I'm not sure why exp creates such a bad tone

This commit is contained in:
Brendan Haines 2024-12-02 22:38:56 -07:00
parent 167a0b7aef
commit 48d559f084

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@ -1,7 +1,7 @@
# %% imports
import copy
from pathlib import Path
from typing import Any, Dict, Optional
from typing import Any, Dict, Optional, Tuple
import adi
import iio
@ -19,16 +19,22 @@ dir_ = Path(__file__).parent
# %% connection
class Charon:
FREQUENCY_OFFSET = 1e6
def __init__(
self,
uri: str,
frequency: npt.ArrayLike = np.linspace(1e9, 2e9, 3),
ports: Tuple[int] = (1,),
):
self.ports = ports
self.frequency = frequency
# everything RF
self.sdr = adi.ad9361(uri=uri)
for attr, expected in [
("adi,2rx-2tx-mode-enable", True),
("adi,gpo-manual-mode-enable", True),
# ("adi,gpo-manual-mode-enable", True),
]:
# available configuration options:
# https://wiki.analog.com/resources/tools-software/linux-drivers/iio-transceiver/ad9361-customization
@ -40,8 +46,8 @@ class Charon:
# TODO: it might be possible to change this on the fly.
# I think we'll actually just fail in __init__ of ad9361 if 2rx-2tx is wrong
self.sdr.rx_lo = int(frequency[0])
self.sdr.tx_lo = int(frequency[0])
self.sdr.rx_lo = int(self.frequency[0])
self.sdr.tx_lo = int(self.frequency[0])
self.sdr.sample_rate = 30e6
self.sdr.rx_rf_bandwidth = int(4e6)
self.sdr.tx_rf_bandwidth = int(4e6)
@ -63,7 +69,7 @@ class Charon:
# 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
self.ctrl.reg_write(0x26, 0x90) # bit 7: AuxDAC Manual, bit 4: GPO Manual
self._set_gpo(0)
self._set_gpo(self.ports[0] - 1)
# TODO: init AuxDAC
def get_config(self) -> Dict[str, Any]:
@ -102,60 +108,155 @@ class Charon:
# 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, offset_frequency: float = 1e6):
# TODO: switch to DDS in Pluto
def generate_tone(f: float, N: int = 1024, fs: Optional[float] = None):
if fs is None:
fs = 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
q = np.sin(2 * np.pi * t * fc) * 2**14
iq = i + 1j * q
def generate_tone(self, f: float, N: int = 1024, fs: Optional[float] = None):
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
q = np.sin(2 * np.pi * t * fc) * 2**14
iq = i + 1j * q
return iq
return iq
def set_output(self, frequency: float, power: float):
# TODO: switch to DDS in Pluto
self.sdr.tx_destroy_buffer()
self.set_output_power(power)
self.sdr.tx_lo = int(frequency - offset_frequency)
offset_frequency = frequency - self.sdr.tx_lo
self.sdr.tx_lo = int(frequency - self.FREQUENCY_OFFSET)
self.sdr.tx_cyclic_buffer = True
self.sdr.tx(generate_tone(offset_frequency))
self.sdr.tx(self.generate_tone(self.FREQUENCY_OFFSET))
def _rx(self) -> npt.ArrayLike:
def _rx(self, count: int = 1) -> npt.ArrayLike:
if count < 1:
raise ValueError
self.sdr.rx_destroy_buffer()
return np.array(self.sdr.rx())
return np.concatenate([np.array(self.sdr.rx()) for _ in range(count)], axis=-1)
# %%
sdr = Charon("ip:192.168.3.1")
# %% initialization
config = sdr.get_config()
config
# %% generate tone
sdr.set_output(frequency=1e9 + sdr.FREQUENCY_OFFSET, power=-5)
# %% capture data
data = sdr._rx(1)
# %%
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,
)
b, a = signal.butter(n, wn, "lowpass", analog=False, output="ba", fs=sdr.sdr.sample_rate)
filt_data = signal.lfilter(b, a, 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
data = sdr._rx()
fig, axs = plt.subplots(2, 1, sharex=True, tight_layout=True)
axs[0].plot(np.real(data).T)
axs[1].plot(np.imag(data).T)
axs[0].set_ylabel("Real")
axs[1].set_ylabel("Imag")
axs[-1].set_xlabel("Time")
axs[0].grid(True)
axs[1].grid(True)
axs[-1].set_xlabel("Sample")
axs[-1].set_xlim(0, data.shape[-1])
fig.show()
# %%
fig, ax = plt.subplots(1, 1, tight_layout=True)
ax.plot(np.real(data).T, np.imag(data).T)
ax.grid(True)
ax.set_aspect("equal")
ax.set_xlabel("Real")
ax.set_ylabel("Imag")
ax.set_xlim(np.array([-1, 1]) * (2 ** (12 - 1) - 1))
ax.set_ylim(ax.get_xlim())
fig.show()
# %% Plot in frequency
f, Pxx_den = signal.periodogram(data, sdr.sample_rate, axis=-1, return_onesided=False)
f, Pxx_den = signal.periodogram(data, sdr.sdr.sample_rate, axis=-1, return_onesided=False)
f_ddc, Pxx_den_ddc = signal.periodogram(ddc_data, sdr.sdr.sample_rate, axis=-1, return_onesided=False)
f_filt, Pxx_den_filt = signal.periodogram(filt_data, sdr.sdr.sample_rate, axis=-1, return_onesided=False)
f = np.fft.fftfreq(data.shape[-1], 1 / sdr.sdr.sample_rate)
Pxx_den = np.fft.fft(data, axis=-1)
Pxx_den_ddc = np.fft.fft(ddc_data, axis=-1)
Pxx_den_filt = np.fft.fft(filt_data, axis=-1)
fft_ddc_tone = np.fft.fft(ddc_tone, axis=-1)
plt.figure()
for cc, chan in enumerate(sdr.rx_enabled_channels):
plt.semilogy(f, Pxx_den[cc], label=f"Channel {chan}")
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])),
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.xlabel("frequency [Hz]")
plt.ylabel("PSD [V**2/Hz]")
# plt.ylim(1e-7, 1e2)
plt.ylim(0)
plt.xlabel("Frequency [Hz]")
plt.ylabel("PSD [$V^2/Hz$]")
plt.title(f"Fc = {sdr.sdr.rx_lo / 1e9} GHz")
plt.gca().xaxis.set_major_formatter(EngFormatter())
plt.grid(True)
plt.show()