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AD9914  linearly sweep

Question asked by waderose on Jan 7, 2018
Latest reply on Jan 17, 2018 by waderose

Hello,I hope to use a AD9914 for linearly sweep, the system clock is 2.5GHz. 

The sweep frequency generated is 200MHz -- 300MHz,  and the frequency step is 1MHz, Step intervals is 37.5ns,

I  use No-Dwell high configuration, so  it can sweep all the time automatic .

Here is my register configuration:

CFR1=0x0101C008

CFR2=0x000C2800

CFR3=0x00041927

CFR4=0x01053120

Digital Ramp Lower Limit=0x147A1E47(register address is 0x04,200MHz)

Digital Ramp Upper Limit=0x1EB851EB(register address is 0x05,300MHz)

Rising Digital Ramp stope=0x001A36E3(register address is 0x06,1MHz)

Falling Digital Ramp stope=0x001A36E3(register address is 0x07,1MHz)

Digital Ramp Rate Register=0x00040004(register address is 0x08,37.5ns)

 

But finally, It just a constant 90MHz output, then I measured the pin 65 ( DROVER) , it is high ..

So  what happend to my AD9914, I just hope to use it to  realize  linearly sweep or Where did I go wrong for my configuration or connection.. thank you !

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