2021-02-16 12:55:11 +01:00
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#!/usr/bin/python3
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print('*** Preprost zvočni spektralni analizator - S53MV 28.09.2020 ***')
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print('*** popravek odziva za EliteBook 8540w - Andrej 11.2.2012 ***')
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print('*** meritev faznega suma - Andrej 15.2.2012 ***')
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fs=192000 #Frekvenca vzročenja zvočnega signala (max 192000Hz)
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pts=2048 #Število točk spektra 0...fs/2 (potenca 2 za učinkovit FFT)
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avg=128 #Število povprečenj spektra
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import sounddevice as sd #Poiskati na spletu in naložiti s pip3!
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import numpy as np #Uporaba učinkovitih funkcij numpy
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import matplotlib.pyplot as plt #Risanje rezultata z matplotlib
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sd.default.device = 0
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fskala=np.linspace(0,fs/2,2*pts+1)[:-1] #Izračunaj frekvenčno skalo [Hz]
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### podatki za kalibracijo sistema
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dSB = -42 #dB
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L = 1256 #metrov
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tau = L*1.4676/3e8
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### popravek odziva
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odziv = np.loadtxt("5mhz-polinom-2048tock.csv", delimiter=',')
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a = odziv[:,1]
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popravek = np.max(a[4:-1])-a[4:-1]
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2021-02-16 13:08:20 +01:00
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f=fskala[4:-1]
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2021-02-16 12:55:11 +01:00
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def spekter(fs,pts,avg,fskala): #Zajem signala z zvočno kartico in povprečenje spektra [dB]
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s=sd.rec(pts*(1+avg),samplerate=fs,channels=1) #Vzorčenje ADC zvočne kartice, 2D polje!
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sd.wait() #Počakaj do konca vzorčenja
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nz=1.e-12 #Dodatek za neničelni argument logaritma
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s2=np.square(s) #Izpis jakosti/max [dB]
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print('Jakost:',"%.1f"%(10*np.log10(nz+np.mean(s2))),'dB Vrh:',"%.1f"%(10*np.log10(nz+np.amax(s2))),'dB',end=' ')
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o=1+np.cos(np.linspace(-np.pi,np.pi,2*pts)) #Okno dvignjeni kosinus
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k=0
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s2=np.zeros(2*pts)
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while k<pts*avg: #Seštevanje moči FFT
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s2=s2+np.square(np.abs(np.fft.rfft(o*s.reshape(-1)[k:k+2*pts],n=4*pts)[:-1]))
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k+=pts
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s=10*np.log10(nz+0.5*s2/pts/pts/avg) #Povprečje [dB]
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print(' Max:',"%.1f"%(np.amax(s)),'dB @',"%.1f"%(fskala[np.argmax(s)]),'Hz')
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return s[4:-1]+popravek
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wfbp=None
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while wfbp!=True: #Prvo risanje spektra z normalizacijo, ponovi s klikom miške
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wfbp=plt.waitforbuttonpress(0.01)
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while wfbp==None: #Zanka risanja spektra, izhod=pritisk tipke ali miške
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s = spekter(fs,pts,avg,fskala)
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Pcal = np.amax(s)
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K = Pcal - 3 - dSB
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2021-02-16 13:08:20 +01:00
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fsum = s - K - 3 - 6 - 20*np.log10(np.sin(fskala[4:-1])*np.pi*tau)
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plt.plot(f, s, f, fsum)
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2021-02-16 12:55:11 +01:00
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fig.canvas.draw()
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wfbp=plt.waitforbuttonpress(0.01)
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plt.close()
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print('*** Konec ***') #pritisk tipke na tipkovnici
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