DAC38RF83: Frequency hoping time & coherency

PRAHLAD Supeda

Part Number: DAC38RF83

Customer is planning to use DAC38RF83 for waveform generation and fast frequency hopping (frequency synthesizing) applications using the built in two DACs in the above RFDAC. And have two quires on the above RFDAC.

1 What time does it take to hop to new frequency?

2 Does the frequency hopping take place coherently?

over 8 years ago

0 Ebenezer Dwobeng over 8 years ago

TI__Genius 9695 points

Hi Prahlad,

1) It will take about 1us or more because you have to use the SPI interface to program DAC to hop between frequencies.
2) For coherent frequency hopping, the 4 DUCs can be programmed to 4 different frequencies and the output combiner/summer used to select between 1 of the 4 frequencies.

Thanks,
Eben.

0 Rudresh Sundararaj over 8 years ago in reply to Ebenezer Dwobeng

Prodigy 50 points

Hi Eben,

1. Does it mean DAC38RF83 has to be pre programmed with 4 different frequencies.
2. Does DAC38RF83 has got the provision to hop frequency using NCO’s by loading frequency tuning word(FTW) as in AD9164. AD9164 has got phase coherent switch and phase continuous switch mode. Please let me know if DAC38RF83 can support the same feature.

Thanks,
Rudresh

0 Ebenezer Dwobeng over 8 years ago in reply to Rudresh Sundararaj

TI__Genius 9695 points

Hi Rudresh,

1. Yes, the DAC has to be programmed with 4 different frequencies
2. We don't have as many NCOs in this DAC and the DAC does not have a phase coherent switch.
Can you send me a message with your email so I can share with you details on another device that is more suitable for your application?

Thanks,
Eben.

0 Rudresh Sundararaj over 8 years ago in reply to Ebenezer Dwobeng

Prodigy 50 points

Hi Eben,

I would like to know the phase noise of internal PLL at 1KHz offset. J26 output on the eval board. It can be of any frequency.

Thanks,

Rudresh

0 Ebenezer Dwobeng over 8 years ago in reply to Rudresh Sundararaj

TI__Genius 9695 points

Hi Rudresh,

See figures 19 ad 23 in DAC38RF83 datasheet for the phase noise performance.

Thanks,
Eben.

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DAC38RF83: Frequency hoping time & coherency