JPS61234627A - Two-wire four-wire converting circuit - Google Patents

Abstract

PURPOSE:To constitute a small-sized two-wire four-wire converting circuit and at the same time, to simplify the setting of a balanced network by not using the passive parts of transformer, etc., but using an active element and resistance. CONSTITUTION:Unbalanced input signals (hereinafter called as four-wire input signals) from a four-wire input terminal are converted into balanced signals by means of operational amplifiers 7 and 8 of the same gain. Moreover, two- wire outputs are supplied to a differential amplifier 11 where they are subjected to subtraction and converted into unbalanced signals. Since four-wire input signals supplied to a balanced network 6 through amplifiers 9 and 10 as balanced signals are converted into unbalanced signals again by a differential amplifier 12 at the same time, subtraction is performed between the two kinds of unbalanced signals at a differential amplifier 13 and the movement of the four-wire input to four-wire output is suppressed. Balanced input signals from a two-wire side terminal 1-2 are outputted from a four-wire output terminal 4 through the amplifier 13 after they are subjected to subtraction by means of the differential amplifier 11.

Description

【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、２線−４線変換回路に関する。[Detailed description of the invention] [Industrial application field] The present invention relates to a 2-wire to 4-wire conversion circuit.

〔従来の技術〕[Conventional technology]

従来の２線−４線変換回路は、第２図に示すように変成
器５と、４綜入力端子から４線出力端４への音声信号の
廻り込み補正用バランス、ネットワーク６とから構成さ
れている。The conventional 2-wire to 4-wire conversion circuit, as shown in FIG. 2, is composed of a transformer 5, a balance for correcting the loop of audio signals from the 4-wire input terminal to the 4-wire output terminal 4, and a network 6. ing.

〔発明が解決しようとする問題点〕[Problem that the invention seeks to solve]

しかしながら、このような２線−４線変換回路では、変
成器５が使用されているため、小型化が困難であるとい
う欠点がおる。また４線入力端３から４線出力端４への
音声信号の廻り込みを補正するバランスネットワークの
素子値の設定が変成器自身の内部抵抗、容量およびイン
ダクタンス等を考慮しなければならないため、複雑にな
るという欠点がある。However, in such a 2-wire to 4-wire conversion circuit, since the transformer 5 is used, there is a drawback that miniaturization is difficult. In addition, setting the element values of the balance network that corrects the looping of the audio signal from the 4-wire input terminal 3 to the 4-wire output terminal 4 is complicated because the internal resistance, capacitance, and inductance of the transformer itself must be considered. It has the disadvantage of becoming

〔問題点を解決するための手段〕[Means for solving problems]

本発明の２線−４線変換回路は、上述の欠点を除去する
ために、変成器をアクティブ素子により構成している。In the 2-wire to 4-wire conversion circuit of the present invention, in order to eliminate the above-mentioned drawbacks, the transformer is constituted by an active element.

〔実施例〕〔Example〕

次に図面を参照して本発明の詳細な説明する。 Next, the present invention will be described in detail with reference to the drawings.

第１図は本発明の一実施例を示す回路図で弗る。FIG. 1 opens with a circuit diagram showing one embodiment of the present invention.

図におい−Ｃ１本発明の変換回路は、４線入力端３から
入力された不平衡信号を平衡信号に変換するだめの演算
増幅器７〜１０と、２線端１，２から入力された平衡信
号を不平衡信号に変換するための差動増幅器１１〜１３
と、２線側のインピーダンスを決定する抵抗１４〜１７
と、バランスネットワーク６とから構成されている。In the figure -C1, the conversion circuit of the present invention includes operational amplifiers 7 to 10 for converting unbalanced signals inputted from a 4-wire input terminal 3 into balanced signals, and balanced signals inputted from 2-wire terminals 1 and 2. Differential amplifiers 11 to 13 for converting into unbalanced signals
and resistors 14 to 17 that determine the impedance on the two-wire side.
and a balance network 6.

