JPH0737371Y2 - Audio equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Outline] A plurality of types of audio units each having a volume adjusting unit such as a volume for adjusting the level of an audio signal are cascaded in multiple stages, and further, a main amplifier is provided at the final stage of these audio units. , The first DC level supplied from the input side of each of the above audio units to the output side of the preceding stage and the second DC level supplied from the input side of the main amplifier to the output side of the final stage. In the case where an audio device that is detected by the detection unit and causes the volume adjusting unit to be in the non-operating state and the operating state, respectively, or a volume non-adjusting unit is mixed in the plurality of types of audio units, the first DC level is set to It is variable, and it is controlled by the control section only when the volume adjustment section of the audio unit of the self stage or the volume adjustment section of the latter stage can operate. The serial first DC level An audio device comprising set to a predetermined level, it is possible to automatically set to allow the volume adjusted by a volume or the like of only one stage for various audio unit.

[Industrial application field]

The present invention relates to an audio device configured by connecting a plurality of types of audio units in cascade.

In a vehicle or the like, generally, various audio units such as a digital audio tape (hereinafter abbreviated as DAT) and a compact disc (hereinafter abbreviated as CD) are connected by a cascade connection method that is easy to interconnect. Of 1
The above audio device is used so that one of them can be selectively operated.

[Conventional technology]

FIG. 4 is a circuit diagram showing an example of a conventional audio device. However, here, three types of audio units 1 of DAT, CD and cassette tape (hereinafter abbreviated as CT)
An audio device configured by connecting -1, 1-2 and 1-3 in this order in cascade, and further connecting a main amplifier (also called a power amplifier) 9 to the final stage CT will be exemplified.

In FIG. 4, three types of audio units 1-1, 1-
DAs 2 and 1-3 have a mechanism for reproducing the audio signal S _a independently from each audio source.
A T player section 8-1, a CD player section 8-2 and a CT player 8-3 are provided respectively. Further, the user can select the above three audio units 1-1, 1-2 and 1
-3, a changeover switch 18 is provided between the output side of each of the audio units 1-1, 1-2 and 1-3 and the audio signal line so that one of them can be selected.
-1, 18-2 and 18-3 are provided. Further, each of the audio devices 1-1, 1-2 and 1-3, usually, suitably a plurality of preamplifier for amplifying the reproduced audio signal S _a, the level of the audio signal Sa A volume adjusting unit 2 such as a volume for changing the volume to adjust the volume is provided. Here, the user operates a button or the like on the front surface of the audio device to select one of the three audio units 1-1, 1-2 and 1-3.
For example, when the first stage DAT is selected, only the changeover switch 18-1 is connected to the signal line, and the remaining two changeover switches 18-2 and 18-3 are disconnected from the signal line. Therefore, the audio signal Sa from the DAT passes through the plurality of preamplifiers and the volume adjusting section 2 in the audio units 1-2 and 1-3 at the second and final stages as they are and is amplified by the main amplifier 9 to a predetermined level. Then, it is transmitted as sound from the speaker 19. However, in this case, the audio signal line has three volume adjusting units 2
Therefore, there is a problem that the operation for adjusting the volume of the voice becomes complicated.

In order to deal with this inconvenience, conventionally, as shown in FIG. 4, all selection switches 3 are connected between the volume adjusting units 2. These selection switches 3 are for making the volume adjusting units 2 inactive or active by, for example, shorting or opening the volume adjusting units 2. Here, by manually operating the selection switch 3, only the selection switch 3 of the audio unit 1-3 (CT in FIG. 4) at the final stage, that is, the stage immediately before the main amplifier 9 is made non-conductive (OFF). Selection switch 3
If all are turned on (ON), the volume can be adjusted by operating the volume adjusting section 2 of only one stage, whichever audio unit is selected and used. Therefore, the operation for adjusting the volume is simpler than the case of using the volume adjusting sections 2 having a plurality of stages.

[Problems to be solved by the device]

As described above, in the case of selectively operating one of a plurality of types of audio units cascade-connected to each other, conventionally, by manually operating each of the plurality of selection switches 3, one stage before the main amplifier 9 is provided. It was made possible to easily adjust the volume only by using the volume adjusting section 2 of the audio unit.

However, in this case, when the user changes the type of the audio unit or the interconnection position of the audio unit, the conduction / non-conduction of each of the selection switches 3 is manually set each time. I have to fix it. Therefore, there is a problem that the manual operation of the selection switch 3 becomes troublesome.

