sweep_b_over_a working

charon_vna/vna.py

@@ -1,7 +1,7 @@
 # %% imports
 import copy
 from pathlib import Path
-from typing import Any, Dict, Optional, Tuple
+from typing import Any, Dict, Tuple
 
 import adi
 import iio
@@ -94,13 +94,24 @@ class Charon:
 
         return config
 
+    def _get_gpo(self) -> int:
+        return (self.ctrl.reg_read(0x27) >> 4) & 0x0F
+
     def _set_gpo(self, value: int) -> None:
         self.ctrl.reg_write(0x27, (value & 0x0F) << 4)  # bits 7-4: GPO3-0
 
     def set_output_power(self, power: float):
-        if power == -5:
+        # FIXME: this is a hack because I don't want to go through re-calibration
-            # FIXME: this is a hack because I don't want to go through re-calibration
+        if power == 5:
-            tx_gain = -8
+            tx_gain = -1
+        elif power == 0:
+            tx_gain = -7
+        elif power == -5:
+            tx_gain = -12
+        elif power == -10:
+            tx_gain = -17
+        elif power == -15:
+            tx_gain = -22
         else:
             raise NotImplementedError()
             # # TODO: correct over frequency
@@ -108,15 +119,13 @@ class Charon:
             # tx_gain = pout.coords["tx_gain"][tx_gain_idx]
         self.sdr.tx_hardwaregain_chan0 = float(tx_gain)
 
-    def generate_tone(self, f: float, N: int = 1024, fs: Optional[float] = None):
+    def generate_tone(self, f: float, fs: float, N: int = 1024, scale: int = 2**14):
-        if fs is None:
-            fs = self.sdr.sample_rate
         fs = int(fs)
         fc = int(f / (fs / N)) * (fs / N)
         ts = 1 / float(fs)
         t = np.arange(0, N * ts, ts)
-        i = np.cos(2 * np.pi * t * fc) * 2**14
+        i = np.cos(2 * np.pi * t * fc) * scale
-        q = np.sin(2 * np.pi * t * fc) * 2**14
+        q = np.sin(2 * np.pi * t * fc) * scale
         iq = i + 1j * q
 
         return iq
@@ -128,73 +137,87 @@ class Charon:
         self.set_output_power(power)
         self.sdr.tx_lo = int(frequency - self.FREQUENCY_OFFSET)
         self.sdr.tx_cyclic_buffer = True
-        self.sdr.tx(self.generate_tone(self.FREQUENCY_OFFSET))
+        # self.sdr.tx(self.generate_tone(f=self.FREQUENCY_OFFSET, fs=self.sdr.sample_rate))
+        self.sdr.dds_single_tone(self.FREQUENCY_OFFSET, scale=0.9, channel=0)
 
-    def _rx(self, count: int = 1) -> npt.ArrayLike:
+    def _rx(self, count: int = 1, fc: float | None = None) -> npt.ArrayLike:
         if count < 1:
             raise ValueError
+
         self.sdr.rx_destroy_buffer()
+        if fc is not None:
+            self.sdr.rx_lo = int(fc)
+        self.sdr.rx_enabled_channels = [0, 1]
+        self.sdr.gain_control_mode_chan0 = "manual"
+        self.sdr.gain_control_mode_chan1 = "manual"
+        self.sdr.rx_hardwaregain_chan0 = 30
+        self.sdr.rx_hardwaregain_chan1 = 30
         return np.concatenate([np.array(self.sdr.rx()) for _ in range(count)], axis=-1)
 
+    def get_b_over_a(self, frequency: float):
+        self.set_output(frequency=frequency, power=-5)
+
+        data = self._rx(1, fc=frequency - self.FREQUENCY_OFFSET)
+        ddc_tone = self.generate_tone(f=-self.FREQUENCY_OFFSET, fs=self.sdr.sample_rate, scale=1)
+        ddc_data = data * ddc_tone
+
+        ddc_rel = ddc_data[1] / ddc_data[0]
+
+        # plt.figure()
+        # plt.plot(
+        #     np.fft.fftshift(np.fft.fftfreq(ddc_data.shape[-1], 1 / self.sdr.sample_rate)),
+        #     np.abs(np.fft.fftshift(np.fft.fft(ddc_data, axis=-1))).T,
+        # )
+        # plt.show()
+
+        # TODO: calculate sos only once
+        n, wn = signal.buttord(
+            wp=0.3 * sdr.FREQUENCY_OFFSET,
+            ws=0.8 * sdr.FREQUENCY_OFFSET,
+            gpass=1,
+            gstop=40,
+            analog=False,
+            fs=self.sdr.sample_rate,
+        )
+        sos = signal.butter(n, wn, "lowpass", analog=False, output="sos", fs=self.sdr.sample_rate)
+        # TODO: figure out why filt sucks. Introduces SO much phase noise (out to several MHz)
+        filt_data = signal.sosfiltfilt(sos, ddc_data, axis=-1)
+
+        filt_rel = filt_data[1] / filt_data[0]
+
+        return np.mean(data[1] / data[0])
+
+    def sweep_b_over_a(self):
+        s = xr.DataArray(
+            np.zeros(
+                len(self.frequency),
+                dtype=np.complex128,
+            ),
+            dims=["frequency"],
+            coords=dict(
+                frequency=self.frequency,
+            ),
+        )
+        for frequency in self.frequency:
+            s.loc[dict(frequency=frequency)] = self.get_b_over_a(frequency=frequency)
+        return s
+
 
