JPH08102794A - Simultaneous speech interphone system - Google Patents

Abstract

PURPOSE: To prevent communication from being interfered and to prevent a sound volume and tone from being changed even when the number of equipments is changed. CONSTITUTION: In this interphone system, plural interphone terminals TE1 to TE8 are connected to common two lines L1 and L2 , power is supplied to the common two lines, audio signals f1 are superimposed and communication is performed. The transmitters 1a of the respective interphone terminals are connected to the common two lines through a constant current circuit 2 for changing an output current by the audio signals, a common load R. connected to a power source for voltage converting the output current is provided in the common two lines and the common two lines and the transmitter are connected to a receiver 1b through a hybrid circuit 3 whose input impedance is high.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a simultaneous call intercom apparatus, and more particularly to a simultaneous call intercom apparatus capable of making simultaneous calls between a plurality of intercom terminals.

[0002]

2. Description of the Related Art Conventionally, a simultaneous call intercom system shown in FIG. 7 has been proposed. In this simultaneous call intercom system, the intercom terminals TE ₁₁ and TE ₁₂ have terminals T
_The transmission lines L ₁₁ and L ₁₂ are connected via ₁₁ and the terminal T ₁₂ . Each of the intercom terminals TE ₁₁ and TE ₁₂ has a handset 51 and a call circuit 52, and the call circuit 52 is provided with a hybrid circuit 53.

To construct such a circuit with an IC, for example, a circuit shown in FIG. 8 has been proposed. In the circuit shown in FIG. 8, the intercom terminal TE ₁₁ is provided with operational amplifiers 61, 62, 63 formed of ICs, and the transmitter 51a of the handset 51 is connected to the operational amplifier 61 and the resistor R ₃₅ to connect the operational amplifier 62 ( -) Side is connected.

The (+) side of the operational amplifier 62 has a reference voltage V
It is connected to f ₁ and the (−) side of the operational amplifier 62 has a resistor R _36.
Is connected to the output side via. The output side of the operational amplifier 62 is connected to the terminal T ₁₁ via the resistor R ₃₀ , and the terminal T ₁₁
Is connected to the (−) side of the operational amplifier 63 via the resistor R _32, and the (+) side of the operational amplifier 63 is connected to the reference voltage Vf ₂ via the resistor R ₃₄ .

The (-) side of the operational amplifier 63 is connected to the output side of the operational amplifier 61 via a resistor R ₃₁ , and the operational amplifier 6
The (−) side of 3 is connected to the output side of the operational amplifier 63 via the resistor R ₃₃ . The output side of the operational amplifier 63 is connected to the handset 51b of the handset 51. The terminal T ₁₂ is connected to the reference potential point, and the intercom terminal TE ₁₂ forms a load resistance R ₄₀ with respect to the intercom terminal TE ₁₁ .

In such a simultaneous call intercom system, the handset 51 of the intercom terminal TE ₁₁ shown in FIG.
The voice signal input from the transmitter 51a of the amplifier is amplified by the operational amplifier 61, inverted and amplified by the operational amplifier 62, and the resistance R
_The output impedance determined by ₃₀ is transmitted to the transmission lines L ₁₁ and L ₁₂ . The audio signals input from the transmission lines L ₁₁ and L ₁₂ are amplified by the operational amplifier 63 and sent to the handset 51b of the handset 51.

Since the voice signal output from the operational amplifier 61 is transmitted to the operational amplifier 63 via the resistor R ₃₁ , this voice signal is multiplied by R ₃₃ / R ₃₁ and becomes the input to the receiver 51b. For example, R ₃₆ / R ₃₅ = 2, R ₃₀ = R ₄₀ , R
_{If 33} / R ₃₁ = R ₃₄ / R ₃₂ , the output of the operational amplifier 61 is −R ₃₆ / R _{35 in the} operational amplifier 62, which is −2 times.

This is -2.1 / for transmission lines L ₁₁ and L _12.
2 = -1 times, and at the output of the operational amplifier 63, R ₃₃ =
If R _31, then −1 / 2 · (R ₃₃ / R ₃₁ +1) = − 1. For this reason, the polarity is opposite to that of the voice signal passing through R ₃₁ , and the magnitude is the same, and no side tone is produced. Here, R ₄₀ is a load resistance of the intercom terminal TE ₁₂ with respect to the intercom terminal TE ₁₁ , and can realize only the one-to-one call shown in FIG. 7.

