kopia lustrzana https://github.com/NanoVNA-Saver/nanovna-saver
363 wiersze
15 KiB
Python
363 wiersze
15 KiB
Python
# NanoVNASaver
|
|
#
|
|
# A python program to view and export Touchstone data from a NanoVNA
|
|
# Copyright (C) 2019, 2020 Rune B. Broberg
|
|
# Copyright (C) 2020,2021 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 PyQt5 import QtWidgets
|
|
|
|
from NanoVNASaver.Formatting import format_frequency
|
|
|
|
from NanoVNASaver.Analysis import Analysis
|
|
|
|
logger = logging.getLogger(__name__)
|
|
|
|
|
|
class BandPassAnalysis(Analysis):
|
|
def __init__(self, app):
|
|
super().__init__(app)
|
|
|
|
self._widget = QtWidgets.QWidget()
|
|
|
|
layout = QtWidgets.QFormLayout()
|
|
self._widget.setLayout(layout)
|
|
layout.addRow(QtWidgets.QLabel("Band pass filter analysis"))
|
|
layout.addRow(
|
|
QtWidgets.QLabel(
|
|
f"Please place {self.app.markers[0].name} in the filter passband."))
|
|
self.result_label = QtWidgets.QLabel()
|
|
self.lower_cutoff_label = QtWidgets.QLabel()
|
|
self.lower_six_db_label = QtWidgets.QLabel()
|
|
self.lower_sixty_db_label = QtWidgets.QLabel()
|
|
self.lower_db_per_octave_label = QtWidgets.QLabel()
|
|
self.lower_db_per_decade_label = QtWidgets.QLabel()
|
|
|
|
self.upper_cutoff_label = QtWidgets.QLabel()
|
|
self.upper_six_db_label = QtWidgets.QLabel()
|
|
self.upper_sixty_db_label = QtWidgets.QLabel()
|
|
self.upper_db_per_octave_label = QtWidgets.QLabel()
|
|
self.upper_db_per_decade_label = QtWidgets.QLabel()
|
|
layout.addRow("Result:", self.result_label)
|
|
|
|
layout.addRow(QtWidgets.QLabel(""))
|
|
|
|
self.center_frequency_label = QtWidgets.QLabel()
|
|
self.span_label = QtWidgets.QLabel()
|
|
self.six_db_span_label = QtWidgets.QLabel()
|
|
self.quality_label = QtWidgets.QLabel()
|
|
|
|
layout.addRow("Center frequency:", self.center_frequency_label)
|
|
layout.addRow("Bandwidth (-3 dB):", self.span_label)
|
|
layout.addRow("Quality factor:", self.quality_label)
|
|
layout.addRow("Bandwidth (-6 dB):", self.six_db_span_label)
|
|
|
|
layout.addRow(QtWidgets.QLabel(""))
|
|
|
|
layout.addRow(QtWidgets.QLabel("Lower side:"))
|
|
layout.addRow("Cutoff frequency:", self.lower_cutoff_label)
|
|
layout.addRow("-6 dB point:", self.lower_six_db_label)
|
|
layout.addRow("-60 dB point:", self.lower_sixty_db_label)
|
|
layout.addRow("Roll-off:", self.lower_db_per_octave_label)
|
|
layout.addRow("Roll-off:", self.lower_db_per_decade_label)
|
|
|
|
layout.addRow(QtWidgets.QLabel(""))
|
|
|
|
layout.addRow(QtWidgets.QLabel("Upper side:"))
|
|
layout.addRow("Cutoff frequency:", self.upper_cutoff_label)
|
|
layout.addRow("-6 dB point:", self.upper_six_db_label)
|
|
layout.addRow("-60 dB point:", self.upper_sixty_db_label)
|
|
layout.addRow("Roll-off:", self.upper_db_per_octave_label)
|
|
layout.addRow("Roll-off:", self.upper_db_per_decade_label)
|
|
|
|
def reset(self):
|
|
self.result_label.clear()
|
|
self.center_frequency_label.clear()
|
|
self.span_label.clear()
|
|
self.quality_label.clear()
|
|
self.six_db_span_label.clear()
|
|
|
|
self.upper_cutoff_label.clear()
|
|
self.upper_six_db_label.clear()
|
|
self.upper_sixty_db_label.clear()
|
|
self.upper_db_per_octave_label.clear()
|
|
self.upper_db_per_decade_label.clear()
|
|
|
|
self.lower_cutoff_label.clear()
|
|
self.lower_six_db_label.clear()
|
|
self.lower_sixty_db_label.clear()
|
|
self.lower_db_per_octave_label.clear()
|
|
self.lower_db_per_decade_label.clear()
|
|
|
|
def runAnalysis(self):
|
|
self.reset()
|
|
pass_band_location = self.app.markers[0].location
|
|
logger.debug("Pass band location: %d", pass_band_location)
|
|
|
|
if len(self.app.data.s21) == 0:
|
|
logger.debug("No data to analyse")
|
|
self.result_label.setText("No data to analyse.")
