add image of my janky cal standard

README.md

@@ -1,5 +1,9 @@
 # Charon VNA
 
+<!-- ![PyPi Downloads](https://img.shields.io/pypi/dm/charon-vna) -->
+<!-- ![Last Commit](https://img.shields.io/gitea/last-commit/brendanhaines/charon-vna?gitea_url=https%3A%2F%2Fgit.brendanhaines.com) -->
+<!-- ![Workflow Status](https://git.brendanhaines.com/brendanhaines/charon-vna/actions/workflows/python_publish.yml/badge.svg) -->
+
 Named after [Pluto's moon](https://en.wikipedia.org/wiki/Charon_(moon)), Charon uses the [ADI Pluto SDR](https://www.analog.com/en/resources/evaluation-hardware-and-software/evaluation-boards-kits/adalm-pluto.html) as a vector network analyzer. The basic usage is as a 1 port VNA but this can be extended to arbitrarily many ports with the addition of a couple RF switches.
 
 ## Installation
@@ -7,7 +11,8 @@ Named after [Pluto's moon](https://en.wikipedia.org/wiki/Charon_(moon)), Charon
 1. Install LibIIO. This is a dependency of [PyADI-IIO](https://wiki.analog.com/resources/tools-software/linux-software/pyadi-iio).
 On Ubuntu 22.04 just run `sudo apt-get install -y libiio-dev`
 
-2. `pip install charon-vna`
+2. Charon releases are published on [PyPi](https://pypi.org/project/charon-vna/). Install using pip:
+`pip install charon-vna`
 
 ## Hardware Setup
 
@@ -17,13 +22,14 @@ You need a few things:
   - Note that you _must_ have two receive ports which means revision C or later of the basic Pluto
 - Directional couplers (1 per port up to 4 ports)
   - I have been using [AAMCS-UDC-0.5G-18G-10dB-Sf](http://www.aa-mcs.com/wp-content/uploads/documents/AAMCS-UDC-0.5G-18G-10dB-Sf.pdf)
-- Charon switch board  - coming soon.
+- [Cerberus RF switch](https://git.brendanhaines.com/brendanhaines/cerberus_sp4t) + [Pluto IO Shield](https://git.brendanhaines.com/brendanhaines/pluto_io_shield)
   - Optional. Without this you'll be limited to S11 and uncalibrated S21 measurements (with required re-cabling)
   - There's nothing special about this particular board, if you want more than 4 ports you can make your own pretty easily. You just need 3 SPxT switches. Note that these switches will see tons of cycles so avoid mechanical switches
 - SMA cables
 - Calibration standard
   - Ideally something with s-parameters measured on a better VNA
   - I have used a basic SMA load and two modified SMA jacks with decent results
+    ![calibration standard](img/calibration_standard.jpg)
 
 ### Pluto Configuration
 
@@ -48,6 +54,7 @@ It will also be accessible over a socket to enable test automation with external
 TBD
 
 ### Power Calibration
+
 I include a default output power lookup table. This is derived from two TX channels of two Pluto SDRs and does not include any of the loss of a coupler or Charon switch board.
 
 Absolute output power is generally not well calibrated for VNAs anyway and has negligible impact on most measurements so this is probably sufficient for most users. If you're trying to run a power sweep this may be insufficient.
@@ -59,6 +66,13 @@ Note that unlike the main calibration, power calibration frequencies do not need
 ## References
 
 #### Pluto Default Connection Settings
-user: `root`
+
-password: `analog`
+- user: `root`
-ip: `192.168.2.1`
+- password: `analog`
+- ip: `192.168.2.1`
+
+## Alternatives
+
+- [NanoVNA](https://nanovna.com/). 2-ports. 50 kHz - 2.7 GHz. Degraded performance above 1.5 GHz. S11 and S21 only.
+- [pluto-network-analyzer](https://github.com/fromconcepttocircuit/pluto-network-analyzer). 2-ports. 100 MHz - 3 GHz. S11 and S21 only. Uses a [wideband RF bridge](https://www.60dbm.com/product/rf-bridge-1-3000-mhz/) instead of a coupler
+- [LibreVNA](https://github.com/jankae/LibreVNA). 2-ports. 100 KHz - 6 GHz. I've never used this but it is almost certainly faster than Charon. Not sure how the performance compares. $700 on [AliExpress](https://www.aliexpress.us/item/3256802242049773.html?gatewayAdapt=glo2usa4itemAdapt)

