JPS5856561A - Loudspeaker telephone set - Google Patents
Loudspeaker telephone setInfo
- Publication number
- JPS5856561A JPS5856561A JP15391381A JP15391381A JPS5856561A JP S5856561 A JPS5856561 A JP S5856561A JP 15391381 A JP15391381 A JP 15391381A JP 15391381 A JP15391381 A JP 15391381A JP S5856561 A JPS5856561 A JP S5856561A
- Authority
- JP
- Japan
- Prior art keywords
- input
- circuit
- output
- rectifying
- transmitting
- 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.)
- Pending
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M9/00—Arrangements for interconnection not involving centralised switching
- H04M9/08—Two-way loud-speaking telephone systems with means for conditioning the signal, e.g. for suppressing echoes for one or both directions of traffic
- H04M9/10—Two-way loud-speaking telephone systems with means for conditioning the signal, e.g. for suppressing echoes for one or both directions of traffic with switching of direction of transmission by voice frequency
Abstract
Description
【発明の詳細な説明】
本発明は音声スイッチ回路を有する拡声電話機に関する
。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a public address telephone having a voice switch circuit.
従来、送話および受話の音声信号の大きさを比較して音
声スイッチ回路を動作させるこの種の拡声電話機では、
送話および受話の音声信号に対し、入出力特性を直線的
にして整流平滑するか、あるいは入出力特性は非直線的
であっても送話および受話の入出力特性を一致させるよ
うに整流平滑し、整流平滑された両川力の大きさを比較
していた。Conventionally, this type of loudspeaker telephone operates an audio switch circuit by comparing the magnitude of the transmitting and receiving audio signals.
Rectification and smoothing is performed on the transmitting and receiving audio signals by making the input/output characteristics linear, or rectification and smoothing is performed so that the input/output characteristics of the transmitting and receiving voices match even if the input/output characteristics are non-linear. Then, the magnitude of the rectified and smoothed forces of both rivers was compared.
送話信号すなわちマイクロホンに入力される信号には通
常の音声信号の他に周囲騒音も含まれているが、上述の
従来の拡声電話機によると。According to the above-mentioned conventional loudspeaker telephone, the transmission signal, that is, the signal input to the microphone includes ambient noise in addition to the normal voice signal.
受話の音声信号は送話に音声信号が無い時でも。Even when there is no audio signal for the outgoing call, the audio signal for the receiving call remains unchanged.
前記周囲騒音と絶えず同じレベル条件でその大きさの比
較が行われる。例えば、線路の損失の大きいときの相手
と通話をするような場合のように、受話の入力信号レベ
ルが小さくなると。Comparison of the magnitude of the ambient noise is always performed under the same level conditions as the ambient noise. For example, when the input signal level for receiving a call becomes low, such as when talking to the other party when line loss is high.
音声スイッチ回路は周囲騒音により送話状態（送話の通
話路の利得が大となり受話の通話路の利得が小となる状
態ンにをシ易く９反対に受話状態（受話の通話路の利得
が犬となシ送話の通話路の利得が小となる状態）に固定
されにくくなるため、スピーカからの受話の音声信号が
途切れたり、ひいて゛は全く聞えなくなるという現象が
発生し易いという欠点があった。The voice switch circuit easily changes to the transmitting state (the gain of the transmitting channel is large and the gain of the receiving channel is small) due to ambient noise, and vice versa. Since it becomes difficult to fix the gain of the transmitting channel with a dog (in which the gain of the transmitting channel becomes small), there is a disadvantage that the received audio signal from the speaker is likely to be interrupted, or even become completely inaudible. Ta.
本発明の目的・け通常の通話性能には影響を与えずに低
レベルの受話人力に対し音声スインチ回路を安定に受話
状態に保持させるようにした拡声電話機を提供すること
にある。SUMMARY OF THE INVENTION An object of the present invention is to provide a loudspeaker telephone capable of stably maintaining a voice switch circuit in a receiving state even with a low level of receiver power without affecting normal speech performance.
