Aloha Habr.
Ua ʻike paha ka nui o ka poʻe kūʻai i ka wati a i ʻole ke kahua hoʻokele manawa i ka Radio Controlled Clock a i ʻole ka hōʻailona Atomic Clock ma ka pahu. He mea maʻalahi kēia, no ka mea, pono ʻoe e kau i ka uaki ma ka papaʻaina, a ma hope o kekahi manawa e hoʻololi koke ia i ka manawa kūpono.
E noʻonoʻo pehea e hana ai a kākau i kahi decoder ma Python.
Aia nā ʻōnaehana hoʻonohonoho manawa like ʻole. ʻO ka mea kaulana loa ma ʻEulopa ʻo ka ʻōnaehana Kelemania , He ʻōnaehana ponoʻī ko Iapana , i ka USA aia kahi ʻōnaehana , a laila. A laila, e pili ana ka moʻolelo e pili ana i ka DCF77, ʻo ia ka mea kūpono loa a hiki i ka hoʻokipa ʻana ma kekahi mau wahi ma ka ʻāpana ʻEulopa o Rūsia a me nā ʻāina e pili ana (ʻo ka poʻe o ka Hikina Hikina hiki ke loaʻa i ka manaʻo kūʻē, akā naʻe, hiki iā lākou ke loaʻa. a nana i ka hoailona Iapana;).
ʻO nā mea a pau i kākau ʻia ma lalo nei e pili ana i ka DCF77.
Hoʻokipa hōʻailona
ʻO DCF77 kahi kikowaena nalu lōʻihi e hana ana ma ke alapine o 77.5 kHz a me ka hoʻouna ʻana i nā hōʻailona ma ka modulation amplitude. Aia ke kikowaena 50KW ma 25 km mai Frankfurt, ua hoʻomaka ka hana ma 1959, a i ka makahiki 1973 ua hoʻohui ʻia ka ʻike i ka manawa kūpono. ʻO ka lōʻihi o ka nalu ma ke alapine o 77 KHz he lōʻihi loa, no laila, ʻoi aku ka maikaʻi o nā ana o ke kahua antenna (kiʻi mai Wikipedia):
Me kēlā ʻano antenna a me ka mana hoʻokomo, uhi ʻia ka wahi hoʻokipa ma kahi o ʻEulopa, Belarus, Ukraine a me kahi hapa o Rūsia.
Hiki i kekahi ke hoʻopaʻa i kahi hōʻailona. No ka hana ʻana i kēia, e hele wale i ka mea hoʻokipa pūnaewele , koho i ke alapine 76.5KHz a me USB modulation ma laila. Pono e wehe ʻia kahi kiʻi e like me kēia:
Ma laila mākou e kaomi i ke pihi download a hoʻopaʻa i kahi ʻāpana i mau minuke lōʻihi. ʻOiaʻiʻo, inā loaʻa iā ʻoe kahi mea hoʻokipa "maoli" hiki ke hoʻopaʻa i ke alapine 77.5KHz, hiki iā ʻoe ke hoʻohana i kēlā.
ʻOiaʻiʻo, ma ka loaʻa ʻana o nā hōʻailona manawa lekiō ma o ka Pūnaewele, ʻaʻole mākou e loaʻa i ka manawa kūpono maoli - ua hoʻouna ʻia ka hōʻailona me ka lohi. Akā ʻo kā mākou pahuhopu wale nō ka hoʻomaopopo ʻana i ke ʻano o ka hōʻailona; no kēia, ʻoi aku ka nui o ka hoʻopaʻa ʻana o ka Pūnaewele. I ke ola maoli, ʻoiaʻiʻo, hoʻohana ʻia nā mea hana kūikawā no ka loaʻa ʻana a me ka decoding; e kūkākūkā ʻia lākou ma lalo nei.
No laila, ua loaʻa iā mākou ka hoʻopaʻa ʻana, e hoʻomaka kākou e hana.
Hoʻoholo hōʻailona
E hoʻouka i ka faila me ka Python a ʻike i kona ʻano:
from scipy.io import wavfile
from scipy import signal
import matplotlib.pyplot as plt
import numpy as np
sample_rate, data = wavfile.read("dcf_websdr_2019-03-26T20_25_34Z_76.6kHz.wav")
plt.plot(data[:100000])
plt.show()
ʻIke mākou i ka modulation amplitude maʻamau:
No ka maʻalahi o ka wehewehe ʻana, e lawe kāua i ka envelope hōʻailona me ka hoʻololi ʻana iā Hilbert:
analytic_signal = signal.hilbert(data)
A = np.abs(analytic_signal)
plt.plot(A[:100000])
Hoʻonui ʻia ka hopena:
E hoʻomaʻemaʻe i ka leo emissions me ka haʻahaʻa-pass kānana, a ma ka manawa like e helu i ka awelika waiwai, i mea e pono ma hope no ka parsing.
b, a = signal.butter(2, 20.0/sample_rate)
zi = signal.lfilter_zi(b, a)
A, _ = signal.lfilter(b, a, A, zi=zi*A[0])
avg = (np.amax(A) + np.amin(A))/2
Ka hopena (laina melemele): kahi hōʻailona hawewe kokoke i maʻalahi ke kālailai.
