GENERAL IF CIRCUIT OF DIGITAL TUNER, ESPECIALLY INCLUDING IF BANDWIDTH SWITCHING CIRCUIT AND IF BAND SWITCHING CIRCUIT TO SWITCH BANDWIDTH ONE CHIP

摘要

PURPOSE: A general IF circuit of a digital tuner is provided to realize the commodity of IF circuit by selecting a plurality of IF bands and a plurality of IF bandwidths in one IF circuit. CONSTITUTION: A general IF circuit of a digital tuner includes a variable filter(110), an IF bandwidth switching circuit(120), an IF band switching circuit(130) and a control circuit(140). The variable filter selectively outputs the IF signal having at least two IF band and IF bandwidth by switching in a multi-stages in response to the switching signal inputted from the outside. The IF bandwidth switching circuit outputs the IF signal having a specific IF bandwidth in the variable filter by outputting the switching signal in response to the size of voltage inputted from outside. The IF band switching circuit outputs the IF signal having a specific IF band in the variable filter by outputting the switching signal in response to the size of voltage inputted from outside. And, the control circuit generates and outputs the control signal to operate the IF bandwidth switching circuit and the IF bandwidth switching circuit.