JPS60823B2 - Sidetone prevention circuit - Google Patents
Sidetone prevention circuitInfo
- Publication number
- JPS60823B2 JPS60823B2 JP10220979A JP10220979A JPS60823B2 JP S60823 B2 JPS60823 B2 JP S60823B2 JP 10220979 A JP10220979 A JP 10220979A JP 10220979 A JP10220979 A JP 10220979A JP S60823 B2 JPS60823 B2 JP S60823B2
- Authority
- JP
- Japan
- Prior art keywords
- circuit
- transistor
- voltage
- resistor
- handset
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M1/00—Substation equipment, e.g. for use by subscribers
- H04M1/58—Anti-side-tone circuits
- H04M1/585—Anti-side-tone circuits implemented without inductive element
Landscapes
- Engineering & Computer Science (AREA)
- Signal Processing (AREA)
- Interconnected Communication Systems, Intercoms, And Interphones (AREA)
Description
【発明の詳細な説明】
本発明は、電話器、インターホン等において同時通話回
路を形成するのに必要な側音防止回路に関するものであ
る。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sidetone prevention circuit necessary for forming a simultaneous call circuit in telephones, intercoms, etc.
従来、側音防止回路を構成する方法としては、コイルに
よるもの、差動増幅器の組合せによるもの、また抵抗器
によるブリッジ回路等が実用化されている。Conventionally, as methods for configuring sidetone prevention circuits, methods using coils, combinations of differential amplifiers, bridge circuits using resistors, etc. have been put into practical use.
これらの方法においては、形状が大きくなったり部品点
数が多くなり、また、部品を少なくすると減衰量が多く
なりすぎる等の欠点があり、例えば機器を４・形化、高
性能化しようとするのが困難であった。本発明は上記の
欠点を除去しようとするもので「以下図面の実施例につ
いて本発明を詳細に説明する。These methods have disadvantages such as the size becomes larger and the number of parts increases, and if the number of parts is reduced, the amount of attenuation becomes too large. was difficult. The present invention seeks to eliminate the above-mentioned drawbacks and will now be described in detail with reference to embodiments of the drawings.
図は、送受器を用いて子機と通話を行なう同時通話イン
ターホンの親機及び子機の構成を示している。The figure shows the configuration of a base unit and a slave unit of a simultaneous call intercom that communicates with a slave unit using a handset.
図は親機１と子機５の通話状態を示しており、マイクロ
ホン２の音声信号はコンデンサＣ，を経て増幅回路３に
より電力増幅されて３ｏに現われる。The figure shows a communication state between the base unit 1 and the handset 5, and the audio signal from the microphone 2 passes through the capacitor C, is amplified by the power of the amplifier circuit 3, and appears at the terminal 3o.
Ｒ，，Ｒ２，Ｒ３はそれぞれ抵抗器である。このとき電
源４から抵抗器Ｒ５，Ｒ６，Ｒ７を通じて、子機５に通
話電流を供給している為、抵抗器Ｒ６及びＲ７には電圧
降下を生じてトランジスタＴｒ，には抵抗器Ｒ８を通じ
てバイアス電圧が印加されており、トランジスタＴｒ，
は動作状態にある。そして電力増幅された音声信号はコ
ンデンサＣ３及び抵抗器Ｒ７を経て端子Ｌ，，Ｌ２より
子機５へ伝送されるが、トランジスタＴｒ，のェミツタ
回路には増幅回路３の出力３ｏより抵抗器Ｒ７と子機５
のインピーダンスにより一定の比率で減衰した信号が加
わる。一方トランジスタＴｒ，のベース回路には増幅回
路３の出力３ｏより抵抗器Ｒ６，Ｒ５によりやはり一定
の比率で減衰した信号が加わり「 ヱミッタ回路、ベー
ス回路のそれぞれの電圧差を入力電圧としてトランジス
タＴｒ，が増幅作用を行なうため、受話器Ｒに現われる
電圧は極めて小さい。従ってこれにより側音防止効果を
得る。次に子機５より伝送されて来た信号電圧は、親機
１の端子Ｌ，，Ｌ２よりトランジスタＴｒ，のェミッタ
回路及び抵抗器Ｒ７に印加される。R, , R2, and R3 are each resistors. At this time, since the communication current is supplied from the power supply 4 to the handset 5 through the resistors R5, R6, and R7, a voltage drop occurs in the resistors R6 and R7, and the bias voltage is applied to the transistor Tr through the resistor R8. is applied, and the transistors Tr,
is in working condition. The power amplified audio signal is then transmitted to the handset 5 from the terminals L, L2 via the capacitor C3 and the resistor R7, but the emitter circuit of the transistor Tr is connected to the resistor R7 from the output 3o of the amplifier circuit 3. Handset 5
A signal is added that is attenuated at a certain ratio due to the impedance of the signal. On the other hand, the base circuit of the transistor Tr is supplied with a signal from the output 3o of the amplifier circuit 3 which is also attenuated at a constant ratio by the resistors R6 and R5. performs an amplification effect, so the voltage appearing at the receiver R is extremely small.Therefore, this provides a sidetone prevention effect.Next, the signal voltage transmitted from the handset 5 is applied to the terminals L, , L2 of the base unit 1. The voltage is applied to the emitter circuit of the transistor Tr and the resistor R7.
