JP2006067369A

JP2006067369A - Amplifier for television reception

Info

Publication number: JP2006067369A
Application number: JP2004249026A
Authority: JP
Inventors: Toshihiro Sugiura; 敏博杉浦
Original assignee: Maspro Denkoh Corp
Current assignee: Maspro Denkoh Corp
Priority date: 2004-08-27
Filing date: 2004-08-27
Publication date: 2006-03-09

Abstract

<P>PROBLEM TO BE SOLVED: To provide an amplifier for television reception with high convenience capable of properly controlling a gain without performing complicated gain control even when the number of channels to be received is fluctuated or a receiving level varies. <P>SOLUTION: The amplifier for television reception has an input terminal 11, an output terminal 12, a first AGC amplifier 20, a second AGC amplifier 30, the first AGC amplifier 20 and the second AGC amplifier 30 are connected between the input terminal 11 and the output terminal 12 in series, a first automatic gain control part 28 compares detection voltage in which an average value of television signals branched by a first output branching means 23 with reference voltage for control when distortion ratio becomes the predetermined one so that the distortion ratio is within a specific range and at a predetermined level, controls an amount of attenuation of a first high frequency signal attenuation means 21 according to this comparison result and a second automatic gain control part 38 controls an amount of attenuation of a second high frequency signal attenuator 31 based on detection voltage in which a peak value of the television signals branched by a second branching circuit 33 is detected. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

本発明は、周波数の異なる複数チャンネルのテレビ信号（高周波信号）を増幅するためのテレビ受信用増幅装置に関する。
The present invention relates to a television receiving amplifying device for amplifying television signals (high frequency signals) of a plurality of channels having different frequencies.

ビルや家庭のテレビ受信システムにおいては、通常、アンテナにて受信したテレビ信号を増幅してテレビ受像機へ伝送するためのテレビ受信用増幅装置（以下単に「増幅装置」ともいう）が設けられるが、増幅装置の利得調整等が適切になされていないと、例えば入力信号の強度が強い場合、増幅装置が飽和して高調波や歪みが発生してしまい、テレビ受像機においてテレビ放送の正常な受信ができなくなるおそれがある。そのため、テレビ受像機にてテレビ放送を正常に受信するためには、増幅装置の利得を適切に調整したり入力信号レベルを最適化したりする必要がある。
ところが、増幅装置の利得を調整するにあたっては、使用場所や電界強度等に応じてより適切な入力レベル・利得に調整する必要があり、その調整量・調整内容は設置場所によって異なる。そのため、増幅装置を設置する際には煩雑な利得調整作業が伴い、一般に施工には熟練が必要であった。
そこで、利得の設定ミス等によりテレビ受像機で正常な受信ができなくなることの無いよう、テレビ信号の強度が大きい場合にその旨を表示するように構成されたテレビ用ブースタも提案されている。具体的には、入出力端子間に減衰器と増幅回路とが設けられ、入力信号を減衰器で所定レベル減衰させた後に増幅回路で増幅させるブースタにおいて、アンテナから入力されたテレビ信号の強度を検出して予め設定された基準値よりも大きいか否かを判定し、その判定結果に基づいて表示部への表示を行うよう構成されている（例えば、特許文献１参照）。
上記特許文献１に記載のテレビ用ブースタによれば、表示部（発光ダイオード）の表示内容（点灯有無）に基づいて、入力されたテレビ信号が予め設定された基準値より大きいか否かを確認しながら敷設・施工することができ、例えば、入力レベルが小さくて発光ダイオードが点灯していない場合は減衰器の減衰量を少な目に設定してブースタ全体としての利得を上げ、逆に、入力レベルが大きくて発光ダイオードが点灯した場合は減衰器の減衰量を多めに設定してブースタ全体としての利得を下げるといった、入力レベルを確認しながら利得を調整できる。そのため、利得設定ミスが少なく、取付性の良いテレビ用ブースタの提供が可能となる。
In a television reception system in a building or home, a television reception amplification device (hereinafter also simply referred to as “amplification device”) for amplifying a television signal received by an antenna and transmitting it to a television receiver is usually provided. If the gain adjustment of the amplifying device is not properly performed, for example, when the input signal strength is strong, the amplifying device is saturated and harmonics and distortion are generated, and the television receiver normally receives the television broadcast. There is a risk that it will not be possible. Therefore, in order to normally receive a television broadcast by the television receiver, it is necessary to appropriately adjust the gain of the amplifying device or optimize the input signal level.
However, when adjusting the gain of the amplifying device, it is necessary to adjust to a more appropriate input level and gain according to the place of use, electric field strength, and the like, and the amount of adjustment and the contents of adjustment differ depending on the installation location. For this reason, when installing the amplifying apparatus, complicated gain adjustment work is involved, and in general, skill is required for construction.
In view of this, a TV booster configured to display when the intensity of a TV signal is high has been proposed so that normal reception cannot be performed by the TV receiver due to a gain setting error or the like. Specifically, an attenuator and an amplifying circuit are provided between the input and output terminals. In a booster that amplifies the input signal by the amplifying circuit after the input signal is attenuated by a predetermined level, the intensity of the TV signal input from the antenna is increased. It is configured to detect and determine whether or not it is larger than a preset reference value, and display on the display unit based on the determination result (see, for example, Patent Document 1).
According to the television booster described in Patent Document 1, whether or not the input television signal is larger than a preset reference value is confirmed based on the display content (lighting on / off) of the display unit (light emitting diode). For example, if the input level is small and the light emitting diode is not lit, set the attenuation amount of the attenuator to a small value to increase the gain of the booster as a whole. When the light-emitting diode is turned on due to a large value, the gain can be adjusted while checking the input level, such as decreasing the gain of the booster as a whole by setting a large amount of attenuation of the attenuator. Therefore, it is possible to provide a TV booster with few gain setting mistakes and good mountability.

