Hello all,
I'm looking for a reference book or any guideline in order to estimate the Equivalent Noise Bandwidth of a low pass bessel filter (4th order).
Do you know a book that could help me to evaluate it ?
For a Bessel it is almost the 3dB point - 1.045x the 3dB frequency. As an example, a 1k resistor has 4.1627nV/rt Hz at 27C. Total noise through a 1Hz 4 pole Bessel is 4.1646nV. This is from simulation with an ideal Bessel transfer function.