LMX2492: Sweep synchronization

user5858775

Part Number: LMX2492
Other Parts Discussed in Thread: LMX2594

Hello,

we use the LMX2492 to generate a frequency sweep using an external ramp increment clock and ramp trigger. For our application it would be advantageous if a ramp that gets triggered again after some time had the same phase relations as the first one.

Is there a way to achieve this synchronization for example by using an external signal to reset the internal dividers at the start of the ramp? If it is not possible with this part, is there another part with synchronization, ramping and external VCO?

Thank You,

Fabian

over 4 years ago

0 Noel Fung over 4 years ago

TI__Guru** 110720 points

Hi Fabian,

Please check if LMX2594 can meet your synchronization requirement. This device support frequency sweep, just like LMX2492. This device also support phase synchronization between the reference clock and RF outputs. Please note there are restrictions on phase synchronization, at some scenario, phase sync are not possible.

0 user5858775 over 4 years ago in reply to Noel Fung

Prodigy 30 points

Hi Noel,

thank you for the quick suggestion. Actually we are already using the LMX2594 in our system for constant frequency signal generation. But for the sweep we need a one octave continuous sweep, thus the need for an external VCO.

Are there any options in this case?

Thank You,

Fabian

0 Noel Fung over 4 years ago in reply to user5858775

TI__Guru** 110720 points

Hi Fabian,

I am afraid I don't have other suggestions.

0 user5858775 over 4 years ago in reply to Noel Fung

Prodigy 30 points

Ok, thank you.

I had another thought: The PLL has integrated PSK modulation but the datasheet is not very detailed on this feature. Is there any chance, that this feature can be used to reset some counter to get a defined phase?

Best regards,

Fabian

0 Noel Fung over 4 years ago in reply to user5858775

TI__Guru** 110720 points

Hi Fabian,

No I don't think that will work, phase synchronization requires specially design logic to align the phases, LMX2492 does not have this logic embedded.

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LMX2492: Sweep synchronization