charon_vna/config_default.py

@@ -3,14 +3,14 @@ import subprocess
 
 import numpy as np
 
-from charon_vna.gui import DEFAULT_CONFIG
+from charon_vna.gui import PATH_CONFIG_DEFAULT
 
 config = dict(
     frequency=np.linspace(80e6, 500e6, 500).tolist(),
     power=-5,
 )
 
-with open(DEFAULT_CONFIG, "w") as f:
+with open(PATH_CONFIG_DEFAULT, "w") as f:
     json.dump(config, f)
 
 # autoformat
@@ -19,7 +19,7 @@ subprocess.run(
         "python",
         "-m",
         "json.tool",
-        DEFAULT_CONFIG.resolve().as_posix(),
+        PATH_CONFIG_DEFAULT.resolve().as_posix(),
-        DEFAULT_CONFIG.resolve().as_posix(),
+        PATH_CONFIG_DEFAULT.resolve().as_posix(),
     ]
 )

charon_vna/gui.py

@@ -3,6 +3,7 @@ import json
 import pickle
 import re
 import sys
+import webbrowser
 from pathlib import Path
 from typing import List
 
@@ -14,23 +15,23 @@ from numpy import typing as npt
 from PySide6.QtGui import QAction, QKeySequence
 from PySide6.QtWidgets import (
     QApplication,
-    QDialogButtonBox,
     QFileDialog,
     QInputDialog,
     QLineEdit,
     QMainWindow,
     QMenu,
     QProgressBar,
+    QTabWidget,
     QVBoxLayout,
     QWidget,
 )
-from vna import Charon
 
 from charon_vna.plots import PlotWidget
 from charon_vna.util import net2s, s2net
+from charon_vna.vna import Charon
 
 # %%
-DEFAULT_CONFIG = Path(__file__).parent / "config_default.json"
+PATH_CONFIG_DEFAULT = Path(__file__).parent / "config_default.json"
 CONFIG_SUFFIX = ".json"
 
 
@@ -43,7 +44,7 @@ class MainWindow(QMainWindow):
     def __init__(self, ip: str | None = None):
         super().__init__()
 
-        self.config_path = DEFAULT_CONFIG
+        self.config_path = PATH_CONFIG_DEFAULT
         with open(self.config_path, "r") as f:
             config = json.load(f)
         self._frequency = config["frequency"]
@@ -96,6 +97,19 @@ class MainWindow(QMainWindow):
         action_cal_solt.triggered.connect(self.calibrate_solt)
         menu_calibration.addAction(action_cal_solt)
 
+        menu_help = QMenu("&Help")
+        menubar.addMenu(menu_help)
+        action_open_homepage = QAction("&Documentation", self)
+        action_open_homepage.triggered.connect(
+            lambda: webbrowser.open("https://git.brendanhaines.com/brendanhaines/charon_vna")
+        )
+        menu_help.addAction(action_open_homepage)
+        action_report_issue = QAction("&Report an Issue", self)
+        action_report_issue.triggered.connect(
+            lambda: webbrowser.open("https://git.brendanhaines.com/brendanhaines/charon_vna/issues")
+        )
+        menu_help.addAction(action_report_issue)
+
         # Content
         window_layout = QVBoxLayout()
 
@@ -104,19 +118,20 @@ class MainWindow(QMainWindow):
         prog_sweep.setMaximum(100)
         prog_sweep.setFormat("%v / %m")
         # prog_sweep.setTextVisible(False)
-        prog_sweep.setValue(50)
+        prog_sweep.setValue(0)
         window_layout.addWidget(prog_sweep)
         self.prog_sweep = prog_sweep
 
