JPH02164164A - Loudspeaker telephone system - Google Patents
Loudspeaker telephone systemInfo
- Publication number
- JPH02164164A JPH02164164A JP32009788A JP32009788A JPH02164164A JP H02164164 A JPH02164164 A JP H02164164A JP 32009788 A JP32009788 A JP 32009788A JP 32009788 A JP32009788 A JP 32009788A JP H02164164 A JPH02164164 A JP H02164164A
- Authority
- JP
- Japan
- Prior art keywords
- loss
- circuit
- level
- reception
- receiving
- 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.)
- Granted
Links
- 230000005540 biological transmission Effects 0.000 claims abstract description 47
- 238000001514 detection method Methods 0.000 abstract description 31
- 230000007423 decrease Effects 0.000 abstract description 4
- 238000010586 diagram Methods 0.000 description 10
- 201000007201 aphasia Diseases 0.000 description 4
- 230000003247 decreasing effect Effects 0.000 description 4
- 230000002238 attenuated effect Effects 0.000 description 2
- 230000005236 sound signal Effects 0.000 description 2
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 210000005069 ears Anatomy 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
Abstract
Description
【発明の詳細な説明】
【発明の目的〕
（産業上の利用分野）
本発明は、拡声電話装置に係り、特に送話が適切に行な
われるようにした拡声電話装置に関する。DETAILED DESCRIPTION OF THE INVENTION OBJECTS OF THE INVENTION (Industrial Field of Application) The present invention relates to a public address telephone device, and more particularly to a public address telephone device that enables appropriate transmission of calls.
（従来の技術）
第３図は、従来の拡声電話装置の一例を示すブロック図
である。マイク１から入力された音声信号は、送話用ア
ンプ２によって増幅された後、送話損失回路３によって
減衰を受け、更にハイブリッド回路４を介して四線５に
送出される。(Prior Art) FIG. 3 is a block diagram showing an example of a conventional loudspeaker telephone device. The audio signal input from the microphone 1 is amplified by the transmitting amplifier 2, attenuated by the transmitting loss circuit 3, and then sent to the four-wire 5 via the hybrid circuit 4.
一方、四線５を伝送されてきた音声信号は、ハイブリッ
ド回路４を介して受話損失回路６に入り、ここで減衰さ
れた後受話用アンプ７により増幅され、スピーカ８から
出力される。送話損失回路３からの信号は、送話検出回
路９に入力される。またハイブリッド回路４からの受話
信号は、受話検出回路１０に入力される。送話検出回路
９及び受話検出回路１０からの出力信号は、それぞれ音
声スイッチ制御回路１１に入力される。この音声スイッ
チ制御回路１１には、受話閾値レベル設定回路１２が出
力する受話閾値レベルが入力されている。音声スイッチ
制御回路１１が出力する制御信号は、送話損失回路３及
び受話損失回路６に人力される。音声スイッチ制御回路
１１は、送話検出回路９及び受話検出回路１０の出力レ
ベルを比較し、その結果に応じて送話損失回路３及び受
話損失回路６のそれぞれの損失量を相反的に増減制御す
る。On the other hand, the audio signal transmitted through the four-wire 5 enters the reception loss circuit 6 via the hybrid circuit 4, is attenuated there, is amplified by the reception amplifier 7, and is output from the speaker 8. The signal from the transmission loss circuit 3 is input to the transmission detection circuit 9. Further, the reception signal from the hybrid circuit 4 is input to the reception detection circuit 10 . Output signals from the transmitting call detection circuit 9 and the receiving call detection circuit 10 are input to the audio switch control circuit 11, respectively. The voice switch control circuit 11 receives the voice reception threshold level output from the voice reception threshold level setting circuit 12 . A control signal output from the voice switch control circuit 11 is manually input to the transmission loss circuit 3 and the reception loss circuit 6. The voice switch control circuit 11 compares the output levels of the transmitting speech detection circuit 9 and the receiving speech detection circuit 10, and reciprocally controls the amount of loss of the transmitting speech loss circuit 3 and the receiving speech loss circuit 6 to increase or decrease according to the result. do.
