TRAP CIRCUIT FOR INTERMEDIAE FREQUENCY CIRCUIT OF TELEVISION RECEIVER

• Main Author: NITANI YASUO
• Format: Patent
• Language: English
• Published: 06.05.1994
• Edition: 5
• Subjects: ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; PICTORIAL COMMUNICATION, e.g. TELEVISION

PURPOSE:To improve the selectivity characteristic of an intermediate frequency circuit by a simple constitution by using a 6.0 MHz trap for attenuating the components of the audio signal of a PAL system as the trap for attenuating the components of the video signal of adjacent channels at the time of receiving a NTSC system. CONSTITUTION:At the time of receiving a PAL system, each control signal 1, 2 of an H level and an L level is inputted in terminals 13, 14, transistors Q3, Q6 are controlled, the input video signal of a terminal 11 is led to the direction of an arrow code (a), 6.0 MHz components are removed by a trap T1, 5.5 MHz and 6.5 MHz components are removed by a trap T2 and they are outputted to a terminal 12. Therefore, as for the output of the video signal inputted from the terminal 11, audio signal components are removed in any BG, I, DK mode. At the time of receiving an NTSC system, the control signals inputted in the terminals 13, 14 are made the H level and the L level, respectively, the video signal from the terminal 11 is made to advance in the direction of arrow (b), 6.0 MHz and 4.5 MHz components are removed by tranps T1, T3 and the video signal components of adjacent channels are removed.