[0009] If the connecting third intercom terminal to the transmission line L ₁₁ and L _12, the impedance of the transmission line L ₁₁ and L ₁₂ becomes a half of the R _30, side tone increases.

[0010]

In such a simultaneous call intercom system, when a plurality of intercom terminals use the transmission lines L ₁₁ and L ₁₂ as a common line to call each other, the calls interfere with each other.

[0011]

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and when a plurality of intercom terminals provided on a common line talk with each other, the calls do not interfere with each other, regardless of the number of units. It is an object of the present invention to provide a simultaneous call intercom device that does not change in volume and sound quality.

[0012]

In order to achieve this object, the simultaneous call intercom system according to the present invention has a common 2
An interphone device in which a plurality of intercom terminals are connected to a line, power is supplied to a common two lines, and a voice signal is superimposed to make a call. The output current of a transmitter of each intercom terminal is changed by a voice signal. A common load connected to the common 2 line via a constant current circuit and connected to a power source to convert the output current into a voltage is provided on the common 2 line, and the common 2 line and the transmitter are connected via a hybrid circuit having a high input impedance. It is like connecting to a handset.

[0013]

Function: The power is supplied to the plurality of intercom terminals connected to the common 2 line via the common 2 line. When the voice signal generated by the transmitter of each intercom terminal is sent to the constant current circuit, the output current of the constant current circuit is output to the common two lines and the voice signal is superimposed.

The output current of the constant current circuit is converted into a voltage and can be taken out from both ends of the common load. Since the handset is connected to the common 2 lines via a hybrid circuit having a high input impedance, the call does not interfere and the volume and sound quality do not change regardless of the number of units.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A simultaneous call intercom system according to the present invention will be described in detail below with reference to FIG. As shown in FIG. 1, the simultaneous call intercom system according to the present invention includes a common 2 line L ₁ ,
Connect a plurality of intercom terminals TE _{1 to} TE ₈ to L ₂ ,
Power is supplied from the device power supply circuit 11 to the common two lines L ₁ and L ₂ , and the voice signal f ₁ is superimposed to make a call.

The transmitter 1 of the handset 1 of each intercom terminal
The a is connected to the common 2 lines L ₁ and L ₂ via the diode bridge 5 via the constant current circuit 2 that changes the output current from the transmission amplifier 4 according to the voice signal. A common load R _{1 that} is connected to a power supply from the device power supply circuit 11 and converts an output current into a voltage is provided on the common 2 lines L ₁ and L ₂ , and
Handset 1 via common 2 lines L ₁ and L ₂ , diode bridge 5 and hybrid circuit 3 with high input impedance
connected to b. The transmission amplifier 4 is connected to one input side of the hybrid circuit 3.

The output side of the constant current circuit 2 is connected to the terminal stabilizing power supply circuit 6 and the diode bridge 5, and the other input side of the hybrid circuit 3 is connected to the output side of the constant current circuit 2. The diode bridge 5 has two common lines L ₁ and L ₂
Are connected to the terminals T ₁ and T ₂ and the reference potential point. Unit power circuit circuit 11 is constituted by an impedance converter circuit 12 and the device stabilized power supply circuit 13, as shown in FIG. 2, the common load R ₁ is the impedance conversion circuit 12
And a capacitor C between the common 2 lines L ₁ and L ₂
Connected via ₁ .

Transistor T of device stabilizing power supply circuit 13
The collector of R ₁ is connected to the power source + B, and the base is connected to the reference potential point via the Zener diode D ₁ .
A resistor R ₃ connected in series between the reference potential point and the power source + B
And capacitor C ₃ are connected, and resistor R ₃ and capacitor C ₃
Is connected to the base of the transistor TR ₁ .

The emitter of the transistor TR ₁ is connected via the capacitor C ₂ to the reference potential point and the emitter of the transistor TR ₂ of the impedance conversion circuit 12 which constitutes the electron L (inductance made circuitically), and the collector is It is connected to _{one of} the common two lines L ₁ and L ₂ L ₁ . The base of the transistor TR ₂ is connected to a connection point of the resistors R ₄ and R ₅ connected to the emitter and the collector, and the capacitor C ₄ is connected between the connection point and the emitter of the transistor TR _2. There is.