なお、マイク１、送話用アンプ２、送話損失回路３、ハ
イブリッド回路４及び回線５により送話路が形成され、
回線５、ハイブリッド回路４、受話損失回路６、受話用
アンプ７及びスピーカ８により受話路が形成される。Note that a transmission path is formed by the microphone 1, the transmission amplifier 2, the transmission loss circuit 3, the hybrid circuit 4, and the line 5,
A receiving path is formed by the line 5, the hybrid circuit 4, the receiving loss circuit 6, the receiving amplifier 7, and the speaker 8.
また受話閾値レベル設定回路１２が発生する受話閾値レ
ベルとは、マイク１からの送話信号がない状態において
、この装置が送話状態から受話状態になる点の回線５に
おける入力レベルである。The receiving threshold level generated by the receiving threshold level setting circuit 12 is the input level on the line 5 at the point where the device changes from the transmitting state to the receiving state when there is no transmitting signal from the microphone 1.
次に第３図の回路の動作について説明する。まず、回線
５からの受話信号が無く、マイク１からの送話信号も無
い状態では、回線５からの入力レベルは受話閾値レベル
よりも低いため、音声スイッチ制御回路１１は送話損失
回路３の損失量を小とし、受話損失回路６の損失量を大
とするように制御し、回路は送話状態となる。この状態
で回線５から受話信号が入り、受話検出回路１０の出力
レベルが増大し、回線５からの受話信号がレベル設定回
路１２で設定した受話閾値レベルよりも大きくなると、
制御回路１１は送話損失回路３の損失量を大とし、受話
損失回路６の損失量を小とする制御を行なう。これによ
り回路は、受話状態となる。Next, the operation of the circuit shown in FIG. 3 will be explained. First, when there is no reception signal from the line 5 and no transmission signal from the microphone 1, the input level from the line 5 is lower than the reception threshold level. Control is performed to reduce the amount of loss and increase the amount of loss in the receiving loss circuit 6, and the circuit enters the transmitting state. In this state, a reception signal is input from the line 5, the output level of the reception detection circuit 10 increases, and when the reception signal from the line 5 becomes higher than the reception threshold level set by the level setting circuit 12,
The control circuit 11 performs control to increase the amount of loss in the transmission loss circuit 3 and to decrease the amount of loss in the reception loss circuit 6. This puts the circuit in the receiving state.
受話信号が、受話閾値レベルより大きく、送話信号もあ
る場合には、制御回路１１は送話検出回路９及び受話検
出回路１０の出力レベルを比較し、その比較結果に応じ
て送話損失回路３及び受話損失回路６の損失量を相反的
に増減する。When the reception signal is higher than the reception threshold level and there is also a transmission signal, the control circuit 11 compares the output levels of the transmission detection circuit 9 and the reception detection circuit 10, and depending on the comparison result, the transmission loss circuit 3 and the reception loss circuit 6 are increased/decreased reciprocally.
第４図は、第３図の回路の切り替わり特性を示す図であ
る。縦軸はマイク１から入力される送話レベルを、横軸
は四線５から人力される受話レベルを示している。FIG. 4 is a diagram showing switching characteristics of the circuit of FIG. 3. The vertical axis represents the transmitting level input from the microphone 1, and the horizontal axis represents the receiving level input manually from the four-wire 5.
曲線Ａは受話状態から送話状態への、曲線Ｂは送話状態
から受話状態への切り替わり特性を示している。Curve A shows the switching characteristics from the receiving state to the sending state, and curve B shows the switching characteristics from the sending state to the receiving state.
今、第４図において、回線５からＮレベルの騒音レベル
が入ったと仮定する。ここで騒音とは、通話相手の送話
器に人力される周囲騒音を意味する。Now, in FIG. 4, it is assumed that a noise level of N level comes in from line 5. Here, noise refers to ambient noise that is manually applied to the transmitter of the other party.
このとき、マイク１からの送話信号がない状態では、受
話検出回路１０の出力レベルは、送話検出回路９の出力
レベルより大きいため、制御回路１１は送話損失回路３
の損失量を大とし、受話損失回路６の損失量を小となる
よう制御し受話状態となる。At this time, when there is no transmitting signal from the microphone 1, the output level of the receiving detecting circuit 10 is higher than the output level of the transmitting detecting circuit 9.
The loss amount of the receiving loss circuit 6 is controlled to be large, and the loss amount of the receiving loss circuit 6 is controlled to be small, and a receiving state is established.
