US 4,052,674 A · VHF tuner device

Abstract

An input device for a tuner utilizing as an amplifier element a bipolar transistor or tetrode metal-oxide-semiconductor field-effect transistor is provided in which an impedance means is connected in parallel with an impedance of an antenna; a capacitor means is inserted between the input terminal of the amplifier element and a group of tuning coils or inductance means for selecting the television channels in the high frequency band when a channel in the high frequency band is selected whereas an inductance means is inserted between the input terminal and a group of tuning coils for selecting the channels in the low frequency band when a channel in the low frequency band is selected; and an impedance means is inserted between the input terminal of the amplifier element and the earth. The tuning frequency band widths or selectivities in both the high and low frequency bands may be made substantially equal without causing the loss due to the impedance mismatching even when the input impedance of the amplifier element varies greatly in response to the change in frequency.

Claims3

Dependent claims

In a tuner device having an input circuit comprised of capacitive reactance means in parallel with an antenna radiation impedance, an antenna circuit having an amplifier with an input electrode, and capacitive means between said electrode and a point of reference potential, and frequency selecting means connected between said input circuit and said amplifier circuit;

the improvement wherein said frequency selecting means comprises first and second groups of inductors, means selectively connecting said input circuit to an end of each of said inductors, capacitor means having one terminal connected to the other ends of said inductors of the group of inductors corresponding to the higher tuning frequencies, inductor means having one terminal connected to the other ends of the inductors of the group of inductors corresponding to the lower tuning frequencies, means selectively connecting the other terminals of said capacitor means and inductor means to said electrode, and a capacitor connected between the other terminal of said capacitor means and a point of reference potential.

Dependencies are inferred from the claim text.

VHF tuner device

Life of this patent

VHF tuner device

Life of this patent

Abstract

Claims3