Sharp Kabushiki Kaisha Corporation

Masahiro Kato

Motohisa Nishina

Masayuki Nibe

Hitoshi Tanaka

Takao Hirano

The present high-frequency distribution circuit includes a switch circuit which passes a high-frequency signal from the other terminal of a high-frequency line to an output terminal if a receiver is connected to the output terminal and which grounds the other terminal of the high-frequency line via a terminator resistor if the receiver is not connected to the output terminal. As seen at an input terminal toward the output terminal, a constant value in resistance is provided regardless of whether the output terminal is used or not.

High-frequency distribution circuit for distributing high-frequency signal

A static electricity protective circuit for use in a high-frequency apparatus for protecting, against static electricity, an internal circuit connected to a signal terminal through which a high-frequency signal and a DC signal are superimposed and transmitted, comprises a high-frequency cut-off element having one end thereof connected to the signal terminal, and a Schottky barrier diode having a cathode thereof connected to other end of the high-frequency cut-off element and an anode thereof connected to ground, wherein the high-frequency cut-off element and the Schottky barrier diode cut off the high-frequency signal and the DC signal respectively and lead static electricity applied to the signal terminal to ground so as to protect the internal circuit against the static electricity.

Static electricity protective circuit and high-frequency circuit apparatus incorporating the same

A control portion detects the presence or absence of a pulse signal provided from a satellite broadcast receiver through a port PO to output a control signal PDOUT. In accordance with control signal PDOUT, a power supply circuit stops a supply of one of a power supply potential BIASfed to LNAA and a power supply potential BIASfed to LNAB. Therefore, the power consumption in an LNB designed for multi-satellite can be reduced and even a satellite broadcast receiver having a small current-supply capability can be connected. In this way, a low noise block down converter for multi-satellite with lower power consumption can be provided.

Satellite broadcast receiving converter with lower power consumption

A satellite broadcasting receiver (LNB) receiving signal radio waves from broadcasting satellites is provided with a low noise amplifier (LNA) amplifying a received signal, and a frequency converting circuit converting an output from the LNA to an intermediate frequency signal for output. The LNA includes four amplifiers in the first stage respectively amplifying four types of different received signals. A power supply control circuit sets a current flowing through one of four amplifiers at a prescribed value and sets currents flowing through all the other amplifiers at 0. Thus, the output from only one amplifier is supplied to the amplifier in the second stage for amplification and further applied to the frequency converting circuit. Accordingly, the amplifiers in the first stage do not simultaneously consume currents, and a switching circuit is not necessary.

Satellite broadcasting receiver receiving signal radio waves two broadcasting satellites

A multilayer substrate ensuring transmission loss as low as when one double-sided substrate is used, while reducing noise, and an LNB converter are provided. The multilayer substrate includes a four-layer substrate having pattern layers sandwiching dielectric layers therebetween. The surface pattern layer provided with a signal line of the microstrip line has a projecting portion. The pattern layer provided with a ground pattern corresponding to the signal line has a portion at least overlapping a root portion of the projecting portion as seen from the top and constituting a surface layer on the other side opposite to the root portion, with no other pattern layer interposed between the relevant portions.

Multilayer substrate and satellite broadcast reception apparatus

A multiple-beam antenna is provided which is capable of receiving radio waves from two satellites by one down converter and readily adjusting a polarization displacement due to a locational difference in receiving areas. Probes for vertically and horizontally polarized waves are inserted to two circular waveguides corresponding to signals from two satellites. One end of each probe is bent to have an angle for adjustment of the polarization displacement where it is installed. The other end of each probe is mounted on a board of a down converter via a through hole.

Multiple-beam antenna

A local oscillator has the following construction so that easier design can be achieved, stable oscillation characteristic can be provided and the manufacturing cost can be reduced. A high impedance line, a ground pattern with a through hole, and a coupling line are formed on a printed circuit board. A chip part, such as HEMT, and a dielectric resonator are mounted thereon by die bonding. A terminal of HEMT is connected to the pattern formed on the printed circuit board by wire bonding. A drain terminal of the HEMT is connected to a bias circuit. The bias circuit includes a stub for grounding, a high impedance line, and a chip capacitor.

Local oscillator having improved oscillation characteristic

The invention provides a two-output low-noise down converter circuit which is improved in the isolation between two outputs. In the two-output low-noise down converter circuit, an input signal is divided into two divisional signals of different polarization systems and then the divisional two signals are processed by two-system signal processing circuits which comprise low-noise amplifiers, band-pass filters, frequency converter circuits and a local oscillator, respectively. The two-output low-noise down converter circuit includes: a switching circuit for performing switching control on the outputs of the two signal processing circuits responsive to the voltages applied to two output terminals, and for selectively outputting two polarized signals to its output terminals; intermediate frequency amplifiers for amplifying the two outputs of the switching circuit and leading out the resulting outputs at the two output terminals; and a control circuit for controlling the turning-on and -off of the power of the intermediate frequency amplifiers responsive to loads of the two output terminals.

Growing community of inventors

Nagaokakyo, Japan

Masahiro Kato