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ADS54J42: NYQUIST ZONE & CTRL NYQUIST Register setting

Mastermind 6480 points

Replies: 2

Views: 110

Part Number: ADS54J42

Hello,

My customer has a question about ADS54J42.

[Q1]

Please tell me the proper setting for NYQUIST ZONE and CTRL NYQUIST.

<Their configuration>

* Input Frequency Range = 75MHz to 475MHz (this is narrow band signal) 

* Sampling Rate = 500MSPS

<My understanding>

* CTRL NYQUIST is always 1.

* Input Frequency < 250MHz, then NYQUIST ZONE = 000

* 250MHz <= Input Frequency < 500MHz, then NYQUIST ZONE = 001

Is my understanding correct ?

[Q2]

There is no such setting in AFE54Jxx GUI.

Is this setting required ?

[Q3]

What does this change?

I understand ADS54J42 is 4 interleaving ADC.

Therefore it will produce interleaving spurs. (DC, fs/4, fs/2 at no input, fs/4 +/- input frequency, fs/2 - input frequency at signal input)

Best Regards,

Hiroshi Katsunaga

  • Guru 63370 points

    Hiroshi,

    Q1. You are correct.

    Q2. The GUI is out of date. The user can either set these registers using the low level view tab or by adding the commands to an existing configuration file (see attached file).

    Q3. This changes how the interleave correction engine operates and improves performance.

    Regards,

    Jim

    2021.ADS54J60_LMF_8224_2NQ.cfg

  • In reply to jim s:

    Hi Jim,

    Thank you for your fast response and clear comments.
    OK, I understood them.

    Thank you for your cooperation.

    Best Regards,
    Hiroshi Katsunaga

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