is shown in fig7 c the filtered signal 108 is shown in the frequency domain in fig7 d the spacing 1 u03b4t between peaks 148 of the spectrum of the filtered signal 108 is determined by the delay time of the delay line 140 in this particular example the delay time is 1 60 of a second which causes the peaks 148 to have a 60 hz spacing this spacing permits the filtered signal 108 to fit precisely in the unused portion of the spectrum between the luminance signal peaks where the chrominance signal peaks are not present the filter 106 embodiment of fig6 is a two tap comb filter obviously comb filters with more than two taps may also be employed the more taps that are used in the comb filter the more narrow the spectral peaks 148 see fig7 d and the greater the attenuation of the signal in the filter stop band between the spectral peaks 148 other filters producing similar spectral characteristics may also be employed with the system 100 referring again to fig4 the modulator 110 is a simple modulator that receives the filter signal 108 and modulates it to fit into the unused portion of the spectrum previously discussed i e the spectral holes the modulator 110 can use any carrier frequency of 3 58 mhz u00b1 k 60 hz 30 hz where k is any.