kopia lustrzana https://github.com/NanoVNA-Saver/nanovna-saver
191 wiersze
7.8 KiB
Python
191 wiersze
7.8 KiB
Python
# NanoVNASaver
|
|
#
|
|
# A python program to view and export Touchstone data from a NanoVNA
|
|
# Copyright (C) 2019, 2020 Rune B. Broberg
|
|
# Copyright (C) 2020ff NanoVNA-Saver Authors
|
|
#
|
|
# This program is free software: you can redistribute it and/or modify
|
|
# it under the terms of the GNU General Public License as published by
|
|
# the Free Software Foundation, either version 3 of the License, or
|
|
# (at your option) any later version.
|
|
#
|
|
# This program 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
|
|
# GNU General Public License for more details.
|
|
#
|
|
# You should have received a copy of the GNU General Public License
|
|
# along with this program. If not, see <https://www.gnu.org/licenses/>.
|
|
import logging
|
|
import math
|
|
from typing import Dict, List
|
|
|
|
from PyQt5 import QtWidgets
|
|
|
|
import NanoVNASaver.AnalyticTools as at
|
|
from NanoVNASaver.Analysis.Base import Analysis, CUTOFF_VALS
|
|
from NanoVNASaver.Formatting import format_frequency
|
|
|
|
logger = logging.getLogger(__name__)
|
|
|
|
|
|
class BandPassAnalysis(Analysis):
|
|
def __init__(self, app):
|
|
super().__init__(app)
|
|
|
|
for label in ('octave_l', 'octave_r', 'decade_l', 'decade_r',
|
|
'freq_center', 'span_3.0dB', 'span_6.0dB', 'q_factor'):
|
|
self.label[label] = QtWidgets.QLabel()
|
|
for attn in CUTOFF_VALS:
|
|
self.label[f"{attn:.1f}dB_l"] = QtWidgets.QLabel()
|
|
self.label[f"{attn:.1f}dB_r"] = QtWidgets.QLabel()
|
|
|
|
layout = self.layout
|
|
layout.addRow(self.label['titel'])
|
|
layout.addRow(
|
|
QtWidgets.QLabel(
|
|
f"Please place {self.app.markers[0].name}"
|
|
f" in the filter passband."))
|
|
layout.addRow("Result:", self.label['result'])
|
|
layout.addRow(QtWidgets.QLabel(""))
|
|
|
|
layout.addRow("Center frequency:", self.label['freq_center'])
|
|
layout.addRow("Bandwidth (-3 dB):", self.label['span_3.0dB'])
|
|
layout.addRow("Quality factor:", self.label['q_factor'])
|
|
layout.addRow("Bandwidth (-6 dB):", self.label['span_6.0dB'])
|
|
layout.addRow(QtWidgets.QLabel(""))
|
|
|
|
layout.addRow(QtWidgets.QLabel("Lower side:"))
|
|
layout.addRow("Cutoff frequency:", self.label['3.0dB_l'])
|
|
layout.addRow("-6 dB point:", self.label['6.0dB_l'])
|
|
layout.addRow("-60 dB point:", self.label['60.0dB_l'])
|
|
layout.addRow("Roll-off:", self.label['octave_l'])
|
|
layout.addRow("Roll-off:", self.label['decade_l'])
|
|
layout.addRow(QtWidgets.QLabel(""))
|
|
|
|
layout.addRow(QtWidgets.QLabel("Upper side:"))
|
|
layout.addRow("Cutoff frequency:", self.label['3.0dB_r'])
|
|
layout.addRow("-6 dB point:", self.label['6.0dB_r'])
|
|
layout.addRow("-60 dB point:", self.label['60.0dB_r'])
|
|
layout.addRow("Roll-off:", self.label['octave_r'])
|
|
layout.addRow("Roll-off:", self.label['decade_r'])
|
|
|
|
self.set_titel("Band pass filter analysis")
|
|
|
|
def runAnalysis(self):
|
|
if not self.app.data.s21:
|
|
logger.debug("No data to analyse")
|
|
self.set_result("No data to analyse.")