-        # window_widget.se
+        plot_widget = QTabWidget()
-        plot_layout = QVBoxLayout()
-        # TODO: handle plots properly
         self.plots = []
-        for type_ in ["logmag", "phase", "vswr", "smith"]:
+        for type_ in [
+            "logmag",
+            "phase",
+            "vswr",
+            "smith",
+        ]:
             self.plots.append(PlotWidget(type_=type_))
-            plot_layout.addWidget(self.plots[-1])
+            plot_widget.addTab(self.plots[-1], type_)
-        plot_widget = QWidget()
-        plot_widget.setLayout(plot_layout)
         window_layout.addWidget(plot_widget)
 
         # Set the central widget of the Window.
@@ -127,6 +142,7 @@ class MainWindow(QMainWindow):
     def saveas_config(self) -> None:
         print("Prompting for save path...")
         dialog = QFileDialog(self)
+        dialog.setNameFilter(f"*{CONFIG_SUFFIX}")
         dialog.setDefaultSuffix(CONFIG_SUFFIX)
         dialog.setAcceptMode(QFileDialog.AcceptMode.AcceptSave)
         if dialog.exec():
@@ -135,8 +151,8 @@ class MainWindow(QMainWindow):
                 raise ValueError(
                     f"{config_path.name} is not a valid configuration file. Must have extension {CONFIG_SUFFIX}"
                 )
-            if config_path == DEFAULT_CONFIG:
+            if config_path == PATH_CONFIG_DEFAULT:
-                raise ValueError(f"Cannot overwrite default configuration file at {DEFAULT_CONFIG}")
+                raise ValueError(f"Cannot overwrite default configuration file at {PATH_CONFIG_DEFAULT}")
             self.config_path = config_path
             print(f"Config path is now {self.config_path.resolve()}")
 
@@ -160,7 +176,7 @@ class MainWindow(QMainWindow):
             self.load_config(self.config_path)
 
     def save_config(self) -> None:
-        if self.config_path == DEFAULT_CONFIG:
+        if self.config_path == PATH_CONFIG_DEFAULT:
             self.saveas_config()
         else:
             print(f"Saving config to {self.config_path.resolve()}")

charon_vna/io_.py

@@ -1,11 +1,94 @@
+import json
+import shutil
+import zipfile
 from pathlib import Path
+from tempfile import TemporaryDirectory
+from typing import List
 