ʻO ka hoʻopaʻa ʻana
Pono mua ʻoe e kiʻi i ke kaʻina bit. He mea maʻalahi loa ka hale hōʻailona.
Hoʻokaʻawale ʻia nā pulses i ʻelua mau manawa. Inā he 0.1s ka mamao ma waena o nā pulupulu (ʻo ia hoʻi. ʻo 0.9s ka lōʻihi o ka pulse), e hoʻohui i ka "0" i ke kaʻina bit; inā he 0.2s ka mamao (ʻo ia hoʻi ka lōʻihi he 0.8s), e hoʻohui i ka "1". Hōʻike ʻia ka hopena o kēlā me kēia minuke e ka pulse "lōʻihi", 2s ka lōʻihi, hoʻihoʻi ʻia ke kaʻina bit i ka ʻole, a hoʻomaka hou ka hoʻopiha.
He maʻalahi ka mea i luna e kākau ma Python.
sig_start, sig_stop = 0, 0
pos = 0
bits_str = ""
while pos < cnt - 4:
if A[pos] < avg and A[pos+1] > avg:
# Signal begin
sig_start = pos
if A[pos] > avg and A[pos+1] < avg:
# Signal end
sig_stop = pos
diff = sig_stop - sig_start
if diff < 0.85*sample_rate:
bits_str += "1"
if diff > 0.85*sample_rate and diff < 1.25*sample_rate:
bits_str += "0"
if diff > 1.5*sample_rate:
print(bits_str)
bits_str = ""
pos += 1
ʻO ka hopena, loaʻa iā mākou kahi kaʻina o nā bits, i kā mākou hiʻohiʻona no ʻelua kekona e like me kēia:
0011110110111000001011000001010000100110010101100010011000
0001111100110110001010100001010000100110010101100010011000
Ma ke ala, he mea hoihoi i ka hōʻailona he "ʻelua papa" o ka ʻikepili. Hoʻopili ʻia ke kaʻina bit me ka hoʻohana ʻana . Ma ke kumumanaʻo, pono kēia e hāʻawi i ka decoding ikaika aʻe i ka hihia o kahi hōʻailona nāwaliwali.
ʻO kā mākou hana hope: loaʻa ka ʻikepili maoli. Hoʻouna ʻia nā bits i hoʻokahi manawa i kēlā me kēia kekona, no laila, loaʻa iā mākou he 59 mau bits, kahi i hoʻopili ʻia ai ka ʻike he nui:
Hōʻike ʻia nā bits ma , a he hoihoi loa lakou. ʻAʻole hoʻohana ʻia nā 15 bits mua, ʻoiai aia nā manaʻo e hoʻohana iā lākou no nā ʻōnaehana hoʻolaha a me ka pale kīwila. Hōʻike ka Bit A1 e hoʻololi ka uaki i ka manawa mālama lā i ka hola aʻe. Hōʻike ka Bit A2 i kahi mea hou , i hoʻohana ʻia i kekahi manawa no ka hoʻoponopono ʻana i ka manawa e like me ke kaʻe ʻana o ka Honua. Hoʻopili nā bits i nā hola, mau minuke, kekona a me ka lā.
No ka poʻe makemake e hoʻokolohua iā lākou iho, hāʻawi ʻia ke code decoding ma lalo o ka mea hao.
