Any good reason for function generator to start off as low as 10 hz? - Page 1
Forum section: electronics / beginners

author: mike3177
author_rank: Contributor
timestamp: July 26, 2016, 03:05:22 pm
content: I'm looking into getting a function generator. I would like to get a pretty decent one that has the ability to be a pulse generator, do square waves, triangles and basically anything you would expect to get out of a good function generator.One of my machines suggests a 10hz to 20 mhz function generator as one of the units needed for calibration. But I am looking at a function generator that is rated 10mhz to 50mhz and seems to be pretty good, but I am concerned that I am missing out on something since the lowest setting is 10mhz?Is there any reason why I would want to get a fun gen that goes as low as 10hz or so? If so then what would you suggest I do... get 2 different units?

author: suicidaleggroll
author_rank: Super Contributor
timestamp: July 26, 2016, 03:10:15 pm
content: Please use the correct abbreviations for SI units, case matters.m = milli = 1e-3M = mega = 1e6When you say "10mhz", do you really mean 10 mHz (.01 Hz), or 10 MHz (10,000,000 Hz)? A function generator that can't go below 10 MHz wouldn't be much use for a general purpose lab instrument, but 10 mHz is fine.As for the question in your thread title, yes a function generator that could go down to 10 Hz could be quite useful, especially if you ever get into audio work. If you never do anything but HF/VHF, then I suppose 10 MHz - 50 MHz would be alright, but that's very limiting.

author: German_EE
author_rank: Super Contributor
timestamp: July 26, 2016, 06:30:46 pm
content: Low frequency signals such as 10Hz could be very useful for testing electro-mechanical items.

author: Brumby
author_rank: Unknown
timestamp: July 27, 2016, 01:12:55 am
content: The question is more easily answered if you can provide us with an idea of the type of applications you would be using it for. Audio would be well served by 10Hz to 50kHz. Electromechanical (at a guess) 0.1Hz to 1kHz(?)For RF, it depends on where you want the top end to be.We really need to have an idea of what you're going to be doing with it.

author: tautech
author_rank: Super Contributor
timestamp: July 27, 2016, 01:58:56 am
content: Quote from: mike3177 on July 26, 2016, 03:05:22 pmI think you're getting confused with specs.10 mhz is correctly spoken as 10 milli Hertz but written as 10 mHz or 10/1000 th of a second.BUT some of the more obscure manufacturers might have incorrectly used "m" when they should have used "u" indicating micro not milli. Traps for the unaware abound all over the internet.Hertz is always correctly referred to as Hz and theappropriatemultiplier or divider added as a prefix.Why do FG's have such low frequencies?There are many examples of use at repetition rates slower than 1 second.I've needed it for glue logic development on several occasions.A popular unit at the moment is the Siglent SDG2042X (40 MHz), it's the lowest BW model in the SDG2000X series that has models to 120 MHz.http://www.siglentamerica.com/pdxx.aspx?id=1364&T=2&tid=16There's a growing thread on them too:https://www.eevblog.com/forum/testgear/the-siglent-sdg2042x-thread/Cheaper options are 2 channel SDG1000 serieshttp://www.siglentamerica.com/pdxx.aspx?id=145&T=2&tid=16Thread:https://www.eevblog.com/forum/testgear/the-sdg1000-and-sdg800-thread/And the even more basic single channel SDG800 series;http://www.siglentamerica.com/pdxx.aspx?id=71&T=2&tid=16All the Siglent generators have a slowest repetition rate spec of 1 uHz.The trick is choosing one that best meets your budgetnowbut allows for future needs.Feel free to ask the forum for further advice.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: July 27, 2016, 03:13:18 am
content: I've used my (analog) function generator below 0.1Hz before. Good for generating sweeps.Tim

author: Paul Moir
author_rank: Frequent Contributor
timestamp: July 27, 2016, 03:20:51 am
content: I recently used mine to simulate the signal from a sensor in a tank that had a stirrer that turned about 1 RPM. A lot handier developing that software on the desk than in production!I'm worried that if it is a 10MHz-50MHz generator, it might be an RF generator rather than a function generator. If so, it's much less useful for non-radio stuff.

author: edp
author_rank: Contributor
timestamp: July 27, 2016, 03:31:01 am
content: My kids have used my el-cheapo to blink LEDs at low frequencies. With sine, square, and triangle waveforms. IKR.... hours of fun.

author: MarkF
author_rank: Super Contributor
timestamp: July 27, 2016, 04:12:37 am
content: You might want to consider the Owon AG101F 10MHz Waveform Generator from Saelig. The Owon Waveform Generators has a good review here on the EEVblog site (Very detailed review of all settings). Go to the Saelig site for higher bandwidths and single or dual channels.

author: mike3177
author_rank: Contributor
timestamp: July 28, 2016, 11:22:01 am
content: Thank you everyone for the replies. It turns out I am an idiot and the one I was looking at is 10 mHz (not 10 MHz) to 50 MHz which makes a lot more sense.I will let you guys know which model I end up going with, thanks for the recommendations.