 import skrf as rf
-from util import net2s
 
 
-# scikit-rf has no way to save files aside from touchstone and pickle
+# scikit-rf has no way to save Calibration objects aside from pickle
-def cal2zarr(cal: rf.calibration.Calibration, outpath: Path):
+def cal2zip(cal: rf.calibration.Calibration, path: Path | str) -> None:
-    ideals = [net2s(net) for net in cal.ideals]
+    path = Path(path)
-    measured = [net2s(net) for net in cal.measured]
+    cal_type = cal.__class__
-    # s.to_zarr(outpath)
+    measured: List[rf.network.Network] = cal.measured
+    ideals: List[rf.network.Network] = cal.ideals
+
+    if cal_type not in [rf.calibration.OnePort]:
+        raise NotImplementedError(f"Calibration {cal_type.__name__} serialization not implemented")
+
+    assert len(ideals) == len(measured)  # this should have already been asserted when cal was instantiated
+
+    with TemporaryDirectory() as temp:
+        dir_temp = Path(temp)
+
+        with zipfile.ZipFile(dir_temp / "archive.zip", "w") as archive:
+            # create a configuration file
+            filename_config = dir_temp / "config.json"
+            with open(filename_config, "w") as f:
+                json.dump(
+                    dict(
+                        cal_type=cal_type.__name__,
+                        num_standards=len(measured),
+                    ),
+                    f,
+                )
+            archive.write(filename_config, str(filename_config.relative_to(dir_temp)))
+
+            # add standard data
+            dir_ideals = dir_temp / "ideals"
+            dir_ideals.mkdir()
+            for ii, ideal in enumerate(ideals):
+                filename = dir_ideals / f"{ii}.s2p"
+                ideal.write_touchstone(filename)
+                archive.write(filename, str(filename.relative_to(dir_temp)))
+
+            # add test data
+            dir_measured = dir_temp / "measured"
+            dir_measured.mkdir()
+            for ii, meas in enumerate(measured):
+                filename = dir_measured / f"{ii}.s2p"
+                meas.write_touchstone(filename)
+                archive.write(filename, str(filename.relative_to(dir_temp)))
+
+            print("Wrote calibration to file")
+            archive.printdir()
+
+        shutil.move(dir_temp / "archive.zip", path)
+
+
+def zip2cal(path: Path | str):
+    path = Path(path)
+    if not path.exists():
+        raise FileNotFoundError(f"Calibration file {path} does not exist")
+
+    with zipfile.ZipFile(path) as archive:
+        archive.printdir()
+
+        config = json.loads(archive.read("config.json"))
+        print(config)
+
+        ideals = list()
+        measured = list()
+
+        with TemporaryDirectory() as temp:
+            dir_temp = Path(temp)
+
+            for ii in range(config["num_standards"]):
+                with open(dir_temp / f"{ii}.s2p", "wb") as f:
+                    f.write(archive.read(f"ideals/{ii}.s2p"))
+                ideals.append(rf.network.Network(dir_temp / f"{ii}.s2p"))
+
+                with open(dir_temp / f"{ii}.s2p", "wb") as f:
+                    f.write(archive.read(f"measured/{ii}.s2p"))
+                measured.append(rf.network.Network(dir_temp / f"{ii}.s2p"))
+
+    cal_type = config["cal_type"]
+    CalClass = getattr(rf.calibration, cal_type)
+    if not issubclass(CalClass, rf.calibration.Calibration):
+        raise ValueError()
+
+    calibration = CalClass(measured=measured, ideals=ideals)
+
+    return calibration

charon_vna/vna.py

@@ -1,11 +1,11 @@
 # %% imports
 import copy
+from enum import IntEnum, unique
 from pathlib import Path
-from typing import Any, Callable, Dict, Tuple
+from typing import Any, Callable, Dict, Literal, Tuple
 
 import adi
-
+import iio
-# import iio
 import numpy as np
 import skrf as rf
 import xarray as xr
@@ -34,14 +34,61 @@ def generate_tone(f: float, fs: float, N: int = 1024, scale: int = 2**14):
     return iq
 
 
+@unique
+class AD9361Register(IntEnum):
+    AUXDAC1_WORD = 0x018
+    AUXDAC2_WORD = 0x019
+    AUXDAC1_CONFIG = 0x01A
+    AUXDAC2_CONFIG = 0x01B
+    AUXADC_CLOCK_DIVIDER = 0x01C
+    AUXADC_CONFIG = 0x01D
+    AUXADC_WORD_MSB = 0x01E
+    AUXADC_WORD_LSB = 0x01F
+    AUTO_GPIO = 0x020
+    AGC_GAIN_LOCK_DELAY = 0x021
+    AGC_ATTACK_DELAY = 0x022
+    AUXDAC_ENABLE_CONTROL = 0x023
+    RX_LOAD_SYNTH_DELAY = 0x024
+    TX_LOAD_SYNTH_DELAY = 0x025
+    EXTERNAL_LNA_CONTROL = 0x026
+    GPO_FORCE_AND_INIT = 0x027
+    GPO0_RX_DELAY = 0x028
+    GPO1_RX_DELAY = 0x029
+    GPO2_RX_DELAY = 0x02A
+    GPO3_RX_DELAY = 0x02B
+    GPO0_TX_DELAY = 0x02C
+    GPO1_TX_DELAY = 0x02D
+    GPO2_TX_DELAY = 0x02E
+    GPO3_TX_DELAY = 0x02F
+    AUXDAC1_RX_DELAY = 0x030
+    AUXDAC1_TX_DELAY = 0x031
+    AUXDAC2_RX_DELAY = 0x032
+    AUXDAC2_TX_DELAY = 0x033
+
+
+@unique
+class AD9361DacVref(IntEnum):
+    VREF_1V0 = 0b00
+    VREF_1V5 = 0b01
+    VREF_2V0 = 0b10
+    VREF_2V5 = 0b11
+
+
+@unique
+class AD9361DacStepFactor(IntEnum):
+    FACTOR_2 = 0b0
+    FACTOR_1 = 0b1
+
+
 class Charon:
     FREQUENCY_OFFSET = 1e6
+    DEFAULT_IP = "192.168.2.1"
 
