2012-10-10 19:25:28 +00:00
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subroutine fil3(x1,n1,c2,n2)
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! FIR real-to-complex filter designed using ScopeFIR
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!
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!-----------------------------------------------
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! fsample (Hz) 12000 Input sample rate
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! Ntaps 113 Number of filter taps
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! fc (Hz) 500 Cutoff frequency
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! fstop (Hz) 750 Lower limit of stopband
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! Ripple (dB) 0.2 Ripple in passband
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! Stop Atten (dB) 50 Stopband attenuation
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! fmix (HZ) 1500 Mixing frequency
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! fout (Hz) 1500 Output sample rate
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! Resulting passband is 1000 - 2000 Hz
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! Suggest calling with n1 = 8*n2 + 105, where n2 is the desired number
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! of 1500 Hz output samples.
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parameter (NTAPS=113)
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2020-03-19 11:19:44 -04:00
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parameter (NH=56) !NTAPS/2
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2012-10-10 19:25:28 +00:00
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parameter (NDOWN=8) !Downsample ratio = 1/8
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real x1(n1)
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complex z
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complex c2(n1/NDOWN)
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! Filter coefficients:
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complex ca(-NH:NH)
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data ca/ &
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(-0.001818142144, 0.000000000000), &
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(-0.000664066641,-0.000664066640), &
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(-0.000000000000,-0.001044063550), &
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( 0.000737290018,-0.000737290010), &
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( 0.000908957610,-0.000000000000), &
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( 0.000444156615, 0.000444156610), &
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(-0.000000000000, 0.000202701460), &
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( 0.000244876473,-0.000244876470), &
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( 0.000978154552, 0.000000000000), &
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( 0.001155650277, 0.001155650270), &
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( 0.000000000000, 0.002243121590), &
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(-0.001927618608, 0.001927618600), &
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(-0.003006201675, 0.000000000000), &
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(-0.002134087852,-0.002134087850), &
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( 0.000000000000,-0.002717699570), &
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( 0.001478946738,-0.001478946730), &
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( 0.001162489032, 0.000000000000), &
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(-0.000005589545,-0.000005589540), &
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(-0.000000000000,-0.001321554800), &
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( 0.001873767954,-0.001873767950), &
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( 0.003843608784,-0.000000000000), &
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( 0.003356874940, 0.003356874940), &
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(-0.000000000000, 0.005218967040), &
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(-0.003640348011, 0.003640348010), &
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(-0.004470167307, 0.000000000000), &
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(-0.002247131477,-0.002247131470), &
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(-0.000000000000,-0.001335998900), &
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(-0.000647656208, 0.000647656200), &
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(-0.003386100636, 0.000000000000), &
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(-0.004114456189,-0.004114456180), &
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( 0.000000000000,-0.007939147960), &
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( 0.006692816134,-0.006692816130), &
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( 0.010145641899, 0.000000000000), &
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( 0.006920770724, 0.006920770720), &
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( 0.000000000000, 0.008285915750), &
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(-0.003992321524, 0.003992321520), &
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(-0.001995842303, 0.000000000000), &
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( 0.001704388774, 0.001704388770), &
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(-0.000000000000, 0.007202515550), &
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(-0.008426458377, 0.008426458370), &
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(-0.016028350845, 0.000000000000), &
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(-0.013430355885,-0.013430355880), &
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(-0.000000000000,-0.020297455950), &
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( 0.013791263729,-0.013791263720), &
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( 0.016298136197,-0.000000000000), &
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( 0.007443596155, 0.007443596150), &
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(-0.000000000000, 0.002223837360), &
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( 0.005924356866,-0.005924356860), &
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( 0.020854478160, 0.000000000000), &
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( 0.024471928130, 0.024471928130), &
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( 0.000000000000, 0.048909701460), &
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(-0.044508219241, 0.044508219240), &
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(-0.075874892030, 0.000000000000), &
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(-0.061450241075,-0.061450241070), &
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( 0.000000000000,-0.095332017640), &
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( 0.071148679982,-0.071148679980), &
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( 0.102420526192, 0.000000000000), &
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( 0.071148679982, 0.071148679980), &
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( 0.000000000000, 0.095332017640), &
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(-0.061450241075, 0.061450241070), &
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(-0.075874892030, 0.000000000000), &
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(-0.044508219241,-0.044508219240), &
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( 0.000000000000,-0.048909701460), &
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( 0.024471928130,-0.024471928130), &
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( 0.020854478160, 0.000000000000), &
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( 0.005924356866, 0.005924356860), &
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(-0.000000000000,-0.002223837360), &
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( 0.007443596155,-0.007443596150), &
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( 0.016298136197,-0.000000000000), &
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( 0.013791263729, 0.013791263720), &
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(-0.000000000000, 0.020297455950), &
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(-0.013430355885, 0.013430355880), &
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(-0.016028350845, 0.000000000000), &
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(-0.008426458377,-0.008426458370), &
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(-0.000000000000,-0.007202515550), &
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( 0.001704388774,-0.001704388770), &
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(-0.001995842303, 0.000000000000), &
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(-0.003992321524,-0.003992321520), &
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( 0.000000000000,-0.008285915750), &
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( 0.006920770724,-0.006920770720), &
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( 0.010145641899, 0.000000000000), &
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( 0.006692816134, 0.006692816130), &
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( 0.000000000000, 0.007939147960), &
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(-0.004114456189, 0.004114456180), &
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(-0.003386100636, 0.000000000000), &
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(-0.000647656208,-0.000647656200), &
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(-0.000000000000, 0.001335998900), &
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(-0.002247131477, 0.002247131470), &
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(-0.004470167307, 0.000000000000), &
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(-0.003640348011,-0.003640348010), &
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(-0.000000000000,-0.005218967040), &
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( 0.003356874940,-0.003356874940), &
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( 0.003843608784,-0.000000000000), &
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( 0.001873767954, 0.001873767950), &
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(-0.000000000000, 0.001321554800), &
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(-0.000005589545, 0.000005589540), &
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( 0.001162489032, 0.000000000000), &
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( 0.001478946738, 0.001478946730), &
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( 0.000000000000, 0.002717699570), &
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(-0.002134087852, 0.002134087850), &
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(-0.003006201675, 0.000000000000), &
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(-0.001927618608,-0.001927618600), &
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( 0.000000000000,-0.002243121590), &
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( 0.001155650277,-0.001155650270), &
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( 0.000978154552, 0.000000000000), &
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( 0.000244876473, 0.000244876470), &
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(-0.000000000000,-0.000202701460), &
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( 0.000444156615,-0.000444156610), &
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( 0.000908957610,-0.000000000000), &
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( 0.000737290018, 0.000737290010), &
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(-0.000000000000, 0.001044063550), &
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(-0.000664066641, 0.000664066640), &
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(-0.001818142144, 0.000000000000)/
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save ca
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n2=(n1-NTAPS+NDOWN)/NDOWN
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k0=NH-NDOWN+1
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! Loop over all output samples
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do i=1,n2
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z=0.
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k=k0 + NDOWN*i
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do j=-NH,NH
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z=z + x1(j+k)*ca(j)
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enddo
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c2(i)=z
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enddo
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return
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end subroutine fil3
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