Noise and sensitivity of video detectors

Hello everyone,
I am working on the design of a square-law video detector. I have simulated the its output noise (in units of V/√Hz). I am wondering on how do I estimate the total output noise for a given video bandwidth. I need this to get an estimate of the minimum detectable RF signal (Tangential signal sensitivity).

Saad

Hi Saad,

Say you have the noise voltage expressed as ε_n [V/√Hz].
Then the (normalized) power spectral density is ε_n² [V²/Hz].
The normalized power in a bandwidth B is ε_n²B [V²]
The rms voltage is V_EF=sqrt(ε_n²B)=ε_n√B [V]

Regards

Z

1. What is it normalized to?
2. Should it not be the integral of ε_n²B ?

You can define ENBW(Equivalent Noise Band Width), if noise spectrum has not 1/f noise.

http://analog.intgckts.com/equivalent-noise-bandwidth/
http://www.highfrequencyelectronics....les&Itemid=189

1) If U is a voltage, U² is called a "normalized power" because i order to have a "true" of "physical" power it must be divided by R. The same applies to ε_n²B: it must be divided by a resistance in order to get the physical power spectral density (psd).

2) ε_n²B is already the integral of the uniform normalized psd ∫ε_n²df between 0 and B.