Dual HDTV/NTSC receiver using sequentially synthesized HDTV and NTSC co- channel carrier frequencies

摘要

A kind of double HDTV/NTSC control tuner receiver includes microprocessor, for synthesizing the carrier frequency and NTSC signal of HDTV signals. The much lower power of the HDTV signals itself is less than NTSC signal. HDTV signals needed for tuner initially synthesizes carrier frequency attempt the narrow band sync detector of detection. High lock detecting signal is generated in detection HDTV signals, so that microprocessor makes a HDTV treatment channel. If when without HDTV signals, which keeps low frequency to control the cochannel ntsc television signal that tuner synthesizes carrier frequency with microprocessor. Height lock detection signal comes from narrow band sync detector, and instruction detects that NTSC cochannels are enabled a microprocessor to the channels NTSC. Receiver is programmed automatically and which type signal stored is present in each television channel and is also shown as by system.