TV Interface RF modulation circuitry

摘要: An interface circuit for selectively generating TV RF signals on one of two adjacent channels is designed with independent oscillator-modulator circuits. The respective double sideband modulated generated by the modulators are respectively passed through separate frequency rejection filters to attenuate lower sound each signals. resultant applied a common bandpass filter via an isolation network. pass band encompasses substantially combination bands broadcast corresponding generated. Consequently signal similar conventional vestigal and higher minus sideband. network provides electrical connection between but establishes relatively constant impedance at output input terminals irrespective changes in impedances so that may be tuned desired resonances without interaction