Abstract: A multiple substrate assembly has a metallic plate sandwiched in between two printed circuit substrates. The metallic plate has cut and erect segments passing through thru-holes formed in at least one substrate, so that printed circuit paths on the outer surfaces of the substrates can be grounded to the metallic plate.

Abstract: An electronic tuner which includes an SHF band section in addition to ordinary UHF and VHF band sections for use in CATV, for example, has a diode and a resistor both connected between the VHF band section and a VHF band mixer stage. A transistor contained in the mixer stage is always appropriately biased by the diode and resistor, whether the mixer stage functions as a mixer or an amplifier.

Abstract: In a frequency synthesizer type electronic tuner comprising a plurality of local oscillators operable in frequency ranges different from each other, only one of said local oscillators being operable in accordance with a received frequency band, and the outputs of the local oscillators being connected with a prescaler constituting a PLL station selecting circuit through a coupling circuit which includes series connected circuits of resistors and capacitors, respectively, characterized in that the resistors in said coupling circuit are connected on the side thereof adjacent to the local oscillators, while the capacitors in the coupling circuit are connected on the side thereof adjacent to the prescaler, so that resistors and capacitors are used in a connecting part between the local oscillator circuit and the prescaler of the tuner thereby the separation between VHF and UHF bands is improved.

Abstract: Herein disclosed is an RF amplifier which is equipped with a high-frequency amplifying element such as a dual gate MOS FET having its first gate fed with a bias voltage and its second gate fed with an AGC voltage, in which a switching diode is fed with a switching voltage thereby to switch the bands, in which the voltage at a voltage dividing point where the switching voltage is divided is used as the bias voltage, and in which the voltage at the dividing point is so raised upon the reception of a high band as to make the effect of the AGC uniform upon the receptions of the low and high bands.

Abstract: An electronic tuner capable of selectively receiving the UHF band and high and low channels in the VHF band is described which has a suitable resistance provided across power supply terminals in order to improve the separation between the VHF mode and the UHF mode.

Abstract: An apparatus for effecting automatic gain control comprises an attenuator employing pin junction diodes, a high-frequency amplifier employing a bipolar type automatic gain controlling transistor or a MOS-FET which is always supplied with automatic gain control signals, and switching means for selectively applying automatic gain control signals to the attenuator, thereby permitting increase of the gain control variable without deteriorating the noise factor and the cross modulation characteristic of the signal.