kopia lustrzana https://github.com/NanoVNA-Saver/nanovna-saver
193 wiersze
7.9 KiB
Python
193 wiersze
7.9 KiB
Python
# NanoVNASaver
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#
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# A python program to view and export Touchstone data from a NanoVNA
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# Copyright (C) 2019, 2020 Rune B. Broberg
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# Copyright (C) 2020,2021 NanoVNA-Saver Authors
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#
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <https://www.gnu.org/licenses/>.
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import logging
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import math
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from typing import Dict
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from PyQt5 import QtWidgets
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import NanoVNASaver.AnalyticTools as at
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from NanoVNASaver.Analysis.Base import Analysis
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from NanoVNASaver.Formatting import format_frequency
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logger = logging.getLogger(__name__)
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CUTOFF_VALS = (3.0, 6.0, 10.0, 20.0, 60.0)
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class BandPassAnalysis(Analysis):
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def __init__(self, app):
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super().__init__(app)
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self._widget = QtWidgets.QWidget()
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layout = QtWidgets.QFormLayout()
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self._widget.setLayout(layout)
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layout.addRow(QtWidgets.QLabel("Band pass filter analysis"))
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layout.addRow(
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QtWidgets.QLabel(
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f"Please place {self.app.markers[0].name}"
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f" in the filter passband."))
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self.label = {
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label: QtWidgets.QLabel() for label in
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('result', 'octave_l', 'octave_r', 'decade_l', 'decade_r',
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'freq_center', 'span_3.0dB', 'span_6.0dB', 'q_factor')
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}
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for attn in CUTOFF_VALS:
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self.label[f"{attn:.1f}dB_l"] = QtWidgets.QLabel()
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self.label[f"{attn:.1f}dB_r"] = QtWidgets.QLabel()
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layout.addRow("Result:", self.label['result'])
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layout.addRow(QtWidgets.QLabel(""))
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layout.addRow("Center frequency:", self.label['freq_center'])
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layout.addRow("Bandwidth (-3 dB):", self.label['span_3.0dB'])
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layout.addRow("Quality factor:", self.label['q_factor'])
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layout.addRow("Bandwidth (-6 dB):", self.label['span_6.0dB'])
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layout.addRow(QtWidgets.QLabel(""))
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layout.addRow(QtWidgets.QLabel("Lower side:"))
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layout.addRow("Cutoff frequency:", self.label['3.0dB_l'])
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layout.addRow("-6 dB point:", self.label['6.0dB_l'])
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layout.addRow("-60 dB point:", self.label['60.0dB_l'])
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layout.addRow("Roll-off:", self.label['octave_l'])
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layout.addRow("Roll-off:", self.label['decade_l'])
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layout.addRow(QtWidgets.QLabel(""))
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layout.addRow(QtWidgets.QLabel("Upper side:"))
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layout.addRow("Cutoff frequency:", self.label['3.0dB_r'])
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layout.addRow("-6 dB point:", self.label['6.0dB_r'])
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layout.addRow("-60 dB point:", self.label['60.0dB_r'])
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layout.addRow("Roll-off:", self.label['octave_r'])
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layout.addRow("Roll-off:", self.label['decade_r'])
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def reset(self):
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for label in self.label.values():
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label.clear()
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def runAnalysis(self):
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if not self.app.data.s21:
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logger.debug("No data to analyse")
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self.label['result'].setText("No data to analyse.")
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return
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self.reset()
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s21 = self.app.data.s21
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gains = [d.gain for d in s21]
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marker = self.app.markers[0]
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if marker.location <= 0 or marker.location >= len(s21) - 1:
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logger.debug("No valid location for %s (%s)",
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marker.name, marker.location)
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self.label['result'].setText(
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f"Please place {marker.name} in the passband.")
