DAC38RF89: How to output Iout and Qout at the same time?

user6193156

Part Number: DAC38RF89
Other Parts Discussed in Thread: DAC38J82

Hi,

In DAC38J82, it can output Iout and Qout at the same time in figure below. How can I do it when use DAC38RF89? It seems that dac38rf89 cannot output Iout and Qout at the same time.

over 3 years ago

0 jim s over 3 years ago

TI__Guru* 91947 points

User,

Yes you can do this with the DAC38RF89. See section 8.3.16 (Wideband DUC mode) on page 50 of the data sheet. The input I data will be sent to DAC A and the input Q data will be sent to DAC B.

Regards,

Jim

0 user6193156 over 3 years ago in reply to jim s

Intellectual 290 points

Jim,

I think that wideband DUC mode can output Iout or Qout only, not output Iout adn Qout at the same time.

0 jim s over 3 years ago in reply to user6193156

TI__Guru* 91947 points

User,

My answer was slightly incorrect. In the wideband DUC mode, the data that would normally go to DAC B is sent to the output summer of CHA, and both outputs are summed to provide a complex output at CHA. See attached. The device can bypass the channel mixers and send the data directly to the DAC's. In this case you could send I and Q data at the same time to both DAC's. This is how the device works in real data mode with no interpolation or NCO.

Regards,

Jim

DAC38RF8x Wideband Mode.pptx

0 user6193156 over 3 years ago in reply to jim s

Intellectual 290 points

Jim,

I mean that In real data mode, I want to output Iin*cos(2π*fnco)-Qin*sin(2π*fnco) and Iin*sin(2π*fnco)+Qin*cos(2π*fnco) at the same time.

How to do it?

Regards,

John

0 jim s over 3 years ago in reply to user6193156

TI__Guru* 91947 points

John,

I am still confused by your request.

1. Are you using real or complex input data?

2. Do you want real or complex output data?

3. Do you plan on using the NCO?

4. Do you plan on using both DAC outputs? If you only plan on using one DAC output, are you trying to get both I and Q data summed together on this one output?

Regards,

Jim

0 user6193156 over 3 years ago in reply to jim s

Intellectual 290 points

Jim,

1. Are you using real or complex input data?-------Complex input data. But I config DAC38RF89 work in real mode,because input data rate is 2.5GSPS.PathAB of DACA for I-channel,and pathAB of DACB for Q-channel.

2. Do you want real or complex output data?-------I want compelx output data.

3. Do you plan on using the NCO?-------Yes, I use NCO.

4. Do you plan on using both DAC outputs? If you only plan on using one DAC output, are you trying to get both I and Q data summed together on this one output? -------I want to use both DAC outputs. DACA output Iin*cos(2π*fnco)-Qin*sin(2π*fnco), and DACB output Iin*sin(2π*fnco)+Qin*cos(2π*fnco). Can this be achieved？

Regards,

John