JPS605650Y2 - Tone burst generation circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tone burst generation circuit that outputs a tone burst signal for a predetermined period of time from when a changeover switch is switched.

Conventionally, for example, in a transceiver, a tone burst signal is outputted for a predetermined period of time from the start of transmission and/or from the end of transmission in order to call a relay station.

Conventionally, such tone/pass generation circuits turn on/off a part of the tone oscillation circuit using a switching circuit using a diode or the like driven by the output of a changeover switch selectively interlocked with a transmission/reception changeover switch. It controlled the oscillation of the oscillation circuit.

Therefore, not only is the oscillation operation unstable, but the power consumption is large, reaching several hundred mW, for example.

The present invention has been made in view of the above, and it is an object of the present invention to provide a tone burst generating circuit which eliminates the above-mentioned drawbacks with a simple configuration.

The present invention will be explained below with reference to examples.

FIG. 1 is a circuit diagram of an embodiment of the present invention.

1 is a tone oscillation circuit; 2 is a switching circuit for turning on/off the application of a power supply voltage of 1 B to the tone oscillation circuit 1;
3 is a changeover switch for controlling the changeover circuit 2;
The selector switch 3 is switched in conjunction with the transmit/receive selector switch of the transceiver.

Now, the contact X side of the changeover switch 3 is assumed to be the transmitting side, and the waist contact Y side is assumed to be the receiving side.

Note that a power supply voltage of 10 B is applied to the movable contact of the changeover switch 3.

The contact X of the changeover switch 3 is connected to the tone oscillation circuit 1 through the diode 4 and the emitter and collector of the transistor 5.
The cathode of the diode 4 is grounded through a series circuit of a switch 6 and a capacitor 7.

On the other hand, the base of the transistor 5 is grounded through the resistor 8 and the collector and emitter of the transistor 9, and the contact Y of the change-over switch 3 is connected to the guide 10 and the resistor 11.
7 and the cathode of the diode 10 is connected to the switch 12 and the switch 13.
Connect the series circuit to ground.

Here, = 1 resistor 7 and resistor 8 are the first resistors. The capacitor 13 and the resistor 11 constitute a second time constant circuit (7).

The effect of the tree-killing system configured as described above will be explained.

(1) Switches 6 and 12 are set to ON], 2. A case will be described in which the movable contact of the changeover switch 3 is switched from contact Y to contact X.

The effect in this case is as shown in Fig. 2a.
With the switching, the voltage at contact X rises to power supply voltage terminal B as shown at A, and the voltage at contact Y falls from power supply voltage +R to zero potential as shown at B.

Due to this switching, the capacitor 7 is charged through the diode 4 according to the time constant of the first time constant circuit.

Therefore, the emitter potential of transistor 5 rises as shown at C in FIG. 2a, and transistor 5 is switched on.

- On the other hand, the charge in the capacitor 13 passes through the resistor 11 and keeps the transistor 9 in an on state, but it is discharged according to the time constant of the second time constant circuit.

Therefore, the base potential of the transistor 9 falls as shown in FIG. 2A (D), and the transistor 9 is finally turned off.

In addition, a voltage is output to the collector of the transistor 5 during the period from when the transistor 5 is turned on until when the transistor 9 is turned off, as shown in E of FIG. It is applied as the power supply voltage of the 1-1 oscillation circuit 1.

Therefore, the tone oscillator circuit 1 outputs a tone burst signal as shown at F in FIG. 2a.

(11) A case will be described in which the switches 6 and 12 are set to the on state and the movable contact of the changeover switch 3 is switched from contact X to contact Y.

The action in this case is as shown in Figure 2. Along with switching of the selector switch 3, the potential of contact X is A as shown in Figure 2.
As shown in FIG. 2, the potential of the contact Y falls to zero, and the potential of the contact Y rises to the power supply voltage terminal B, as shown in FIG.