本発明によれば、送話および受話の音声信号をそれぞれ
送話および受話整流平滑回路によって整流平滑し、該送
話および受話整流平滑回路の出力の大きさを比較して音
声スイッチ回路を動作させる拡声電話機において、上記
送話整流平滑回路の入出力特性に、低レベルの入力に対
する出力が上記受話整流平滑回路の入出力特性よりも抑
圧されるように、非直線特性をもたせたことを特徴とす
る拡声電話機が得られる。According to the present invention, the transmitting and receiving voice signals are rectified and smoothed by the transmitting and receiving rectifying and smoothing circuits, respectively, and the magnitudes of the outputs of the transmitting and receiving rectifying and smoothing circuits are compared to operate the voice switch circuit. In the public address telephone, the input/output characteristics of the transmitting rectifying and smoothing circuit are provided with non-linear characteristics such that the output in response to a low level input is suppressed more than the input/output characteristics of the receiving rectifying and smoothing circuit. You can get a loudspeaker telephone that does this.
次に本発明の実施例について図面を参照して説明する。Next, embodiments of the present invention will be described with reference to the drawings.
第１図を参照すると２本発明の実施例は、マイクロホン
１に入力される送話信号がマイクアンプ２．音声スイッ
チ回路６．送話アンプ４゜ハイブリット回路５を介して
線路端＋６に出力される。一方、線路端＋６に線路より
入力された受話信号はハイブリッド回路５．受話アンプ
７、音声スイッチ回路ろ、スピーカアンプ８を介してス
ピーカ９にて再生される。またマイクアンプ２の出力は
送話整流平滑回路１０の入力端子１６に入力され、送話
整流平滑回路ＩＣ１：出力端子１４に整流平滑された直
流電圧を出力する。Referring to FIG. 1, in the two embodiments of the present invention, the transmission signal input to the microphone 1 is transmitted to the microphone amplifier 2. Audio switch circuit 6. The signal is outputted to the line end +6 via the transmitting amplifier 4° hybrid circuit 5. On the other hand, the receiving signal input from the line to the line end +6 is transmitted to the hybrid circuit 5. The signal is reproduced by the speaker 9 via the receiver amplifier 7, the audio switch circuit, and the speaker amplifier 8. The output of the microphone amplifier 2 is input to the input terminal 16 of the transmitting rectifying and smoothing circuit 10, and outputs the rectified and smoothed DC voltage to the output terminal 14 of the transmitting rectifying and smoothing circuit IC1.
一方スビーカアンプ８の入力は受話整流平滑回路１１の
入力端子１５に入力され、受話整流平滑回路１１は出力
端子１６に整流平滑された直流電圧を出力する。比較回
路１２は、前記出力端子１４と出力端子１６の直流電圧
の大きさを比較し。On the other hand, the input of the speaker amplifier 8 is input to the input terminal 15 of the receiving rectifying and smoothing circuit 11, and the receiving rectifying and smoothing circuit 11 outputs a rectified and smoothed DC voltage to the output terminal 16. The comparison circuit 12 compares the magnitude of the DC voltage at the output terminal 14 and the output terminal 16.
音声スイッチ回路６を動作させる。例えば、出力端子１
４の電圧が出力端子１６の電圧より大きい場合比較回路
１２は音声スイッチ回路３を送話状態に制呻する。The audio switch circuit 6 is operated. For example, output terminal 1
When the voltage at output terminal 4 is greater than the voltage at output terminal 16, comparator circuit 12 controls voice switch circuit 3 to the transmitting state.
受話整流平滑回路１１ば、入出力特性が直線的になるよ
うに以下の如く構成される。すなわち。The receiving rectifying and smoothing circuit 11 is configured as follows so that the input/output characteristics are linear. Namely.
入力端子１５から抵抗器Ｒ５を介し演算増幅器（オペア
ンプ）１８の反転入力端に接続する。The input terminal 15 is connected to the inverting input terminal of an operational amplifier 18 via a resistor R5.
前記反転入力端と前記オペアンプ１８の出力端との間に
、抵抗器Ｒ６とダイオードＤ、との直列回路と、ダイオ
ードＤ３とを、並列接続して。A series circuit of a resistor R6 and a diode D, and a diode D3 are connected in parallel between the inverting input terminal and the output terminal of the operational amplifier 18.