ここで、マイク１から送話信号を入力して回線５に通話
可能な送話レベルを送出するためには、第４図のＰ点以
上のレベルが必要となる。このレベル以上では送話検出
回路９の出力レベルが受話検出回路１０の出力レベルよ
り大きくなり、制御回路１１は送話損失回路３の損失量
を小とし、受話損失回路６の損失量を大となるよう制御
し送話状態となる。Here, in order to input a voice signal from the microphone 1 and send it to the line 5 at a voice level that allows a conversation, a level equal to or higher than point P in FIG. 4 is required. Above this level, the output level of the transmitting speech detection circuit 9 becomes higher than the output level of the receiving speech detection circuit 10, and the control circuit 11 reduces the loss amount of the transmitting speech loss circuit 3 and increases the loss amount of the receiving speech loss circuit 6. It is controlled so that it becomes a transmitting state.
このように送話損失回路３及び受話損失回路６の損失量
を相反的に増減させるのは、ハイブリッド回路４におけ
る送話信号の受話側への回り込み及びスピーカ８からマ
イク１への音響結合を考えた場合に、マイク１、送話用
アンプ２、送話損失回路３、ハイブリッド回路４、受話
１に失回路６、受話用アンプ７、スピーカ８及びマイク
１のループのトータルゲインが送話及び受話状態のいず
れの場合でも、１倍以下となるようにするためである。The reason for reciprocally increasing and decreasing the amount of loss in the transmitting loss circuit 3 and the receiving loss circuit 6 is to take into consideration the looping of the transmitting signal to the receiving side in the hybrid circuit 4 and the acoustic coupling from the speaker 8 to the microphone 1. In this case, the total gain of the loop of microphone 1, transmitting amplifier 2, transmitting loss circuit 3, hybrid circuit 4, receiving loss circuit 6, receiving amplifier 7, speaker 8, and microphone 1 is equal to the transmitting and receiving loss circuits. This is to ensure that it is 1 times or less in any case.
これにより装置の発振を防ｎ二している。This prevents oscillation of the device.
（発明が解決しようとする課題）
上述したようにノイズレベルＮが受話閾値レベルＲより
大きい場合には、マイク１の入力レベルがＰのレベル以
上でなければ送話状態とはならない。(Problem to be Solved by the Invention) As described above, when the noise level N is higher than the reception threshold level R, the transmission state does not occur unless the input level of the microphone 1 is equal to or higher than the level P.
例えば、この拡声電話装置を用いて、音声により呼びを
かけ、音声により応答する場合を考える。For example, consider a case where a call is made by voice using this loudspeaker telephone device, and a call is responded by voice.
通話相手からの受話信号（音声による呼び信号）は、回
線５、受話損失回路６及び受話用アンプ７を介してスピ
ーカ８から出力される。A reception signal (voice call signal) from the other party is outputted from the speaker 8 via the line 5, the reception loss circuit 6, and the reception amplifier 7.
スピーカ８から出力された音声呼びに対し、マイク１を
通して応答する場合、通話相手からの騒音レベルＮが受
話閾値レベルＲより低い場合には、受話信号がなくなる
と送話状態となるが、騒音レベルが受話閾値レベルＲよ
り大きい場合には、マイク入力レベルがＰ点以上になら
なければ送話状態とならない。この場合、マイク１から
の応答は送話損失回路３で損失が入った状態で回線５へ
出て行く。When answering a voice call output from the speaker 8 through the microphone 1, if the noise level N from the other party is lower than the receiving threshold level R, the transmitting state will occur when the receiving signal disappears, but the noise level When is greater than the receiving threshold level R, the transmitting state does not occur unless the microphone input level reaches point P or higher. In this case, the response from the microphone 1 is output to the line 5 with a loss in the transmission loss circuit 3.
つまり、通話者がこの拡声電話装置から離れたところに
いて、送話レベルが小さい場合には送話状態とならず、
送話信号が相手に届かないという問題がある。In other words, if the caller is far away from the loudspeaker telephone device and the transmitting level is low, the transmitting state will not occur.
There is a problem in that the transmitting signal does not reach the other party.
本発明は、このような問題点を解消するためになされた
もので、送話レベルが小さくても送話信号が相手方に届
くようにした拡声電話装置を提供することを目的とする
。The present invention has been made to solve these problems, and an object of the present invention is to provide a loudspeaker telephone device in which a transmission signal can reach the other party even if the transmission level is low.
