Abstract: The level of the harmonics of oscillation signals for synchronous detection to be inputted to a mixer circuit for converting frequencies is suppressed low.

Abstract: An integrated circuit is mounted on a printed board in a state in which a first edge thereof is located to face to a first side of the printed board and a second edge adjacent to the first edge is located to face to a second side adjacent to the first side of the printed board. A power supply terminal provided on the first edge of the integrated circuit, an AGC terminal and an oscillator terminal respectively provided to a third edge are connected to external terminals via conductive patterns extended to the first side on the printed board. An electrode for measurement is provided in the vicinity of the second side on the printed board and an intermediate frequency output terminal provided on a second edge of the integrated circuit is connected to the electrode via a conductive pattern extended from the second edge to the second side on the printed board.

Abstract: An intermediate-frequency (IF) coupled-circuit for a television tuner is provided, which is connected between an IF amplifying stage and a video-signal-selection filter, and which comprises a parallel circuit having a second capacitor connected in parallel to a series circuit having a resistor for impedance matching, an inductor, and a first capacitor which are connected in series, wherein the series circuit resonates at the frequency component of the selected channel, and the parallel circuit resonates at the frequency component of the channel lower than and adjacent to the selected channel, thereby functioning as a trap for removing the frequency component of the channel lower than and adjacent to the selected channel.

Abstract: 1. The object of the invention is to configure so that a video intermediate-frequency signal and a voice intermediate-frequency signal respectively included in an adjacent channel can be damped without having an effect upon a tuning characteristic of an intermediate frequency tuning circuit. 2.

Abstract: A video-apparatus-tuner mounting board includes a television tuner mounted on the board; a predetermined circuit to be connected to pins connected to an internal circuit of the television tuner; through holes arranged in a line, into which pins are inserted; and conductor lands, formed around the through holes, to be connected to the pins. Of the conductor lands, first conductor lands connected to the pins of a specific television tuner to be mounted on the board are connected to the predetermined circuit and to second conductor lands, which are not connected to the pins of the specific television tuner.

Abstract: The level of the harmonics of oscillation signals for synchronous detection to be inputted to a mixer circuit for converting frequencies is suppressed low.

Abstract: An integrated circuit is mounted on a printed board in a state in which a first edge thereof is located to face to a first side of the printed board and a second edge adjacent to the first edge is located to face to a second side adjacent to the first side of the printed board. A power supply terminal provided on the first edge of the integrated circuit, an AGC terminal and an oscillator terminal respectively provided to a third edge are connected to external terminals via conductive patterns extended to the first side on the printed board. An electrode for measurement is provided in the vicinity of the second side on the printed board and an intermediate frequency output terminal provided on a second edge of the integrated circuit is connected to the electrode via a conductive pattern extended from the second edge to the second side on the printed board.

Abstract: A TV tuner unit is provided with a tuner section for frequency-converting an input TV signal into an intermediate frequency signal, the tuner section having a mixing circuit for frequency conversion, and an oscillation circuit for inputting a local oscillation signal to the mixing circuit; a PLL circuit section for setting a frequency of the local oscillation signal through a tuning voltage by supplying the tuning voltage to the local oscillation circuit; and a video intermediate frequency circuit section for amplifying and detecting the intermediate frequency signal and thereby outputting a video signal and an audio signal, the video intermediate frequency circuit section having at least an intermediate frequency amplification circuit, a video detection circuit, and an audio detection circuit.

Abstract: A video-apparatus-tuner mounting board includes a television tuner mounted on the board; a predetermined circuit to be connected to pins connected to an internal circuit of the television tuner; through holes arranged in a line, into which pins are inserted; and conductor lands, formed around the through holes, to be connected to the pins. Of the conductor lands, first conductor lands connected to the pins of a specific television tuner to be mounted on the board are connected to the predetermined circuit and to second conductor lands, which are not connected to the pins of the specific television tuner.

Abstract: The object of the invention is to configure so that a video intermediate-frequency signal and a voice intermediate-frequency signal respectively included in an adjacent channel can be damped without having an effect upon a tuning characteristic of an intermediate frequency tuning circuit.

Abstract: An intermediate-frequency (IF) coupled-circuit for a television tuner is provided, which is connected between an IF amplifying stage and a video-signal-selection filter, and which comprises a parallel circuit having a second capacitor connected in parallel to a series circuit having a resistor for impedance matching, an inductor, and a first capacitor which are connected in series, wherein the series circuit resonates at the frequency component of the selected channel, and the parallel circuit resonates at the frequency component of the channel lower than and adjacent to the selected channel, thereby functioning as a trap for removing the frequency component of the channel lower than and adjacent to the selected channel.

Abstract: Between one end of a high-band tuning coil in a primary tuning circuit and one end of a high-band tuning coil in a secondary tuning circuit, a first switch diode and a second switch diode connected in series are provided. A second coupling coil is provided between the ground and the connection point of the first switch diode and the second switch diode. Both first switch diode and second switch diode are set to a continuity state or a non-continuity state to switch between a high-band state and a low-band state.

Abstract: Between one end of a high-band tuning coil in a primary tuning circuit and one end of a high-band tuning coil in a secondary tuning circuit, a first switch diode and a second switch diode connected in series are provided. A second coupling coil is provided between the ground and the connection point of the first switch diode and the second switch diode. Both first switch diode and second switch diode are set to a continuity state or a non-continuity state to switch between a high-band state and a low-band state.