Qustions about Allen’s Book

[cherryic]

Hi all, I have been reading P. E. Allen’s famous book <<CMOS Analog Circuit Design>> for 2 months, but I find some questions there, can anyone help me?

In page 403, there is a line “However, the 1/f noise is aliased around clock frequencies…,” cuz I am not a native speaker so I don’t know what does it mean here.
In page 408, the first paragraph, there is a √2.548x10^-17, but I can’t find this quantity in previous context, I don’t know where does it come from.

Thank you in advance.

Best regards,
Terry

 

[leichen_gy]

Hi Terry,

In answering your first query, Allen is emphasizing the importance of 1/f noise not only at low frequency, but also at high frequency around clock frequency. He then gives high frequency MOSFET VCO as an example.
This is to clear our common misunderstanding that since 1/f noise is only significant at low frequency, we can ignore 1/f noise at high frequency.

On your second question, I GUESS the number may be wrong, it is referring to the thermal noise, the number may be 1.562*10^-17 in the middle of Pg 407.