半波整流回路を構成する。前記抵抗器Ｒ６とダイオード
Ｄ４との接続点より充電時定数を決定する抵抗器Ｒ７ヲ
介し平滑用コンデンサＣ２および出力端子１６に接続す
る。Configure a half-wave rectifier circuit. The connection point between the resistor R6 and the diode D4 is connected to the smoothing capacitor C2 and the output terminal 16 via a resistor R7 which determines the charging time constant.
また、送話整流平滑回路１０ｒＩ′ｉ、入出力特性が低
レベルで抑圧された非直線特性が得られるように以下の
如く構成される。すなわち、入力端子１６から抵抗器Ｒ
，ヲ介し演算増幅器（オペアン７”）１７０反転入力端
に接続する。前記反転入力端と前記オペアンプ１７の出
力端との間に。Further, the transmitting rectifying and smoothing circuit 10rI'i is constructed as follows so that the input/output characteristics can be suppressed at a low level and non-linear characteristics can be obtained. That is, from the input terminal 16 to the resistor R
, is connected to the inverting input terminal of an operational amplifier (op-amp 7'') 170 between the inverting input terminal and the output terminal of the operational amplifier 17.
抵抗器Ｒ２とダイオードＤ２との直列回路と、ダイオー
ドＤ１と、非直線特性を生じさせるだめの抵抗器Ｒ３と
を、並列に接続して、半波整流回路全構成する。前記抵
抗器Ｒ２とダイオードＤ２との接続点より充電時定敷金
決定する抵′抗器Ｒ１を介し平滑用コンデンサＣ１およ
び出力端子１４に接続する。A series circuit of a resistor R2 and a diode D2, a diode D1, and a resistor R3 that causes nonlinear characteristics are connected in parallel to form the entire half-wave rectifier circuit. A connection point between the resistor R2 and the diode D2 is connected to the smoothing capacitor C1 and the output terminal 14 via a resistor R1 which determines a fixed deposit during charging.
更に本発明の送話および受話整流平滑回路１０および１
１の特性について詳述すると、送話整流平滑回路１００
入力端子１３の入力レベルの波高値ｅＴと出力端子１４
の直流電圧ＥＴとの関係は、ダイオードＤ２の純方向抵
抗をｒ、とし、充電時定数Ｒ４・Ｃ７に比べ放電時定数
（Ｒ２十Ｒ４） Ｃ＋が十分に犬とすると、使用するオ
ペアンプの特性は高入力・低出力抵抗で利得が非常に大
きいため２次式で表わされる。Further, the transmitting and receiving rectifying and smoothing circuits 10 and 1 of the present invention
1, the transmitting rectifying and smoothing circuit 100
Peak value eT of input level of input terminal 13 and output terminal 14
Assuming that the pure directional resistance of the diode D2 is r, and the discharge time constant (R20R4) C+ is sufficiently large compared to the charging time constant R4・C7, the characteristics of the operational amplifier used are as follows. Since the gain is very large due to high input and low output resistance, it is expressed by a quadratic equation.
ダイオードＤ２の純方向抵抗ｒｆはダイオードＤ２に流
れる電流により変化し、入力レベルｅ が犬きいときは
小さな値となり、ｅＴが小さくなると急激に大きな値と
なるだめ、前記（１）式において抵抗器Ｒ２およびＲ３
ｆ ｒｆの変化に対し適切な値に選定することにより、
入力レベルｅＴが大きな値では一直流電圧ＥＴとの関係
はほぼ直線的になり＋ ｅｒが小さくなるとＥＴを抑
圧するように非直線特性をもつことになる。The pure directional resistance rf of the diode D2 changes depending on the current flowing through the diode D2, and it becomes a small value when the input level e is high, and suddenly becomes a large value when eT becomes small. and R3
By selecting an appropriate value for changes in f rf,
When the input level eT has a large value, the relationship with one DC voltage ET is almost linear, and when +er becomes small, it has nonlinear characteristics so as to suppress ET.