特開平９−１３０６８６号公報JP-A-9-130686

しかしながら、上記特許文献１に記載のテレビ用ブースタにおいては、当該ブースタの設置場所や電界強度に応じて、入力レベルが上記ブースタに予め設定された基準値より大きくならないように、すなわち表示部が何らかの表示をしないように減衰器を調整するのであるが、例えば、宅内での分配損失等を考慮しながら端末レベルを出来うる限り高くしたい場合を考えると、入力レベルが基準値より大きくならない範囲で最大の入力レベルが入力されるように減衰器の量を調整すること、つまり出来る限り減衰量を小さく設定することも考えられる。
このような場合に、入力レベルに大きな変動が生じてブースタに規定より大きな入力信号が入力されると、ブースタが飽和して高調波や歪みが規格の範囲を越えて発生してしまい、テレビ受像機においてテレビ放送の正常な受信ができなくなることが考えられる。またこのとき、仮にテレビ受像機においてテレビ放送の受信障害が無かったとしても、ブースタに備えられた表示部が、入力レベルオーバーである旨の表示をし続けることになり、ユーザーに不信を与えるといった問題があった。
一方、入力レベルの変動に適切に対応できるブースタとして、ピーク値検波による自動利得調整回路（以下「ＡＧＣ回路」と称す）を備えることにより出力レベルを補償して一定となるようにしたテレビ共聴用増幅装置が知られている。これは、増幅装置を構成する増幅部からの出力信号（つまり増幅後の信号）のピーク値を検波し、このピーク値に基づいて増幅部の利得を調整して出力レベルを一定に制御するものである。
しかし、このように構成された増幅装置であっても、例えばピーク電圧が変わらずにチャンネル数が増えた場合を考えると、入力されている信号の合成電力が増え、この合成電力に基づいて増幅器が作動するため，増幅器の最大入力レベルを超えてしまい，歪が発生して正常なテレビ信号を出力できなくなってしまうという問題が発生する。
特に近年、地上波デジタル放送が新たに始まり、従来のアナログ放送のＵＨＦ帯域に、従来のアナログ放送波に加えて地上波デジタル放送のチャンネルが増えることとなっている。この時、アナログ放送の受信時にテレビ受像機においてテレビ放送の正常な受信をしていた場合でも、地上波デジタル放送波の信号が入力信号に加算されて、アナログ放送と地上波デジタル放送との信号の合成電力がテレビ受信用増幅装置の最大入力レベルを超えてしまうといったことが考えられる。この合成電力の増大によって増幅装置が飽和してしまい、高調波や歪みが規格値を超えて発生し、テレビ受像機においてテレビ放送の正常な受信ができなくなるといった問題が考えられる。そのため、改めて適正入力レベルとなるように表示部を見ながら調整する必要がある。
本発明は上記課題に鑑みなされたものであり、設置場所によってテレビ信号レベルの違いがあっても、また，受信するチャンネル数の増減があっても，煩雑な利得調整を行うことなく利得を適切に調整可能な、利便性の高いテレビ受信用増幅装置を提供することを目的とする。
他の目的は，増幅回路の能力（特に最大出力レベル）を最大限に引き出せる高出力なテレビ受信用増幅装置を提供することである。
However, in the television booster described in Patent Literature 1, the input level does not become larger than the reference value preset in the booster according to the installation location of the booster and the electric field strength, that is, the display unit is The attenuator is adjusted so that it is not displayed.For example, when considering the case where the terminal level is to be as high as possible while considering distribution loss in the home, the maximum is within the range where the input level does not exceed the reference value. It is also conceivable to adjust the amount of the attenuator so that the input level is input, that is, to set the attenuation amount as small as possible.
In such a case, if the input level fluctuates greatly and an input signal larger than the specified value is input to the booster, the booster will saturate and harmonics and distortion will occur beyond the standard range. It is conceivable that normal reception of television broadcasts cannot be performed on the machine. At this time, even if there is no TV broadcast reception failure in the television receiver, the display unit provided in the booster will continue to display that the input level is over, causing distrust to the user. There was a problem.
On the other hand, as a booster that can appropriately cope with fluctuations in the input level, an automatic gain adjustment circuit (hereinafter referred to as “AGC circuit”) using peak value detection is provided to compensate for the output level so that the output level becomes constant. Amplifying devices are known. This is to detect the peak value of the output signal (that is, the amplified signal) from the amplifying unit constituting the amplifying device and adjust the gain of the amplifying unit based on this peak value to control the output level to be constant. It is.
However, even in the case of the amplification device configured as described above, for example, when the number of channels is increased without changing the peak voltage, the combined power of the input signal is increased, and the amplifier is based on the combined power. Causes the problem that the maximum input level of the amplifier is exceeded, distortion occurs, and normal television signals cannot be output.
In particular, in recent years, terrestrial digital broadcasting has been newly started, and channels of terrestrial digital broadcasting have been increased in the UHF band of conventional analog broadcasting in addition to conventional analog broadcasting waves. At this time, even if the television receiver is receiving the analog broadcast normally when the analog broadcast is received, the signal of the analog broadcast and the digital terrestrial broadcast is added to the input signal. It is conceivable that the combined power exceeds the maximum input level of the television receiving amplifier. There is a problem that the amplification device is saturated due to the increase of the combined power, and harmonics and distortions exceed the standard value, and the television receiver cannot receive the television broadcast normally. Therefore, it is necessary to make an adjustment while looking at the display unit so that the appropriate input level is obtained again.
The present invention has been made in view of the above problems, and even if there is a difference in the television signal level depending on the installation location, and even if the number of channels to be received is increased or decreased, the gain can be appropriately adjusted without performing complicated gain adjustment. It is an object of the present invention to provide a television receiver amplifier that can be easily adjusted and is highly convenient.
Another object of the present invention is to provide a high-output television receiving amplifying apparatus that can maximize the capacity of the amplifier circuit (especially the maximum output level).

上記課題を解決するために，請求項１の発明は，テレビ放送波受信用のアンテナにて受信したテレビ信号を増幅して端末側に伝送するために用いられるテレビ受信用増幅装置において、
筐体に入力端子と出力端子と，第１のＡＧＣ増幅器と第２のＡＧＣ増幅器を備え，前記第1のＡＧＣ増幅器と前記第２のＡＧＣ増幅器は，前記入力端子と前記出力端子間に直列に接続されると共に，前記第１のＡＧＣ増幅器には，第１の増幅手段と，第１の信号減衰手段と，前記第１の増幅手段にて増幅されたテレビ信号の一部を分岐させる第１の出力分岐手段と，前記第１の増幅手段による増幅後のテレビ信号の歪率が所定の規格範囲内となるように，前記第１の出力分岐手段により分岐されたテレビ信号に基づいて前記第１の信号減衰手段の減衰量を制御するための第１の自動利得調整手段とを備え，前記第２のＡＧＣ増幅器には，第２の増幅手段と，第２の信号減衰手段と，前記第２の増幅手段にて増幅されたテレビ信号の一部を分岐させる第２の出力分岐手段と，前記第２の増幅手段による増幅後のテレビ信号が所定レベルとなるように，前記第２の出力分岐手段により分岐されたテレビ信号に基づいて前記第２の信号減衰手段の減衰量を制御するための第２の自動利得調整手段とを備え，前記入力端子に入力されるテレビ信号の信号レベル及び波数が変動しても，出力端子から常に所定レベルのテレビ信号が出力されるように構成される。
In order to solve the above problems, the invention of claim 1 is a television reception amplifying apparatus used for amplifying a television signal received by a television broadcast wave receiving antenna and transmitting it to the terminal side.
The housing includes an input terminal, an output terminal, a first AGC amplifier, and a second AGC amplifier, and the first AGC amplifier and the second AGC amplifier are connected in series between the input terminal and the output terminal. The first AGC amplifier is connected to a first amplifying means, a first signal attenuating means, and a first branching part of the television signal amplified by the first amplifying means. Output branch means and the television signal branched by the first output branch means so that the distortion rate of the television signal amplified by the first amplifier means falls within a predetermined standard range. A first automatic gain adjusting means for controlling an attenuation amount of the first signal attenuating means, and the second AGC amplifier includes a second amplifying means, a second signal attenuating means, and the first attenuating means. A part of the TV signal amplified by the amplification means 2 is branched. Second output branching means for generating the second signal based on the television signal branched by the second output branching means so that the television signal amplified by the second amplifying means has a predetermined level. A second automatic gain adjusting means for controlling the attenuation amount of the attenuating means, and even if the signal level and wave number of the television signal inputted to the input terminal fluctuate, the television signal always having a predetermined level from the output terminal. Is configured to be output.

