Forums

Looking for a DDS module 10kHz-1MHz, 2Vrms sine into 50ohms

Started by Joerg February 2, 2013
On Feb 3, 4:56=A0pm, Joerg <inva...@invalid.invalid> wrote:
> langw...@fonz.dk wrote: > > On Feb 3, 4:29 pm, Joerg <inva...@invalid.invalid> wrote: > >> langw...@fonz.dk wrote: > >>> On Feb 3, 2:50 am, Joerg <inva...@invalid.invalid> wrote: > >>>> For a tester project I need a DDS source, should be a module but wit=
h
> >>>> some decent output power and if possible a display. SPI or RS232 sty=
le
> >>>> control would be nice. So far I only found this kind: > >>>>http://www.amazon.com/SG1005-Signal-Generator-Source-Function/dp/B008=
...
> >>>> Some comments are not so enthusing though:http://www.elecfreaks.com/=
279.html
> >>>> Can't find a manual for it or any decent info. Does anyone know wher=
e,
> >>>> or has a suggestion for a better module? Need 10kHz to 1MHz (higher > >>>> would be nice) range, 2Vrms or so sine wave into a 50ohms load. Pric=
e is
> >>>> not so important, can be $100/module. > >>>> Hacking is no problem, for example to get around a RS232/USB chip > >>>> because I can't really use USB. Sine wave quality doesn't have to be > >>>> super stellar, slight distortion would be ok. But I can't use a big =
boxy
> >>>> function generator since it has to be integrated in the tester. > >>>> -- > >>>> Regards, Joerg > >>>>http://www.analogconsultants.com/ > >>>https://www.sparkfun.com/products/9169? > >>> you'd need a buffer but you said you didn't mind a bit of hacking > >> Then I might a well just buy the bare chip, it's cheaper :-) > > > but then you'll need a pcb, xtal regulator, etc. and have to build it > > with this you just need a buffer amp. You don't have something laying > > around with ~3-4x gain that can drive 50R? > > Oh, I can build it, just a simple amp. But another board to be roached > in. If it has to be that way then so be it. I'd also have to build an > LCD module, plus some sort of encoder for local control. >
I see, if you don't have anything to control it with then it is a bit more work than just a buffer how about something like this: http://imall.iteadstudio.com/im120723003.htm= l open source hard and software, even comes with a programmer if you want to do you own software -Lasse
langwadt@fonz.dk wrote:
> On Feb 3, 4:56 pm, Joerg <inva...@invalid.invalid> wrote: >> langw...@fonz.dk wrote: >>> On Feb 3, 4:29 pm, Joerg <inva...@invalid.invalid> wrote: >>>> langw...@fonz.dk wrote: >>>>> On Feb 3, 2:50 am, Joerg <inva...@invalid.invalid> wrote: >>>>>> For a tester project I need a DDS source, should be a module but with >>>>>> some decent output power and if possible a display. SPI or RS232 style >>>>>> control would be nice. So far I only found this kind: >>>>>> http://www.amazon.com/SG1005-Signal-Generator-Source-Function/dp/B008... >>>>>> Some comments are not so enthusing though:http://www.elecfreaks.com/279.html >>>>>> Can't find a manual for it or any decent info. Does anyone know where, >>>>>> or has a suggestion for a better module? Need 10kHz to 1MHz (higher >>>>>> would be nice) range, 2Vrms or so sine wave into a 50ohms load. Price is >>>>>> not so important, can be $100/module. >>>>>> Hacking is no problem, for example to get around a RS232/USB chip >>>>>> because I can't really use USB. Sine wave quality doesn't have to be >>>>>> super stellar, slight distortion would be ok. But I can't use a big boxy >>>>>> function generator since it has to be integrated in the tester. >>>>>> -- >>>>>> Regards, Joerg >>>>>> http://www.analogconsultants.com/ >>>>> https://www.sparkfun.com/products/9169? >>>>> you'd need a buffer but you said you didn't mind a bit of hacking >>>> Then I might a well just buy the bare chip, it's cheaper :-) >>> but then you'll need a pcb, xtal regulator, etc. and have to build it >>> with this you just need a buffer amp. You don't have something laying >>> around with ~3-4x gain that can drive 50R? >> Oh, I can build it, just a simple amp. But another board to be roached >> in. If it has to be that way then so be it. I'd also have to build an >> LCD module, plus some sort of encoder for local control. >> > > I see, if you don't have anything to control it with then it is a bit > more work than just a buffer > > how about something like this: http://imall.iteadstudio.com/im120723003.html > > open source hard and software, even comes with a programmer if you > want to > do you own software >
Thanks! That looks like a very good candidate. Not sure why it needs 4W of power but I can supply that. The display looks like the one on my Nokia phone so should have a backlight. If not we'll just supply flashlights :-) I don't like that open coil switcher inductor, makes for lots of EMI. But this my home turf so I can deal with that. -- Regards, Joerg http://www.analogconsultants.com/