Due to this switching, the charge in the capacitor 7 is discharged according to the time constant of the first time constant circuit, and the emitter potential of the transistor 5 decreases as shown in FIG. Switch to.

During this time, the capacitor 13 is charged according to the time constant of the second time constant circuit, and the base potential of the transistor 9 rises as shown at D in FIG. 2, turning the transistor 9 on.

Therefore, the collector of transistor 5 has E as shown in Figure 2.
As shown in (during the period from when transistor 9 switches on to when transistor 5 switches off, a voltage is output, and this voltage is applied to the tone oscillation circuit 1 at the power supply voltage E .

Therefore, the tone oscillator circuit 1 outputs a tone burst signal as shown at F in the second diagram.

As is clear from the above (1) and (11), switch 6
and 12 are set to the on state, the tone burst signal is output as if the selector switch 3 is changed, that is, for a predetermined period from the start of transmission and for a predetermined period from the end of transmission (start of reception).

Further, this predetermined period can be determined by setting the time constants of the first and second time constant circuits.

tiii) Next, a case will be described in which the switches 6 and 6 are set to the off state, the switch 12 is set to the on state, and the movable contact of the changeover switch 3 is switched from the contact Y to the contact X.

The action in the second case is as shown in Fig. 2C, and the contact point
, the voltage at contact Y and the base potential of transistor 9 are shown in A of FIG. 2a.

The cases are the same as those shown in B and D, respectively, but since the switch 6 is in the OFF state, the emitter potential of the transistor 5 rises as shown in C in FIG. state.

Therefore, a voltage is output to the collector of the transistor 5 as shown in E in FIG. 2C, and the tone oscillation circuit 1 is
A tone burst signal is output as shown in F of FIG.

(Iψ Switch 6 is set to OFF state, switch 12 is set to ON state, and the variable fluid of changeover switch 3 is set to contact
The case when switching from contact point Y to contact point Y will be explained.

The action in this case is as shown in Fig. 2d, and the contact point
The voltage at contact Y, the voltage at contact Y, and the changes in the base potential of transistor 9 are the same as in the case shown in FIG. The voltage decreases as shown, and the transistor 5 is turned off at the same time as the changeover switch 3 is switched.

Therefore, no voltage appears at the collector of the transistor 5 as shown at E in FIG. 2d, the tone oscillation circuit 1 does not oscillate as shown at F in FIG. 2d, and no tone burst signal is output.

As is clear from the above (iii) and ■, when the switch 6 is set to the OFF state and the switch 12 is set to the ON state, only when the changeover switch 3 is switched to the contact X side,
That is, a tone burst signal is output for a predetermined period only at the start of transmission.

(■) Next, a case will be described in which the switch 6 is set to the on state, the switch 12 is set to the off state, and the movable contact of the changeover switch 3 is switched from the contact Y to the contact X.

The action in this case is as shown in Fig. 2e, and the contact point
The voltage at contact Y, the voltage at contact Y, and the changes in the emitter potential of transistor 5 are the same as those shown in A, B, and C of FIG. As shown at D in FIG. 2e, the falling taste transistor 9 is turned off at the same time as the selector switch 3 is switched.

Therefore, no voltage appears at the collector of the transistor 5 as shown in E of FIG. 2e, and the tone oscillation circuit 1 does not oscillate as shown in F of FIG. 2e, so that no tone burst signal is output.

υ11 A case will be described in which the switch 6 is set to the on state, the switch 12 is set to the off state, and the movable contact of the changeover switch 3 is switched from contact X to contact Y.

The action in this case is as shown in Fig. 2f, and the contact point
The changes in the voltage at contact Y, the voltage at contact Y, and the emitter potential of transistor 5 are the same as those shown in Figure 2A, B, and C, respectively, but since switch 12 is in the OFF state, the base potential of transistor 9 is The voltage rises as shown at D in FIG.