請求項２の発明は，請求項１に記載のテレビ受信用増幅装置において，前記第１の自動利得調整手段は，前記第１の出力分岐手段により分岐されたテレビ信号の平均値または実効値を検波する第１の検波回路と，前記第１の増幅手段の歪率が所定の規格範囲内であってかつ該第１の増幅手段による増幅後のテレビ信号があらかじめ設定された最大レベルであるときの該テレビ信号を前記第１の検波回路にて検波した検波電圧を制御用基準電圧として，制御用基準電圧と前記第１の検波回路による検波電圧とを比較し，該比較結果に応じて前記第１の信号減衰手段の減衰量を制御する比較・制御回路とからなる第１のＡＧＣ回路で構成し，前記第２の自動利得調整手段は，前記第２の出力分岐手段により分岐されたテレビ信号のピーク値を検波する第２の検波回路と，基準電圧と前記第２の検波回路にて検波された検波電圧とを比較し，該比較結果に応じて前記第２の信号減衰手段の減衰量を制御する比較・制御回路とからなる第２のＡＧＣ回路で構成される。
According to a second aspect of the present invention, in the television reception amplifying device according to the first aspect, the first automatic gain adjusting means calculates an average value or an effective value of the television signal branched by the first output branching means. When the distortion of the first detection circuit to detect and the first amplification means is within a predetermined standard range, and the television signal amplified by the first amplification means is at a preset maximum level. The control signal is compared with the detection voltage by the first detection circuit using the detection voltage obtained by detecting the television signal of the first detection circuit by the first detection circuit as a control reference voltage, and the detection voltage is compared with the detection voltage by the first detection circuit. A first AGC circuit comprising a comparison / control circuit for controlling the attenuation amount of the first signal attenuating means, and the second automatic gain adjusting means is a television branched by the second output branching means. Detect peak value of signal A second detection circuit that compares the reference voltage with the detection voltage detected by the second detection circuit, and controls the amount of attenuation of the second signal attenuation means according to the comparison result. The second AGC circuit is composed of a control circuit.

請求項１の発明によれば，上記課題を解決するために，請求項１の発明は，テレビ放送波受信用のアンテナにて受信したテレビ信号を増幅して端末側に伝送するために用いられるテレビ受信用増幅装置において、
筐体に入力端子と出力端子と，第１のＡＧＣ増幅器と第２のＡＧＣ増幅器を備え，前記第1のＡＧＣ増幅器と前記第２のＡＧＣ増幅器は，前記入力端子と前記出力端子間に直列に接続されると共に，前記第１のＡＧＣ増幅器には，第１の増幅手段と，第１の信号減衰手段と，前記第１の増幅手段にて増幅されたテレビ信号の一部を分岐させる第１の出力分岐手段と，前記第１の増幅手段による増幅後のテレビ信号の歪率が所定の規格範囲内となるように，前記第１の出力分岐手段により分岐されたテレビ信号に基づいて前記第１の信号減衰手段の減衰量を制御するための第１の自動利得調整手段とを備え，前記第２のＡＧＣ増幅器には，第２の増幅手段と，第２の信号減衰手段と，前記第２の増幅手段にて増幅されたテレビ信号の一部を分岐させる第２の出力分岐手段と，前記第２の増幅手段による増幅後のテレビ信号が所定レベルとなるように，前記第２の出力分岐手段により分岐されたテレビ信号に基づいて前記第２の信号減衰手段の減衰量を制御するための第２の自動利得調整手段とを備え，前記入力端子に入力されるテレビ信号の信号レベル及び波数が変動しても，出力端子から常に所定レベルのテレビ信号が出力されるように構成したので，
設置場所によってテレビ信号レベルの違いがあっても、また，受信するチャンネル数の増減があっても，煩雑な利得調整を行うことなく利得を適切に調整可能な、利便性の高いテレビ受信用増幅装置を提供することができる。
According to the first aspect of the present invention, in order to solve the above problem, the first aspect of the present invention is used for amplifying a television signal received by a television broadcast wave receiving antenna and transmitting it to the terminal side. In an amplification device for television reception,
The housing includes an input terminal, an output terminal, a first AGC amplifier, and a second AGC amplifier, and the first AGC amplifier and the second AGC amplifier are connected in series between the input terminal and the output terminal. The first AGC amplifier is connected to a first amplifying means, a first signal attenuating means, and a first branching part of the television signal amplified by the first amplifying means. Output branch means and the television signal branched by the first output branch means so that the distortion rate of the television signal amplified by the first amplifier means falls within a predetermined standard range. A first automatic gain adjusting means for controlling an attenuation amount of the first signal attenuating means, and the second AGC amplifier includes a second amplifying means, a second signal attenuating means, and the first attenuating means. A part of the TV signal amplified by the amplification means 2 is branched. Second output branching means for generating and the second signal based on the television signal branched by the second output branching means so that the television signal amplified by the second amplification means has a predetermined level. A second automatic gain adjusting means for controlling the attenuation amount of the attenuating means, and even if the signal level and wave number of the television signal inputted to the input terminal fluctuate, the television signal always having a predetermined level from the output terminal. Is configured to output
Even if there is a difference in the TV signal level depending on the installation location, or the number of channels to be received is increased or decreased, the gain can be adjusted appropriately without complicated gain adjustment. An apparatus can be provided.

請求項２の発明によれば，請求項１に記載のテレビ受信用増幅装置において，前記第１の自動利得調整手段は，前記第１の出力分岐手段により分岐されたテレビ信号の平均値または実効値を検波する第１の検波回路と，前記第１の増幅手段の歪率が所定の規格範囲内であってかつ該第１の増幅手段による増幅後のテレビ信号があらかじめ設定された最大レベルであるときの該テレビ信号を前記第１の検波回路にて検波した検波電圧を制御用基準電圧として，制御用基準電圧と前記第１の検波回路による検波電圧とを比較し，該比較結果に応じて前記第１の信号減衰手段の減衰量を制御する比較・制御回路とからなる第１のＡＧＣ回路で構成し，前記第２の自動利得調整手段は，前記第２の出力分岐手段により分岐されたテレビ信号のピーク値を検波する第２の検波回路と，基準電圧と前記第２の検波回路にて検波された検波電圧とを比較し，該比較結果に応じて前記第２の信号減衰手段の減衰量を制御する比較・制御回路とからなる第２のＡＧＣ回路で構成したので，
増幅回路の能力（特に最大出力レベル）を最大限に引き出せる高出力なテレビ受信用増幅装置を提供することである。
According to a second aspect of the present invention, in the television reception amplifying device according to the first aspect, the first automatic gain adjusting means is an average value or an effective value of the television signal branched by the first output branching means. A first detection circuit for detecting a value, and a distortion factor of the first amplifying means is within a predetermined standard range, and a television signal amplified by the first amplifying means is at a preset maximum level. Using a detection voltage obtained by detecting the television signal at a certain time by the first detection circuit as a control reference voltage, the control reference voltage and the detection voltage by the first detection circuit are compared, and the comparison result is determined. A first AGC circuit comprising a comparison / control circuit for controlling the attenuation amount of the first signal attenuation means, and the second automatic gain adjustment means is branched by the second output branch means. TV signal peak value The second detection circuit for detecting, the comparison for comparing the reference voltage and the detection voltage detected by the second detection circuit, and controlling the attenuation amount of the second signal attenuation means according to the comparison result Since it is composed of the second AGC circuit consisting of the control circuit,
An object of the present invention is to provide a high-output television receiving amplifying device capable of maximizing the capability (particularly the maximum output level) of an amplifier circuit.

以下に，本発明を具体化した実施形態の例を，図面を基に詳細に説明する。
Hereinafter, an example of an embodiment embodying the present invention will be described in detail with reference to the drawings.