（課題を解決するための手段）
本発明は、送話信号を第１の送話損失回路を介して回線
に送出する送話路と、回線からの受話信号を第１の受話
損失回路を介してスピーカから出力する受話路と、送話
信号レベルと受話信号レベルとを予め定めた受話閾値レ
ベルと比較しその結果に応じて第１の送話損失回路及び
第１の受話損失回路のそれぞれの損失量を相反的に増減
制御する制御回路とを備えた拡声電話装置において、第
１の送話損失回路及び受話損失回路に直列に第２の送話
損失回路及び第２の受話損失回路を送話路及び受話路に
設け、回線からの騒音レベルが受諾閾値レベルを越えた
ときには受話状態にある第２の送話損失回路の損失量を
騒音レベルの大きさに比例した量だけ小さくし、第２の
受話損失回路の損失量を騒音レベルに比例した量だけ大
きくなるよう制御する損失制御回路を更に設けたもので
ある。(Means for Solving the Problems) The present invention provides a transmission path for transmitting a transmission signal to a line via a first transmission loss circuit, and a transmission path for transmitting a reception signal from the line through a first reception loss circuit. The receiving channel output from the speaker, the transmitting signal level, and the receiving signal level are compared with a predetermined receiving threshold level, and the first transmitting loss circuit and the first receiving loss circuit are controlled according to the results. In a public address telephone device equipped with a control circuit that reciprocally controls increase/decrease in loss amount, a second transmitting loss circuit and a second receiving loss circuit are connected in series to the first transmitting loss circuit and the receiving loss circuit. A second transmitting loss circuit is provided in the speaking path and the receiving path, and when the noise level from the line exceeds the acceptance threshold level, the loss amount of the second transmitting loss circuit which is in the receiving state is reduced by an amount proportional to the magnitude of the noise level. A loss control circuit is further provided to control the loss amount of the reception loss circuit No. 2 to increase by an amount proportional to the noise level.
（作 用）
本発明では、送話損失回路と受話損失回路を２つに分割
し、回線からの受話の騒音レベルが受話閾値レベルより
大きい場合の受話状態において、送話の損失回路の損失
量を騒音レベルの大きさに比例した量だけ小さく、受話
の損失回路の損失量を同じ量だけ大きくするように動作
する損失制御回路を設け、分割された送話及び受話損失
回路の一方をこの損失制御回路により制御するように構
成されているため、受話の騒音が大きい場合でも、また
送話信号が小さくても損失の無い送話信号を相手通話者
に送ることが出来る。(Function) In the present invention, the transmitting loss circuit and the receiving loss circuit are divided into two, and the amount of loss in the transmitting loss circuit is determined in the receiving state when the noise level of the receiving voice from the line is higher than the receiving threshold level. A loss control circuit is provided that operates to reduce the loss by an amount proportional to the magnitude of the noise level and increase the loss amount in the receiving loss circuit by the same amount, and one of the divided transmitting and receiving loss circuits is set to reduce this loss by an amount proportional to the magnitude of the noise level. Since it is configured to be controlled by a control circuit, even if the noise of the receiving call is large or the sending signal is small, a lossless sending signal can be sent to the other party.
（実施例）
以下、本発明の一実施例を図面に基づいて詳細に説明す
る。(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.
第１図は、本発明の一実施例を示すブロック図で、第３
図に示す従来の回路と同一部分には同一符号を付しその
詳細説明は省略する。FIG. 1 is a block diagram showing one embodiment of the present invention.
Components that are the same as those in the conventional circuit shown in the figure are given the same reference numerals, and detailed explanation thereof will be omitted.
