dB) microphone inputs also useful when testing low level signals such as microphones, preamps and phono cartriges- has both ADC and DAC: works as a signal generator, basic oscilloscope, low noise and low distortion signal/spectrum analyser- Works as a Bode plotter, Frequency Response Analyser and Audio Analyser down to -100dB THD+N using REW or other similar free software- supports scripting for both inputs and outputs (yes, pink noise can be generated additionally to any arbitrary signal)- some of them have MIDI in/out - also useful when troubleshooting pro audio synths/keyboards- some of them have digital inputs and outputs - useful when troubleshooting DAC's, ADC's, CD players, AV recievers etc.- can be used as a general purpose audio interface: high-quality playback, recording voice, recording instruments, keyboards, podcasting, vlogging etc.Downsides of an USB audio interface compared with a traditional Signal Generator+Oscilloscope:- AC coupled- limited to 96kHz bandwidth- cannot be used to measure/probe voltages larger than 20Vpp and DC-coupled signals - you still need an oscilloscope for that- requires a laptop/computer- can create bogus ground loops or noise artifacts when powered from computer's USBLook for Focusrite, MOTU, RME or Universal Audio's entry to mid-level interfaces: Scarlett Solo/2i2/4i4, MOTU M2/M4 etc.Hope this helps,Mihai

author: rpschultz13
author_rank: Contributor
timestamp: August 20, 2025, 12:23:26 pm
content: Quote from: themadhippy on August 20, 2025, 12:56:03 amIt's interesting you quote Rod Elliot. I've talked to him a couple times and I learned a lot from his State Variable Filters pages; my preamp has multiple SVF's.https://sound-au.com/articles/state-variable.htm

author: 2N3055
author_rank: Super Contributor
timestamp: August 20, 2025, 01:39:16 pm
content: Quote from: rusoaie on August 20, 2025, 07:05:12 amRigol scopes with built in AWG look like a good idea until you realize AWG are very limited (compared to external one) and that Rigol Bode plot (FRA analysis) does not work.Also, audio interfaces you mention cost in the area of 200-300 €.In which case, maybe better save up for QuantAsylum and have a proper audio analyser.

author: rpschultz13
author_rank: Contributor
timestamp: August 22, 2025, 12:03:26 am
content: So I bought the Siglent SDG1022x+ from Saelig, might get it Saturday. Thanks for pushing me in the right direction.First thing I’ll do is learn how to do a sine sweep into a bode plot on my SDS804XHD.But how would white or pink noise into a bode plot be different?

author: tautech
author_rank: Super Contributor
timestamp: August 22, 2025, 12:49:11 am
content: Quote from: rpschultz13 on August 22, 2025, 12:03:26 amNothing to learn at all as you set the Bode plot parameters into the scopes Bode plot menu for the scope to take control of the AWG to sweep the frequency range you have already set.FYI Bode plot is more correctly called FRA (frequency response analysis) where traditionally a sine wave is swept over a range and the resultant amplitude displays how your filter impacts on amplitude and at which frequencies.Go back and follow the links I posted before and the screenshots taken.

author: antenna
author_rank: Frequent Contributor
timestamp: August 22, 2025, 02:55:38 am
content: I downloaded a free app on my phone that does 6 kinds of noise, including pink. Its called Frequency Sound Generator by DCZT on Google play store.

author: rpschultz13
author_rank: Contributor
timestamp: August 26, 2025, 11:41:44 pm
content: Holy cow batman, it worked! This is an acoustic guitar preamp circuit that I designed. The plot attached has all the knobs at center except the NOTCH, which is about 300 Hz. The circuit has a built in HPF of 60 Hz or so which is evident.Thanks for all the help! Wo hoo!

author: rpschultz13
author_rank: Contributor
timestamp: August 26, 2025, 11:44:39 pm
content: Not sure why all the images didn't work.

author: tautech
author_rank: Super Contributor
timestamp: August 27, 2025, 12:02:47 am
content: For USB screen captures just use the Save button on the scopes front panel without the need to get into the Save menu and your menus will still be visible.Your setting of Inverted screenshot will remain if you need it to.Loading images to the forum has a few traps but if you use (more attachments) andneverthe 1st attachment not much can go wrong unless you use a wrong filetype.

author: rpschultz13
author_rank: Contributor
timestamp: August 27, 2025, 12:06:35 pm
content: [ Specified attachment is not available ]Just trying to figure out the image thing. Same plot as before only 24 pts/decade instead of 12.