図１は、本実施形態のテレビ受信システムの概略構成を示す説明図である。本実施形態のテレビ受信システム１は、ビルや住戸内において各種テレビ放送を視聴するために設けられるものであり、図１に示す如く、ＶＨＦ帯の放送電波を受信するＶＨＦアンテナ２と、ＵＨＦ帯の放送電波を受信するＵＨＦアンテナ３と、衛星放送（ＢＳ）の電波を受信するＢＳアンテナ４とを備えており、これら各アンテナ２，３，４からの受信電波（以下「テレビ信号」という）は、それぞれ同軸ケーブル２ａ，３ａ，４ａによってテレビ受信用増幅装置１０に伝送される。
そして、上記各テレビ信号は増幅装置１０内で合成・増幅され、その出力は同軸ケーブル５を介して宅内に引き込まれる。同軸ケーブル５には分配器６が接続されており、増幅装置１０からの出力が４分配される。この分配出力のうち１系統は、同軸ケーブル７、テレビ端子８を介してＶＵ・ＢＳ分波器９に接続され、このＶＵ・ＢＳ分波器９のＶＵ側にはテレビ受像機９ａが、ＢＳ側にはＢＳチューナー９ｂが接続されている。
FIG. 1 is an explanatory diagram showing a schematic configuration of the television receiving system of the present embodiment. A television receiving system 1 of the present embodiment is provided for viewing various television broadcasts in a building or a dwelling unit. As shown in FIG. 1, a VHF antenna 2 for receiving broadcast waves in the VHF band, and a UHF band UHF antenna 3 for receiving the broadcasting radio waves and BS antenna 4 for receiving the satellite broadcasting (BS) radio waves, and the received radio waves (hereinafter referred to as “TV signals”) from these antennas 2, 3, 4. Are transmitted to the television receiver amplifying apparatus 10 through coaxial cables 2a, 3a, and 4a, respectively.
The television signals are combined and amplified in the amplification device 10, and the output is drawn into the house via the coaxial cable 5. A distributor 6 is connected to the coaxial cable 5, and four outputs from the amplifying apparatus 10 are distributed. One of the distributed outputs is connected to a VU / BS demultiplexer 9 via a coaxial cable 7 and a TV terminal 8. A TV receiver 9 a is connected to the VU side of the VU / BS demultiplexer 9. A BS tuner 9b is connected to the side.

次に、本実施形態のテレビ受信システム１を構成するテレビ受信用増幅装置１０について、図２に基づいて説明する。尚，図２ではＵＨＦ帯のテレビ信号を増幅する増幅部のみを記載している。テレビ受信用増幅装置１０は、筐体に入力端子１１と出力端子１２を備えている。テレビ受信用増幅装置１０は、入力端子１１と出力端子１２との間に、第１のＡＧＣ増幅器２０と第２のＡＧＣ増幅器３０が直列に接続されており，それぞれ，入力端子１１は前記第１のＡＧＣ増幅器２０の入力端子２０ａと接続されており，また，出力端子１２は前記第２のＡＧＣ増幅器３０の出力端子３０ｂと接続されている。また，第１のＡＧＣ増幅器２０の出力端子２０ｂと第２のＡＧＣ増幅器３０の入力端子３０ａが接続されている。
Next, the television reception amplifying apparatus 10 constituting the television reception system 1 of the present embodiment will be described with reference to FIG. In FIG. 2, only the amplifying unit for amplifying the UHF band television signal is shown. The television reception amplifying apparatus 10 includes an input terminal 11 and an output terminal 12 in a casing. In the television receiving amplifying apparatus 10, a first AGC amplifier 20 and a second AGC amplifier 30 are connected in series between an input terminal 11 and an output terminal 12, and the input terminal 11 is connected to the first terminal. The AGC amplifier 20 is connected to the input terminal 20 a, and the output terminal 12 is connected to the output terminal 30 b of the second AGC amplifier 30. Further, the output terminal 20 b of the first AGC amplifier 20 and the input terminal 30 a of the second AGC amplifier 30 are connected.

第１のＡＧＣ増幅器２０は，テレビ信号を減衰させるための第１の高周波信号減衰器２１，テレビ信号を増幅するための第１の増幅回路２２，テレビ信号の一部を分岐して取り出すための第１の分岐回路２３と，第１の自動利得調整部（第１のＡＧＣ回路）２８で構成されている。
第１の自動利得調整部２８は，受信帯域外の不要信号を除去するためのフィルタ２４，受信帯域内のテレビ信号の平均値電圧を検出するための平均値検波回路２５，基準電圧と検波電圧を比較し第１の高周波信号減衰器２１の減衰量を制御するための第１の比較・制御部２６，第１の増幅部の最大出力レベルに対応する基準電圧を生成するための第１の基準電圧回路２７から構成されている。
The first AGC amplifier 20 includes a first high-frequency signal attenuator 21 for attenuating the TV signal, a first amplifier circuit 22 for amplifying the TV signal, and a part of the TV signal for branching out. The first branch circuit 23 and a first automatic gain adjustment unit (first AGC circuit) 28 are included.
The first automatic gain adjustment unit 28 includes a filter 24 for removing unnecessary signals outside the reception band, an average value detection circuit 25 for detecting an average value voltage of a television signal within the reception band, a reference voltage and a detection voltage. And a first comparison / control unit 26 for controlling the attenuation amount of the first high-frequency signal attenuator 21, and a first voltage for generating a reference voltage corresponding to the maximum output level of the first amplification unit. The reference voltage circuit 27 is configured.

第１の高周波信号減衰器２１には制御入力端子２１ａを備えており，減衰量は，制御入力端子２１ａを介して，第１の自動利得調整部２８からの制御信号によって制御される。この第１の自動利得調整部２８は、第１の分岐回路２３からの分岐出力に基づいて第１の高周波信号減衰器２１への制御信号を生成するためのものである。
The first high-frequency signal attenuator 21 includes a control input terminal 21a, and the amount of attenuation is controlled by a control signal from the first automatic gain adjustment unit 28 via the control input terminal 21a. The first automatic gain adjustment unit 28 is for generating a control signal to the first high-frequency signal attenuator 21 based on the branch output from the first branch circuit 23.

第１のフィルタ２４は、第１の分岐回路２３の分岐出力端子２３ａに接続されており、第１の増幅回路２２で増幅する信号の周波数帯（本実施例ではＵＨＦ帯）と同様の周波数帯の信号を通過させる。この第１のフィルタ２４は、例えばバンドパスフィルタにて構成してもよいし、ハイパスフィルタとローパスフィルタとを組合せて構成してもよく、その具体的な構成（種類）は問わない。この第１のフィルタ２４によって、通過帯域外に発生する妨害電波（例えば、携帯電話からの電波等）により第１の自動利得調整部２８の主機能であるＡＧＣ機能（自動利得調整機能）が誤作動するのを防止できる。ただし、妨害電波の影響を考える必要がない場合など、特に必要ない場合はこの第１のフィルタ２４は使用しなくてもよい。
The first filter 24 is connected to the branch output terminal 23a of the first branch circuit 23, and has the same frequency band as the frequency band of the signal amplified by the first amplifier circuit 22 (UHF band in this embodiment). Pass the signal. The first filter 24 may be configured by, for example, a band pass filter, or may be configured by combining a high pass filter and a low pass filter, and its specific configuration (type) is not limited. By this first filter 24, an AGC function (automatic gain adjustment function) which is a main function of the first automatic gain adjustment unit 28 is erroneously caused by an interference wave (for example, a radio wave from a mobile phone) generated outside the pass band. It can be prevented from operating. However, the first filter 24 may not be used when it is not particularly necessary, such as when it is not necessary to consider the influence of the jamming radio wave.

平均値検波回路２５は、フィルタ２４から出力された分岐出力信号を取り込み、前記第１の増幅回路２２の出力レベルの強度を検出するものである。この平均値検波回路２５は、具体的には、例えば信号検波用のダイオードによる検波回路とコンデンサ及び抵抗等で構成した平滑回路からなり，前記コンデンサ及び抵抗の時定数を適切な値に設定することにより，前記分岐出力信号の平均値に対応する検波電圧を出力するようになっている。平均値検波することにより，分岐出力信号，換言すると入力端子１１に入力された複数チャンネルのテレビ信号（本実施例ではＵＨＦ帯のテレビ信号）の電力和に相当する検波電圧を得ることができる。
The average value detection circuit 25 takes in the branch output signal output from the filter 24 and detects the intensity of the output level of the first amplifier circuit 22. Specifically, the average value detection circuit 25 includes, for example, a detection circuit using a signal detection diode and a smoothing circuit including a capacitor and a resistor, and sets the time constants of the capacitor and the resistor to appropriate values. Thus, a detection voltage corresponding to the average value of the branch output signals is output. By detecting the average value, it is possible to obtain a detection voltage corresponding to the sum of the power of the branch output signal, in other words, the TV signal of a plurality of channels input to the input terminal 11 (UHF band TV signal in this embodiment).

