AnsweredAssumed Answered

Syncronous Frequency and amplitude sweep with DDS

Question asked by vladgavr on Oct 16, 2017
Latest reply on Oct 18, 2017 by vladgavr

Dear all,
I'm looking for an RF signal generator system, based on DDS or other technology, which would be able to generate externally triggered linear RF sweeps (triggering the ramp start would be enough).

 

The ramp could be continuous or stepwise (it may reach up to 2048 points), with each step lasting around 10 us. The RF range for this application could be from 50 to 300 MHz, with RF sweeps spanning up to 50 MHz in 2 ms.

 

Furthermore, it would be desirable to control the RF power for each frequency step, in order to compensate for non-linearities in the equipment driven by the RF signal. Could this be done synchronously with the frequency sweep? If it is not directly possible, I could foresee using an independent fast variable attenuator at the output, would this work?

 

I looked through the product selector and these are the DDS models with evaluation board that fulfill my desired frequency range:

  • AD9910/12 (up to 400 MHz analog output, have 700 mW output power)
  • AD9914/15 (up to 1750 MHz analog output, have 2mW output power)
  • AD9858 (up to 500 Mhz, no amplitude control)

I'm not sure where to look in the datasheets for the minimum ramp slope step time interval, could you suggest this?

Did I miss any other DDS solution? Which one may be the best choice?


Thank you very much,
Best regards

Vladislav

Outcomes