METHOD FOR FORMING TELEVISION SIGNAL

摘要

PURPOSE:To form a television signal having an aspect ratio with the shorter side at the top while said signal can be compatible with an NTSC system television by separating in terms of time base the low frequency component of an auxiliary image signal from the television signal having graphic information whose aspect ratio is larger than 4:3. CONSTITUTION:An image separation circuit 2 separates a main image signal made up of images in areas with aspect ratio 4:3 and an auxiliary image signal made up of images in areas shown by shadowed areas S from the television signal. According to the NTSC system the main image signal is encoded and supplied to a time base multiplex circuit 28. An LPF 24 and a subtractor 25 separate a low frequency component with high energy and a high frequency component with low energy from the auxiliary image signal. The both components are supplied to a time base compression circuit 26 and a time base expansion circuit 27. The low frequency component included in the auxiliary image signal subjected to time base compression is multiplexed in terms of time base, and supplied to a frequency base multiplex circuit 29.