次に，第１の比較・制御部２６は、平均値検波回路２５から出力される検出値（検波電圧）を取り込み、基準値（基準電圧Ｖｒｅｆ１）と比較することによって、当該第１の増幅回路２２からの出力レベルが所定の基準レベルを超えているか否かを判定するものであり、例えばオペレーショナルアンプと抵抗等で構成した演算回路を用いて構成される。
Next, the first comparison / control unit 26 takes in the detection value (detection voltage) output from the average value detection circuit 25 and compares it with the reference value (reference voltage Vref1), thereby the first amplification circuit. 22 is used to determine whether the output level exceeds a predetermined reference level. For example, it is configured using an arithmetic circuit composed of an operational amplifier and a resistor.

第１の基準電圧回路２７は、第１の比較・制御部２６における比較・判定の基準となる基準電圧Ｖｒｅｆ１を生成するものであり、電源電圧Ｖｃｃを抵抗や可変抵抗器の組合せによる抵抗比でもって分圧することにより、所望の基準電圧Ｖｒｅｆ１を生成できるよう構成されている。
そして，本実施例では前記基準電圧として，前記第１の増幅回路２２の歪率が所定の規格範囲内であってかつ該第１の増幅回路２２による増幅後のテレビ信号があらかじめ設定された最大レベルであるときの該テレビ信号を前記平均値検波回路にて検波した検波電圧と同一の値に設定している。
The first reference voltage circuit 27 generates a reference voltage Vref1 as a reference for comparison / determination in the first comparison / control unit 26, and the power supply voltage Vcc is expressed by a resistance ratio by a combination of a resistor and a variable resistor. Thus, by dividing the voltage, a desired reference voltage Vref1 can be generated.
In this embodiment, as the reference voltage, the distortion factor of the first amplifier circuit 22 is within a predetermined standard range, and a television signal amplified by the first amplifier circuit 22 is set to a preset maximum. The television signal at the level is set to the same value as the detection voltage detected by the average value detection circuit.

次に，第２のＡＧＣ増幅器３０について説明する。第２のＡＧＣ増幅器３０は，テレビ信号を減衰させるための第２の高周波信号減衰器３１，テレビ信号を増幅するための第２の増幅回路３２，テレビ信号の一部を分岐して取り出すための第２の分岐回路３３と，第２の自動利得調整部（第２のＡＧＣ回路）３８で構成されている。第２の自動利得調整部３８は，受信帯域外の不要信号を除去するためのフィルタ３４，受信帯域内のテレビ信号のピーク値電圧を検出するためのピーク値検波回路３５，基準電圧と検波電圧を比較し第２の高周波信号減衰器３１の減衰量を制御するための第２の比較・制御部３６，基準電圧を生成するための第２の基準電圧回路３７から構成されている。
Next, the second AGC amplifier 30 will be described. The second AGC amplifier 30 includes a second high-frequency signal attenuator 31 for attenuating the television signal, a second amplifier circuit 32 for amplifying the television signal, and a part for extracting and branching out the television signal. A second branch circuit 33 and a second automatic gain adjustment unit (second AGC circuit) 38 are included. The second automatic gain adjustment unit 38 includes a filter 34 for removing unnecessary signals outside the reception band, a peak value detection circuit 35 for detecting a peak value voltage of the television signal within the reception band, a reference voltage and a detection voltage. And a second comparison / control unit 36 for controlling the attenuation amount of the second high-frequency signal attenuator 31 and a second reference voltage circuit 37 for generating a reference voltage.

第２の高周波信号減衰器３１には制御入力端子３１ａを備えており，減衰量は，制御入力端子３１ａを介して，第２の自動利得調整部３８からの制御信号によって制御される。この第２の自動利得調整部３８は、第２の分岐回路３３からの分岐出力に基づいて第２の高周波信号減衰器３１への制御信号を生成するものである。
The second high-frequency signal attenuator 31 includes a control input terminal 31a, and the amount of attenuation is controlled by a control signal from the second automatic gain adjustment unit 38 via the control input terminal 31a. The second automatic gain adjustment unit 38 generates a control signal to the second high-frequency signal attenuator 31 based on the branch output from the second branch circuit 33.

次に，第２のフィルタ３４は、上記同様の目的により使用されている。具体的には，第２の分岐回路３３の分岐出力端子３３ａに接続されており、第２の増幅回路３２で増幅する信号の周波数帯（本実施例ではＵＨＦ帯）と同様の周波数帯の信号を通過させる。この第２のフィルタ３４は、例えばバンドパスフィルタにて構成してもよいし、ハイパスフィルタとローパスフィルタとを組合せて構成してもよく、その具体的な構成（種類）は問わない。この第２のフィルタ３４によって、通過帯域外に発生する妨害電波（例えば、携帯電話からの電波等）により第２の自動利得調整部３８の主機能であるＡＧＣ機能（自動利得調整機能）が誤作動するのを防止できる。ただし、妨害電波の影響を考える必要がない場合など、特に必要ない場合はこの第２のフィルタ３４は使用しなくてもよい。
Next, the second filter 34 is used for the same purpose as described above. Specifically, the signal is connected to the branch output terminal 33a of the second branch circuit 33 and has a frequency band similar to the frequency band of the signal amplified by the second amplifier circuit 32 (UHF band in this embodiment). Pass through. The second filter 34 may be configured by, for example, a band pass filter, or may be configured by combining a high pass filter and a low pass filter, and its specific configuration (type) is not limited. The second filter 34 causes the AGC function (automatic gain adjustment function), which is the main function of the second automatic gain adjustment unit 38, to be erroneously caused by interference radio waves (for example, radio waves from a mobile phone) generated outside the passband. It can be prevented from operating. However, the second filter 34 may not be used when it is not particularly necessary, such as when it is not necessary to consider the influence of the jamming radio wave.

ピーク値検波回路３５は、フィルタ３４から出力された分岐出力信号を取り込み、前記第２の増幅回路３２の出力レベルの強度を検出するものである。このピーク値検波回路３５は、具体的には、例えば信号検波用のダイオードによる検波回路とコンデンサ及び抵抗等で構成した積分回路からなり，前記コンデンサ及び抵抗の時定数を適切な値に設定することにより，前記分岐出力信号のピーク値に対応する検波電圧を出力するようになっている。ピーク値検波することにより，分岐出力信号，換言すると入力端子１１に入力された複数チャンネルのテレビ信号（本実施例ではＵＨＦ帯のテレビ信号）のピーク電圧に相当する検波電圧を得ることができる。
The peak value detection circuit 35 receives the branch output signal output from the filter 34 and detects the intensity of the output level of the second amplifier circuit 32. Specifically, the peak value detection circuit 35 is composed of, for example, a detection circuit using a signal detection diode and an integration circuit composed of a capacitor, a resistor, and the like, and the time constants of the capacitor and the resistor are set to appropriate values. Thus, a detection voltage corresponding to the peak value of the branch output signal is output. By detecting the peak value, it is possible to obtain a detection voltage corresponding to the peak voltage of the branch output signal, in other words, a TV signal of a plurality of channels input to the input terminal 11 (in this embodiment, a UHF band TV signal).