The present invention has been made in view of the above problems, and is one of a plurality of types of audio units that are connected in series.
It is an object of the present invention to provide an audio device in which the volume can be easily adjusted without causing the user to manually operate the selection switch when selectively operating one of them.

[Means for Solving the Problems]

FIG. 1A is a block diagram showing the first principle configuration of the present invention. In this case, plural types of audio units 1-1 to 1
-N are cascaded together to form an audio device. However, hereinafter, the player section and the changeover switch (both in FIG. 4) in each audio unit will be omitted. Further, only one of the plurality of preamplifiers will be shown as a representative. The same components as those described above are designated by the same reference numerals.

Here, a plurality of types of audio units 1-1 to 1-N
The first DC level supply unit 4 is provided on the input side of each of the. Further, the second DC level supply unit 5 is provided on the input side of the main amplifier 9. Further, a detection unit 6 is provided on the output side of each of the plurality of types of audio units 1-1 to 1-N. The detection unit 6 includes a first DC level supply unit 4
Also, the first DC level and the second DC level supplied from the second DC level supply section 5 are detected to make the selection switch 3 conductive and non-conductive, respectively. In this case, in order to prevent the DC current from the DC level supply units 4 and 5 from entering the audio signal line,
Multiple capacitors are inserted.

FIG. 1B is a block diagram showing the second principle configuration of the present invention. In this case, plural types of audio units 1-1 to 1
In -N, at least one volume non-adjusting unit (only one volume non-adjusting unit 10 is shown in FIG. 1B) without the volume adjusting unit 2 and the selection switch 3 is mixed.

Here, a first DC level supply unit 4'for supplying a variable first DC level is provided. Furthermore, all audio units 1-1 to 1-including the volume unadjusted unit
A control unit 7 is provided on the output side of the detection unit 6 in each N. The control unit 7 is provided with a plurality of types of audio units 1
When the volume adjusting unit 2 of the audio unit of the first stage in -1 to 1-N is operable or when the volume adjusting unit of the stage subsequent to the audio unit is operable, the first
The direct current level is set to a predetermined level. In this case as well, as in FIG. 1A, a plurality of capacitors are inserted in the audio signal line.

[Action]

In FIG. 1A, the first DC level is supplied from the first DC level supply unit 4 to the output side of the audio unit at the preceding stage, and the second DC level supply unit 5 is provided to the audio unit 1-N at the final stage. There is a difference from the second DC level supplied to the output side. For example, when the first DC level is set higher than the second DC level, the level of the detection signal S _d output from the detection unit 6 of a certain audio unit is one level and another audio unit is connected in the subsequent stage. In all cases, it becomes "H" (High), and becomes "L" (Low) only when the main amplifier 9 is connected to the next stage. Here, if it is set in advance so that the selection switch 3 becomes conductive when the level of the detection signal S _d is “H” and becomes non-conductive when the level of the detection signal S _d is “L”, one stage before the main amplifier 9 is provided. The volume adjusting section 2 of the audio unit 1-N is opened so that only the volume adjusting section 2 can automatically operate, and the volume can be adjusted with only one stage.

On the other hand, as shown in FIG. 1B, even when the volume non-adjustment units are mixed, the volume of the audio unit 1-N immediately preceding the main amplifier 9 in the audio unit having the volume adjusting unit 2 is mixed. The adjusting unit 2 can be automatically operated by the second DC level supplying unit 5. Further, the first DC level is set to a predetermined level, for example, "H" by the control unit 7 of the audio unit 1-N, and the operation of the sound volume adjusting unit 2 of the self stage is performed one step before. -Transmit to N-1. Further, in this audio unit 1-N-1, the fact that the volume adjusting unit 2 is in the non-operating state and one volume adjusting unit 2 in the subsequent stage is operable is explained to the audio unit 1-N-2 in the previous stage. introduce. On the other hand, even when the audio unit 1-N-1 is a volume non-adjusting unit, one volume adjusting unit 2 in the latter stage
Is operable. In this way, if the control unit 7 successively informs that one volume adjusting unit 2 in the subsequent stage is operable, a plurality of types of audio units 1-1 to 1 including a volume non-adjusting unit can be transmitted.
The volume of each of 1-N can be adjusted in only one step. When the volume non-adjusting unit 1-N is located at the final stage, the volume cannot be adjusted, so at this time, the power source or the like may be turned off.