     calibration: rf.calibration.Calibration | None = None
 
     def __init__(
         self,
-        ip: str = "192.168.2.1",
+        ip: str = DEFAULT_IP,
         frequency: npt.ArrayLike = np.linspace(1e9, 2e9, 3),
         ports: Tuple[int] = (1,),
     ):
@@ -49,7 +96,8 @@ class Charon:
         self.frequency = frequency
 
         # everything RF
-        self.sdr = adi.ad9361(uri=f"ip:{ip}")
+        uri = f"ip:{ip}"
+        self.sdr = adi.ad9361(uri=uri)
         for attr, expected in [
             ("adi,2rx-2tx-mode-enable", True),
             # ("adi,gpo-manual-mode-enable", True),
@@ -81,14 +129,16 @@ class Charon:
         self.sdr.tx_hardwaregain_chan0 = -10
 
         # # switch control
-        # ctx = iio.Context(uri)
+        ctx = iio.Context(uri)
-        # self.ctrl = ctx.find_device("ad9361-phy")
+        self.ctrl = ctx.find_device("ad9361-phy")
-        # # raw ad9361 register accesss:
+        # raw ad9361 register accesss:
-        # # https://ez.analog.com/linux-software-drivers/f/q-a/120853/control-fmcomms3-s-gpo-with-python
+        # https://ez.analog.com/linux-software-drivers/f/q-a/120853/control-fmcomms3-s-gpo-with-python
-        # # https://www.analog.com/media/cn/technical-documentation/user-guides/ad9364_register_map_reference_manual_ug-672.pdf  # noqa: E501
+        # https://www.analog.com/media/cn/technical-documentation/user-guides/ad9364_register_map_reference_manual_ug-672.pdf  # noqa: E501
-        # self.ctrl.reg_write(0x26, 0x90)  # bit 7: AuxDAC Manual, bit 4: GPO Manual
+        self.ctrl.reg_write(AD9361Register.EXTERNAL_LNA_CONTROL, 0x90)  # bit 7: AuxDAC Manual, bit 4: GPO Manual
-        # self._set_gpo(self.ports[0] - 1)
+        self.ctrl.reg_write(AD9361Register.AUXDAC_ENABLE_CONTROL, 0x3F)
-        # # TODO: init AuxDAC
+        self._set_gpo(0b0000)
+        self._set_dac_code(value=0, channel=1)
+        self._set_dac_code(value=0, channel=2)
 
     def get_config(self) -> Dict[str, Any]:
         config = dict()
@@ -113,28 +163,74 @@ class Charon:
         return config
 
     def _get_gpo(self) -> int:
-        return (self.ctrl.reg_read(0x27) >> 4) & 0x0F
+        return (self.ctrl.reg_read(AD9361Register.GPO_FORCE_AND_INIT) >> 4) & 0x0F
 