Further, as shown in FIG. 3, as the device power supply circuit, the device power supply circuit 11a in which the common load R ₁ connected to the device stabilizing power supply circuit 13 is provided as the impedance conversion circuit 12a may be used. . In this case, the device stabilizing power supply circuit 13 of the device power supply circuit 11a is the same as the circuit shown in FIG. 2, and the common load R ₁ is provided as the impedance conversion circuit 12a.

Intercom terminals TE _{1 to} TE ₈ shown in FIG.
4 and 5 show the terminal stabilized power supply circuit 6 of FIG. The diode bridge 5 shown in FIG. 1 is connected to the collector of the transistor TR ₃ of the terminal stabilizing power supply circuit 6 shown in FIG. The collector of the transistor TR ₃ is connected to the reference potential point via the resistor R ₆ and the capacitor C ₆ .

The connection point of the resistors R ₆ and the capacitor C ₆ is the base of the transistor TR ₃ is connected, the base of the transistor TR ₃ is connected to a reference potential point via a Zener diode D _2. The emitter of the transistor TR ₃ is connected to the other end of a capacitor C ₅ whose one end is connected to a reference potential point, and power + B is supplied from the emitter of the transistor TR ₃ to each circuit.

When the resistance value of the resistor R ₆ connected to the collector of the transistor TR ₃ is increased, the input impedance is increased. Intercom terminals TE _{1 to} TE ₈ shown in FIG.
FIG. 5 shows the terminal stabilizing power supply circuit 6 of FIG. The terminal stabilizing power supply circuit 6 shown in FIG. 5 constitutes an electron L (inductance made circuitically), and the diode bridge 5 shown in FIG. 1 is connected to the collector of the transistor TR ₄ of the terminal stabilizing power supply circuit 6. Has been done.

The base of the transistor TR ₄ is connected to the connection point of the resistors R ₇ and R ₈ connected to the emitter and collector, and the capacitor C ₇ is connected between this connection point and the emitter of the transistor TR _4. Has been done. The emitter of the transistor TR ₄ is connected to the other end of the capacitor C ₈ whose one end is connected to the reference potential point, and power + B is supplied from the emitter of the transistor TR ₄ to each circuit.

The intercom terminals TE _{1 to} TE ₈ shown in FIG.
FIG. 6 shows an example in which each circuit of FIG. 6 is composed of operational amplifiers OP _{1 to} OP ₃ .
Shown in In FIG. 6, the transmitter 1 a of the handset 1 is connected to the (−) side of the operational amplifier OP ₂ forming the transmitter amplifier 4 and the resistor R.
₁₆ are connected via a, of the operational amplifier OP ₂ (-) between the side and the output side resistor R ₁₅ is connected, (+) side is connected to the central potential point CZ.

The output side of the operational amplifier OP ₂ is connected to the (−) side of the operational amplifier OP ₃ via the resistor R ₁₇ . (+) Of the operational amplifier OP ₁ that constitutes the hybrid circuit 3
The side is connected to the central potential point CZ via a resistor R ₁₄ ,
A resistor R ₁₁ is connected between the (−) side and the output side.

The output side of the operational amplifier OP ₁ is connected to the handset 1b of the handset ₁ , and the (−) side of the operational amplifier OP ₁ is connected to the diode bridge 5 via the resistor R ₁₂ and the capacitor C _11.
Is connected to The (−) side of the operational amplifier OP ₁ is connected to the output side of the operational amplifier OP ₂ via the resistor R ₁₃ .

Operational amplifier OP ₃ constituting the constant current circuit 2
The (+) side of is connected to the output side via the resistors R ₂₀ and R ₁₉ , and is connected to the central potential point CZ via the resistor R ₂₁ . The connection point of the resistors R ₂₀ and R ₁₉ is connected to the central potential point CZ via the resistor R ₂₂ . A resistor R ₁₈ is connected between the (−) side and the output side. Operational amplifier O
The output side of P ₃ is connected to the diode bridge 5 via a resistor R ₁₉ and a capacitor C ₁₁ . The terminal stabilizing power supply circuit 6 is connected to the diode bridge 5 side of the capacitor C ₁₁ .

