TUNER CIRCUIT WITH LOOP THROUGH FUNCTION

摘要

The tuner circuit comprises a HF input and a HF output with a loop through function, wherein a variable capacitance diode is coupled with a first terminal to the HF input and with a second terminal to the HF output for providing a passive loop through function. The variable capacitance diode is in particular in a passing mode, when no DC reverse voltage is applied, for providing a passive loop through function. In a preferred embodiment, the tuner circuit is designed for reception of television channels, and for the variable capacitance diode one or two tuning variable capacitance diode is used being designed for satellite tuners with a frequency range of 1-2 GHz, or a specially designed variable capacitance diode with a capacitance ratio C1/C25>18 at a frequency of 1 MHz for DC reverse voltages of 1 and 25 Volts is used.