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_dbv.py
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_dbv.py
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# -*- coding: utf-8 -*-
# _dbv.py
# This module provides the dbv function.
# Copyright 2013 Giuseppe Venturini
# This file is part of python-deltasigma.
#
# python-deltasigma is a 1:1 Python replacement of Richard Schreier's
# MATLAB delta sigma toolbox (aka "delsigma"), upon which it is heavily based.
# The delta sigma toolbox is (c) 2009, Richard Schreier.
#
# python-deltasigma is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# LICENSE file for the licensing terms.
"""This module provides the dbv() function, used to convert a voltage gain to dB.
"""
import numpy as np
from ._undbv import undbv
from ._utils import carray, restore_input_form, save_input_form
def dbv(x):
"""Calculate the dB equivalent of the voltage ratio ``x``.
.. math::
G_{dB} = 20 \\mathrm{log}_{10}(|x|)
**Parameters:**
x : scalar or sequence
The voltage (ratio) to be converted.
**Returns:**
GdB : scalar or sequence
The input voltage (ratio) expressed in dB.
.. seealso:: :func:`undbv`, :func:`db`, :func:`dbp`, :func:`dbm`
"""
iform = save_input_form(x)
x = carray(x)
y = -np.inf*np.ones(x.shape)
nonzero = (x != 0)
y[nonzero] = 20.*np.log10(np.abs(x[nonzero]))
return restore_input_form(y, iform)