JPH0339935U

JPH0339935U -

Info

Publication number: JPH0339935U
Application number: JP10093289U
Authority: JP
Priority date: 1989-08-29
Filing date: 1989-08-29
Publication date: 1991-04-17

Description

[Brief explanation of drawings]

第１図は本考案にかかるＢＳチユーナの入力回
路の一実施例を示すブロツク図、第２図は第１図
の要部を具体的に示す回路図である。第３図は本
考案の第２実施例のブロツク図、第４図は第３図
の要部を具体的に示す回路図である。第５図は本
考案の第３の実施例の要部を具体的に示す回路図
である。第６図は従来のＡＢスイツチを用いたＢ
Ｓチユーナへの衛星放送受信アンテナの接続方法
を示す図、第７図はＡＢスイツチ回路の具体例を
示す回路図、第８図は第６図に示すＢＳチユーナ
のアツテネータの回路図である。１１…入力端子、１２…ハイパスフイルタ、１
３，１３Ａ，１３Ｂ…可変アツテネータ、１４Ａ
，１４Ｂ…広帯域アンプ、１６…入力段ＲＦ回路
、１７Ａ，１７Ｂ，１８…スイツチ、１１３Ａ，
１１３Ｂ…固定アツテネータ。 FIG. 1 is a block diagram showing one embodiment of the input circuit of a BS tuner according to the present invention, and FIG. 2 is a circuit diagram specifically showing the main parts of FIG. 1. FIG. 3 is a block diagram of a second embodiment of the present invention, and FIG. 4 is a circuit diagram specifically showing the main parts of FIG. 3. FIG. 5 is a circuit diagram specifically showing the main parts of the third embodiment of the present invention. Figure 6 shows B using the conventional AB switch.
7 is a circuit diagram showing a specific example of an AB switch circuit, and FIG. 8 is a circuit diagram of an attenuator of the BS tuner shown in FIG. 6. 11...Input terminal, 12...High pass filter, 1
3, 13A, 13B...variable attenuator, 14A
, 14B... Wideband amplifier, 16... Input stage RF circuit, 17A, 17B, 18... Switch, 113A,
113B...Fixed attenuator.

Claims

[Claims for Utility Model Registration] 1. A circuit comprising a plurality of circuits in which an input terminal, a high-pass filter, an attenuator, and a wideband amplifier are connected in cascade, and by switching the power supply to the plurality of wideband amplifiers, the output of the wideband amplifier can be adjusted. An input circuit for a BS tuner characterized by a switch means for selectively coupling to a single input stage RF circuit. 2. A utility model registration claim characterized in that a switching diode is interposed in series in the power supply circuit of the broadband amplifier, and the output of the broadband amplifier is coupled to a single input stage RF circuit via the diode. The input circuit of the BS tuner described in item 1. 3. The attenuator is of a variable type, and the AGC voltage circuit that controls the attenuator is provided with a switch means that is linked to the presence or absence of power supply to the wideband amplifier, so that the amount of signal attenuation is maximized when no power is supplied to the wideband amplifier. An input circuit for a BS tuner according to claim 1 or 2 of the utility model registration claim. 4. The BS tuner according to claim 1 or 2, wherein the attenuator is of a fixed type, and a single variable attenuator is disposed before a single input stage RF circuit. input circuit. 5. A power supply circuit that supplies power from the input terminal to a converter disposed outside is provided with a switch means that is linked to whether or not power is being supplied to the broadband amplifier, and the power to the converter is turned off when no reception is being received. An input circuit for a BS tuner according to claim 1 or 2 or 3 or 4 of a certain utility model registration claim.