摘要
现行频谱安排中,未能避免中频二次谐波干扰并也存在着本振辐射对邻近电视的干扰。分析避免干扰的条件并提出留出空白频带的方案。认为图象中频最佳值应取为38.75MHz,可使各频道的本振及二次谐波落在频道的间隔处,从而根本上解决干扰问题。这一选取较高中频的方案也适于特高频频段。
In present TV frequency spectrum, the second harmonic interference of medium frequency and the local oscillation to nearby TV recivers are in existance. Based on analysis of conditions to avoid the interferences, presents the new proposal, i.e., reversing suitable dead inteval bands. Calculation and spectrum show that 38. 75 MHz may be selected as optimal image medium frequency. So that the local oscillation and second harmonic may be setted in intervals between higer frequency chanels, and then the problem on intrference can be solved basically. The proposal selecting higher medium frequency is suitable for UHF band.
关键词
电视广播系统
频域分析
干扰
Television broadcasting system
Frequency domain analysis
Interferences
Interference protection measures
Frequency allocation