本発明では、送話損失回路及び受話損失回路をそれぞれ
第１及び第２の送話損失回路１３．１４及び第１及び第
２の受話損失回路１６．１５に分割している。また、騒
音検出回路１８の人力を受話検出回路１０の人力に接続
している。ここで、騒音検出回路１８と受話検出回路１
０との相違は、検出時定数の相違にある。つまり、騒音
は長時間に亘ってほぼ一定のレベルにあり、一方受話音
声は短時間でレベルが変動するため、騒音検出回路１８
は長い時定数に、また受話検出回路１０は短い時定数に
設定されて、騒音検出回路１８は騒音のレベルのみを検
出するようになっている。さらに、損失量制御回路１７
を設け、これに受話検出回路１０及び受話閾値レベル設
定回路１２の出力、更に騒音検出回路１８の出力を入力
してそれぞれを比較し、比較結果に応じて第２の送話損
失回路１４及び第２の受話損失回路１５の損失量を相反
的に制御している。騒音レベルが、受話閾値レベルより
も大きい場合には、それらの差に比例した量だけ、損失
量制御回路１７は第２の送話損失回路１４の損失量を小
さく、第２の受話損失回路１５の損失量を大きくするよ
うに制御する。In the present invention, the transmitting loss circuit and the receiving loss circuit are divided into first and second transmitting loss circuits 13.14 and first and second receiving loss circuits 16.15, respectively. Further, the human power of the noise detection circuit 18 is connected to the human power of the reception detection circuit 10. Here, the noise detection circuit 18 and the reception detection circuit 1
The difference from 0 lies in the difference in detection time constant. In other words, noise remains at a nearly constant level over a long period of time, while the level of received voice fluctuates over a short period of time, so the noise detection circuit 18
is set to a long time constant, and the reception detection circuit 10 is set to a short time constant, so that the noise detection circuit 18 detects only the noise level. Furthermore, the loss amount control circuit 17
The outputs of the receiving voice detection circuit 10 and the receiving voice threshold level setting circuit 12 and the output of the noise detection circuit 18 are inputted thereto and compared. The loss amount of the second receiving loss circuit 15 is controlled reciprocally. When the noise level is higher than the reception threshold level, the loss amount control circuit 17 reduces the loss amount of the second transmission loss circuit 14 by an amount proportional to the difference therebetween, and reduces the loss amount of the second reception loss circuit 15 by an amount proportional to the difference therebetween. control to increase the amount of loss.
第２図は、第１図の回路の送話及び受話切り替わり特性
を示す図である。FIG. 2 is a diagram showing the transmitting and receiving switching characteristics of the circuit of FIG. 1.
次に第１図の回路の動作を説明する。第２図において、
従来の第４図に相当する騒音レベルＮと同じ、騒音レベ
ルが四線５から入力されたものと仮定する。騒音レベル
Ｎは、騒音検出回路１８より検出され、マイク１からの
送話信号がなく、受話信号は騒音信号のみで、音声によ
る受話信号が無い場合には、損失量制御回路１７に入力
される３つの入力は、騒音検出回路１８を通ってきたレ
ベルが１番大きいため、損失量制御回路１７は第２の送
話損失回路１４の損失量を、騒音検出回路１８の出力レ
ベルと受話閾値レベルとの差に比例した量だけ小さくし
、第２の受話損失回路１５の損失量を同じ量だけ大きく
する。Next, the operation of the circuit shown in FIG. 1 will be explained. In Figure 2,
It is assumed that the same noise level N as the conventional noise level N corresponding to FIG. 4 is input from the four-line line 5. The noise level N is detected by the noise detection circuit 18, and is input to the loss amount control circuit 17 when there is no transmission signal from the microphone 1, the reception signal is only a noise signal, and there is no audio reception signal. Since the level of the three inputs that has passed through the noise detection circuit 18 is the highest, the loss amount control circuit 17 adjusts the loss amount of the second transmission loss circuit 14 by adjusting the output level of the noise detection circuit 18 and the reception threshold level. , and the loss amount of the second reception loss circuit 15 is increased by the same amount.
制御回路１１による第１の送話損失回路１３及び第１の
受話損失回路１６の制御は、従来と同じである。The control of the first transmission loss circuit 13 and the first reception loss circuit 16 by the control circuit 11 is the same as the conventional one.
従って、この場合、第１の送話損失回路１３の損失量を
大きく、第１の受話損失回路１６の損失量を小さくする
。Therefore, in this case, the amount of loss in the first transmitting loss circuit 13 is increased, and the amount of loss in the first receiving loss circuit 16 is decreased.
この状態では第２の送話損失回路１４の損失量が小さい
ため、送話損失回路９に入力されるレベルはその分だけ
大きく、音声スイッチ制御回路１１はその分だけ送話状
態にしやすい状態となる。In this state, since the amount of loss in the second transmission loss circuit 14 is small, the level input to the transmission loss circuit 9 is correspondingly large, and the voice switch control circuit 11 is in a state where it is easier to enter the transmission state. Become.
