JPH0369946U - - Google Patents
Info
- Publication number
- JPH0369946U JPH0369946U JP12788289U JP12788289U JPH0369946U JP H0369946 U JPH0369946 U JP H0369946U JP 12788289 U JP12788289 U JP 12788289U JP 12788289 U JP12788289 U JP 12788289U JP H0369946 U JPH0369946 U JP H0369946U
- Authority
- JP
- Japan
- Prior art keywords
- transistor
- base
- circuit
- bias circuit
- resistor
- 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
- 230000005540 biological transmission Effects 0.000 claims 2
- 238000005513 bias potential Methods 0.000 claims 1
- 230000007423 decrease Effects 0.000 claims 1
- 230000005236 sound signal Effects 0.000 claims 1
- 238000010586 diagram Methods 0.000 description 2
Description
第１図は本考案の一実施例のＤＴＭＦ／送話切
換回路の回路図、第２図は従来のＤＴＭＦ／送話
切換回路の回路図である。
FIG. 1 is a circuit diagram of a DTMF/speech switching circuit according to an embodiment of the present invention, and FIG. 2 is a circuit diagram of a conventional DTMF/speech switching circuit.
Claims (1)
のトランジスタと、ダイアラーからのダイアルト
ーン信号がベースに入力し上記第１のトランジス
タと並列接続した第２のトランジスタと、該第１
及び第２のトランジスタの内のオンしたトランジ
スタと差動回路を構成する第３のトランジスタと
、上記第１のトランジスタのベースバイアス回路
と、上記第２のトランジスタのベースバイアス回
路とを具備するＤＴＭＦ／送話切換回路において
、 上記第１のトランジスタのベースバイアス回路
の抵抗を接地し、上記第２のトランジスタのベー
ス電位の低下により上記抵抗に電流を供給して第
１のベースバイアス回路のバイアス電位を上昇さ
せ、上記第１のトランジスタをオフ、上記第２の
トランジスタをオンさせることを特徴とするＤＴ
ＭＦ／送話切換回路。[Scope of claim for utility model registration] The first part where the audio signal from the microphone is input to the base
a second transistor whose base receives a dial tone signal from the dialer and which is connected in parallel with the first transistor;
and a third transistor forming a differential circuit with the turned-on transistor of the second transistor, a base bias circuit of the first transistor, and a base bias circuit of the second transistor. In the transmission switching circuit, a resistor of the base bias circuit of the first transistor is grounded, and a current is supplied to the resistor as the base potential of the second transistor decreases to change the bias potential of the first base bias circuit. DT, which turns off the first transistor and turns on the second transistor.
MF/transmission switching circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12788289U JPH0369946U (en) | 1989-11-02 | 1989-11-02 |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12788289U JPH0369946U (en) | 1989-11-02 | 1989-11-02 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0369946U true JPH0369946U (en) | 1991-07-12 |
Family
ID=31675621
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP12788289U Pending JPH0369946U (en) | 1989-11-02 | 1989-11-02 |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0369946U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR200450449Y1 (en) * | 2010-03-29 | 2010-10-04 | 도기호 | Nourishment liquid injector |
-
1989
- 1989-11-02 JP JP12788289U patent/JPH0369946U/ja active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR200450449Y1 (en) * | 2010-03-29 | 2010-10-04 | 도기호 | Nourishment liquid injector |
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