A Low-Noise Amplifier for Submarine Electric Field Signal Based on Chopping Amplification Technology

. 2024 Feb 22;24(5):1417. doi: 10.3390/s24051417

Simple description for symbols
Mnemonic	Description	Unit
EIVNS	equivalent input voltage noise spectrum	$n V / \sqrt H z$
$v_{i}$	input signal of chopper amplifier circuit	V
$v_{m}$	signal modulated	V
$n$	magnification of transformer	$\$
$A$	magnification of amplification module	$\$
$m_{1}$	signal used to modulate	V
$m_{2}$	signal used to demodulate	V
$v_{o s}$	offset generated from amplification module	V
$v_{n}$	noise generated from amplification module	V
$v_{d m}$	signal demodulated	V
$v_{o s d m}$	$v_{o s}$ demodulated	V
$v_{n d m}$	$v_{n}$ demodulated	V
$v_{o s r}$	$v_{o s d m}$ filtered	V
$v_{n r}$	$v_{n d m}$ filtered	V
$f_{c h o p}$	frequency of $m_{1}$ or $m_{2}$	kHz
$e_{s i m u l a t e d}$	estimation value of equivalent input noise spectral density	$n V / \sqrt H z$
$e_{m e a s u r e d}$	experimental value of equivalent input noise spectral density	$n V / \sqrt H z$
$V 2$	source of input signal in Multisim	V
$B_{w}$	noise bandwidth	$\$
$k$	Boltzmann constant	J/K
$T$	temperature	K
$E_{p a r}$	RMS of noise voltage from modulation	nV
$E_{s e c}$	RMS of noise voltage from transformer	nV
$E_{A}$	RMS of noise voltage from amplification	nV
$E_{D}$	RMS of noise voltage from demodulation	nV
$E_{s e r}$	RMS of noise voltage from filter	nV
$G a i n 1$	magnification of chopper amplifier in simulation	$\$
$G a i n 2$	magnification of chopper amplifier in experimentation	$\$