圧ＥＲとの関係はダイオードＤ４の純方向抵抗ｒ；とじ
、送話整流平滑回路の場合と同様に考えると２次式で表
わされる。The relationship with the voltage ER is expressed by a quadratic equation when considered in the same manner as in the case of the transmitting rectifying and smoothing circuit.
上記（２）式ではダイオードＤ４の純方向抵抗ｒには依
存されずに入力レベルｅ と直流電圧ＥＲとの関係は直
線的になる。In the above equation (2), the relationship between the input level e and the DC voltage ER becomes linear regardless of the pure directional resistance r of the diode D4.
以上に説明した入出力特性の一例を第２図に示す。第２
図において実線で表示した特性が受話整流平滑回路１１
の入出力特性を示し、また入力レベルの大きい値のとき
の実線部分と入力レベルの小さな値のときの破線で表示
した部分とが送話整流平滑回路１０の入出力特性を示す
。FIG. 2 shows an example of the input/output characteristics explained above. Second
The characteristics indicated by the solid line in the figure are the receiving rectifier and smoothing circuit 11.
The solid line portion when the input level is a large value and the broken line portion when the input level is a small value represent the input/output characteristics of the transmitting rectifying and smoothing circuit 10.
拡声電話機が使用される通常の状態では送話の音声信号
は周囲騒音より大きいため、第２図に示す直線的な特性
の部分で直流電圧ＥＴが出力されるが、周囲騒音に対し
ては破線で示された非直線的な特性部分で直流電圧Ｅ、
が出力され抑圧されるので、低レベルの受話人力に対し
て周囲騒音による影響が少なくなり、音声スイッチ回路
６は安定に受話状態を保持できるようになる。なお本実
施例では非直線特性を得るために抵抗器Ｒ３として説明
したが、これをコンデンサに置き替えた場合でも同様の
効果を有する。Under normal conditions when a public address telephone is used, the voice signal of the outgoing call is louder than the ambient noise, so the DC voltage ET is output in the linear characteristic section shown in Figure 2, but the broken line with respect to the ambient noise DC voltage E in the non-linear characteristic part shown by
is output and suppressed, so that the influence of ambient noise on low-level listener power is reduced, and the voice switch circuit 6 can stably maintain the listening state. In this embodiment, the resistor R3 is used in order to obtain non-linear characteristics, but the same effect can be obtained even when this is replaced with a capacitor.
本発明は以上説明したように、送話整流平滑回路の入出
力特性に、低レベルの入力に対する出力が受話整流平滑
回路の入出力特性よりも抑圧させ骨ように、非直線特性
をもたせたことにより２通常の音声信号での音声スイッ
チ回路の動作に影響を与えず、低レベルの受話人力の場
合に周囲騒音によって生じる受話の途切れなど軽減する
効果を有し、安定に音声スイッチ回路が動作する拡声電
話機を提供できる。As explained above, the present invention has a non-linear characteristic in the input/output characteristics of the transmitting rectifying and smoothing circuit so that the output in response to a low level input is suppressed more than the input/output characteristics of the receiving rectifying and smoothing circuit. 2.It does not affect the operation of the voice switch circuit with normal voice signals, has the effect of reducing interruptions in reception caused by ambient noise when the receiver's power is low, and allows the voice switch circuit to operate stably. We can provide public address telephones.
