UNIVERSAL TV TUNER HAVING PLURAL BROADCASTING RECEPTION FUNCTIONS

摘要

PURPOSE: A universal TV tuner having plural broadcasting reception functions is provided to voluntarily select a desired broadcasting scheme irrespective of a use area and a use purpose and watch TV by the selected broadcasting scheme. CONSTITUTION: An RF(Radio Frequency) AGC(Automatic Gain Control) amplifying unit(21) amplifies an inputted TV signal. A primary frequency converting unit(22) converts an input signal from the RF AGC amplifying unit into a primary IF(Intermediated Frequency) signal. A primary IF filter(23) passes a band of the primary IF signal from the primary frequency converting unit. A secondary frequency converting unit(24) converts the primary IF signal from the primary IF filter into a secondary IF signal. A secondary IF filter(25) passes a band of the second IF signal from the secondary frequency converting unit. An IF AGC amplifying unit(26) amplifies the secondary IF signal from the secondary IF filter. A broadcasting scheme selecting unit(31) selects one of a plurality of broadcasting schemes. A system gain control unit(32) controls the entire gain of a system corresponding to the broadcasting scheme selected by the broadcasting scheme selecting unit.