Regarding RMS magnitude signal monitoring feature of AD9640 ADC, The datasheet says that,

"For rms magnitude mode, the value in the signal monitor result (SMR) register is a 20-bit fixed-point number."

How long is the word length and fraction length of 20-bits?

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Thank you

Jason Lee

Hi Jason,

I have this feedback below from our digital team that may help offer a little more insight for you:

"The way I view this is that the ADC is a signed 1.13 signal(14-bit) and the RMS output is an unsigned 0’20(The ‘ means unsigned). Looking at it this way all bits are Fractional, and the largest signal you can have is -1.0. Signal are in the range [ -1.0, 1.0 - 2^-13]If you view the ADC as integer bits then this has 13 Integer bits and 7 Fractional bits."It would then be my understanding that you have a word length of 13 bits and fraction length of 7 bits.

Regards,

Jonathan