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AD9959 frequency linear sweep down

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Product Number: AD9959

Hi guys, I'm trying to use the linear sweep mode of AD9959 to sweep the frequency down. It seems that it can sweep from s0 to e0 but the e0 frequency must be larger. I tried to let p0 always 1 (I'm using channel 0) such that it starts at e0 but obviously it still has to finish the sweep up. Correct me if I'm wrong since I'm really interested in achieving this sweeping-down function! 

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[edited by: zyli at 2:19 AM (GMT -4) on 10 Aug 2022]
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  • Hi, yes! 

    CFR: {0x80, 0x43, 0x00}
    CFTW0: 100MHz in hex (4 bytes)
    CW1: 90MHz in hex (4 bytes)
    RDW: 1 (4 bytes)
    FDW: 1 (4 bytes)
    LSRR: {1, 1} in hex (I tried different LSRRs, but none works)

    and also set the p0 to be low to ramp down. I mean, if I set p0=1 and CFTW0=90MHz, CW1=100MHz then it can ramp up; however it doesn't work the other way.