STEMlab 122.88-16 - DC coupled version

Have an idea? Post it here! - Looking for developers? Ask here as well!
Post Reply
fbalakirev
Posts: 41
Joined: Thu Sep 03, 2015 6:56 pm

STEMlab 122.88-16 - DC coupled version

Post by fbalakirev » Tue Jan 15, 2019 9:58 pm

It seems that newly announced STEMlab 122.88-16 SDR will have AC coupled inputs.

If that's the case, would there be an option or easy mod to make it DC coupled? I could see us interested in getting at least couple dozen boards if that's the case, otherwise we'll have to pass...

Ste_Trat
Posts: 12
Joined: Wed Oct 25, 2017 2:51 pm

Re: STEMlab 122.88-16 - DC coupled version

Post by Ste_Trat » Sat Feb 02, 2019 10:09 am

You could circumvent this problem by modulating the DC Signal / chopping it, with a AD633JR.
The DC component = Amplitude of the newly generated signal.

Another option is to use a DC to frequency converter.

User avatar
renegade264
Posts: 14
Joined: Mon Apr 08, 2019 1:08 pm

Re: STEMlab 122.88-16 - DC coupled version

Post by renegade264 » Wed Aug 26, 2020 12:23 pm

Hey, to revive a dead thread a little bit.

I have x3 122.88-16 SDRs and I need to modify both the ADC and DAC front ends to bypass the transformers as I need to generate low frequency square waves on the DAC and I need the frequencies below 300 KHz which is the cut off frequency of the transformers. Unfortunately I really require the x3 larger FPGA for a dual channel floating point processor and the 16 bit ADC for that extra 20 dB of dynamic range.

I will be using the MAX9321, on the ADC front end, this will convert the single ended input to differential, I believe this is the same chip they use on the 125-14 models, I will use two TSSOP4 adapter boards and sit them on top of the transformer and use copper wire and manually solder the necessary connections. On the DAC side of things I will again bypass the transformer, I don't think there is a way to utilise the both the positive and negative current sources for DC to 62.5 MHz operation. (I don't think the 125-14 uses both current sources either).

I will keep this thread updated with pictures about how this goes, in the next couple of weeks.

Best Regards Ren.

Post Reply
jadalnie klasyczne ekskluzywne meble wypoczynkowe do salonu ekskluzywne meble tapicerowane ekskluzywne meble do sypialni ekskluzywne meble włoskie

Who is online

Users browsing this forum: No registered users and 2 guests