kopia lustrzana https://github.com/NanoVNA-Saver/nanovna-saver
220 wiersze
8.0 KiB
Python
220 wiersze
8.0 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) 2020ff 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 PyQt6 import QtWidgets
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import NanoVNASaver.AnalyticTools as at
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from NanoVNASaver.Analysis.Base import Analysis, CUTOFF_VALS
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from NanoVNASaver.Formatting import format_frequency
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logger = logging.getLogger(__name__)
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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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for label in (
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"octave_l",
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"octave_r",
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"decade_l",
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"decade_r",
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"freq_center",
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"span_3.0dB",
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"span_6.0dB",
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"q_factor",
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):
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self.label[label] = QtWidgets.QLabel()
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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 = self.layout
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layout.addRow(self.label["titel"])
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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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)
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)
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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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self.set_titel("Band pass filter analysis")
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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.set_result("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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if (peak := self.find_center(gains)) < 0:
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return
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peak_db = gains[peak]
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logger.debug("Filter center pos: %d(%fdB)", peak, peak_db)
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# find passband bounderies
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cutoff_pos = self.find_bounderies(gains, peak, peak_db)
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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": math.sqrt(
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cutoff_freq["3.0dB_l"] * cutoff_freq["3.0dB_r"]
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),
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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"] = at.calculate_rolloff(
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s21, cutoff_pos["10.0dB_l"], cutoff_pos["20.0dB_l"]
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)
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result["octave_r"], result["decade_r"] = at.calculate_rolloff(
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s21, cutoff_pos["10.0dB_r"], cutoff_pos["20.0dB_r"]
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)
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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)}" f" ({cutoff_gain[label]:.1f} dB)"
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)
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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[1].setFrequency(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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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",
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cutoff_gain["3.0dB_l"],
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cutoff_gain["3.0dB_r"],
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)
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self.set_result(
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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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)
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return
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self.set_result(f"Analysis complete ({len(s21)} points)")
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def derive_60dB(
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self, cutoff_pos: dict[str, int], cutoff_freq: dict[str, float]
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):
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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 (
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math.isnan(cutoff_freq["60.0dB_l"])
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and cutoff_pos["20.0dB_l"] != -1
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and cutoff_pos["10.0dB_l"] != -1
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):
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cutoff_freq["60.0dB_l"] = cutoff_freq["10.0dB_l"] * 10 ** (
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5
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* (
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math.log10(cutoff_pos["20.0dB_l"])
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- math.log10(cutoff_pos["10.0dB_l"])
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)
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)
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if (
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math.isnan(cutoff_freq["60.0dB_r"])
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and cutoff_pos["20.0dB_r"] != -1
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and cutoff_pos["10.0dB_r"] != -1
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):
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cutoff_freq["60.0dB_r"] = cutoff_freq["10.0dB_r"] * 10 ** (
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5
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* (
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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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)
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def find_center(self, gains: list[float]) -> int:
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marker = self.app.markers[0]
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if marker.location <= 0 or marker.location >= len(gains) - 1:
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logger.debug(
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"No valid location for %s (%s)", marker.name, marker.location
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)
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self.set_result(f"Please place {marker.name} in the passband.")
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return -1
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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.set_result("Bandpass center not found")
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return -1
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return peak
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def find_bounderies(
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self, gains: list[float], peak: int, peak_db: float
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) -> dict[str, int]:
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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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)
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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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)
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return cutoff_pos
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