先ず、４線入力端子からの不平衡入力信号（以下４線入
力信号）は同じゲインの演算増幅器７および８により平
衡信号に変換さする。この時増幅器７，８の出力は互い
に逆位相となるため、２線出力信号は抵抗Ｒ１〜Ｒ８で
決定されるゲインの２倍とムる。また、増幅器７，８の
出力インピーダンスは等測的に零オームと考えられるた
め、２線側インピーダンスは抵抗１４．１５により決定
される。この２線出力はまた、差動増幅器１１に供給さ
れて引算ざｎ不平衡信号に変換される。このとき、増＠
ｓ　９　＊　１０　ｔ″介してバランスネットワーク６
に平衡信号として供給された４線入力信号も、差動増幅
器１２により不平衡信号にｂび変換されるため、差動増
幅器１３において、これら２つの不平衡信号の引算が行
われ、４＋１ｆｉ！入力の４線出力への廻り込みが抑圧
される。以上の動作は、第１図の４線入力が２線側に出
力されるが４線出力には出力され々い動作に対応する。First, an unbalanced input signal (hereinafter referred to as a 4-wire input signal) from a 4-wire input terminal is converted into a balanced signal by operational amplifiers 7 and 8 having the same gain. At this time, the outputs of the amplifiers 7 and 8 have opposite phases to each other, so that the two-wire output signal has twice the gain determined by the resistors R1 to R8. Furthermore, since the output impedance of the amplifiers 7 and 8 is isometrically considered to be zero ohm, the impedance on the two-wire side is determined by the resistor 14.15. This two-wire output is also supplied to the differential amplifier 11 and converted into a subtracted unbalanced signal. At this time, increase @
Balance network 6 through s 9 * 10 t''
The 4-wire input signal supplied as a balanced signal is also converted into an unbalanced signal by the differential amplifier 12, so the differential amplifier 13 subtracts these two unbalanced signals, and 4+1fi! Input input to the 4-wire output is suppressed. The above operation corresponds to the operation in which the 4-wire input shown in FIG. 1 is output to the 2-wire side, but is hardly output to the 4-wire output.

次に、２線側端子１−２からの平衡入力信号は差動増幅
器１１により引算さ７″Ｌだ後、増幅器１３を介して４
線出力端４から出力される。Next, the balanced input signal from the 2-wire side terminals 1-2 is subtracted by the differential amplifier 11 to 7"L, and then passed through the amplifier 13 to 4"L.
It is output from the line output end 4.

〔発明の効果〕〔Effect of the invention〕

以上のように、本発明においては、変成器等のパッシブ
部品を使用することなく、アクティブ素子と抵抗を使用
することにより小型の２線−４線変換回路を構成できる
とともに、比較的簡単にバランスネットワークを設定す
ることが可能となる。As described above, in the present invention, a compact 2-wire to 4-wire conversion circuit can be configured by using active elements and resistors without using passive components such as transformers, and it is relatively easy to balance the circuit. It becomes possible to set up the network.

【図面の簡単な説明】[Brief explanation of drawings]

第１図は本発明の一実施例を示す回路図、第２図は従来
の２線−４線変換Ｎ路を示す回路図である。 第１図において、FIG. 1 is a circuit diagram showing an embodiment of the present invention, and FIG. 2 is a circuit diagram showing a conventional 2-wire to 4-wire conversion N path. In Figure 1,

Claims (1)

【特許請求の範囲】[Claims] ４線回線から与えられる不平衡信号を第１の平衡信号に
変換して２線回線に出力する第１の増幅器と、前記４線
回線からの不平衡信号を第２の平衡信号に変換する第２
の増幅器と、この第２の増幅器の出力に接続した平衡回
路網と、前記第１の平衡信号を第１の不平衡信号に変換
する第１の差動増幅器と、前記第２の平衡信号を第２の
不平衡信号に変換する第２の差動増幅器と、４線回線に
接続され前記第１および第２の不平衡信号の差分を取る
第３の差動増幅器とから構成したことを特徴とする２線
−４線変換回路。a first amplifier that converts an unbalanced signal provided from the four-wire line into a first balanced signal and outputs it to the two-wire line; and a first amplifier that converts the unbalanced signal from the four-wire line into a second balanced signal. 2
an amplifier, a balanced circuitry connected to the output of the second amplifier, a first differential amplifier for converting the first balanced signal into a first unbalanced signal, and a first differential amplifier for converting the first balanced signal into a first unbalanced signal; It is characterized by being comprised of a second differential amplifier that converts into a second unbalanced signal, and a third differential amplifier that is connected to a 4-wire line and takes the difference between the first and second unbalanced signals. 2-wire to 4-wire conversion circuit.