DIY Frequency Generator - Page 1
Forum section: electronics / general

author: MostlyCarbon
author_rank: Newbie
timestamp: May 21, 2011, 07:47:32 pm
content: So I was searching for a DIY Frequency meter... after a couple of links what do I discover but this:http://kitsrus.com/pdf/k101.pdfDesigned by none other than Dave Jones.

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: May 21, 2011, 08:52:51 pm
content: Well it is an 1996 design ..I look forward for the 2011 version of it .Because I found similar modern ones to retail at 250-350 Euros ..And I am not that happy about it.

author: saturation
author_rank: Super Contributor
timestamp: May 21, 2011, 09:08:21 pm
content: Here is Dave's old website with more details.http://www.alternatezone.com/electronics/hsfg.htmAn updated FGhttp://www.alternatezone.com/electronics/dds.htm

author: Zero999
author_rank: Super Contributor
timestamp: May 22, 2011, 02:41:11 pm
content: The problem is a MAX038 is discontinued.It's not too hard to do this yourself. It's pretty easy to build a triangle wave generator and connect it to a waveshaper to get a sinewave

author: Drirr
author_rank: Regular Contributor
timestamp: May 22, 2011, 06:29:12 pm
content: similar to MAX038 is XR2206 but it is not as good as maximYou can get it fron ebay.My function generator with MAX038https://picasaweb.google.com/lh/photo/Xdu0BZAp_WBLtluE6QL8Xw?feat=directlinkhttps://picasaweb.google.com/lh/photo/vVw_ivHASd3q53AeGTA9jQ?feat=directlinkBut I'd rather have DDS

author: toli
author_rank: Frequent Contributor
timestamp: May 23, 2011, 06:45:46 am
content: Any other chips available to replace the Maxim?I wanted to build something like this a few months ago but couldn't find anything that was close to the Maxim spec wise.

author: Mechatrommer
author_rank: Super Contributor
timestamp: May 23, 2011, 07:16:37 am
content: how much is your planned budget?

author: Drirr
author_rank: Regular Contributor
timestamp: May 23, 2011, 07:26:17 am
content: Check it out....http://shop.ebay.com/i.html?_from=R40&_trksid=p5197.m570.l1313&_nkw=MAX038&_sacat=See-All-CategoriesIt is hard to get MAX038 cheaper

author: Mechatrommer
author_rank: Super Contributor
timestamp: May 23, 2011, 07:47:55 am
content: yea! and you are going to need thisand thisand probably this

author: toli
author_rank: Frequent Contributor
timestamp: May 23, 2011, 08:33:03 am
content: Could be a stupid question, but I know there are quite a few fake parts on eBay such as AD8610/20 opamps, OPA627/637, etc.Are you sure there aren't any MAX038 counterfeits?

author: MostlyCarbon
author_rank: Newbie
timestamp: May 23, 2011, 09:27:20 am
content: Can anyone recommend a more recent DIY Function Generator Kit?Sparkfun has a kit based on the XR-2206 but I think the XR-2206 is being discontinued:http://www.exar.com/Files/ChangeNotifications/PDN_11-0112-01-1033.pdf

author: Drirr
author_rank: Regular Contributor
timestamp: May 23, 2011, 09:45:11 am
content: and ICL8308?

author: Zero999
author_rank: Super Contributor
timestamp: May 23, 2011, 04:35:42 pm
content: The ICL8308 went before the MAX038.I don't know if the XR2206 is really discontiniued, it's still sold by RS and Farnell, although the later is US and out of stock.

author: Slobodan
author_rank: Regular Contributor
timestamp: May 23, 2011, 05:10:09 pm
content: I don't think that XR2206 is discontinued either. It is fairly available in Serbia.

author: RCMR
author_rank: Frequent Contributor
timestamp: May 25, 2011, 05:33:57 am
content: If your needs are minimal -- perhaps this might be of some use:http://www.goodluckbuy.com/sg1005-5mhz-signal-generator-source-module-w-dds-function.htmlThe price is right!

author: saturation
author_rank: Super Contributor
timestamp: May 25, 2011, 10:21:59 am
content: While supplies last, consider the Hantek 3x25:http://shop.ebay.com/?_nkw=hantek%203x25&rvr_id=234972903787&clk_rvr_id=234972903787Extensive posts on eevblog, just find the thread.

author: MostlyCarbon
author_rank: Newbie
timestamp: May 25, 2011, 11:52:32 am
content: Here's a release from Exar about the chip.http://www.exar.com/Files/ChangeNotifications/PDN_11-0112-01-1033.pdfThey took the last orders just recently, so get em if you still can !!I wrote MAXIM and it seems the MAX038 was discontinued in 2006:"Good morning, thank you for contacting Maxim.The MAX038 was discontinued in 2006, Maxim does not have direct replacement for this part.For technical applications assistance in choosing an alternated part number please go to the link:http://www.maxim-ic.com/support/"So I guess all MAX038s on Ebay are (mostly) knock-offs? Seems weird that they'd still have stock that old if they were originals.Also, If there were enough demand that they're making a knock-off.. why then wouldn't Maxim keep making the part?(just use the usual looooong lead time)Direct Digital Synthesis seems hard (insert whiney voice). I've yet to check the link just above, wish me luck!

author: slburris
author_rank: Frequent Contributor
timestamp: May 25, 2011, 04:20:35 pm
content: How about this little board as a building block for a generator:0-60Mhz sine waves, make a square ware with a comparator.http://midnightdesignsolutions.com/dds60/index.htmlScott