 # %%
-sdr = Charon("ip:192.168.3.1")
+sdr = Charon("ip:192.168.3.1", frequency=np.linspace(1e9, 1.1e9, 11))
 
 # %% initialization
 config = sdr.get_config()
+print(sdr.ctrl.debug_attrs["adi,rx-rf-port-input-select"].value)
+print(sdr.ctrl.debug_attrs["adi,tx-rf-port-input-select"].value)
 config
 
 # %% generate tone
-sdr.set_output(frequency=1e9 + sdr.FREQUENCY_OFFSET, power=-5)
+fc = 1e9
+sdr.set_output(frequency=fc + sdr.FREQUENCY_OFFSET, power=-5)
 
 # %% capture data
-data = sdr._rx(1)
+data = sdr._rx(1, fc=fc)
-
-# %%
-fig, axs = plt.subplots(2, 2, sharex=True, tight_layout=True)
-# ddc_tone = np.exp(
-#     -1j * 2 * np.pi * (sdr.FREQUENCY_OFFSET / sdr.sdr.sample_rate) * np.arange(data.shape[-1]), dtype=np.complex128
-# )
-ddc_tone = sdr.generate_tone(-sdr.FREQUENCY_OFFSET) * 2**-14
-ddc_data = data * ddc_tone
-axs[0][0].plot(np.real(ddc_data).T, label="DDC")
-axs[1][0].plot(np.imag(ddc_data).T, label="DDC")
-ddc_rel = ddc_data[1] / ddc_data[0]
-axs[0][1].plot(np.real(ddc_rel).T, label="DDC")
-axs[1][1].plot(np.imag(ddc_rel).T, label="DDC")
-n, wn = signal.buttord(
-    wp=0.3 * sdr.FREQUENCY_OFFSET,
-    ws=0.8 * sdr.FREQUENCY_OFFSET,
-    gpass=1,
-    gstop=40,
-    analog=False,
-    fs=sdr.sdr.sample_rate,
-)
-sos = signal.butter(n, wn, "lowpass", analog=False, output="sos", fs=sdr.sdr.sample_rate)
-filt_data = signal.sosfiltfilt(sos, ddc_data, axis=-1)
-axs[0][0].plot(np.real(filt_data).T, label="FILT")
-axs[1][0].plot(np.imag(filt_data).T, label="FILT")
-filt_rel = filt_data[1] / filt_data[0]
-axs[0][1].plot(np.real(filt_rel).T, label="FILT")
-axs[1][1].plot(np.imag(filt_rel).T, label="FILT")
-s = np.mean(filt_rel)
-axs[0][1].axhline(np.real(s), color="k")
-axs[1][1].axhline(np.imag(s), color="k")
-
-axs[0][0].grid(True)
-axs[1][0].grid(True)
-axs[0][1].grid(True)
-axs[1][1].grid(True)
-
-axs[0][0].legend(loc="lower right")
-axs[1][0].legend(loc="lower right")
-axs[0][1].legend(loc="lower right")
-axs[1][1].legend(loc="lower right")
-
-axs[0][0].set_ylabel("Real")
-axs[1][0].set_ylabel("Imag")
-axs[0][0].set_title("By Channel")
-axs[0][1].set_title("Relative")
 
 # %% Plot in time
 fig, axs = plt.subplots(2, 1, sharex=True, tight_layout=True)
@@ -221,35 +244,16 @@ fig.show()
 
 # %% Plot in frequency
 f = np.fft.fftfreq(data.shape[-1], 1 / sdr.sdr.sample_rate)
-RX_BITS = 10
+RX_BITS = 12  # for each of i, q (including sign bit)
-Pxx_den = np.fft.fft(data, axis=-1) / (len(data) * 2 ** (2 * RX_BITS))
+fft_data = np.fft.fft(data, axis=-1, norm="forward") / (2 ** (RX_BITS - 1))
-Pxx_den_ddc = np.fft.fft(ddc_data, axis=-1) / (len(ddc_data) * 2 ** (2 * RX_BITS))
-Pxx_den_filt = np.fft.fft(filt_data, axis=-1) / (len(filt_data) * 2 ** (2 * RX_BITS))
-fft_ddc_tone = np.fft.fft(ddc_tone, axis=-1) / (len(ddc_tone))
 plt.figure()
 for cc, chan in enumerate(sdr.sdr.rx_enabled_channels):
-    # plt.plot(
-    #     np.fft.fftshift(f),
-    #     db20(np.fft.fftshift(Pxx_den[cc])),
-    #     label=f"Channel {chan}",
-    # )
     plt.plot(
         np.fft.fftshift(f),
-        db20(np.fft.fftshift(Pxx_den_ddc[cc])),
+        db20(np.fft.fftshift(fft_data[cc])),
         label=f"Channel {chan}",
     )
-    plt.plot(
-        np.fft.fftshift(f),
-        db20(np.fft.fftshift(Pxx_den_filt[cc])),
-        label=f"Channel {chan}",
-    )
-# plt.plot(
-#     np.fft.fftshift(f),
-#     db20(np.fft.fftshift(fft_ddc_tone)),
-#     label="DDC Tone",
-# )
 plt.legend()
-# plt.ylim(1e-7, 1e2)
 plt.ylim(-100, 0)
 plt.xlabel("Frequency [Hz]")
 plt.ylabel("Power [dBfs]")