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

[Joerg]

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...TF8&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.

 

[[email protected]]

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.

https://www.sparkfun.com/products/9169 ?

you'd need a buffer but you said you didn't mind a bit of hacking


-Lasse

 

[Jon Kirwan]

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...TF8&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.

http://www.ebay.com/itm/DDS-LCD1602..._Measurement_Equipment_ET&hash=item43b0446aa6

Several kinds of outputs, 50 ohm, ttl, etc. Even has a knob
and comes with power, too. But since it is Hong Kong, I'd
write and make sure they know it's going to 60Hz, 110VAC so
they provide the RIGHT part with it.

Jon

 

[Jon Kirwan]

http://www.ebay.com/itm/DDS-LCD1602..._Measurement_Equipment_ET&hash=item43b0446aa6

Several kinds of outputs, 50 ohm, ttl, etc. Even has a knob
and comes with power, too. But since it is Hong Kong, I'd
write and make sure they know it's going to 60Hz, 110VAC so
they provide the RIGHT part with it.

Jon

Ah. Crap. Looks like the SAME unit!!

hehe. Sorry, Jörg.

Jon

 

[Joerg]

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

 

[Joerg]

http://www.ebay.com/itm/DDS-LCD1602..._Measurement_Equipment_ET&hash=item43b0446aa6

Several kinds of outputs, 50 ohm, ttl, etc. Even has a knob
and comes with power, too. But since it is Hong Kong, I'd
write and make sure they know it's going to 60Hz, 110VAC so
they provide the RIGHT part with it.

That seems to be the very same module as in my link. It comes under all
sorts of part numbers and names.

What I (so far) have not found is any useful documentation about these
boards.

 

[Joerg]

B008N7M5KU/ref=sr_1_1?ie=UTF8&qid=1359855256&sr=8-1&keywords=SG1005+DDS

Not sure if it fits your needs (no display) but on Ebay there are lots of
cheap AD9850 or AD9851 based modules starting at less than $5.
Source code for programming can be easily found around the net.

Yes, those can be bought everywhere. But no LCD, no output buffer amp,
bare bones. Those are almost like buying the bare chip. I am looking for
something I can screw into a tester and have some local control as well.

Worst case I'll have to order a module like in my link and reverse
engineer it so I can arrive at a hack that makes it work in our tester.

 

[[email protected]]

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?


-Lasse

 

[Joerg]

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.

 

[[email protected]]

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


-Lasse

 

[Joerg]

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.

 

[Joerg]

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:

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.

 

[Mr Stonebeach]

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

 

[Joerg]

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.

 

[Tauno Voipio]

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.

 

[Joerg]

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