EMRFD Message Archive 11764

Message Date From Subject
11764 2015-10-12 09:16:53 lawrence_joy Function Generator

Has anyone duplicated or attempted to build "A Simple yet Precise Function Generator for the Experimenter" by Rubens Fernandes, VK5FE, that appeared in the 2013-05/06 issue of QEX? Or should I look in my 2015 ARRL Handbook or online for something else? Comments?


73 de 9V1MI/WN8P, Larry

11765 2015-10-12 10:28:54 David J Nushardt Re: Function Generator
Yeah, but it's been awhile, there used to be a xr 2206 function generator on a chip , not sure if they are still available, try Jamco there was a kit for that, Also through Jamco Vellerman kits come to mind.

Dave N9OOQ

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11768 2015-10-12 12:00:09 Jim Strohm Re: Function Generator
Alas, Exar EOL-ed this interesting chip in 2011.  It appears that some are still available on fleabay, but "caveat emptor."

73
Jim N6OTQ

11769 2015-10-12 13:11:41 Rod Re: Function Generator
Larry,

This may be of interest to you:

https://www.sparkfun.com/products/11420

Also, Using a resistor R2R network (available from Digikey) , one can do
arbitrary
waveform generation with 8 bit D/A resolution. I found an article online
(don't have
an immediate reference- try googling) with open source software, and it
has been on my to-do list.

Rod KM6SN
11775 2015-10-13 07:03:21 lawrence_joy Re: Function Generator

Rod, I looked at that Sparkfun project before when I was looking around. It does go to 3 MHz but the output has a dc offset of Vcc/2 and the output amplitude is 1 V pp. Neither of these parameters is adjustable or variable. I suppose I could add external circuitry, but I don't want to dink with it at this time.


I generally don't find what I am looking for when doing Internet searches. I either put too much information in, not enough, not in the proper order, or not the right words. So, if you find the article of "arbitrary waveform generation with 8 bit D/A resolution with open source software" please let me know. I can be reached at the e-mail address given

11780 2015-10-14 15:27:05 kerrypwr Re: Function Generator
The ICL8308 is a classic function-generator-on-a-chip.

Although obsolete they seem to be readily available at low cost.

Maximum frequency is about 200kHz or about 20kHz with only moderate distortion; I think that that is about right for a function generator which is not a true RF signal generator.

The data sheet (go to http://www.intersil.com) and search for 8038)  contains suggested circuits and there are many on the 'net; this one, picked at random, looks useful.

http://electronics-diy.com/electronic_schematic.php?id=112

Kerry VK2TIL.

11781 2015-10-14 21:57:33 arfghans Re: Function Generator
I'll put in another vote for the 8038 as a basic function generator. Very easy to apply. Just add range switching and an output amp/attenuator. THD is ok for anything but critical distortion measurements. I built such an instrument while in high school in the 70s and it served me well for decades. No computer required :-)

By the way, that chip was designed by the great Hans Camenzind, the guy who also brought us the 555. 

Gary, NA6O
11782 2015-10-15 08:55:30 Riccardo Montagut... Re: Function Generator
What about the MAX038? It's a 0.1Hz-20mhz and can output sine, triangle, sawtooth, square and ttl waveforms! 

I would like to try it, does someone has already tried it?


Riccardo

Inviato da iPhone

Il giorno 15/ott/2015, alle ore 06:57, gwj@wb9jps.com [emrfd] <emrfd@yahoogroups.com> ha scritto:

 

I'll put in another vote for the 8038 as a basic function generator. Very easy to apply. Just add range switching and an output amp/attenuator. THD is ok for anything but critical distortion measurements. I built such an instrument while in high school in the 70s and it served me well for decades. No computer required :-)


By the way, that chip was designed by the great Hans Camenzind, the guy who also brought us the 555. 

Gary, NA6O

11785 2015-10-15 12:54:38 Todd F. Carney / ... Re: Function Generator
11786 2015-10-15 13:00:22 Dana Myers Re: Function Generator
11842 2015-10-24 10:05:23 lawrence_joy Re: Function Generator
To all of those who responded to my request, thank you. It appears that all of the analog function generator ICs have gone the way of the slide rule and digital techniques prevail. I have decided to build the classic Wein Bridge opamp sinusoidal waveform, multi-frequency, audio frequency generator out of my 2015 ARRL Handbook, with some modifications.

73 de 9V1MI/WN8P, Larry
11843 2015-10-24 20:16:18 David J Nushardt Re: Function Generator

Sounds good, along the lines of the classic wein bridge design ,I saw a article in a book by a famous analog design engineer , who is no longer with us , but his books and application notes so are, forgive me I'm blanking on his name, he worked for Linear Technologies.

He designed a modern ultra low distortion version of the classic hp wein bridge oscillator,as I recall the parts will run about 60- 80 bucks but it's ultra  low distortion, its quite a  project.
I believe the diagram is on the web in pdf. For free, you will have to do some searching for it.

Sorry my brain is not cooperating, I had two strokes and cml leukemia, maybe someone can help me with the name Jim comes to mind, and the book the article is from, both the designer and  the circuit is famous.  Can someone help me, to recall this, Jim Williams is his name just clicked in  but he has several not so cheap analog design books , I'm still having trouble recalling the book I seen this moder version of the classic hp wein bridge Oscillator in.

73's best of luck.
Dave
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11844 2015-10-24 20:31:28 n2msqrp Re: Function Generator
Dave,

You are correct. Jim Williams was an Application Engineer for Linear Devices. Here is information about his book:

<http://www.linear.com/designtools/acd_book.php>

Ironically, Jim did not bother getting and Engineering degree but worked in the MIT Instrumentation Lab to learn his trade.

I first learned about him when he wrote an excellent series of articles about temperature measurements in EDN magaine in the 1970's.

I still have those articles stashed away in my file cabinet.

Mike N2MS


----- Original Message -----
11845 2015-10-24 22:06:58 David J Nushardt Re: Function Generator

Yes, jim williams, but the books I'm talking about are the ones Amazon has  he also wrote numerous application notes available on the web by searching for Jim Williams application notes, the actual article I'm talking about was a modern version of the hp 200C oscillator , I think, he scribbled a schematic using all LT parts and modern components , it was his version of the hp 200 c oscillator, using modern mostly  available components, the only thing was a opto isolator that was a little difficult to find.
Thanks!
73's Dave

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11846 2015-10-24 22:17:12 David J Nushardt Re: Function Generator

I found it, just google, Jim Williams version of the hp oscillator. Its a very interesting article.
Dave

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