|
|
return
|
|
|
|
if pass_band_location < 0:
|
|
logger.debug("No location for %s", self.app.markers[0].name)
|
|
self.result_label.setText(
|
|
f"Please place {self.app.markers[0].name} in the passband.")
|
|
return
|
|
|
|
pass_band_db = self.app.data.s21[pass_band_location].gain
|
|
|
|
logger.debug("Initial passband gain: %d", pass_band_db)
|
|
|
|
initial_lower_cutoff_location = -1
|
|
for i in range(pass_band_location, -1, -1):
|
|
if (pass_band_db - self.app.data.s21[i].gain) > 3:
|
|
# We found a cutoff location
|
|
initial_lower_cutoff_location = i
|
|
break
|
|
|
|
if initial_lower_cutoff_location < 0:
|
|
self.result_label.setText("Lower cutoff location not found.")
|
|
return
|
|
|
|
initial_lower_cutoff_frequency = self.app.data.s21[initial_lower_cutoff_location].freq
|
|
|
|
logger.debug("Found initial lower cutoff frequency at %d", initial_lower_cutoff_frequency)
|
|
|
|
initial_upper_cutoff_location = -1
|
|
for i in range(pass_band_location, len(self.app.data.s21), 1):
|
|
if (pass_band_db - self.app.data.s21[i].gain) > 3:
|
|
# We found a cutoff location
|
|
initial_upper_cutoff_location = i
|
|
break
|
|
|
|
if initial_upper_cutoff_location < 0:
|
|
self.result_label.setText("Upper cutoff location not found.")
|
|
return
|
|
|
|
initial_upper_cutoff_frequency = self.app.data.s21[initial_upper_cutoff_location].freq
|
|
|
|
logger.debug("Found initial upper cutoff frequency at %d", initial_upper_cutoff_frequency)
|
|
|
|
peak_location = -1
|
|
peak_db = self.app.data.s21[initial_lower_cutoff_location].gain
|
|
for i in range(initial_lower_cutoff_location, initial_upper_cutoff_location, 1):
|
|
db = self.app.data.s21[i].gain
|
|
if db > peak_db:
|
|
peak_db = db
|
|
peak_location = i
|
|
|
|
logger.debug("Found peak of %f at %d", peak_db, self.app.data.s11[peak_location].freq)
|
|
|
|
lower_cutoff_location = -1
|
|
pass_band_db = peak_db
|
|
for i in range(peak_location, -1, -1):
|
|
if (pass_band_db - self.app.data.s21[i].gain) > 3:
|
|
# We found the cutoff location
|
|
lower_cutoff_location = i
|
|
break
|
|
|
|
lower_cutoff_frequency = self.app.data.s21[lower_cutoff_location].freq
|
|
lower_cutoff_gain = self.app.data.s21[lower_cutoff_location].gain - pass_band_db
|
|
|
|
if lower_cutoff_gain < -4:
|
|
logger.debug("Lower cutoff frequency found at %f dB"
|
|
" - insufficient data points for true -3 dB point.",
|
|
lower_cutoff_gain)
|
|
logger.debug("Found true lower cutoff frequency at %d", lower_cutoff_frequency)
|
|
|
|
self.lower_cutoff_label.setText(
|
|
f"{format_frequency(lower_cutoff_frequency)}"
|
|
f" ({round(lower_cutoff_gain, 1)} dB)")
|
|
|
|