第１図は本発明の一実施例を部分的にブロフク図で示し
た回路図、第２図は第１図の送話および受話整流平滑回
路１０および１１の入出力特性の一例を示す特性図であ
る。
１・・・マイクロホン、 ２・・・マイクアンプ。
３・・・音声スイッチ回路、４・・・送話アンプ。
５・・・ハイブリッド回路、６＝；・線路端子。
７・・・受話アンプ、 ８・・・スピーカアンプ。
９・・・スピーカ、 １０・・・送話整流平滑回路。
１１・・・受話整流平滑回路、１２・・・比較回路。
１３、１５・・・入力端子、 １４．１６・・・出力
端子。
１７、１８・・・オペアンプ、Ｒ１−Ｒ７・・・抵抗器
。
Ｄ、〜Ｄ４・・・ダイオード、Ｃ１，Ｃ２・・・コンデ
ンサ。FIG. 1 is a circuit diagram partially showing an embodiment of the present invention in the form of a block diagram, and FIG. 2 is a characteristic diagram showing an example of the input/output characteristics of the transmitting and receiving rectifying and smoothing circuits 10 and 11 of FIG. 1. It is. 1...Microphone, 2...Mic amplifier. 3...Audio switch circuit, 4...Talking amplifier. 5...Hybrid circuit, 6=;・Line terminal. 7... Receiving amplifier, 8... Speaker amplifier. 9... Speaker, 10... Transmission rectification and smoothing circuit. 11...Reception rectification smoothing circuit, 12...Comparison circuit. 13, 15... Input terminal, 14.16... Output terminal. 17, 18... operational amplifier, R1-R7... resistor. D, ~D4...diode, C1, C2... capacitor.
Claims (1)
話整流平滑回路によって整流平滑し、該送話および受話
整流平滑回路の出力の大きさを比較して音声スイッチ回
路を動作させる拡声電話機において、上記送話整流平滑
回路の入出力特性に、低レベルの入力に対する出力が上
記受話整流平滑回路の入出力特性よりも抑圧されるよう
に、非直線特性をもたせたことを特徴とする拡声電話機
。1. A loudspeaker telephone that rectifies and smoothes the transmitting and receiving audio signals by transmitting and receiving rectifying and smoothing circuits, respectively, and compares the magnitudes of the outputs of the transmitting and receiving rectifying and smoothing circuits to operate a voice switch circuit, A loudspeaker telephone set, characterized in that the input/output characteristics of the transmitting rectifying and smoothing circuit are provided with non-linear characteristics so that the output for low-level inputs is suppressed more than the input/output characteristics of the receiving rectifying and smoothing circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15391381A JPS5856561A (en) | 1981-09-30 | 1981-09-30 | Loudspeaker telephone set |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15391381A JPS5856561A (en) | 1981-09-30 | 1981-09-30 | Loudspeaker telephone set |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS5856561A true JPS5856561A (en) | 1983-04-04 |
Family
ID=15572836
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15391381A Pending JPS5856561A (en) | 1981-09-30 | 1981-09-30 | Loudspeaker telephone set |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5856561A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5883008A (en) * | 1981-11-13 | 1983-05-18 | Dainippon Ink & Chem Inc | Production of styrene resin |
| JPS60182250A (en) * | 1984-02-29 | 1985-09-17 | Nippon Telegr & Teleph Corp <Ntt> | Voice switch circuit of loudspeaker telephone set |
| JPH01212950A (en) * | 1988-02-19 | 1989-08-25 | Matsushita Electric Ind Co Ltd | Telephone system |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5220104B2 (en) * | 1972-11-17 | 1977-06-01 | ||
| JPS552780A (en) * | 1978-06-23 | 1980-01-10 | Nippon Jiryoku Senko Kk | Dephosphorizing method for slag |
-
1981
- 1981-09-30 JP JP15391381A patent/JPS5856561A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5220104B2 (en) * | 1972-11-17 | 1977-06-01 | ||
| JPS552780A (en) * | 1978-06-23 | 1980-01-10 | Nippon Jiryoku Senko Kk | Dephosphorizing method for slag |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5883008A (en) * | 1981-11-13 | 1983-05-18 | Dainippon Ink & Chem Inc | Production of styrene resin |
| JPH0334482B2 (en) * | 1981-11-13 | 1991-05-22 | Dainippon Ink & Chemicals | |
| JPS60182250A (en) * | 1984-02-29 | 1985-09-17 | Nippon Telegr & Teleph Corp <Ntt> | Voice switch circuit of loudspeaker telephone set |
| JPH0334710B2 (en) * | 1984-02-29 | 1991-05-23 | Nippon Denshin Denwa Kk | |
| JPH01212950A (en) * | 1988-02-19 | 1989-08-25 | Matsushita Electric Ind Co Ltd | Telephone system |
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