nanovna-saver/src/NanoVNASaver/Settings/Sweep.py

#  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
from dataclasses import dataclass, replace
from enum import Enum
from math import log
from threading import Lock
from typing import Iterator, NamedTuple

logger = logging.getLogger(__name__)


class SweepMode(Enum):
    SINGLE = 0
    CONTINOUS = 1
    AVERAGE = 2


class Properties(NamedTuple):
    name: str = ""
    mode: "SweepMode" = SweepMode.SINGLE
    averages: tuple[int, int] = (3, 0)
    logarithmic: bool = False


@dataclass
class Sweep:
    start: int = 3600000
    end: int = 30000000
    points: int = 101
    segments: int = 1
    properties: "Properties" = Properties()

    def __post_init__(self):
        self.lock = Lock()
        self.check()
        logger.debug("%s", self)

    def copy(self) -> "Sweep":
        return replace(self)

    @property
    def span(self) -> int:
        return self.end - self.start

    @property
    def stepsize(self) -> int:
        return round(self.span / (self.points * self.segments - 1))

    def check(self):
        if (
            self.segments <= 0
            or self.points <= 0
            or self.start < 0
            or self.end <= 0
            or self.stepsize < 1
        ):
            raise ValueError(f"Illegal sweep settings: {self}")

    def _exp_factor(self, index: int) -> float:
        return 1 - log(self.segments + 1 - index) / log(self.segments + 1)

    def get_index_range(self, index: int) -> tuple[int, int]:
        if not self.properties.logarithmic:
            start = self.start + index * self.points * self.stepsize
            end = start + (self.points - 1) * self.stepsize
        else:
            start = round(self.start + self.span * self._exp_factor(index))
            end = round(self.start + self.span * self._exp_factor(index + 1))
        logger.debug("get_index_range(%s) -> (%s, %s)", index, start, end)
        return start, end

    def get_frequencies(self) -> Iterator[int]:
        for i in range(self.segments):
            start, stop = self.get_index_range(i)
            step = (stop - start) / self.points
            freq = start
            for _ in range(self.points):
                yield round(freq)
                freq += step