self.app.markers[1].setFrequency(str(lower_cutoff_frequency))
|
|
self.app.markers[1].frequencyInput.setText(str(lower_cutoff_frequency))
|
|
|
|
upper_cutoff_location = -1
|
|
pass_band_db = peak_db
|
|
for i in range(peak_location, len(self.app.data.s21), 1):
|
|
if (pass_band_db - self.app.data.s21[i].gain) > 3:
|
|
# We found the cutoff location
|
|
upper_cutoff_location = i
|
|
break
|
|
|
|
upper_cutoff_frequency = self.app.data.s21[upper_cutoff_location].freq
|
|
upper_cutoff_gain = self.app.data.s21[upper_cutoff_location].gain - pass_band_db
|
|
if upper_cutoff_gain < -4:
|
|
logger.debug("Upper cutoff frequency found at %f dB"
|
|
" - insufficient data points for true -3 dB point.",
|
|
upper_cutoff_gain)
|
|
|
|
logger.debug("Found true upper cutoff frequency at %d", upper_cutoff_frequency)
|
|
|
|
self.upper_cutoff_label.setText(
|
|
f"{format_frequency(upper_cutoff_frequency)}"
|
|
f" ({round(upper_cutoff_gain, 1)} dB)")
|
|
self.app.markers[2].setFrequency(str(upper_cutoff_frequency))
|
|
self.app.markers[2].frequencyInput.setText(str(upper_cutoff_frequency))
|
|
|
|
span = upper_cutoff_frequency - lower_cutoff_frequency
|
|
center_frequency = math.sqrt(
|
|
lower_cutoff_frequency * upper_cutoff_frequency)
|
|
q = center_frequency / span
|
|
|
|
self.span_label.setText(format_frequency(span))
|
|
self.center_frequency_label.setText(
|
|
format_frequency(center_frequency))
|
|
self.quality_label.setText(str(round(q, 2)))
|
|
|
|
self.app.markers[0].setFrequency(str(round(center_frequency)))
|
|
self.app.markers[0].frequencyInput.setText(str(round(center_frequency)))
|
|
|
|
# Lower roll-off
|
|
|
|
lower_six_db_location = -1
|
|
for i in range(lower_cutoff_location, -1, -1):
|
|
if (pass_band_db - self.app.data.s21[i].gain) > 6:
|
|
# We found 6dB location
|
|
lower_six_db_location = i
|
|
break
|
|
|
|
if lower_six_db_location < 0:
|
|
self.result_label.setText("Lower 6 dB location not found.")
|
|
return
|
|
lower_six_db_cutoff_frequency = self.app.data.s21[lower_six_db_location].freq
|
|
self.lower_six_db_label.setText(
|
|
format_frequency(lower_six_db_cutoff_frequency))
|
|
|
|
ten_db_location = -1
|
|
for i in range(lower_cutoff_location, -1, -1):
|
|
if (pass_band_db - self.app.data.s21[i].gain) > 10:
|
|
# We found 6dB location
|
|
ten_db_location = i
|
|
break
|
|
|
|
twenty_db_location = -1
|
|
for i in range(lower_cutoff_location, -1, -1):
|
|
if (pass_band_db - self.app.data.s21[i].gain) > 20:
|
|
# We found 6dB location
|
|
twenty_db_location = i
|
|
break
|
|
|
|
sixty_db_location = -1
|
|
for i in range(lower_six_db_location, -1, -1):
|
|
if (pass_band_db - self.app.data.s21[i].gain) > 60:
|
|
# We found 60dB location! Wow.
|
|
sixty_db_location = i
|
|
break
|
|
|
|
if sixty_db_location > 0:
|
|
if sixty_db_location > 0:
|
|
sixty_db_cutoff_frequency = self.app.data.s21[sixty_db_location].freq
|
|
self.lower_sixty_db_label.setText(
|
|
format_frequency(sixty_db_cutoff_frequency))
|
|
elif ten_db_location != -1 and twenty_db_location != -1:
|
|
ten = self.app.data.s21[ten_db_location].freq
|
|
twenty = self.app.data.s21[twenty_db_location].freq
|
|
sixty_db_frequency = ten * \
|
|
10 ** (5 * (math.log10(twenty) - math.log10(ten)))
|
|
self.lower_sixty_db_label.setText(
|
|
f"{format_frequency(sixty_db_frequency)} (derived)")
|
|
else:
|
|
self.lower_sixty_db_label.setText("Not calculated")
|
|
|
|
if ten_db_location > 0 and twenty_db_location > 0 and ten_db_location != twenty_db_location:
|
|
octave_attenuation, decade_attenuation = self.calculateRolloff(
|
|
ten_db_location, twenty_db_location)
|
|
self.lower_db_per_octave_label.setText(
|
|
str(round(octave_attenuation, 3)) + " dB / octave")
|
|
self.lower_db_per_decade_label.setText(
|
|
str(round(decade_attenuation, 3)) + " dB / decade")
|
|
else:
|
|
self.lower_db_per_octave_label.setText("Not calculated")
|
|
self.lower_db_per_decade_label.setText("Not calculated")
|
|
|
|
# Upper roll-off
|
|
|
|
upper_six_db_location = -1
|
|
for i in range(upper_cutoff_location, len(self.app.data.s21), 1):
|
|
if (pass_band_db - self.app.data.s21[i].gain) > 6:
|
|
# We found 6dB location
|
|
upper_six_db_location = i
|
|
break
|
|
|
|
if upper_six_db_location < 0:
|
|
self.result_label.setText("Upper 6 dB location not found.")
|
|
return
|
|
upper_six_db_cutoff_frequency = self.app.data.s21[upper_six_db_location].freq
|
|
self.upper_six_db_label.setText(
|
|
format_frequency(upper_six_db_cutoff_frequency))
|
|
|
|
six_db_span = upper_six_db_cutoff_frequency - lower_six_db_cutoff_frequency
|
|
|
|
self.six_db_span_label.setText(
|
|
format_frequency(six_db_span))
|
|
|
|
ten_db_location = -1
|
|
for i in range(upper_cutoff_location, len(self.app.data.s21), 1):
|
|
if (pass_band_db - self.app.data.s21[i].gain) > 10:
|
|
# We found 6dB location
|
|
ten_db_location = i
|
|
break
|
|
|
|
twenty_db_location = -1
|
|
for i in range(upper_cutoff_location, len(self.app.data.s21), 1):
|
|
if (pass_band_db - self.app.data.s21[i].gain) > 20:
|
|
# We found 6dB location
|
|
twenty_db_location = i
|
|
break
|
|
|
|
sixty_db_location = -1
|
|
for i in range(upper_six_db_location, len(self.app.data.s21), 1):
|
|
if (pass_band_db - self.app.data.s21[i].gain) > 60:
|
|
# We found 60dB location! Wow.
|
|
sixty_db_location = i
|
|
break
|
|
|
|
if sixty_db_location > 0:
|
|
sixty_db_cutoff_frequency = self.app.data.s21[sixty_db_location].freq
|
|
self.upper_sixty_db_label.setText(
|
|
format_frequency(sixty_db_cutoff_frequency))
|
|
elif ten_db_location != -1 and twenty_db_location != -1:
|
|
ten = self.app.data.s21[ten_db_location].freq
|
|
twenty = self.app.data.s21[twenty_db_location].freq
|
|
sixty_db_frequency = ten * \
|
|
10 ** (5 * (math.log10(twenty) - math.log10(ten)))
|
|
self.upper_sixty_db_label.setText(
|
|
f"{format_frequency(sixty_db_frequency)} (derived)")
|
|
else:
|
|
self.upper_sixty_db_label.setText("Not calculated")
|
|
|
|
if ten_db_location > 0 and twenty_db_location > 0 and ten_db_location != twenty_db_location:
|
|
octave_attenuation, decade_attenuation = self.calculateRolloff(
|
|
ten_db_location, twenty_db_location)
|
|
self.upper_db_per_octave_label.setText(
|
|
f"{round(octave_attenuation, 3)} dB / octave")
|
|
self.upper_db_per_decade_label.setText(
|
|
f"{round(decade_attenuation, 3)} dB / decade")
|
|
else:
|
|
self.upper_db_per_octave_label.setText("Not calculated")
|
|
self.upper_db_per_decade_label.setText("Not calculated")
|
|
|
|
if upper_cutoff_gain < -4 or lower_cutoff_gain < -4:
|
|
self.result_label.setText(
|
|
f"Analysis complete ({len(self.app.data.s11)} points)\n"
|
|
f"Insufficient data for analysis. Increase segment count.")
|
|
else:
|
|
self.result_label.setText(
|
|
f"Analysis complete ({len(self.app.data.s11)} points)")
|