|
|
return
|
|
|
|
self.reset()
|
|
s21 = self.app.data.s21
|
|
gains = [d.gain for d in s21]
|
|
|
|
if (peak := self.find_center(gains)) < 0:
|
|
return
|
|
peak_db = gains[peak]
|
|
logger.debug("Filter center pos: %d(%fdB)", peak, peak_db)
|
|
|
|
# find passband bounderies
|
|
cutoff_pos = self.find_bounderies(gains, peak, peak_db)
|
|
cutoff_freq = {
|
|
att: s21[val].freq if val >= 0 else math.nan
|
|
for att, val in cutoff_pos.items()
|
|
}
|
|
cutoff_gain = {
|
|
att: gains[val] if val >= 0 else math.nan
|
|
for att, val in cutoff_pos.items()
|
|
}
|
|
logger.debug("Cuttoff frequencies: %s", cutoff_freq)
|
|
logger.debug("Cuttoff gains: %s", cutoff_gain)
|
|
|
|
self.derive_60dB(cutoff_pos, cutoff_freq)
|
|
|
|
result = {
|
|
'span_3.0dB': cutoff_freq['3.0dB_r'] - cutoff_freq['3.0dB_l'],
|
|
'span_6.0dB': cutoff_freq['6.0dB_r'] - cutoff_freq['6.0dB_l'],
|
|
'freq_center':
|
|
math.sqrt(cutoff_freq['3.0dB_l'] * cutoff_freq['3.0dB_r']),
|
|
}
|
|
result['q_factor'] = result['freq_center'] / result['span_3.0dB']
|
|
|
|
result['octave_l'], result['decade_l'] = at.calculate_rolloff(
|
|
s21, cutoff_pos["10.0dB_l"], cutoff_pos["20.0dB_l"])
|
|
result['octave_r'], result['decade_r'] = at.calculate_rolloff(
|
|
s21, cutoff_pos["10.0dB_r"], cutoff_pos["20.0dB_r"])
|
|
|
|
for label, val in cutoff_freq.items():
|
|
self.label[label].setText(
|
|
f"{format_frequency(val)}"
|
|
f" ({cutoff_gain[label]:.1f} dB)")
|
|
for label in ('freq_center', 'span_3.0dB', 'span_6.0dB'):
|
|
self.label[label].setText(format_frequency(result[label]))
|
|
self.label['q_factor'].setText(f"{result['q_factor']:.2f}")
|
|
|
|
for label in ('octave_l', 'decade_l', 'octave_r', 'decade_r'):
|
|
self.label[label].setText(f"{result[label]:.3f}dB/{label[:-2]}")
|
|
|
|
self.app.markers[0].setFrequency(f"{result['freq_center']}")
|
|
self.app.markers[1].setFrequency(f"{cutoff_freq['3.0dB_l']}")
|
|
self.app.markers[2].setFrequency(f"{cutoff_freq['3.0dB_r']}")
|
|
|
|
if cutoff_gain['3.0dB_l'] < -4 or cutoff_gain['3.0dB_r'] < -4:
|
|
logger.warning(
|
|
"Data points insufficient for true -3 dB points."
|
|
"Cutoff gains: %fdB, %fdB", cutoff_gain['3.0dB_l'],
|
|
cutoff_gain['3.0dB_r'])
|
|
self.set_result(
|
|
f"Analysis complete ({len(s21)} points)\n"
|
|
f"Insufficient data for analysis. Increase segment count.")
|
|
return
|
|
self.set_result(f"Analysis complete ({len(s21)} points)")
|
|
|
|
def derive_60dB(self,
|
|
cutoff_pos: Dict[str, int],
|
|
cutoff_freq: Dict[str, float]):
|
|
"""derive 60dB cutoff if needed an possible
|
|
|
|
Args:
|
|
cutoff_pos (Dict[str, int])
|
|
cutoff_freq (Dict[str, float])
|
|
"""
|
|
if (math.isnan(cutoff_freq['60.0dB_l']) and
|
|
cutoff_pos['20.0dB_l'] != -1 and cutoff_pos['10.0dB_l'] != -1):
|
|
cutoff_freq['60.0dB_l'] = (
|
|
cutoff_freq["10.0dB_l"] *
|
|
10 ** (5 * (math.log10(cutoff_pos['20.0dB_l']) -
|
|
math.log10(cutoff_pos['10.0dB_l']))))
|
|
if (math.isnan(cutoff_freq['60.0dB_r']) and
|
|
cutoff_pos['20.0dB_r'] != -1 and cutoff_pos['10.0dB_r'] != -1):
|
|
cutoff_freq['60.0dB_r'] = (
|
|
cutoff_freq["10.0dB_r"] *
|
|
10 ** (5 * (math.log10(cutoff_pos['20.0dB_r']) -
|
|
math.log10(cutoff_pos['10.0dB_r'])
|
|
)))
|
|
|
|
def find_center(self, gains: List[float]) -> int:
|
|
marker = self.app.markers[0]
|
|
if marker.location <= 0 or marker.location >= len(gains) - 1:
|
|
logger.debug("No valid location for %s (%s)",
|
|
marker.name, marker.location)
|
|
self.set_result(f"Please place {marker.name} in the passband.")
|
|
return -1
|
|
|
|
# find center of passband based on marker pos
|
|
if (peak := at.center_from_idx(gains, marker.location)) < 0:
|
|
self.set_result("Bandpass center not found")
|
|
return -1
|
|
return peak
|
|
|
|
def find_bounderies(self,
|
|
gains: List[float],
|
|
peak: int, peak_db: float) -> Dict[str, int]:
|
|
cutoff_pos = {}
|
|
for attn in CUTOFF_VALS:
|
|
cutoff_pos[f"{attn:.1f}dB_l"] = at.cut_off_left(
|
|
gains, peak, peak_db, attn)
|
|
cutoff_pos[f"{attn:.1f}dB_r"] = at.cut_off_right(
|
|
gains, peak, peak_db, attn)
|
|
return cutoff_pos
|