Thus, according to the present invention, when one of a plurality of types of audio devices is selectively operated, the volume can be easily adjusted by using only the one-step volume or the like without a troublesome operation such as manual operation of the selection switch. It becomes possible to do.

〔Example〕

FIG. 2A is a circuit diagram showing an embodiment based on the first principle of the present invention. In this case, three types of audio units 1-1,1
2 and 1-3 exemplify an audio device configured by cascading each other.

Here, the first DC level supply unit 4 sets a first DC level supplied from the first power source 14 such as a battery and the output side of the audio unit at the preceding stage from the first power source 14. 1 setting resistor 24. Further, the second DC level supply section 5 (FIG. 1A) has a second setting resistor 15 for setting the second DC level supplied from the ground to the audio unit 1-3 at the third stage (final stage). Have Further, the detection unit 6 adjusts the DC level input to the comparator 36 to an appropriate value by comparing the first DC level and the second DC level with a predetermined reference voltage V _r. It has a power source 16 for adjustment such as a battery and a resistance 26 for adjustment.

If the first DC level is higher than the reference voltage V _r and the second DC level is lower than the reference voltage V _r , the power sources 14, 16 and the resistors 15, 24 and 26, etc. If set in advance, the levels of the detection signal S _d become “H” and “L”, respectively, when the first DC level and the second DC level are input. Here, if the selection switch 3 is preset to be conductive and non-conductive when the level of the detection signal S _d is “H” and “L”, respectively, three types of audio units 1-1, 1 -2 and 1-3 are cascade-connected, only the third-stage selection switch 3 is automatically turned off, and only the third-stage volume adjusting section 2 is operable. Therefore, even if the three types of audio units 1-1, 1-2 and 1-3 are cascaded in any order, the volume can always be adjusted only by the volume adjusting section 2 immediately before the main amplifier. It is not necessary to bother the user by manually operating the switch 3.

FIG. 2B is a circuit diagram showing an embodiment based on the second principle of the present invention. In this case, an audio device constituted by connecting one volume non-adjusting unit 10 between two types of audio units 1-1 and 1-3 having the volume adjusting unit 2 is shown as a representative.

Here, the first DC level supply section 4'has a variable power supply 14 'for changing the first DC level. Further, as the control unit 7, there is provided a control gate 17 which is composed of a logic circuit and controls the voltage value of the variable power source 14 '. Further, on the output side of the control gate, there is provided a display unit 27 for displaying that the volume adjustment of the audio device is impossible.

The control gate has two input terminals, and the detection signal S _d and the volume adjustment function display signal are supplied from these input terminals.
S _v is input. The level of the volume adjusting function display signal S _v becomes “L” only when the volume adjusting section 2 of the own stage is operable, that is, when the volume adjusting function of the audio unit of the own stage is operating, the above-mentioned volume function If is not working or is not working, it becomes "H". The relationship between the input and output levels of the control gate 17 is shown in the table below.

Based on this table, the operation of the control gate 17 in each audio unit will be described in order from the final stage. First of all,
In the third stage (final stage) audio unit 1-3, the level of the detection signal S _d becomes “L” due to the second setting resistor 15. Next, since the selection switch 3 becomes non-conducting and the volume adjusting function of its own stage operates, the volume adjusting function display signal S _v becomes “L”.
Becomes As a result, the control gate 17 of the unit 1-3 is
Output level becomes "H" and the first DC level also becomes "H". Therefore, in the second-stage volume non-adjustment unit 10, the detection signal S _d becomes “H” due to the first DC level. Since the unit 10 does not have the volume adjusting function, the volume adjusting function display signal S _v remains “H”. As a result, the output level of the control gate 17 of the unit 1-2 becomes "H" and the first DC level also becomes "H". Therefore, in the first-stage audio unit 1-1, the detection signal S _d becomes “H” due to the first DC level. Further, since the selection switch 3 becomes conductive and the volume adjusting function does not work, the volume adjusting function display signal S _v becomes “H”. As a result,
The output level 17 of the control gate 17 of the unit 1-1 becomes "H" and the first DC level also becomes "H". That is,
If all the first DC levels of the audio units are set to "H" by the control gate 17, even in the audio apparatus of FIG. 2B, the volume adjustment of only one stage is possible as in the case of FIG. 2A. In this case, the control gate 17 can be
One audio unit (the last audio unit 1-3 in FIG. 2B) plays a role of transmitting the fact that the volume adjusting function works one after another.

