Abstract: A television broadcast receiving apparatus can change an oscillation frequency of a local oscillation signal or a tuning frequency of an intermediate frequency signal in a reception channel, and changes the reception characteristic to an optimum reception characteristic. In this way, the television broadcast receiving apparatus effectively reduces SN ratio deterioration due to interference of the outside of a reception band such as adjacent channel interference.

Abstract: A television broadcast receiving apparatus can change an oscillation frequency of a local oscillation signal or a tuning frequency of an intermediate frequency signal in a reception channel, and changes the reception characteristic to an optimum reception characteristic. In this way, the television broadcast receiving apparatus effectively reduces SN ratio deterioration due to interference of the outside of a reception band such as adjacent channel interference.

Abstract: A tuner section 1 includes: an RF signal input terminal 2 via which multichannel RF signals are supplied; an AGC circuit 4, by which the RF signal input terminal 2 is followed, for fixing or controlling a gain in accordance with a first gain control signal; a broadband amplifying circuit 5, by which the AGC circuit 4 is followed; an AGC circuit 6, by which the broadband amplifying circuit 5 is followed, for fixing or controlling a gain in accordance with a second gain control signal,; a mixer circuit 7 for selecting and picking out a target channel signal from signals supplied from the AGC circuit 6; and an AGC switching circuit 15 for controlling gains of the AGC circuit 4 and the AGC circuit 6 by selecting whether to fix or to control a gain of the AGC circuit 4 while selecting whether to fix or to control a gain of the AGC circuit 6.

Abstract: Circuits and buses directed to analog signal processing are accommodated in a cabinet functioning as an electromagnetic shielding. Circuits and buses directed to digital signal processing are disposed outside the cabinet. In order to minimize generation of noise from the bus through which digital data is transmitted, a microprocessor combines a plurality of signals and data as digital data for output onto a bus from one I/O port. A decoder that receives and separates the combined data is provided in the cabinet. Data is transferred between the microprocessor and the decoder through one bus. As a result, a digital/analog common tuner has the influence of noise generated from a digital signal processing system on the analog signal processing system suppressed, improving the reception properties.

Abstract: Circuits and buses directed to analog signal processing are accommodated in a cabinet functioning as an electromagnetic shielding. Circuits and buses directed to digital signal processing are disposed outside the cabinet. In order to minimize generation of noise from the bus through which digital data is transmitted, a microprocessor combines a plurality of signals and data as digital data for output onto a bus from one I/O port. A decoder that receives and separates the combined data is provided in the cabinet. Data is transferred between the microprocessor and the decoder through one bus. As a result, a digital/analog common tuner has the influence of noise generated from a digital signal processing system on the analog signal processing system suppressed, improving the reception properties.

Abstract: An integrated service network system is provided which allows a user to select a network that guarantees no bandwidth and/or a network that guarantees the bandwidth.

Abstract: A tuner for both digital and analog use that can receive both digital broadcast and analog broadcast signals, includes a signal input terminal; a frequency conversion section which converts and inputted signal to an IF signal; and a switching/distributing section which, based on the type of received signal (analog/digital), switches a destination to which to send the IF signal or distributes the IF signal. There is also a down-converter section, that further converts the IF signal into a Low IF signal; a terminal for output of the IF signal. The aforementioned components are all contained in a single body that performs an electromagnetic seal function. Operation of the switching/distributing section and/or the down-converter section may be controlled by a control signal from a structural element within the body.

Abstract: An input high frequency signal passes through a PIN diode having a variable high frequency resistance and is output from an AGC circuit. The PIN diode is connected so as to be biased forward between an AGC signal level and a fixed voltage level (such as ground potential). A bias resistor and a coil are connected in series between a node on the output side of the PIN diode and a node supplied with the ground potential. More specifically, the resistor and the coil are inserted in parallel between the transmission path for high frequency signals and the ground potential.