ここで増幅回路３は負帰還増幅が行なわれるようになっ
ており、出力インピーダンスは非常に４・さし、性質を
もっていて、ほぼ交流的に接地された状態に近い。従っ
て、子機５からの信号電圧はベース回路の抵抗器Ｒ６，
Ｒ５には殆んど流れずェミッタ回路にコンデンサＣ４を
介して大部分印加されることになる。従ってトランジス
タＴｒ，は増幅回路３の出力インピーダンスが非常に小
さいことから実質的にベース接地増幅回路として作用し
、コレクタに接続された受話器Ｒに信号が現われ、受話
回路を構成することになる。なお図においてＲ３，Ｒ４
はそれぞれ抵抗器、Ｃ２，Ｃ４はそれぞれコンデンサで
ある。以上説明したように本発明回路は送話時には、増
幅回路３の出力信号を、トランジスタＴｒ，のベース回
路の抵抗器Ｒ６，Ｒ５によってベース回路の減衰電圧と
する一方、ェミッタ回路には抵抗器Ｒ７と子機５のイン
ピーダンスによるェミツタ回路の減衰電圧として与える
ことにより、その誤差電圧を小さくすることによって側
音防止効果を得るものである。Here, the amplifier circuit 3 is configured to carry out negative feedback amplification, and its output impedance is extremely 4.degree., so that it is almost in an alternating current grounded state. Therefore, the signal voltage from the handset 5 is applied to the resistor R6 of the base circuit.
Almost no current flows into R5, and most of it is applied to the emitter circuit via capacitor C4. Therefore, since the output impedance of the amplifier circuit 3 is very small, the transistor Tr acts essentially as a common base amplifier circuit, and a signal appears at the receiver R connected to the collector, forming a receiver circuit. In addition, R3, R4 in the figure
are each a resistor, and C2 and C4 are each a capacitor. As explained above, in the circuit of the present invention, when transmitting a call, the output signal of the amplifier circuit 3 is made into the attenuated voltage of the base circuit by the resistors R6 and R5 of the base circuit of the transistor Tr, while the resistor R7 is connected to the emitter circuit. By giving this as an attenuation voltage of the emitter circuit due to the impedance of the slave unit 5, the sidetone prevention effect is obtained by reducing the error voltage.
そして受話時には、送話増幅回路３の出力端子３ｏを受
話信号の接地点としてトランジスタＴｒ，をベース接地
増幅の動作を行なわせることによって受話回路を構成し
ている。更にトランジスタＴｒ，のベースバイアス兼信
号減衰回路は子機５への通話電流供給回路として作用さ
せることができる特徴を有している。さらにこのような
回路は全体を非常に小型に構成できる利点がある。When receiving a call, a receiving circuit is constructed by using the output terminal 3o of the transmitting amplifier circuit 3 as a grounding point for the receiving signal, and causing the transistor Tr to perform a common base amplification operation. Furthermore, the base bias and signal attenuation circuit of the transistor Tr has a feature that it can be used as a communication current supply circuit to the handset 5. Furthermore, such a circuit has the advantage that the entire circuit can be constructed very compactly.
図は本発明側音防止回路の接続図である。
１・・・・・・親機、２・・・・・・マイクロホン、３
……増幅回路ト４・・…・電源、５…・・・子機、Ｒ５
，Ｒ６，Ｒ７……抵抗器、Ｔｒ，……トランジスタ、Ｒ
……受話器。The figure is a connection diagram of the sidetone prevention circuit of the present invention. 1...Base unit, 2...Microphone, 3
...Amplifier circuit 4...Power supply, 5...Slave unit, R5
, R6, R7...Resistor, Tr,...Transistor, R
...Telephone receiver.
Claims (1)
ランジスタを用い、親機からの送話時には、前記２組の
抵抗減衰回路の差電圧を上記トランジスタの入力電圧と
し、エミツタ接地増幅器として動作させて側音防止効果
を得、子機からの受話時にはエミツタ側に接続された抵
抗減衰回路の電圧降下をエミツタ入力電圧としてベース
接地増幅回路を構成すると共に前記２組の抵抗減衰回路
を通じて子機回路へ電源供給を行なうことを特徴とする
側音防止回路。1. Two sets of resistance attenuation circuits and one transistor are used on the output side of the amplifier circuit, and when transmitting a call from the base unit, the differential voltage between the two sets of resistance attenuation circuits is used as the input voltage of the transistor, and a common emitter amplifier is used. When receiving a call from the handset, the voltage drop of the resistor attenuation circuit connected to the emitter side is used as the emitter input voltage to form a base-grounded amplifier circuit, and the voltage drop is transmitted through the two sets of resistor attenuation circuits. A sidetone prevention circuit characterized by supplying power to a cordless handset circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10220979A JPS60823B2 (en) | 1979-08-13 | 1979-08-13 | Sidetone prevention circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10220979A JPS60823B2 (en) | 1979-08-13 | 1979-08-13 | Sidetone prevention circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5627557A JPS5627557A (en) | 1981-03-17 |
| JPS60823B2 true JPS60823B2 (en) | 1985-01-10 |
Family
ID=14321264
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10220979A Expired JPS60823B2 (en) | 1979-08-13 | 1979-08-13 | Sidetone prevention circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS60823B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6353168A (en) * | 1986-08-21 | 1988-03-07 | Toyoda Gosei Co Ltd | Steering wheel |
| US11344186B2 (en) | 2018-04-19 | 2022-05-31 | Fujifilm Corporation | Endoscope optical system and endoscope |
-
1979
- 1979-08-13 JP JP10220979A patent/JPS60823B2/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6353168A (en) * | 1986-08-21 | 1988-03-07 | Toyoda Gosei Co Ltd | Steering wheel |
| US11344186B2 (en) | 2018-04-19 | 2022-05-31 | Fujifilm Corporation | Endoscope optical system and endoscope |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5627557A (en) | 1981-03-17 |
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