# -*- coding: utf-8 -*-
"""
Read an amtant.cal file provided by Zonge.
Apparently, the file includes the 6th and 8th harmonic of the given frequency, which
is a fancy way of saying f x 6 and f x 8.
"""
# =============================================================================
# Imports
# =============================================================================
from pathlib import Path
import numpy as np
from mt_metadata.timeseries.filters import FrequencyResponseTableFilter
from mt_metadata.utils.mttime import MTime
from mth5.utils.mth5_logger import setup_logger
# =============================================================================
# Variables
# =============================================================================
[docs]class CoilResponse:
def __init__(self, calibration_file=None, angular_frequency=False):
self.logger = setup_logger(f"{__name__}.{self.__class__.__name__}")
self.coil_calibrations = {}
self._n_frequencies = 48
self.calibration_file = calibration_file
self.angular_frequency = angular_frequency
if calibration_file:
self.read_antenna_file()
@property
def calibration_file(self):
return self._calibration_fn
@calibration_file.setter
def calibration_file(self, fn):
if fn is not None:
self._calibration_fn = Path(fn)
else:
self._calibration_fn = None
[docs] def file_exists(self):
"""
Check to make sure the file exists
:return: True if it does, False if it does not
:rtype: boolean
"""
if self.calibration_file is None:
return False
if self.calibration_file.exists():
return True
return False
[docs] def read_antenna_file(self, antenna_calibration_file=None):
"""
Read in the Antenna file to frequency, amplitude, phase of the proper
harmonics (6, 8)
.. note:: Phase is measureed in milli-radians and will be converted
to radians.
:param antenna_calibration_file: path to antenna.cal file provided by Zonge
:type antenna_calibration_file: string or Path
"""
if antenna_calibration_file is not None:
self.calibration_file = antenna_calibration_file
cal_dtype = [
("frequency", float),
("amplitude", float),
("phase", float),
]
with open(self.calibration_file, "r") as fid:
lines = fid.readlines()
self.coil_calibrations = {}
ff = -2
for line in lines:
if "antenna" in line.lower():
f = float(line.split()[2].strip())
if self.angular_frequency:
f = 2 * np.pi * f
ff += 2
elif len(line.strip().split()) == 0:
continue
else:
line_list = line.strip().split()
ant = line_list[0]
amp6 = float(line_list[1])
phase6 = float(line_list[2]) / 1000
amp8 = float(line_list[3])
phase8 = float(line_list[4]) / 1000
try:
self.coil_calibrations[ant]
except KeyError:
self.coil_calibrations[ant] = np.zeros(
self._n_frequencies, dtype=cal_dtype
)
self.coil_calibrations[ant][ff] = (f * 6, amp6, phase6)
self.coil_calibrations[ant][ff + 1] = (f * 8, amp8, phase8)
[docs] def get_coil_response_fap(self, coil_number):
"""
Read an amtant.cal file provided by Zonge.
Apparently, the file includes the 6th and 8th harmonic of the given frequency, which
is a fancy way of saying f * 6 and f * 8.
:param coil_number: ANT4 4 digit serial number
:type coil_number: int or string
:return: Frequency look up table
:rtype: :class:`mt_metadata.timeseries.filters.FrequencyResponseTableFilter`
"""
if self.coil_calibrations is {}:
self.read_antenna_file(self.calibration_file)
if self.has_coil_number(coil_number):
cal = self.coil_calibrations[str(int(coil_number))]
fap = FrequencyResponseTableFilter()
fap.frequencies = cal["frequency"]
fap.amplitudes = cal["amplitude"]
fap.phases = cal["phase"]
fap.units_in = "millivolts"
fap.units_out = "nanotesla"
fap.name = f"coil_{coil_number}"
fap.instrument_type = "ANT4 induction coil"
fap.calibration_date = MTime(
self.calibration_file.stat().st_mtime
).isoformat()
return fap
else:
self.logger.error(
f"Could not find {coil_number} in {self.calibration_file}"
)
raise KeyError(
f"Could not find {coil_number} in {self.calibration_file}"
)
[docs] def has_coil_number(self, coil_number):
"""
Test if coil number is in the antenna file
:param coil_number: ANT4 serial number
:type coil_number: int or string
:return: True if the coil is found, False if it is not
:rtype: boolean
"""
if self.file_exists():
coil_number = str(int(coil_number))
if coil_number in self.coil_calibrations.keys():
return True
self.logger.error(
f"Could not find {coil_number} in {self.calibration_file}"
)
return False
return False