     def _set_gpo(self, value: int) -> None:
-        self.ctrl.reg_write(0x27, (value & 0x0F) << 4)  # bits 7-4: GPO3-0
+        self.ctrl.reg_write(AD9361Register.GPO_FORCE_AND_INIT, (value & 0x0F) << 4)  # bits 7-4: GPO3-0
+
+    def _set_dac_voltage(self, voltage: float, channel: Literal[1, 2]):
+        raise NotImplementedError()
+
+    def _set_dac_code(
+        self,
+        value: int,
+        channel: Literal[1, 2],
+        vref: AD9361DacVref = AD9361DacVref.VREF_1V0,
+        step_factor: AD9361DacStepFactor = AD9361DacStepFactor.FACTOR_2,
+    ) -> None:
+        if channel not in [1, 2]:
+            raise ValueError(f"Invalid channel {channel}. Must be 1 or 2")
+
+        if value > 0x3FF or value < 0:
+            raise ValueError("Invalid value for 10 bit DAC. Must be between 0 and 0x3FF (inclusive)")
+
+        vref = AD9361DacVref(vref)
+        step_factor = AD9361DacStepFactor(step_factor)
+
+        # https://www.analog.com/media/cn/technical-documentation/user-guides/ad9364_register_map_reference_manual_ug-672.pdf
+        # page 13
+        # vout = 0.97 * vref + (0.000738 + 9e-6 * (vref * 1.6 - 2)) * auxdac_word[9:0] * step_factor - 0.3572 * step_factor + 0.05
+        # vout ~= (vref - 0.3572 * step_factor) + 0.000738 * auxdac_word[9:0] * step_factor
+        # which gives a 1.5V swing with step_factor == 2 and 0.75V swing with step_factor == 1
+        # vref basically just changes the minimum voltage with negligible impact on output scaling
+
+        self.ctrl.reg_write(
+            AD9361Register.__getitem__(f"AUXDAC{channel}_WORD"),
+            (value >> 2) & 0xFF,
+        )
+        self.ctrl.reg_write(
+            AD9361Register.__getitem__(f"AUXDAC{channel}_CONFIG"),
+            (value & 0x3) | (vref.value << 2) | (step_factor << 4),
+        )
+
+    def _get_dac_code(self, channel: Literal[1, 2]) -> Tuple[float, AD9361DacVref, AD9361DacStepFactor]:
+        word = self.ctrl.reg_read(AD9361Register.__getitem__(f"AUXDAC{channel}_WORD"))
+        config = self.ctrl.reg_read(AD9361Register.__getitem__(f"AUXDAC{channel}_CONFIG"))
+
+        value = (word << 2) + (config & 0x3)
+        vref = AD9361DacVref((config >> 2) & 0x3)
+        step_factor = AD9361DacStepFactor((config >> 4) & 0x1)
+
+        return (value, vref, step_factor)
+
+    def _get_dac_voltage(self) -> float:
+        raise NotImplementedError()
 
     def set_output_power(self, power: float):
-        # FIXME: this is a hack because I don't want to go through re-calibration
+        pout = xr.DataArray(
-        if power == 5:
+            [-15, -10, -5, 0, 5],
-            tx_gain = -1
+            dims=["tx_gain"],
-        elif power == 0:
+            coords=dict(
-            tx_gain = -7
+                # TODO: correct over frequency
-        elif power == -5:
+                frequency=1e9,  # FIXME: I'm not sure at what frequency I generated this table
-            tx_gain = -12
+                tx_channel=0,
-        elif power == -10:
+                tx_gain=[-22, -17, -12, -7, -1],
-            tx_gain = -17
+            ),
-        elif power == -15:
+        )
-            tx_gain = -22
+
-        else:
+        tx_gain_idx = np.abs(pout - power).argmin(dim="tx_gain")
-            raise NotImplementedError()
+        tx_gain = pout.coords["tx_gain"][tx_gain_idx]
-            # # TODO: correct over frequency
+
-            # tx_gain_idx = np.abs(pout.sel(tx_channel=0) - power).argmin(dim="tx_gain")
-            # tx_gain = pout.coords["tx_gain"][tx_gain_idx]
         self.sdr.tx_hardwaregain_chan0 = float(tx_gain)
 
     def set_output(self, frequency: float, power: float):
@@ -220,6 +316,7 @@ class Charon:
         )
         for ff, freq in enumerate(s.frequency.data):
             if callback is not None:
+                # report progress during sweep
                 callback(ff, len(s.frequency))
             self.set_output(frequency=freq, power=-5)
             self.sdr.rx_destroy_buffer()
@@ -231,7 +328,9 @@ class Charon:
             self.sdr.rx_hardwaregain_chan1 = 40
             rx = self.sdr.rx()
             s.loc[dict(frequency=freq)] = np.mean(rx[1] / rx[0])
+
         if callback is not None:
+            # mark capture as complete
             callback(len(s.frequency), len(s.frequency))
 
         return s