def prepare_audio_filters(): forder = 256 forderd = 0 tf_rangel = 100000 tf_rangeh = 170000 # audio filters tf = SP['audio_lfreq'] N, Wn = sps.buttord([(tf-tf_rangel) / (freq_hz / 2.0), (tf+tf_rangel) / (freq_hz / 2.0)], [(tf-tf_rangeh) / (freq_hz / 2.0), (tf+tf_rangeh)/(freq_hz / 2.0)], 1, 15) Baudl, Aaudl = sps.butter(N, Wn, btype='bandpass') tf = SP['audio_rfreq'] N, Wn = sps.buttord([(tf-tf_rangel) / (freq_hz / 2.0), (tf+tf_rangel) / (freq_hz / 2.0)], [(tf-tf_rangeh) / (freq_hz / 2.0), (tf+tf_rangeh)/(freq_hz / 2.0)], 1, 15) N, Wn = sps.buttord([(tf-tf_rangel) / (freq_hz / 2.0), (tf+tf_rangel) / (freq_hz / 2.0)], [(tf-tf_rangeh) / (freq_hz / 2.0), (tf+tf_rangeh)/(freq_hz / 2.0)], 5, 15) Baudr, Aaudr = sps.butter(N, Wn, btype='bandpass') N, Wn = sps.buttord(0.016 / (afreq / 2.0), 0.024 / (afreq / 2.0), 2, 15) audiolp_filter_b, audiolp_filter_a = sps.butter(N, Wn) # USE FIR audiolp_filter_b = sps.firwin(257, .020 / (afreq / 2.0)) audiolp_filter_a = [1.0] N, Wn = sps.buttord(3.1 / (freq / 2.0), 3.5 / (freq / 2.0), 1, 20) audiorf_filter_b, audiorf_filter_a = sps.butter(N, Wn, btype='lowpass') [Baudrf_FDLS, Aaudrf_FDLS] = fdls.FDLS_fromfilt(audiorf_filter_b, audiorf_filter_a, forder, forderd, 0) SP['fft_audiorf_lpf'] = Faudrf = np.fft.fft(Baudrf_FDLS, blocklen) [Baudiolp_FDLS, Aaudiolp_FDLS] = fdls.FDLS_fromfilt(audiolp_filter_b, audiolp_filter_a, forder, forderd, 0) FiltAPost = np.fft.fft(Baudiolp_FDLS, blocklen) SP['fft_audiolpf'] = FiltAPost * FiltAPost #* FiltAPost [Baudl_FDLS, Aaudl_FDLS] = fdls.FDLS_fromfilt(Baudl, Aaudl, forder, forderd, 0) [Baudr_FDLS, Aaudr_FDLS] = fdls.FDLS_fromfilt(Baudr, Aaudr, forder, forderd, 0) Faudl = np.fft.fft(Baudl_FDLS, blocklen) Faudr = np.fft.fft(Baudr_FDLS, blocklen) SP['fft_audio_left'] = Faudrf * Faudl * fft_hilbert SP['fft_audio_right'] = Faudrf * Faudr * fft_hilbert
def prepare_video_filters(): # TODO: test these CLV+innerCAV parameters. Should be same on PAL+NTSC t1 = 25 t2 = 13.75 [tf_b, tf_a] = sps.zpk2tf(-t2*(10**-8), -t1*(10**-8), t1 / t2) SP['f_emp'] = sps.bilinear(tf_b, tf_a, 1/(freq_hz/2)) # RF BPF and analog audio cut filters SP['f_videorf_bpf'] = sps.butter(1, [SP['vbpf'][0]/(freq_hz/2), SP['vbpf'][1]/(freq_hz/2)], btype='bandpass') if SP['analog_audio'] == True: SP['f_aleft_stop'] = sps.butter(1, [(SP['audio_lfreq'] - 750000)/(freq_hz/2), (SP['audio_lfreq'] + 750000)/(freq_hz/2)], btype='bandstop') SP['f_aright_stop'] = sps.butter(1, [(SP['audio_rfreq'] - 750000)/(freq_hz/2), (SP['audio_rfreq'] + 750000)/(freq_hz/2)], btype='bandstop') # standard post-demod LPF lowpass_filter_b, lowpass_filter_a = sps.butter(SP['vlpf_order'], SP['vlpf_freq']/(freq_hz/2), 'low') # post-demod deemphasis filter [tf_b, tf_a] = sps.zpk2tf(-SP['deemp'][1]*(10**-8), -SP['deemp'][0]*(10**-8), SP['deemp'][0] / SP['deemp'][1]) SP['f_deemp'] = sps.bilinear(tf_b, tf_a, 1/(freq_hz/2)) # if AC3: #SP['f_arightcut'] = sps.butter(1, [(2650000)/(freq_hz/2), (3150000)/(freq_hz/2)], btype='bandstop') # prepare for FFT: convert above filters to FIR using FDLS techniques first forder = 256 forderd = 0 [Bbpf_FDLS, Abpf_FDLS] = fdls.FDLS_fromfilt(SP['f_videorf_bpf'][0], SP['f_videorf_bpf'][1], forder, forderd, 0, phasemult = 1.00) [Bemp_FDLS, Aemp_FDLS] = fdls.FDLS_fromfilt(SP['f_emp'][0], SP['f_emp'][1], forder, forderd, 0) [Bdeemp_FDLS, Adeemp_FDLS] = fdls.FDLS_fromfilt(SP['f_deemp'][0], SP['f_deemp'][1], forder, forderd, 0) [Bplpf_FDLS, Aplpf_FDLS] = fdls.FDLS_fromfilt(lowpass_filter_b, lowpass_filter_a, forder, forderd, 0) Fbpf = np.fft.fft(Bbpf_FDLS, blocklen) Femp = np.fft.fft(Bemp_FDLS, blocklen) SP['fft_video'] = Fbpf * fft_hilbert if SP['analog_audio'] == True: [Bcutl_FDLS, Acutl_FDLS] = fdls.FDLS_fromfilt(SP['f_aleft_stop'][0], SP['f_aleft_stop'][1], forder, forderd, 0, phasemult = 1.00) [Bcutr_FDLS, Acutr_FDLS] = fdls.FDLS_fromfilt(SP['f_aright_stop'][0], SP['f_aright_stop'][1], forder, forderd, 0, phasemult = 1.00) Fcutl = np.fft.fft(Bcutl_FDLS, blocklen) Fcutr = np.fft.fft(Bcutr_FDLS, blocklen) SP['fft_video'] *= (Fcutl * Fcutr) SP['fft_video_inner'] = SP['fft_video'] * Femp # Post processing: lowpass filter + deemp Fplpf = np.fft.fft(Bplpf_FDLS, blocklen) Fdeemp = np.fft.fft(Bdeemp_FDLS, blocklen) SP['fft_post'] = Fplpf * Fdeemp # determine freq offset and mult for output stage hz_ire_scale = (SP['videorf_100ire'] - SP['videorf_0ire']) / 100 minn = SP['videorf_0ire'] + (hz_ire_scale * -60) SP['output_minfreq'] = sminn = minn / (freq_hz / tau) out_scale = 65534.0 / (SP['ire_max'] - SP['ire_min']) SP['output_scale'] = (freq_hz / tau) * (out_scale / hz_ire_scale)
w, hbpf = freqz(Bbpf, Abpf, worN=1024) w, hcutl = freqz(Bcutl, Acutl, worN=1024) w, hcutr = freqz(Bcutl, Acutr, worN=1024) h = hbpf * hcutl * hcutr w = w / (np.pi * 2.0) Am = np.absolute(h) Th = np.angle(h) [Bfdls, Afdls] = FDLS(w, Am, Th, forder, forderd, 0) utils.doplot(Bfdls, Afdls) exit() [Bbpf_FDLS, Abpf_FDLS] = fdls.FDLS_fromfilt(Bbpf, Abpf, forder, forderd, 0) [Bcutl_FDLS, Acutl_FDLS] = fdls.FDLS_fromfilt(Bcutl, Acutl, forder, forderd, 0) [Bcutr_FDLS, Acutr_FDLS] = fdls.FDLS_fromfilt(Bcutr, Acutr, forder, forderd, 0) Fbpf = np.fft.fft(Bbpf_FDLS, blocklen) Fcutl = np.fft.fft(Bcutl_FDLS, blocklen) Fcutr = np.fft.fft(Bcutr_FDLS, blocklen) [Baudl_FDLS, Aaudl_FDLS] = fdls.FDLS_fromfilt(Baudl, Aaudl, forder, forderd, 0) [Baudr_FDLS, Aaudr_FDLS] = fdls.FDLS_fromfilt(Baudr, Aaudr, forder, forderd, 0) Faudl = np.fft.fft(Baudl_FDLS, blocklen) Faudr = np.fft.fft(Baudr_FDLS, blocklen) Fhilbert = np.fft.fft(hilbert_filter, blocklen)
btype='bandstop')
Bcutr, Acutr = sps.butter(1, [2.416 / (freq / 2), 3.176 / (freq / 2)],
btype='bandstop')
Bcut, Acut = sps.butter(1, [2.055 / (freq / 2), 3.176 / (freq / 2)],
btype='bandstop')
# AC3 - Bcutr, Acutr = sps.butter(1, [2.68/(freq/2), 3.08/(freq/2)], btype='bandstop')
#utils.doplot(Bcut, Acut)
lowpass_filter_b, lowpass_filter_a = sps.butter(5, (4.4 / (freq / 2)), 'low')
forder = 256
forderd = 0
[Bbpf_FDLS, Abpf_FDLS] = fdls.FDLS_fromfilt(Bbpf,
Abpf,
forder,
forderd,
0,
phasemult=1.00)
[Bcutl_FDLS, Acutl_FDLS] = fdls.FDLS_fromfilt(Bcutl,
Acutl,
forder,
forderd,
0,
phasemult=1.00)
[Bcutr_FDLS, Acutr_FDLS] = fdls.FDLS_fromfilt(Bcutr,
Acutr,
forder,
forderd,
0,
phasemult=1.00)