次に，第２の比較・制御部３６は、ピーク値検波回路３５から出力される検出値（検波電圧）を取り込み、基準値（基準電圧Ｖｒｅｆ２）と比較することによって、当該第２の増幅回路３２からの出力レベルが所定の基準レベルを超えているか否かを判定するものであり、例えばオペレーショナルアンプと抵抗等で構成した演算回路を用いて構成される。
Next, the second comparison / control unit 36 takes in the detection value (detection voltage) output from the peak value detection circuit 35 and compares it with the reference value (reference voltage Vref2), thereby the second amplification circuit. It is determined whether or not the output level from 32 exceeds a predetermined reference level. For example, it is configured using an arithmetic circuit composed of an operational amplifier and a resistor.

第２の基準電圧回路３７は、第２の比較・制御部３６における比較・判定の基準となる基準電圧Ｖｒｅｆ２を生成するものであり、電源電圧Ｖｃｃを抵抗や可変抵抗器の組合せによる抵抗比でもって分圧することにより、所望の基準電圧Ｖｒｅｆ２を生成できるよう構成されている。
また，この基準電圧を調整できるようにすることにより，第２のＡＧＣ増幅器３０の出力レベル換言するとテレビ受信用増幅装置１０の出力レベルを任意の値に設定できる。
The second reference voltage circuit 37 generates a reference voltage Vref2 as a reference for comparison / determination in the second comparison / control unit 36, and the power supply voltage Vcc is expressed by a resistance ratio by a combination of a resistor and a variable resistor. Thus, by dividing the voltage, a desired reference voltage Vref2 can be generated.
Further, by making this reference voltage adjustable, the output level of the second AGC amplifier 30, in other words, the output level of the television receiving amplifying apparatus 10 can be set to an arbitrary value.

次に，テレビ受信用増幅装置１０の動作について説明する。
入力端子１１から入力されたテレビ信号、ここでは例えばＵＨＦ帯（４７０〜７７０ＭＨｚ）の信号について説明する。ＵＨＦ帯のテレビ信号は入力端子１１を介して，テレビ受信用増幅装置１０に取り込まれる。
Next, the operation of the television receiving amplifying apparatus 10 will be described.
A television signal input from the input terminal 11, for example, a UHF band (470 to 770 MHz) signal will be described here. The UHF band television signal is taken into the television receiving amplifying device 10 via the input terminal 11.

受信用増幅装置１０に取り込まれたＵＨＦ帯のテレビ信号は第１のＡＧＣ増幅器２０の入力端子２０ａを介して，第１のＡＧＣ増幅器２０に取り込まれる。
第１のＡＧＣ増幅器２０に取り込まれたテレビ信号は第１の高周波信号減衰器２１、第１の増幅回路２２、第１の分岐回路２３を介して出力端子２０ｂに出力されると共に，出力信号の一部が分岐出力端子２３ａを介して，第１の自動利得調整部２８に出力される。
The UHF band television signal captured by the reception amplifying apparatus 10 is captured by the first AGC amplifier 20 via the input terminal 20 a of the first AGC amplifier 20.
The television signal captured by the first AGC amplifier 20 is output to the output terminal 20b via the first high-frequency signal attenuator 21, the first amplifier circuit 22, and the first branch circuit 23, and the output signal A part is output to the first automatic gain adjustment unit 28 via the branch output terminal 23a.

そして，第１の自動利得調整部２８に出力されたテレビ信号は第１のフィルタ２４で受信帯域以外の不要信号が除去され平均値検波回路２５に出力される。
平均値検波回路２５では入力された受信帯域内のテレビ信号を検波してその平均値電圧を第１の比較・制御部２６に出力する。このように，テレビ信号を平均値検波することにより，上述したように検波回路の部品点数を少なくでき，その結果検波回路を簡単に構成できる。
Then, unnecessary signals other than the reception band are removed from the television signal output to the first automatic gain adjustment unit 28 by the first filter 24 and output to the average value detection circuit 25.
The average value detection circuit 25 detects the inputted television signal within the reception band and outputs the average value voltage to the first comparison / control unit 26. Thus, by detecting the average value of the television signal, the number of parts of the detection circuit can be reduced as described above, and as a result, the detection circuit can be easily configured.

そして，第１の比較・制御部２６は検波電圧と，第１の基準電圧回路２７で発生した基準電圧と比較し，基準電圧より，検波電圧の方が大きければ，前記、第１の高周波信号減衰器２１の減衰量が大きくなるように制御して，第１のＡＧＣ増幅器は利得が下がるようになる。一方，基準電圧より，検波電圧の方が小さければ，第１の高周波信号減衰器２１の減衰量が小さくなるように制御して，第１のＡＧＣ増幅器の利得が上がるようになる。
The first comparison / control unit 26 compares the detected voltage with the reference voltage generated by the first reference voltage circuit 27. If the detected voltage is larger than the reference voltage, the first high-frequency signal is compared. The gain of the first AGC amplifier is lowered by controlling the attenuation amount of the attenuator 21 to be increased. On the other hand, if the detection voltage is smaller than the reference voltage, the gain of the first AGC amplifier is increased by controlling the attenuation amount of the first high-frequency signal attenuator 21 to be small.

ここで，第１の基準電圧回路２７で発生する基準電圧は前記第１の増幅手段の歪率が所定の規格範囲内であってかつ該第１の増幅手段による増幅後のテレビ信号があらかじめ設定された最大レベルであるときの該テレビ信号を前記平均値検波回路にて検波した検波電圧と一致する値に設定されている。
Here, the reference voltage generated by the first reference voltage circuit 27 is set in advance so that the distortion factor of the first amplifying means is within a predetermined standard range and the television signal amplified by the first amplifying means is preset. The television signal at the maximum level is set to a value that coincides with the detection voltage detected by the average value detection circuit.

このように基準電圧を設定しているので，入力信号の波数が変動しても，常に，第１の増幅回路２２が持つ最大出力レベルを維持でき第１の増幅回路２２の能力を最大限に引き出すことができる。
Since the reference voltage is set in this way, the maximum output level of the first amplifier circuit 22 can always be maintained even when the wave number of the input signal fluctuates, and the capability of the first amplifier circuit 22 is maximized. It can be pulled out.

次に，第１のＡＧＣ増幅器２０から出力されたテレビ信号は第１のＡＧＣ増幅器２０の出力端子２０ｂ，第２のＡＧＣ増幅器３０の入力端子３０ａを介して，第２のＡＧＣ増幅器３０に取り込まれる。
Next, the television signal output from the first AGC amplifier 20 is taken into the second AGC amplifier 30 via the output terminal 20 b of the first AGC amplifier 20 and the input terminal 30 a of the second AGC amplifier 30. .

第２のＡＧＣ増幅器３０に取り込まれたテレビ信号は第２の高周波信号減衰器３１、第２の増幅回路３２、第２の分岐回路３３，出力端子３０ｂを介して出力端子１２に出力されると共に，出力信号の一部が分岐出力端子３３ａを介して，第２の自動利得調整部３８に出力される。
The television signal captured by the second AGC amplifier 30 is output to the output terminal 12 via the second high-frequency signal attenuator 31, the second amplifier circuit 32, the second branch circuit 33, and the output terminal 30b. , A part of the output signal is output to the second automatic gain adjustment unit 38 via the branch output terminal 33a.

そして，第２の自動利得調整部３８に出力されたテレビ信号は第２のフィルタ３４で受信帯域以外の不要信号が除去されピーク値検波回路３５に出力される。
ピーク値検波回路３５では入力された受信帯域内のテレビ信号を検波してそのピーク値電圧を第２の比較・制御部３６に出力する。
The television signal output to the second automatic gain adjustment unit 38 is output to the peak value detection circuit 35 after the unnecessary signal other than the reception band is removed by the second filter 34.
The peak value detection circuit 35 detects the input television signal within the reception band and outputs the peak value voltage to the second comparison / control unit 36.