Operational amplifier OP of constant current circuit 2₃Is baite
Resistor R in the ral current source circuit₁₇, Resistance R₁₈, Resistance R
₁₉, Resistance R₂₀, Resistance R_{twenty one}The resistance value of R₁₈,
R₁₉, R ₂₀, R_{twenty one}And R₁₉+ R₂₀/ R_{twenty one}= R₁₈/ R₁₉
If so, operational amplifier OP₃Has no output impedance
It becomes the limit. Concurrent call interphone configured in this way
Terminal device, a plurality of intercom terminals TE₁~ TE₈
1a of the handset 1 of the intercom terminal
The audio signal generated by the
P₂Is amplified by the operational amplifier OP of the constant current circuit 2₂Applied to
Is done. This audio signal is output from the diode bridge 5
Two-way line L₁, L₂Sent to other intercom terminals.
From the diode bridge 5 and hybrid circuit 3
The receiver 1b of the receiver 1 can receive the call. Other intercom end
Similarly, the call from the end is received by the above intercom terminal.
I can talk.

In this case, the operational amplifier OP of the constant current circuit 2
The output impedance of _3, the input impedance of the terminal stabilizing power supply circuit 6, and the input impedance of the hybrid circuit 3 are high impedances, and the common 2 line L ₁₁ ,
Even if the number of intercom terminals TE _{1 to} TE ₈ using L ₁₂ as a common transmission line changes, the volume and sound quality do not change.

[0031]

As is apparent from the above description, according to the simultaneous call intercom system of the present invention, a plurality of intercom terminals are connected to the common 2 line, power is supplied to the common 2 line, and a voice signal is transmitted. An intercom device for superimposing a call, in which a transmitter of each intercom terminal is connected to a common 2 wire via a constant current circuit that changes an output current according to a voice signal, and is connected to a power source to convert the output current into a voltage. The common load is provided on the common 2 wire, and the common 2 wire and the transmitter are connected to the receiver via the constant current circuit with high output impedance and the hybrid circuit with high input impedance, so that the call may interfere even if the number of units changes. No change will occur in volume and sound quality.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a simultaneous call intercom system according to the present invention.

FIG. 2 is a circuit diagram showing an embodiment of an apparatus power supply circuit used in the simultaneous call intercom apparatus according to the present invention.

FIG. 3 is a circuit diagram showing another embodiment of a device power supply circuit used in the simultaneous call intercom device according to the present invention.

FIG. 4 is a circuit diagram showing an embodiment of a terminal stabilizing power supply circuit used in the simultaneous call intercom system according to the present invention.

FIG. 5 is a circuit diagram showing another embodiment of the terminal stabilizing power supply circuit used in the simultaneous call intercom system according to the present invention.

FIG. 6 is a circuit diagram showing an embodiment of a simultaneous call intercom system according to the present invention.

FIG. 7 is a configuration diagram of a conventional simultaneous call intercom device.

FIG. 8 is a circuit diagram of a conventional simultaneous call intercom device.

[Explanation of symbols]

1 ・ ・ Handset 1b ・ ・ ・ ・ Handset 2 ・ ・ ・ ・ Constant current circuit 3 ・ ・ ・ ・ Hybrid circuit L ₁ , L ₂・ ・ ・ ・ ・ ・ Common 2 wires R ₁ ··· Common load TE _{1 to} TE ₈ ··· Intercom terminal f ₁ ··· Voice signal 1a ··· Handset

Claims (1)

[Claims] 1. A plurality of intercom terminals (TE _{1 to} TE ₈ ) are connected to a common 2 line (L ₁ , L ₂ ), a power source is supplied to the common 2 line, and a voice signal (f ₁ ) is superimposed. An intercom device for making a call by connecting the transmitter (1a) of each intercom terminal to the common 2 line via a constant current circuit (2) that changes the output current according to the voice signal, A common load (R ₁ ) connected to convert the output current into a voltage is provided on the common 2 line, and the common 2 line and the transmitter are connected to a receiver (1b) via a hybrid circuit (3) having a high input impedance. A simultaneous call intercom device that is connected to.