#34 - implementing input impedance setting

src/spectrumdevice/devices/digitiser/digitiser_channel.py

@@ -13,7 +13,8 @@
 )
 from spectrumdevice.exceptions import SpectrumCardIsNotADigitiser
 from spectrumdevice.settings.card_dependent_properties import CardType
-from spectrumdevice.settings.channel import VERTICAL_OFFSET_COMMANDS, VERTICAL_RANGE_COMMANDS
+from spectrumdevice.settings.channel import INPUT_IMPEDANCE_COMMANDS, InputImpedance, VERTICAL_OFFSET_COMMANDS, \
+    VERTICAL_RANGE_COMMANDS
 
 
 class SpectrumDigitiserChannel(AbstractSpectrumChannel, SpectrumDigitiserChannelInterface):
@@ -79,3 +80,15 @@ def set_vertical_offset_in_percent(self, offset: int) -> None:
         """
         self._parent_device.write_to_spectrum_device_register(VERTICAL_OFFSET_COMMANDS[self._number], offset)
         self._vertical_offset_in_percent = offset
+
+    @property
+    def input_impedance(self) -> InputImpedance:
+        """The current input impedance setting of the channel (50 Ohm or 1 MOhm)"""
+        impedance_binary_value = self._parent_device.read_spectrum_device_register(
+            INPUT_IMPEDANCE_COMMANDS[self._number]
+        )
+        return InputImpedance(impedance_binary_value)
+
+    def set_input_impedance(self, input_impedance: InputImpedance) -> None:
+        self._parent_device.write_to_spectrum_device_register(INPUT_IMPEDANCE_COMMANDS[self._number],
+                                                              input_impedance.value)

src/spectrumdevice/devices/digitiser/digitiser_interface.py

@@ -14,6 +14,7 @@
 from spectrumdevice.devices.abstract_device import SpectrumChannelInterface, SpectrumDeviceInterface
 from spectrumdevice.settings import AcquisitionMode, AcquisitionSettings
 from spectrumdevice import Measurement
+from spectrumdevice.settings.channel import InputImpedance
 
 
 class SpectrumDigitiserChannelInterface(SpectrumChannelInterface, ABC):
@@ -42,6 +43,15 @@ def set_vertical_offset_in_percent(self, offset: int) -> None:
     def convert_raw_waveform_to_voltage_waveform(self, raw_waveform: ndarray) -> ndarray:
         raise NotImplementedError()
 
+    @property
+    @abstractmethod
+    def input_impedance(self) -> InputImpedance:
+        raise NotImplementedError()
+
+    @abstractmethod
+    def set_input_impedance(self, input_impedance: InputImpedance) -> None:
+        raise NotImplementedError()
+
 
 class SpectrumDigitiserInterface(SpectrumDeviceInterface, ABC):
     """Defines the public interface for control of all Spectrum digitiser devices, be they StarHub composite devices

src/spectrumdevice/settings/__init__.py

@@ -11,6 +11,7 @@
 
 from spectrumdevice.settings.card_dependent_properties import ModelNumber
 from spectrumdevice.settings.card_features import CardFeature, AdvancedCardFeature
+from spectrumdevice.settings.channel import InputImpedance
 from spectrumdevice.settings.device_modes import AcquisitionMode, ClockMode
 from spectrumdevice.settings.io_lines import IOLineMode, AvailableIOModes
 from spectrumdevice.settings.transfer_buffer import (
@@ -76,6 +77,8 @@ class AcquisitionSettings:
     """The voltage range to apply to each enabled channel in mW."""
     vertical_offsets_in_percent: List[int]
     """The DC offset to apply to each enabled channel as percentages of their vertical ranges."""
+    input_impedances: List[InputImpedance]
+    """The input impedance settings to apply to each channel"""
     timestamping_enabled: bool
     """If True, Measurements will include the time at which the acquisition was triggered. Increases latency by ~10 ms.
     """

src/spectrumdevice/settings/channel.py

@@ -13,6 +13,14 @@
     SPCM_STOPLVL_HOLDLAST,
     SPCM_STOPLVL_LOW,
     SPCM_STOPLVL_ZERO,
+    SPC_50OHM0, SPC_50OHM1, SPC_50OHM10, SPC_50OHM11, SPC_50OHM12, SPC_50OHM13, SPC_50OHM14, SPC_50OHM15, SPC_50OHM2,
+    SPC_50OHM3,
+    SPC_50OHM4,
+    SPC_50OHM5,
+    SPC_50OHM6,
+    SPC_50OHM7,
+    SPC_50OHM8,
+    SPC_50OHM9,
     SPC_AMP0,
     SPC_AMP1,
     SPC_AMP2,
@@ -219,3 +227,28 @@ class SpectrumChannelName(Enum):
     CHANNEL13 = CHANNEL13
     CHANNEL14 = CHANNEL14
     CHANNEL15 = CHANNEL15
+
+
+class InputImpedance(Enum):
+    FIFTY_OHM = 1
+    ONE_MEGA_OHM = 0
+
+
+INPUT_IMPEDANCE_COMMANDS = (
+    SPC_50OHM0,
+    SPC_50OHM1,
+    SPC_50OHM2,
+    SPC_50OHM3,
+    SPC_50OHM4,
+    SPC_50OHM5,
+    SPC_50OHM6,
+    SPC_50OHM7,
+    SPC_50OHM8,
+    SPC_50OHM9,
+    SPC_50OHM10,
+    SPC_50OHM11,
+    SPC_50OHM12,
+    SPC_50OHM13,
+    SPC_50OHM14,
+    SPC_50OHM15,
+)