そして，第２の比較・制御部３６は検波電圧と，第２の基準電圧回路３７で発生した基準電圧と比較し，基準電圧より，検波電圧の方が大きければ，前記、第２の高周波信号減衰器３１の減衰量が大きくなるように制御して，第２のＡＧＣ増幅器は利得が下がるようになる。一方，基準電圧より，検波電圧の方が小さければ，第２の高周波信号減衰器３１の減衰量が小さくなるように制御して，第２のＡＧＣ増幅器の利得が上がるようになる。
尚，本実施例では第１の検波回路として，テレビ信号の平均値電圧が出力されるようにしているが，テレビ信号の実効値電圧が出力されるようにしてもよい。実効値検波回路を使用すると検波電圧を抵抗負荷に供給したときに，直流と同じ電力を発生することができ，電力を計測するためには好適である。 Then, the second comparison / control unit 36 compares the detected voltage with the reference voltage generated by the second reference voltage circuit 37. If the detected voltage is larger than the reference voltage, the second high-frequency signal is output. By controlling the attenuation amount of the attenuator 31 so as to increase, the gain of the second AGC amplifier decreases. On the other hand, if the detection voltage is smaller than the reference voltage, the gain of the second AGC amplifier is increased by controlling the attenuation amount of the second high-frequency signal attenuator 31 to be small.
In this embodiment, the average voltage of the television signal is output as the first detection circuit, but the effective voltage of the television signal may be output. When the effective value detection circuit is used, when the detection voltage is supplied to the resistance load, the same electric power as that of the direct current can be generated, which is suitable for measuring the electric power.

このように構成することにより，本実施形態のテレビ受信用増幅装置１０は、受信するテレビ信号の波数増加による合成電力の増加にも対応できる。即ち、近年においてＵＨＦ帯では、従来のアナログ放送ばかりでなく、新しく地上波デジタル放送が開始されることになっており、この地上波デジタル放送波は、ＵＨＦ帯の低域周波数帯が用いられる。そのため、従来この周波数帯を利用していたアナログ放送を、地上波デジタル放送とは重ならない周波数帯に変更するアナログ周波数変更対策（アナアナ変換）を行い、地上波デジタル放送とアナログ放送とのサイマル放送が行われることになっている。このサイマル放送によって、ＵＨＦ帯のチャンネル数が増えることとなり、テレビ受信用増幅装置１０に入力されるテレビ信号の合成電力が増える場合があるのである。
By configuring in this way, the television receiving amplifying apparatus 10 of the present embodiment can cope with an increase in combined power due to an increase in the wave number of the received television signal. That is, in recent years, not only conventional analog broadcasting but also terrestrial digital broadcasting is newly started in the UHF band, and the low frequency band of the UHF band is used for this terrestrial digital broadcasting wave. For this reason, analog frequency change measures (ana-ana conversion) have been implemented to change analog broadcasts that previously used this frequency band to frequency bands that do not overlap with terrestrial digital broadcasts, and simultaneous broadcasts between terrestrial digital broadcasts and analog broadcasts. Is supposed to be done. This simulcast increases the number of channels in the UHF band, which may increase the combined power of the TV signal input to the TV reception amplifying apparatus 10.

次に，テレビ受信用増幅装置１０の出力特性について図３を基に詳細に説明する。図３（ａ）は入力波数に対する出力特性の関係を示すグラフで，点線は第１のＡＧＣ増幅器の出力特性を示しており,入力されたテレビ信号の波数が増加するに伴い,出力レベルが低下している。これは，第１の増幅回路２２への入力電力が増加するため，第１の増幅回路２２の歪率が規格範囲内になるように第１の高周波減衰器の減衰量が大きくなるよう第１の自動利得調整部が作動するためである。実線は第２のＡＧＣ増幅器の出力特性を示しており,入力されたテレビ信号の波数が増加しても出力レベルが一定になっていることがわかる。これは，出力レベルが所定値になるように第２の自動利得調整部が作動して,第２の高周波減衰器の減衰量を調整することにより,出力レベルを一定の値にしている。
一方，図３（ｂ）は入力レベルに対する出力特性の関係を示すグラフで，本実施例の場合，テレビ信号の入力レベルが７５ｄＢμから９０ｄＢμの範囲内であれば,一定の出力レベル１０３ｄＢμが得られていることがわかる。
Next, the output characteristics of the television receiving amplifying apparatus 10 will be described in detail with reference to FIG. FIG. 3A is a graph showing the relationship of the output characteristics with respect to the input wave number, and the dotted line shows the output characteristics of the first AGC amplifier, and the output level decreases as the wave number of the input television signal increases. is doing. This is because the input power to the first amplifier circuit 22 is increased, so that the first high-frequency attenuator has a large attenuation so that the distortion factor of the first amplifier circuit 22 is within the standard range. This is because the automatic gain adjustment section of the system operates. The solid line indicates the output characteristics of the second AGC amplifier, and it can be seen that the output level is constant even when the wave number of the input television signal increases. This is because the second automatic gain adjustment unit operates so that the output level becomes a predetermined value and the attenuation level of the second high-frequency attenuator is adjusted to make the output level constant.
On the other hand, FIG. 3B is a graph showing the relationship of the output characteristics with respect to the input level. In this embodiment, if the input level of the television signal is in the range of 75 dBμ to 90 dBμ, a constant output level of 103 dBμ is obtained. You can see that

以上詳述したように，本実施形態における第１の基準電圧は、第１の増幅回路２２の歪率が規格範囲内となる所定レベルのテレビ信号が第１の増幅回路２２から出力されたときにその出力されたテレビ信号を平均値検波回路２５にて検波した検波電圧に設定している。そのため、将来的にチャンネル数の増加による合成電力の増加が予想される地域にこのテレビ受信用増幅装置１０を設置したとしても、その合成電力増加に対応して第１の自動利得調整部２８が利得を適切に調整するため、改めて手作業による煩雑な調整等をする必要がなく、利便性の高いテレビ受信用増幅装置１０を提供することができる。
また，テレビ信号の入力レベルの変動に対しては，第２の自動利得調整部３８により，第２の増幅回路３２の出力レベルが所定値になるように第２のＡＧＣ増幅器３０が動作するのでテレビ信号の入力レベルが変化してもほぼ一定の出力レベルを得ることができ安定した受信が可能となる。
As described in detail above, the first reference voltage in the present embodiment is obtained when a first level television signal is output from the first amplification circuit 22 so that the distortion factor of the first amplification circuit 22 is within the standard range. The detected television signal is set to a detection voltage detected by the average value detection circuit 25. Therefore, even if this television reception amplifying apparatus 10 is installed in an area where an increase in combined power due to an increase in the number of channels is expected in the future, the first automatic gain adjustment unit 28 responds to the increase in combined power. In order to adjust the gain appropriately, it is not necessary to make a manual adjustment again, and the television receiving amplifying apparatus 10 with high convenience can be provided.
Further, since the second AGC amplifier 30 operates so that the output level of the second amplifier circuit 32 becomes a predetermined value by the second automatic gain adjustment unit 38 with respect to fluctuations in the input level of the television signal. Even if the input level of the TV signal changes, a substantially constant output level can be obtained and stable reception is possible.