Therefore, a voltage is output to the collector of the transistor 5 as shown in E in FIG.
A tone burst signal is output as shown in F of FIG.

As is clear from the above (■) and 01), when the switch 6 is set to the on state and the switch 12 is set to the off state, only when the changeover switch 3 is switched to the contact Y side,
That is, only at the end of transmission, a tone burst signal is output for a predetermined period from then on.

Qll) Next, a case will be described in which the switches 6 and 12 are set to the OFF state and the movable contact of the changeover switch 3 is switched from the contact Y to the contact X.

The action in this case is as shown in Figure 2g, and the contact point
The voltage at contact Y, the voltage at contact Y, and the changes in the emitter potential of transistor 5 are the same as those shown in A, B, and C of FIG. This is the same as the case shown in .

Therefore, at the same time as the changeover switch 3 is switched, the transistor 9
is in the off state, and the collector of transistor 5 has a second
No voltage appears as shown at E in FIG. 2g, and the tone oscillation circuit 1 does not oscillate as shown at F in FIG.

輔 Switches 6 and 12 are set to the off state,
A case will be described in which the movable contact of the changeover switch 3 is switched from contact X to contact Y.

The action in this case is as shown in the second diagram, and the contact point
, the voltage at contact Y, and the changes in the emitter potential of transistor 5 are the same as those shown in A, B, and C of FIG. 2d, respectively, and the changes in the base potential of transistor 9 are the same as shown in D of FIG. This is the same as the case shown in .

Therefore, at the same time as the changeover switch 3 is switched, the transistor 5
is in the off state, and the collector of transistor 5 has a second
As shown at E in the diagram, no voltage appears, and as shown at F in the second diagram, the tone oscillation circuit 1 does not oscillate and no tone burst signal is output.

As is clear from the above Qli) and QiO, switch 6
and 12 are set to the OFF state, no tone burst signal is output even if the selector switch 3 is switched.

As is clear from the above (1) to (riOl) (switch 6
and by setting 12 on/off states,
Whether to output a tone burst signal when switching switch 2 or switch 3, that is, whether to output a tone burst signal for a predetermined period from the start of transmission and/or for a predetermined period from the end of transmission. can be controlled.

Note that although the above description has been made using an example of case a using bipolar transistors, it goes without saying that field effect transistors may be used instead of bipolar transistors.

As explained above, according to the present invention, by setting a switch that disconnects or connects the capacitor constituting the time constant circuit from the circuit, a tone burst signal is generated for a predetermined period of time from the time of switching each time the changeover switch is changed. generate a tone burst signal for a predetermined period of time from the time of the changeover each time the changeover switch is toggled to one side; With a simple configuration, it is possible to select whether to generate a tone burst signal or not to generate a tone burst signal at all.

Furthermore, since the application of the power supply voltage to the tone oscillation circuit is controlled, oscillation is stable and power consumption is reduced.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of an embodiment of the present invention. FIGS. 2a to 2h are waveform diagrams for explaining the operation of an embodiment of the present invention. 1...Tone oscillation circuit, 2...Switching circuit, 3...Switching switch, 4 and 10...
...diode, 5 and 9...transistor, 6 and 12 switch, 7 and 13...
capacitor.

Claims (1)

[Scope of utility model registration request] a tone oscillator, a changeover switch to which a power supply voltage is applied to a movable contact, first and second diodes connected to one fixed contact and the other fixed contact of the changeover switch, respectively; a first transistor connected between the diode and the power supply terminal of the tone oscillator; a second transistor connecting the base or gate of the first transistor to ground via a first resistor; a second resistor connected between the second diode and the base or gate of the second transistor;
The first transistor is connected to a first connection point between the first diode and the first transistor via a first switch.
a first capacitor that is selectively charged to a voltage at a connection point of the second capacitor, and a first capacitor that is connected via a second switch to a second connection point between the second diode and the second resistor; and a second capacitor selectively charged to the voltage at the connection point.