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return
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# find center of passband based on marker pos
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if (peak := at.center_from_idx(gains, marker.location)) < 0:
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self.label['result'].setText("Bandpass center not found")
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return
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peak_db = gains[peak]
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logger.debug("Bandpass center pos: %d(%fdB)", peak, peak_db)
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# find passband bounderies
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cutoff_pos = {}
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for attn in CUTOFF_VALS:
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cutoff_pos[f"{attn:.1f}dB_l"] = at.cut_off_left(
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gains, peak, peak_db, attn)
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cutoff_pos[f"{attn:.1f}dB_r"] = at.cut_off_right(
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gains, peak, peak_db, attn)
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cutoff_freq = {
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att: s21[val].freq if val >= 0 else math.nan
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for att, val in cutoff_pos.items()
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}
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cutoff_gain = {
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att: gains[val] if val >= 0 else math.nan
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for att, val in cutoff_pos.items()
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}
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logger.debug("Cuttoff frequencies: %s", cutoff_freq)
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logger.debug("Cuttoff gains: %s", cutoff_gain)
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self.derive_60dB(cutoff_pos, cutoff_freq)
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result = {
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'span_3.0dB': cutoff_freq['3.0dB_r'] - cutoff_freq['3.0dB_l'],
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'span_6.0dB': cutoff_freq['6.0dB_r'] - cutoff_freq['6.0dB_l'],
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'freq_center': int(
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math.sqrt(cutoff_freq['3.0dB_l'] * cutoff_freq['3.0dB_r'])),
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}
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result['q_factor'] = result['freq_center'] / result['span_3.0dB']
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result['octave_l'], result['decade_l'] = self.calculateRolloff(
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cutoff_pos["10.0dB_l"], cutoff_pos["20.0dB_l"])
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result['octave_r'], result['decade_r'] = self.calculateRolloff(
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cutoff_pos["10.0dB_r"], cutoff_pos["20.0dB_r"])
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for label, val in cutoff_freq.items():
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self.label[label].setText(
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f"{format_frequency(val)}"
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f" ({cutoff_gain[label]:.1f} dB)")
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for label in ('freq_center', 'span_3.0dB', 'span_6.0dB'):
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self.label[label].setText(format_frequency(result[label]))
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self.label['q_factor'].setText(f"{result['q_factor']:.2f}")
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for label in ('octave_l', 'decade_l', 'octave_r', 'decade_r'):
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self.label[label].setText(f"{result[label]:.3f}dB/{label[:-2]}")
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self.app.markers[0].setFrequency(f"{result['freq_center']}")
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self.app.markers[0].frequencyInput.setText(f"{result['freq_center']}")
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self.app.markers[1].setFrequency(f"{cutoff_freq['3.0dB_l']}")
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self.app.markers[1].frequencyInput.setText(f"{cutoff_freq['3.0dB_l']}")
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self.app.markers[2].setFrequency(f"{cutoff_freq['3.0dB_r']}")
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self.app.markers[2].frequencyInput.setText(f"{cutoff_freq['3.0dB_r']}")
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if cutoff_gain['3.0dB_l'] < -4 or cutoff_gain['3.0dB_r'] < -4:
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logger.warning(
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"Data points insufficient for true -3 dB points."
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"Cutoff gains: %fdB, %fdB", cutoff_gain['3.0dB_l'], cutoff_gain['3.0dB_r'])
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self.label['result'].setText(
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f"Analysis complete ({len(s21)} points)\n"
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f"Insufficient data for analysis. Increase segment count.")
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return
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self.label['result'].setText(
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f"Analysis complete ({len(s21)} points)")
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def derive_60dB(self,
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cutoff_pos: Dict[str, int],
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cutoff_freq: Dict[str, float]):
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"""derive 60dB cutoff if needed an possible
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Args:
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cutoff_pos (Dict[str, int])
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cutoff_freq (Dict[str, float])
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"""
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if (math.isnan(cutoff_freq['60.0dB_l']) and
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cutoff_pos['20.0dB_l'] != -1 and cutoff_pos['10.0dB_l'] != -1):
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cutoff_freq['60.0dB_l'] = (
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cutoff_freq["10.0dB_l"] *
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10 ** (5 * (math.log10(cutoff_pos['20.0dB_l']) -
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math.log10(cutoff_pos['10.0dB_l']))))
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if (math.isnan(cutoff_freq['60.0dB_r']) and
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cutoff_pos['20.0dB_r'] != -1 and cutoff_pos['10.0dB_r'] != -1):
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cutoff_freq['60.0dB_r'] = (
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cutoff_freq["10.0dB_r"] *
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10 ** (5 * (math.log10(cutoff_pos['20.0dB_r']) -
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math.log10(cutoff_pos['10.0dB_r'])
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)))
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