# Source code for deltasigma._dbv

# -*- 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

[docs]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)