When a volume non-adjustment unit is connected to one front stage of the main amplifier 9, the detection signal S _d is “L” and the volume adjustment function display signal S _v is “H”, and the screen of the display unit 27 is displayed. An error is displayed. That is, in this case, since the volume non-adjusting unit 10 cannot adjust the volume and an excessive volume may be transmitted, it is necessary to automatically turn off the power source and the like.

FIG. 3 is a circuit diagram showing a modification of FIG. 2A. In this case, the volume non-adjustment unit 10 is provided immediately before the main amplifier 9.
Is representatively shown, and further, the case where the audio unit 1-1 having the volume adjusting section 2 is connected to the immediately preceding stage is shown as a representative.

Here, an error message is displayed on the screen of the display unit 27 of the volume non-adjusting unit 10, and the mute circuit 22 is operated to automatically mute the volume. Therefore, the
As shown in FIG. 2B, there is no possibility of damaging the speaker 19 or the like due to excessive volume without turning off the power. In this case, the control gate 17 of the volume non-adjusting unit 10 sets the first DC level on the output side of the audio unit 1-1 to "L".
If set to, the volume adjusting section 2 of the audio unit 1-1 becomes operable. Therefore, volume adjustment in audio units other than the volume unadjusted unit 10
This can be easily performed by the volume adjusting unit 2 of the audio unit 1-1.

In the above modification, since the existing mute circuit can be used for the general audio unit, the area occupied by the circuit and the cost are increased as compared with the embodiment based on the above-mentioned second principle (FIG. 2B). There is no.

[Effect of the Invention] As described above, according to the present invention, when one of a plurality of types of audio units cascade-connected to each other is selectively operated, the operation can be performed without manually operating the selection switch. It is possible to realize an audio device in which the volume can be easily adjusted by the volume of only the stage. Therefore, the user does not have to bother with the manual operation or the like when adjusting the volume.

[Brief description of drawings]

FIG. 1A is a block diagram showing a first principle configuration of the present invention, FIG. 1B is a block diagram showing a second principle configuration of the present invention, and FIG. 2A is a circuit diagram showing an embodiment based on the first principle of the present invention. 2B is a circuit diagram showing an embodiment based on the second principle of the present invention, FIG. 3 is a circuit diagram showing a modified example of FIG. 2B, and FIG. 4 is a circuit diagram showing an example of a conventional audio device. is there. In the figure, 1-1 to 1-N ... Audio unit, 2 ... Volume adjustment section, 3 ... Selection switch, 4 ... First DC level supply section, 5 ... Second DC level supply section, 6 ... … Detection unit, 7…
… Control unit, 9… Main amplifier.

Claims (2)

[Scope of utility model registration request] 1. A volume adjusting section (2) for adjusting the volume by changing the level of an audio signal (S _a ), and by shorting / opening the volume adjusting section (2), the volume adjusting section (2) A plurality of kinds of audio units (1-1 to 1-N) each having a selection switch (3) for selecting non-operation / operation and respectively connected in cascade, and the plurality of kinds of audio units (1 -1 to 1-N) and a main amplifier (9) connected to the final stage of the audio device, the audio device having a main amplifier (9) connected to the input side of each of the plurality of types of audio units (1-1 to 1-N). 1 DC level supply section (4)
A second DC level supply section (5) provided on the input side of the main amplifier (9), and provided on the output side of each of the plurality of types of audio units (1-1 to 1-N), and , Detecting the first DC level and the second DC level supplied from the first DC level supply section (4) and the second DC level supply section (5) respectively, and turning on the selection switch (3) respectively. An audio device, comprising: a detection unit (6) for non-conduction. 2. The plurality of types of audio units (1-1
1 to N) is at least one volume non-adjusting unit that does not have the volume adjusting unit (2) and the selection switch (3), and the first DC level supplying unit (4) has the first The DC level is variable, and when the volume adjusting section (2) of the audio unit of the plurality of types of audio units (1-1 to 1-N) is operable, or the volume adjustment of a stage subsequent to the audio unit. When part (2) is operational,
The control unit (7) for setting the first DC level to a predetermined level is provided on the output side of the detection unit (6).
The audio device described.