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: May 25, 2011, 06:01:24 pm
content: I found two MAX038 in my own city in Greece ,it is new old stock ( 10 years back ) at 46 EUR its ...It do not know if it worth even getting them .Do they support adjustable duty cycle in the square waves ?

author: bilko
author_rank: Frequent Contributor
timestamp: May 25, 2011, 06:14:41 pm
content: I think so, but you can do that with a 555 timer chip

author: ElektroQuark
author_rank: Unknown
timestamp: May 26, 2011, 06:47:15 am
content: Analog Devices has present this recently :http://www.analog.com/en/rfif-components/direct-digital-synthesis-dds/ad9837/products/product.html?utm_source=cheetah&utm_medium=email&utm_campaign=11-05-ProcessControl

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: May 26, 2011, 09:36:54 am
content: Quote from: EdoNork on May 26, 2011, 06:47:15 amOn the specs they say : The output frequency and phase are software programmable, allowing easy tuning.This info for me that I am not expert in suchsoftware programmabledevices ,it is by self one good reason so to forget about it, and start running away .

author: A-sic Enginerd
author_rank: Regular Contributor
timestamp: May 26, 2011, 06:18:42 pm
content: Quote from: EdoNork on May 26, 2011, 06:47:15 amI've actually been looking at their AD5932 part as the base for my own home built func gen. Pretty sweet little device. Did a quick basic proto with PIC talking to it just to be sure I understood how to program it (and the PIC also actually.....since it's been about 15 yrs since the last time I used a PIC)I was also looking at the 9833 (similar to the '37 you pointed out). A bit simpler to use. Would be a good start for someone that doesn't want to get as involved with the software side of it. Still requires some programming, but it's pretty straight forward.

author: Zero999
author_rank: Super Contributor
timestamp: May 26, 2011, 09:23:32 pm
content: Quote from: yachtronics on May 25, 2011, 06:14:41 pmNot quite, the MAX038 can go up to 20MHz, a 555 can only make 500kHz, a cheap option for variable duty cycle/frequency square waves is 74HC logic.

author: bilko
author_rank: Frequent Contributor
timestamp: May 26, 2011, 11:01:09 pm
content: Quote from: Hero999 on May 26, 2011, 09:23:32 pmYes, but I don't know any DMM's that can measure duty cycle at 20MHz

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: May 27, 2011, 12:39:44 am
content: Well the truth is that I own one low cost generator , got it as KIT and uses the :2N3819BC546TL082CN from ST electronics.It can do easily 2Hz - 30KHz ( actually 26,500 Hz )Three outputs - Sinusoidal - square - sawFrequency and volume control.I got some tips from an expert in my town,he said that if you use cheaper IC than Max038 , you will need to add few additional circuits ,so to improve the signal , and eliminate harmonics.But those additional improvements , its his own secret and he does not share it.

author: saturation
author_rank: Super Contributor
timestamp: May 27, 2011, 09:15:40 am
content: At least the Agilent 1252a can; but its easier with any DSO, analyzing and viewing waveforms are what its better at.Quote from: yachtronics on May 26, 2011, 11:01:09 pm

author: Zero999
author_rank: Super Contributor
timestamp: May 27, 2011, 04:55:31 pm
content: Quote from: yachtronics on May 26, 2011, 11:01:09 pmWhat's that got to do with it? I don't remember seeing a requirement for your shit DVM being able to measure the output. The duty cycle and frequency can also be calculated using the component values, regardless of whether you're using a 555 timer, a MAX038 or anything else.

author: bilko
author_rank: Frequent Contributor
timestamp: May 27, 2011, 09:18:13 pm
content: Quote from: Hero999 on May 27, 2011, 04:55:31 pmNo need to get personalI don't measure duty cycle wth a DVM, but some readers might. The suggestion was in relation to being to adjust duty cycle on the 038 chips. Nobody specified using a 038, the OP was asking about a cheap function generator

author: Mechatrommer
author_rank: Super Contributor
timestamp: May 27, 2011, 09:36:49 pm
content: Quote from: yachtronics on May 27, 2011, 09:18:13 pmno. he was asking thediyfunction generator that turn out the part to be obsolete.

author: Zero999
author_rank: Super Contributor
timestamp: May 27, 2011, 09:40:27 pm
content: A part which just so happened to be the MAX038. Iit was nothing personal, the 555 won't cut the mustard at that frequency and it can't output a sinewave, the only way is to filter the output but that's frequency sensitive.

author: bilko
author_rank: Frequent Contributor
timestamp: May 27, 2011, 09:41:40 pm
content: Quote from: MostlyCarbon on May 21, 2011, 07:47:32 pmOk, I was wrong, he did not ask about a CHEAP function generator...

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: May 28, 2011, 12:45:35 am
content: Quote from: Mechatrommer on May 27, 2011, 10:20:35 pmCould be , but you forgot that you need an oscilloscope first , before you even start ..Add this too, in the total bill ..

author: Mechatrommer
author_rank: Super Contributor
timestamp: May 28, 2011, 11:09:45 am
content: Quote from: Kiriakos-GR on May 28, 2011, 12:45:35 amyes its an expensive initial investment. it will be a waste if you plannig 1 or 2 project only. but diying 100 projects can save you alot later. off topic

author: Zero999
author_rank: Super Contributor
timestamp: May 29, 2011, 10:15:04 pm
content: The topic has moved on a bit.If all that's required is a cheap and easy low frequency function generator (1Hz to 100kHz or so). It should be easy to build with common jelly bean parts. Attached is a simple triangle to sine wave shaper. A triangle wave generator can be easily be made using an LM393, the wave shaper can use something like the TL082 and if a low impedance output is required, the LM386 can be used as a buffer.