ここで、本実施形態の構成要素と本発明の構成要素の対応関係を明らかにする。本実施形態において、第１の高周波信号減衰器２１は本発明（請求項１）の第１の信号減衰手段に相当し、第１の増幅回路２２は本発明の第１の増幅手段に相当し、第１の分岐回路２３は本発明の第１の出力分岐手段に相当し、第１の自動利得調整部２８は本発明の第１の自動利得調整手段に相当する。また，第２の高周波信号減衰器３１は本発明の第２の信号減衰手段に相当し、第２の増幅回路３２は本発明の第２の増幅手段に相当し、第２の分岐回路３３は本発明の第２の出力分岐手段に相当し、第２の自動利得調整部３８は本発明の第２の自動利得調整手段に相当し，平均値検波回路２５が第１の検波回路に相当し，ピーク値検波回路３５が第２の検波回路に相当する。
Here, the correspondence between the components of the present embodiment and the components of the present invention will be clarified. In the present embodiment, the first high-frequency signal attenuator 21 corresponds to the first signal attenuating means of the present invention (Claim 1), and the first amplifier circuit 22 corresponds to the first amplifying means of the present invention. The first branch circuit 23 corresponds to the first output branching means of the present invention, and the first automatic gain adjustment unit 28 corresponds to the first automatic gain adjustment means of the present invention. The second high frequency signal attenuator 31 corresponds to the second signal attenuating means of the present invention, the second amplifier circuit 32 corresponds to the second amplifying means of the present invention, and the second branch circuit 33 is The second automatic gain adjustment unit 38 corresponds to the second automatic gain adjustment unit of the present invention, and the average value detection circuit 25 corresponds to the first detection circuit. The peak value detection circuit 35 corresponds to the second detection circuit.

尚，本発明は上記実施の形態に限定されるものではなく，以下に例示するように，本発明の趣旨を逸脱しない範囲で各部を適宜に変更して実施することも可能である。
たとえば，本実施例では，第１の増幅回路２２，第２の増幅回路３２を１段で構成したが，２以上で構成してもよい。また，本実施例ではフィルタ２４，３４の通過帯域幅として，受信帯域幅と同一に設定したが，特定の帯域に限定してＡＧＣ動作するようにしても良い。また，第１の比較・制御部２６，第２の比較・制御部３６の制御出力信号で，表示装置を設けても良い。表示装置を設けることにより，制御状況が容易に把握できる。
It should be noted that the present invention is not limited to the above-described embodiment, and can be implemented by appropriately changing each part without departing from the spirit of the present invention, as exemplified below.
For example, in the present embodiment, the first amplifier circuit 22 and the second amplifier circuit 32 are configured in one stage, but may be configured in two or more. In this embodiment, the pass bandwidth of the filters 24 and 34 is set to be the same as the reception bandwidth, but the AGC operation may be limited to a specific bandwidth. Further, a display device may be provided by the control output signals of the first comparison / control unit 26 and the second comparison / control unit 36. By providing a display device, the control status can be easily grasped.

実施形態のテレビ受信システムの概略構成を示す説明図である。It is explanatory drawing which shows schematic structure of the television receiving system of embodiment. 実施形態のテレビ受信用増幅装置の概略構成を示すブロック図である。It is a block diagram which shows schematic structure of the amplifier for television reception of embodiment. 実施形態のテレビ受信用増幅装置を構成する増幅回路の出力特性を説明するための説明図であり、（ａ）は入力波数に対する出力特性の関係を示すグラフ、（ｂ）は入力レベルに対する出力特性の関係を示すグラフを示す。It is explanatory drawing for demonstrating the output characteristic of the amplifier circuit which comprises the amplifier for television reception of embodiment, (a) is a graph which shows the relationship of the output characteristic with respect to an input wave number, (b) is the output characteristic with respect to an input level. The graph which shows the relationship of is shown.

Explanation of symbols

１…テレビ受信システム、２…ＶＨＦアンテナ、２ａ，３ａ，４ａ，５，７…同軸ケーブル、３…ＵＨＦアンテナ、４…ＢＳアンテナ、６…分配器、８…テレビ端子、９…ＶＵ・ＢＳ分波器、９ａ…テレビ受像機、９ｂ…ＢＳチューナ、１０…テレビ受信用増幅装置、１１…入力端子、１２…出力端子、２０…第１のＡＧＣ増幅器、２１…第１の高周波信号減衰器、２２…第１の増幅回路、２３…第１の分岐回路、２３ａ…第１の分岐出力端子、２４…第１のフィルタ、２５…平均値検波回路（第１の検波回路）、２６…第１の比較・制御部、２７…第１の基準電圧回路、２８…第１の自動利得調整部、３０…第２のＡＧＣ増幅器、３１…第２の高周波信号減衰器、３２…第２の増幅回路、３３…第２の分岐回路、３３ａ…第２の分岐出力端子、３４…第２のフィルタ、３５…ピーク値検波回路（第２の検波回路）、３６…第２の比較・制御部、３７…第２の基準電圧回路、３８…第２の自動利得調整部。 DESCRIPTION OF SYMBOLS 1 ... Television receiving system, 2 ... VHF antenna, 2a, 3a, 4a, 5, 7 ... Coaxial cable, 3 ... UHF antenna, 4 ... BS antenna, 6 ... Distributor, 8 ... Television terminal, 9 ... VU / BS 9a ... TV receiver, 9b ... BS tuner, 10 ... amplifier for TV reception, 11 ... input terminal, 12 ... output terminal, 20 ... first AGC amplifier, 21 ... first high frequency signal attenuator, DESCRIPTION OF SYMBOLS 22 ... 1st amplifier circuit, 23 ... 1st branch circuit, 23a ... 1st branch output terminal, 24 ... 1st filter, 25 ... Average value detection circuit (1st detection circuit), 26 ... 1st Comparison / control unit 27: first reference voltage circuit 28 ... first automatic gain adjustment unit 30 ... second AGC amplifier 31 ... second high-frequency signal attenuator 32 ... second amplification circuit , 33 ... second branch circuit, 33a ... second branch output terminal 34 ... second filter, 35 ... peak value detection circuit (second detection circuit), 36 ... second comparison / control unit, 37 ... second reference voltage circuit, 38 ... second automatic gain adjustment unit .

Claims

In a television reception amplification apparatus used for amplifying a television signal received by a television broadcast wave reception antenna and transmitting the amplified signal to the terminal side,
An input terminal and an output terminal on the housing,
A first AGC amplifier and a second AGC amplifier;
The first AGC amplifier and the second AGC amplifier are connected in series between the input terminal and the output terminal;
The first AGC amplifier includes a first amplifying unit, a first signal attenuating unit, and a first output branching unit for branching a part of the television signal amplified by the first amplifying unit. The first signal attenuating means is based on the television signal branched by the first output branching means so that the distortion rate of the television signal amplified by the first amplifying means falls within a predetermined standard range. First automatic gain adjusting means for controlling the amount of attenuation of
The second AGC amplifier includes second amplifying means, second signal attenuating means, and second output branching means for branching a part of the television signal amplified by the second amplifying means. The attenuation amount of the second signal attenuation means is controlled based on the television signal branched by the second output branch means so that the television signal amplified by the second amplification means becomes a predetermined level. A second automatic gain adjusting means for
And a television signal of a predetermined level is always output from the output terminal even if the signal level and wave number of the television signal input to the input terminal fluctuate.

The first automatic gain adjusting means includes a first detection circuit for detecting an average value or an effective value of the television signal branched by the first output branching means, and a distortion factor of the first amplification means is predetermined. For detecting a television signal detected by the first detector circuit when the television signal amplified by the first amplification means is at a preset maximum level. As a reference voltage, a comparison / control circuit that compares the control reference voltage with the detection voltage of the first detection circuit and controls the attenuation amount of the first signal attenuation means according to the comparison result is provided. 1 AGC circuit,
The second automatic gain adjusting means is detected by a second detection circuit for detecting a peak value of the television signal branched by the second output branching means, a reference voltage and the second detection circuit. The detection voltage is compared, and a second AGC circuit comprising a comparison / control circuit for controlling the attenuation amount of the second signal attenuation means according to the comparison result is provided. The amplifying device for television reception as described.