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import os
import sys
import math
import airspyhf
import matplotlib
import numpy
import pylab
import pygame
from pygame import gfxdraw
CENTER_FREQ = 4e6
SAMPLE_RATE = 196e3
SAMPLE_NUM = 2048
GAIN = 'auto'
SCREEN_X = 1025
SCREEN_Y = 320
MOVE_STEP = 0.1e6
# init RTLSDR and if no then go out
try:
pass
except IOError:
print
"Probably RTLSDR device not attached"
sys.exit(0)
# config rtlsdr device
#rtl.sample_rate = SAMPLE_RATE
#rtl.center_freq = CENTER_FREQ
#rtl.gain = GAIN
def iq_abs(c):
return (math.sqrt((c.real ** 2 + c.imag ** 2)))
# point should be normalised to 0.0 ... 1.0
def color_normalise(point):
ret = (255, 0, 0)
# blue
if (point < 0.3):
ret = (0, 0, int(point * 255 * 3.3))
# yello
elif (point < 0.7):
ret = (0, int((point - 0.3) * 255 * 2.5), 0)
# red
elif (point <= 1.0):
ret = (int((point - 0.7) * 255 * 3.3), 0, 0)
else:
# print "Color Error ", point
pass
return ret
def color_mapping(x):
"assumes -50 to 0 range, returns color"
r = int((x + 50) * 255 // 50)
r = max(0, r)
r = min(255, r)
return (r, r, 100)
# def draw_Hz( surface, x, y, hz ):
arr = [[0 for i in range(0, SCREEN_X)] for j in range(0, SCREEN_Y)]
# init all pygame modules audio,video and more
pygame.init()
# [NEW] creates screen surface using constants
screen = pygame.display.set_mode((SCREEN_X, SCREEN_Y))
#samples = rtl.read_samples(SAMPLE_NUM)
samples = []
run = True
line = 0
while run:
# print "update"
# check for all events that where ocure
for event in pygame.event.get():
# if some one clicked on close button
if event.type == pygame.QUIT:
# terminate programm
run = False
# don't waste your time by waiting while event loop will end
break
elif event.type == pygame.KEYDOWN:
if event.key == pygame.K_LEFT:
print
"Left"
rtl.center_freq -= MOVE_STEP
print
"Center freq: ", rtl.center_freq, " Hz"
elif event.key == pygame.K_RIGHT:
print
"Right"
rtl.center_freq += MOVE_STEP
print
"Center freq: ", rtl.center_freq, " Hz"
width = SCREEN_X
height = SCREEN_Y
samples = rtl.read_samples(SAMPLE_NUM)
spect = numpy.fft.fft(samples)
spect = spect[0:len(spect) / 2]
# (1/(Fs*N)) * abs(xdft).^2;
spect_n = [(1.0 / (SAMPLE_NUM * len(spect))) * iq_abs(x) ** 2 for x in spect]
spect_n = (10 * numpy.log10(spect_n)).tolist()
# total data size
spect_len = len(spect_n)
# calculate amount spect points per pixel without rounding
pixel_width = spect_len / SCREEN_X + 1
pixel_steps = spect_len / pixel_width
for step in range(0, pixel_steps):
avg = 0.0
for i in range(0, pixel_width):
avg += spect_n[step * pixel_width + i]
avg /= pixel_width
# print avg
# gfxdraw.pixel( screen, step, line, color_normalise((100-abs(avg))/10))
gfxdraw.pixel(screen, step, line, color_mapping(avg))
# draw central freq
font = pygame.font.Font(None, 20)
text = font.render(str(rtl.center_freq / 1e6), 1, (200, 30, 30), (0, 0, 0))
screen.blit(text, (SCREEN_X / 2, SCREEN_Y - 20))
text = font.render(str((rtl.center_freq + SAMPLE_RATE / 2) / 1e6), 1, (200, 30, 30), (0, 0, 0))
screen.blit(text, (SCREEN_X - 40, SCREEN_Y - 20))
text = font.render(str((rtl.center_freq - SAMPLE_RATE / 2) / 1e6), 1, (200, 30, 30), (0, 0, 0))
screen.blit(text, (20, SCREEN_Y - 20))
pygame.display.flip()
line += 1
if (line > SCREEN_Y):
line = 0
pygame.quit
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