つまり、受話状態から送話状態への切り替わり曲線は、
第２図の曲線Ｃに変更され、Ｐ点とＱ点間のレベル差が
第２の送話損失回路１４の損失量を小さくしたレベル分
に等しい。In other words, the switching curve from the receiving state to the speaking state is
The curve is changed to curve C in FIG. 2, and the level difference between point P and point Q is equal to the level at which the loss amount of the second transmission loss circuit 14 is reduced.
またこのとき、マイク１からハイブリッド回路４を通り
、スピーカ８を介してマイク１に戻ってくるトータルの
ループゲインが１倍以下になるためには、損失量制御回
路１７は第２の送話損失回路１４で小さくした損失量の
分だけ第２の受話損失回路１５に損失を入れる必要があ
る。At this time, in order for the total loop gain from the microphone 1 through the hybrid circuit 4 and back to the microphone 1 via the speaker 8 to be 1 times or less, the loss amount control circuit 17 must control the second transmission loss. It is necessary to add a loss to the second reception loss circuit 15 corresponding to the amount of loss reduced by the circuit 14.
この状態では、スピーカ８からの受話出力は損失が入り
、その分だけ騒音の出力が抑えられる。In this state, there is a loss in the reception output from the speaker 8, and the noise output is suppressed by that amount.
このように回線５からの信号が騒音信号のみの場合には
、切り替わり曲線は曲線Ｃのように変更され、小さなマ
イク入力レベルでも送話状態となり得る。In this way, when the signal from line 5 is only a noise signal, the switching curve is changed to curve C, and even a small microphone input level can result in a transmitting state.
次にこの状態で回線５から受話音声信号が入ってきてそ
のレベルが騒音レベルより大きい場合には、受話検出回
路１０の出力レベルが騒音検出回路１８の出力レベルよ
りも大きくなるため、第２の送話損失回路１４の損失量
を大とし、第２の受話損失回路１５の損失量を小とすこ
とにより、切り替わり曲線をＡの位置に戻すことが出来
る。Next, in this state, if a received voice signal comes in from the line 5 and its level is higher than the noise level, the output level of the received voice detection circuit 10 will be higher than the output level of the noise detection circuit 18, so the second By increasing the amount of loss in the transmission loss circuit 14 and decreasing the amount of loss in the second reception loss circuit 15, the switching curve can be returned to the position A.
これによりスピーカ８から出力される受話信号は、損失
の無い受話信号となる。受話音声信号が無くなり、騒音
のみとなると、切り替わり曲線はＣの線に戻る。As a result, the received signal output from the speaker 8 becomes a lossless received signal. When the received voice signal disappears and only noise remains, the switching curve returns to line C.
以上説明したように、本発明では受話騒音があった場合
、受話状態から送話状態へ切り替わる切り替わり曲線が
従来に比べ低い位置に変更されるため、従来に比べ送話
状態になりやすいという利点がある。As explained above, in the present invention, when there is noise during reception, the switching curve for switching from the reception state to the transmission state is changed to a lower position than in the past, so the advantage is that the transmission state is more likely to occur than in the past. be.
このため送話者がこの拡声電話装置から離れたところに
いて、送話レベルが小さいような場合でも、送話信号が
損失無く通話相手に届くことになる。Therefore, even if the person speaking is far away from the loudspeaker telephone device and the transmission level is low, the transmission signal will reach the other party without loss.
また騒音のみがある場合、スピーカから出力される騒音
レベルは損失が入り抑えられるため、通話者は騒音が耳
障りで無くなるという利点もある。Further, when there is only noise, the noise level output from the speaker is suppressed due to loss, so there is an advantage that the noise is no longer harsh on the ears of the caller.
第１図は、本発明の一実施例を示すブロック図、第２図
は、第１図のブロック図における切り替わり特性図、第
３図は、従来の拡声電話装置の一例を示すブロック図、
第４図は、第３図のブロック図における切り替わり特性
図である。
１・・・マイク、２・・・送話用アンプ、４・・・ハイ
ブリッド回路、５・・・回線、７・・・受話用アンプ、
８・・・スピーカ、９・・・送話検出回路、１０・・・
受話検出回路、１１・・・音声スイッチ制御回路、１２
・・・受話閾値レベル設定回路、１３・・・第１の送話
損失回路、１４・・・第２の送話損失回路、１５・・・
第２の受話損失回路、
１６・・・第１の受話損失回路、
１７・・・損失量側
御回路、
１８・・・騒音検出回路。FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a switching characteristic diagram in the block diagram of FIG. 1, and FIG. 3 is a block diagram showing an example of a conventional loudspeaker telephone device.