Joerg wrote:
> langwadt@fonz.dk wrote: >> On Feb 3, 4:56 pm, Joerg <inva...@invalid.invalid> wrote: >>> langw...@fonz.dk wrote: >>>> On Feb 3, 4:29 pm, Joerg <inva...@invalid.invalid> wrote: >>>>> langw...@fonz.dk wrote: >>>>>> On Feb 3, 2:50 am, Joerg <inva...@invalid.invalid> wrote: >>>>>>> For a tester project I need a DDS source, should be a module but with >>>>>>> some decent output power and if possible a display. SPI or RS232 style >>>>>>> control would be nice. So far I only found this kind: >>>>>>> http://www.amazon.com/SG1005-Signal-Generator-Source-Function/dp/B008... >>>>>>> Some comments are not so enthusing though:http://www.elecfreaks.com/279.html >>>>>>> Can't find a manual for it or any decent info. Does anyone know where, >>>>>>> or has a suggestion for a better module? Need 10kHz to 1MHz (higher >>>>>>> would be nice) range, 2Vrms or so sine wave into a 50ohms load. Price is >>>>>>> not so important, can be $100/module. >>>>>>> Hacking is no problem, for example to get around a RS232/USB chip >>>>>>> because I can't really use USB. Sine wave quality doesn't have to be >>>>>>> super stellar, slight distortion would be ok. But I can't use a big boxy >>>>>>> function generator since it has to be integrated in the tester. >>>>>>> -- >>>>>>> Regards, Joerg >>>>>>> http://www.analogconsultants.com/ >>>>>> https://www.sparkfun.com/products/9169? >>>>>> you'd need a buffer but you said you didn't mind a bit of hacking >>>>> Then I might a well just buy the bare chip, it's cheaper :-) >>>> but then you'll need a pcb, xtal regulator, etc. and have to build it >>>> with this you just need a buffer amp. You don't have something laying >>>> around with ~3-4x gain that can drive 50R? >>> Oh, I can build it, just a simple amp. But another board to be roached >>> in. If it has to be that way then so be it. I'd also have to build an >>> LCD module, plus some sort of encoder for local control. >>> >> I see, if you don't have anything to control it with then it is a bit >> more work than just a buffer >> >> how about something like this: http://imall.iteadstudio.com/im120723003.html >> >> open source hard and software, even comes with a programmer if you >> want to >> do you own software >> > > Thanks! That looks like a very good candidate. Not sure why it needs 4W > of power but I can supply that. The display looks like the one on my > Nokia phone so should have a backlight. If not we'll just supply > flashlights :-) > > I don't like that open coil switcher inductor, makes for lots of EMI. > But this my home turf so I can deal with that. >
Someone demo'ed it on Youtube: https://www.youtube.com/watch?v=_yEtQFMJdtU Looks nice. The frequency dialing is weird through. CCW makes it go up, maybe the programmer is also designing faucets :-) I guess since the firmware is open one can correct for oddities like that. A bit concerning is the frequency instability mentioned here but that may have to do with the switch mode converter on there: http://blog.tkjelectronics.dk/2011/09/review-iemp-v1-0-simple-arduino-dds-signal-generator/ Instability is a showstopper for me but hopefully it's just a minor screw-up that can be corrected. -- Regards, Joerg http://www.analogconsultants.com/
On Feb 3, 5:29=A0pm, Joerg <inva...@invalid.invalid> wrote:
> Then I might a well just buy the bare chip, it's cheaper :-)
Q: What did Joerg say to his girlfriend at the restaurant teble when they went out together to dine on the Valentine's? A: "What would you like to order, my sweet dear little fattie?" Regards, Mikko
On Sat, 02 Feb 2013 17:50:59 -0800, Joerg wrote:

> For a tester project I need a DDS source, should be a module but with > some decent output power and if possible a display. SPI or RS232 style > control would be nice. So far I only found this kind: > > http://www.amazon.com/SG1005-Signal-Generator-Source-Function/dp/
B008N7M5KU/ref=sr_1_1?ie=UTF8&qid=1359855256&sr=8-1&keywords=SG1005+DDS
> > Some comments are not so enthusing though: > http://www.elecfreaks.com/279.html > > Can't find a manual for it or any decent info. Does anyone know where, > or has a suggestion for a better module? Need 10kHz to 1MHz (higher > would be nice) range, 2Vrms or so sine wave into a 50ohms load. Price is > not so important, can be $100/module. > > Hacking is no problem, for example to get around a RS232/USB chip > because I can't really use USB. Sine wave quality doesn't have to be > super stellar, slight distortion would be ok. But I can't use a big boxy > function generator since it has to be integrated in the tester.
There are some DDS modules that are popular for amateur radio work; you may want to search around using terms like "QRP" and "transmitter" or "QRP" and "local oscillator". I know there's at least one QRP transmitter that uses a DDS as its oscillator; that should give you 1 to 5 watts out, with perhaps a need to modify an output filter to get down to the lower frequency you want. -- My liberal friends think I'm a conservative kook. My conservative friends think I'm a liberal kook. Why am I not happy that they have found common ground? Tim Wescott, Communications, Control, Circuits & Software http://www.wescottdesign.com
Tim Wescott wrote:
> On Sat, 02 Feb 2013 17:50:59 -0800, Joerg wrote: > >> For a tester project I need a DDS source, should be a module but with >> some decent output power and if possible a display. SPI or RS232 style >> control would be nice. So far I only found this kind: >> >> http://www.amazon.com/SG1005-Signal-Generator-Source-Function/dp/ > B008N7M5KU/ref=sr_1_1?ie=UTF8&qid=1359855256&sr=8-1&keywords=SG1005+DDS >> Some comments are not so enthusing though: >> http://www.elecfreaks.com/279.html >> >> Can't find a manual for it or any decent info. Does anyone know where, >> or has a suggestion for a better module? Need 10kHz to 1MHz (higher >> would be nice) range, 2Vrms or so sine wave into a 50ohms load. Price is >> not so important, can be $100/module. >> >> Hacking is no problem, for example to get around a RS232/USB chip >> because I can't really use USB. Sine wave quality doesn't have to be >> super stellar, slight distortion would be ok. But I can't use a big boxy >> function generator since it has to be integrated in the tester. > > There are some DDS modules that are popular for amateur radio work; you > may want to search around using terms like "QRP" and "transmitter" or > "QRP" and "local oscillator". >
I looked in that market and most of the DDS are quite deeply embedded in a transceiver or receiver. Like this: http://www.nikkemedia.fi/juma-tx1/ I have even seen a DDS synthesizer in a tube amplifier somewhere.
> I know there's at least one QRP transmitter that uses a DDS as its > oscillator; that should give you 1 to 5 watts out, with perhaps a need to > modify an output filter to get down to the lower frequency you want. >
The filter usually doesn't have to be adjusted in a DDS unless the master clock or something like that is changed. -- Regards, Joerg http://www.analogconsultants.com/
On 2/3/2013 2:18 PM, Mr Stonebeach wrote:
> On Feb 3, 5:29 pm, Joerg <inva...@invalid.invalid> wrote: >> Then I might a well just buy the bare chip, it's cheaper :-) > > Q: What did Joerg say to his girlfriend at the restaurant > teble when they went out together to dine on the Valentine's? > > > > > > > > > > A: "What would you like to order, my sweet dear little fattie?" > > Regards, > Mikko >
Of course, in Finland sausage is considered a vegetable. ;) Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 USA +1 845 480 2058 hobbs at electrooptical dot net http://electrooptical.net
On 3.2.13 10:55 , Phil Hobbs wrote:
> > Of course, in Finland sausage is considered a vegetable. ;) > > Cheers > > Phil Hobbs >
Yep. The leading brand is HK Blue. But it is damn good when roasted on a stick like marshmallows in the big West. -- -Tauno
Tauno Voipio wrote:
> On 3.2.13 10:55 , Phil Hobbs wrote: >> >> Of course, in Finland sausage is considered a vegetable. ;) >> >> Cheers >> >> Phil Hobbs >> > > Yep. The leading brand is HK Blue. > > But it is damn good when roasted on a stick like > marshmallows in the big West. >
Have you ever tried Johnsonville Brats? (Bratwurst). Roasted over a wood fire, outdoors, yumm. I could eat 3-4 in a row but of course that's not healthy so I restrict myself to one. Nothing better than standing around the fire with a beer in hand, discussing politics, cars and football :-) -- Regards, Joerg http://www.analogconsultants.com/