GUI.py

import numpy as np
import matplotlib.pyplot as plt
import time
from rtlsdr import RtlSdr
from matplotlib.widgets import TextBox

# configure SDR
sdr = RtlSdr()
sdr.sample_rate = 2.4e6
sdr.gain = 'auto'

Fs = sdr.sample_rate
Ts = 1/Fs # sample period
N = 256*1024
noise_power = 2

# create the figure and axis for the plot
fig, ax = plt.subplots()
ax.set_xlabel("Frequency [Hz]")
ax.set_ylabel("Magnitude [dB]")

ax.grid(True)
def submit(text):
   
    sdr.center_freq = float(text)

    while True:
        samples = sdr.read_samples(N)
        PSD = np.abs(np.fft.fft(samples))**2 / (N*Fs)
        PSD_log = 10.0*np.log10(PSD)
        PSD_shifted = np.fft.fftshift(PSD_log)
        print(PSD_shifted)

        f = np.linspace(-Fs/2, Fs/2, N, endpoint=False) + sdr.center_freq

        ax.clear()
        ax.plot(f, PSD_shifted)
        ax.set_xlabel("Frequency [Hz]")
        ax.set_ylabel("Magnitude [dB]")
        ax.grid(True)
        plt.pause(0.01) # pause briefly to show the plot
    sdr.close()

txbox = fig.add_axes([0.3, 0.02, 0.5, 0.07])
text_box = TextBox(txbox, 'Enter Center Frequency', initial='')
text_box.on_submit(submit)
plt.show()