FIG. 4 is a switching characteristic diagram in the block diagram of FIG. 3. 1... Microphone, 2... Sending amplifier, 4... Hybrid circuit, 5... Line, 7... Receiving amplifier,
8...Speaker, 9...Talking detection circuit, 10...
Receiving call detection circuit, 11...Voice switch control circuit, 12
... Reception threshold level setting circuit, 13... First transmission loss circuit, 14... Second transmission loss circuit, 15...
2nd receiving loss circuit, 16... 1st receiving loss circuit, 17... Loss amount side control circuit, 18... Noise detection circuit.
Claims (1)
送話路と、回線からの受話信号を第１の受話損失回路を
介してスピーカから出力する受話路と、送話信号レベル
と受話信号レベルとを予め定めた受話閾値レベルと比較
しその結果に応じて前記第１の送話損失回路及び前記第
１の受話損失回路のそれぞれの損失量を相反的に増減制
御する制御回路とを備えた拡声電話装置において、前記
第１の送話損失回路及び受話損失回路に直列に第２の送
話損失回路及び第２の受話損失回路を前記送話路及び前
記受話路に設け、前記回線からの騒音レベルが前記受話
閾値レベルを越えたときには受話状態にある前記第２の
送話損失回路の損失量を前記騒音レベルの大きさに比例
した量だけ小さくし、前記第２の受話損失回路の損失量
を前記騒音レベルに比例した量だけ大きくなるよう制御
する損失制御回路を設けたことを特徴とする拡声電話装
置。A transmission path for transmitting a transmission signal to a line via a first transmission loss circuit, a reception path for outputting a reception signal from the line from a speaker via a first reception loss circuit, and a transmission signal level. and a reception signal level with a predetermined reception threshold level, and a control circuit that reciprocally controls the amount of loss of each of the first transmission loss circuit and the first reception loss circuit according to the result. In the loudspeaker telephone device, a second sending loss circuit and a second receiving loss circuit are provided in the sending path and the receiving path in series with the first sending loss circuit and the receiving loss circuit, When the noise level from the line exceeds the reception threshold level, the loss amount of the second transmission loss circuit in the receiving state is reduced by an amount proportional to the magnitude of the noise level, and the second reception is performed. A loudspeaker telephone device comprising a loss control circuit that controls the loss amount of the loss circuit to increase by an amount proportional to the noise level.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63320097A JP2746963B2 (en) | 1988-12-19 | 1988-12-19 | Loudspeaker equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63320097A JP2746963B2 (en) | 1988-12-19 | 1988-12-19 | Loudspeaker equipment |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02164164A true JPH02164164A (en) | 1990-06-25 |
| JP2746963B2 JP2746963B2 (en) | 1998-05-06 |
Family
ID=18117681
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63320097A Expired - Fee Related JP2746963B2 (en) | 1988-12-19 | 1988-12-19 | Loudspeaker equipment |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2746963B2 (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5132042A (en) * | 1974-09-11 | 1976-03-18 | Jukan Fujimoto | Kucho oyobi haienyokeihotsukibokadanpa |
| JPS60126950A (en) * | 1983-12-13 | 1985-07-06 | Toshiba Corp | Public-address telephone set |
| JPS60182250A (en) * | 1984-02-29 | 1985-09-17 | Nippon Telegr & Teleph Corp <Ntt> | Voice switch circuit of loudspeaker telephone set |
-
1988
- 1988-12-19 JP JP63320097A patent/JP2746963B2/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5132042A (en) * | 1974-09-11 | 1976-03-18 | Jukan Fujimoto | Kucho oyobi haienyokeihotsukibokadanpa |
| JPS60126950A (en) * | 1983-12-13 | 1985-07-06 | Toshiba Corp | Public-address telephone set |
| JPS60182250A (en) * | 1984-02-29 | 1985-09-17 | Nippon Telegr & Teleph Corp <Ntt> | Voice switch circuit of loudspeaker telephone set |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2746963B2 (en) | 1998-05-06 |
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| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |