Review of dirt cheap chinese "UD-B DDS" freq gen, off from eBay

[Mashpriborintorg]

Hi, I got this dirt cheap frequency generator, and I believe such an unusual weird thing deserves a review.

Pros:

- Dirt cheap (45 euros including delivery),  and yeah it makes a signal as far as I can see
- Built quality is cost effective but not too catastrophic, actually I was expecting something worse
- Good BNC sockets, and good Arduino compatible LCD panel.
- Came with a decent quality USB powerbrick and BNC to crocodile cord, which are always handy to have.
- Frequency, up to 2MHz can be set digit by digit
- Probably enough for basic hobby use


Cons:

- Came raw in a air bubble enveloppe, without retail box, without user manual
- User interface is minimalist and not so convenient
- The rotary buttons are not easy to set, no readout of the offset and amplitude, oscilloscope needed for it
- Provided USB cord was not the correct kind for the device !!! but seems to be ok for an Arduino, at least
- Lack of functions
- Lack of a hi-stability oscillator, seems it runs from a regular quartz
- Square wave shows ripple above 1 MHz
- It's not a Tek or a HP :-p

Here are the photos:

[T4P]

Altera Max ! 

[cybergibbons]

That looks like some fairly strong ringing on the square wave...

[alm]

Does terminating the output into 50 ohm at the scope end reduce the ringing?

[Kozmyk]

I bought one last year - UDB1105 5MHz with Sweep
It's OK up to around 1MHz. After that it gets noisy and ringy.
Terminating the line did nothing for me.

The sweep on mine has a fixed range. I'll have to fire it up to check the start/end points.
Has it's uses though (audio injection)

Now the Hantek DDS-3x25 - that does the business (with the Goltek software) 

[Kozmyk]

at least good to know it has some use

Credit where it's due.