Nīnau
def decode(bits):
if bits[0] != '0' or bits[20] != '1':
return
minutes, hours, day_of_month, weekday, month, year = map(convert_block,
(bits[21:28], bits[29:35], bits[36:42], bits[42:45],
bits[45:50], bits[50:58]))
days = ('Sunday', 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday', 'Sunday')
print('{dow}, {dom:02}.{mon:02}.{y}, {h:02}:{m:02}'.format(h=hours, m=minutes, dow=days[weekday],
dom=day_of_month, mon=month, y=year))
def convert_ones(bits):
return sum(2**i for i, bit in enumerate(bits) if bit == '1')
def convert_tens(bits):
return 10*convert_ones(bits)
def right_parity(bits, parity_bit):
num_of_ones = sum(int(bit) for bit in bits)
return num_of_ones % 2 == int(parity_bit)
def convert_block(bits, parity=False):
if parity and not right_parity(bits[:-1], bits[-1]):
return -1
ones = bits[:4]
tens = bits[4:]
return convert_tens(tens) + convert_ones(ones)
Ke holo mākou i ka papahana, e ʻike mākou i ka hopena e like me kēia:
0011110110111000001011000001010000100110010101100010011000
Tuesday, 26.03.19, 21:41
0001111100110110001010100001010000100110010101100010011000
Tuesday, 26.03.19, 21:42
ʻOiaʻiʻo, ʻo ia ka mea kilokilo. ʻO ka pōmaikaʻi o ia ʻōnaehana he mea maʻalahi loa ka decoding a hiki ke hana ʻia ma kekahi, ʻo ka microcontroller maʻalahi loa. Helu wale mākou i ka lōʻihi o nā pulses, hōʻiliʻili i 60 bits, a ma ka hopena o kēlā me kēia minuke loaʻa iā mākou ka manawa kūpono. Ke hoʻohālikelike ʻia me nā ʻano hana ʻē aʻe o ka hoʻonohonoho manawa (GPS, no ka laʻana, a i ʻole ke Akua ʻole, ka Pūnaewele:), ʻaʻohe pono o ka hoʻonohonoho ʻana i ka lekiō - no ka laʻana, holo ma kahi o hoʻokahi makahiki ma 2 mau pihi AA. No laila, hana ʻia nā wristwatches me ka hoʻonohonoho lekiō, ʻaʻole e haʻi ʻia, ʻoiaʻiʻo, nā wati pā a i ʻole nā wati alanui.
ʻO ka ʻoluʻolu a me ka maʻalahi o ka DCF e huki pū i nā mea hoihoi DIY. No $ 10-20 wale nō hiki iā ʻoe ke kūʻai i kahi module antenna i mākaukau me kahi mea hoʻokipa mākaukau a me ka hoʻopuka TTL, hiki ke hoʻopili ʻia i kahi Arduino a i ʻole ka mana ʻē aʻe.
Ua kākau ʻia no Arduino . Eia naʻe, ua ʻike mua ʻia ʻo nā mea āu e hana ai ma kahi microcontroller, e hoʻopau ʻoe me ka uaki a i ʻole ke kahua hoʻokele manawa. Me kēlā ʻano mea, maʻalahi loa ka loaʻa ʻana o ka manawa kūpono, hāʻawi ʻia, ʻoiaʻiʻo, aia ʻoe i ka wahi hoʻokipa. ʻAe, hiki iā ʻoe ke kau i ka palapala "Atomic Clock" ma kāu wati, a ma ka manawa like e wehewehe i nā poʻe āpau ua hoʻonohonoho pono ʻia ka hāmeʻa me ka hoʻohana ʻana i ka uaki atomika.
Hiki i ka poʻe makemake ke hoʻomaikaʻi i ka wati o ko lākou kupunawahine kahiko ma ke kau ʻana i kahi mīkini hou me ka hoʻonohonoho radio.
Hiki iā ʻoe ke loaʻa i kekahi ma ebay me ka hoʻohana ʻana i nā huaʻōlelo "Radio Controlled Movement".
A ʻo ka hope loa, he hack ola no ka poʻe i heluhelu a hiki i kēia manawa. ʻOiai inā ʻaʻohe mea hoʻoili lekiō hoʻokahi i loko o kekahi mau tausani kilomita, maʻalahi ka hana ʻana i hoʻokahi iā ʻoe iho. Aia kahi polokalamu ma Google Play i kapa ʻia ʻo "DCF77 Emulator" e hoʻopuka ana i kahi hōʻailona i nā headphone. Ua ʻōlelo ka mea kākau inā ʻoe e hoʻopuni i ke kaula headphone a puni ka uaki, e ʻohi ia i ka hōʻailona (ke noʻonoʻo nei au pehea, ʻoiai ʻaʻole e hana nā headphone maʻamau i kahi hōʻailona 77 kHz, akā ma muli paha o nā harmonics). Ma kaʻu uaki... Android ʻAʻole i holo pono ka Polokalamu 9—ʻaʻohe leo iki (a ʻaʻole paha wau i lohe—he 77 kHz ia, ma hope o nā mea a pau. :)), akā malia paha e ʻoi aku ka maikaʻi o kekahi. Eia naʻe, kūkulu kekahi poʻe i kā lākou mea hana hōʻailona DCF piha ponoʻī, kahi mea maʻalahi ke hana me ka hoʻohana ʻana i kahi Arduino a i ʻole ESP32:
(kumuwaiwai )
hopena
Ua maʻalahi a maʻalahi ka ʻōnaehana DCF. Me ke kōkua o kahi mea hoʻokipa maʻalahi a maʻalahi, hiki iā ʻoe ke loaʻa ka manawa kūpono i nā manawa a pau a me nā wahi āpau, ʻoiaʻiʻo ma ka wahi hoʻokipa. Me he mea lā ʻoiai ʻoiai ka laha ʻana o ka digitalization a me ka Internet of Things, e koi ʻia kēlā mau hoʻonā maʻalahi no ka manawa lōʻihi.
Source: www.habr.com
