JP2580238B2 - Signal switching device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to a signal switching device used for switching an input signal in a CD player or the like.

Summary of the Invention

The present invention relates to a signal switching device configured to disconnect an extra load connected to the direct line and avoid sound quality deterioration when performing reproduction on a direct line such as a CD or DAT.

[Prior art]

2. Description of the Related Art A signal switching device of this type is conventionally known as shown in FIG. Here, multiple signal input terminals 10
For example, a signal from a CD is input to the input terminal 101, and signals for a tape player, a tuner, and a record player are input to the input terminals 102, 103, and 104, respectively. Also, the input terminal 101
Is connected to a direct input signal path 106 for supplying an input signal directly to the power amplifier 105,
The input signal path 106 includes a switch
107a intervenes, and switches between inputting the input signal to the power amplifier 105 via the volume 108 and cutting off the input signal. The input terminals 101 to 104 are connected to another input signal path 110 via switches 109a, 109b, 109c and 109d of another changeover switch row 109, and the input signal path 110 is connected to a required signal processing circuit, For example, tone amplifier 1
11 to the switch 107b of the changeover switch array 107, and further through the volume 108, the power amplifier 1
An input signal is supplied to the power amplifier 105. The switch 107b switches between supplying the input signal passing through the tone amplifier 111 to the power amplifier 105 and cutting off the input signal. Further, the input terminals 101 to 104 are connected to another output path 113 via switches 112a, 112b, 112c and 112d of still another changeover switch array 112,
The output path 113 is provided with, for example, an output terminal 114 to a tape recorder. Each of the switches 107, 109 and 112 is controlled by a microcomputer 115, and the microcomputer 115 receives control information from an external key matrix 116. . In the figure, reference numeral 117 denotes a power supply circuit for the power amplifier 115 and the tone amplifier 111. Thus, in the key matrix 116, for example, switch 1
When selecting and turning on 07a, the switch 107b is turned off. Thus, an input signal such as a CD is supplied directly to the power amplifier 105 via the direct input signal path 106. When the switch 107b is selected and turned on by the key matrix 116, the switch 107a is turned off. As a result, an input signal enters the tone amplifier 11 via another input signal path 110, is subjected to signal processing, and is then input to the power amplifier 105.

[Problems to be solved by the invention]

However, in the signal switching device, for example, the input terminal 10
Even if a signal is input from 1 to the power amplifier 105 via the switch 107a, if the switches 109a and 112a in the changeover switch rows 109 and 112 are selected, the input impedance of the tone amplifier 111 and the output terminal to the recorder If the input impedance of the device connected to 114 is
Leads to the direct input signal path 106,
Affects sound quality. Also, tone amplifier 111
Signal is input to the power amplifier 105 via the tone amplifier 111 and the power supply circuit 117, for example, an increase in crosstalk from another input position, a deterioration in channel separation, and, in particular, from the other position. There is a disadvantage that adverse effects such as jumping of high-frequency distortion occur. In view of the above, the present invention controls the switch of one input signal path selected for the power amplifier to be in an on state, and controls the switches of another input signal path or another output path to be in an off state. It is an object of the present invention to provide a signal switching device in which another input signal path, an output path, and the like are separated from the input signal path, and a control mode is set so as not to adversely affect the electric signal.

[Means for Solving the Problems]

For this reason, in the present invention, a plurality of input terminals, a first changeover switch connected to some of the input terminals as inputs, a signal processing circuit to which an output of the first changeover switch is input, Some of the input terminals and the output of the signal processing circuit are connected as inputs, a second changeover switch for selecting one of the inputs and supplying it to the power amplifier, and some of the input terminals are connected as inputs. A third changeover switch, an output terminal for outputting an output of the third changeover switch, and input means for inputting a signal changeover instruction;
Control means for controlling the switching of the first to third changeover switches in response to a signal switching instruction from the input means, wherein one of the input terminals to be selected by the signal switching instruction is selected. When a signal path from one to the power amplifier is formed by at least the second changeover switch, a first mode in which all other signal paths are cut off by the first to third changeover switches, and the above-mentioned mode to be selected should be selected. A second mode in which one of the input terminals is selected by the third switch and output to the output terminal is further provided so as to be selectable.

【Example】

Hereinafter, an embodiment of the present invention will be specifically described with reference to FIG. Here, there are a plurality of signal input terminals 1 to 5, for example, a signal from a CD is input to input terminal 1, a signal from DAT is input to input terminal 2, and input terminals 3, 4, 5 Are supplied with signals for a tape player, a tuner, and a record player, respectively. A power amplifier 6 is connected to the input terminals 1 and 2.
Direct input signal paths 7 and 8 for directly supplying an input signal to the input signal paths 7 and 8 are connected to switches 9a and 9b of a changeover switch array 9 as a second changeover switch. It is interposed, and switches between inputting the input signal to the power amplifier 6 through the volume 10 and switching off. In addition, the input terminals 1 to
5 is a changeover switch array 11 as another first changeover switch
Are connected to another input signal path 12 via the respective switches 11a, 11b, 11c, 11d and 11e. The input signal path 12 is a required signal processing circuit, for example, a tone amplifier capable of adjusting sound quality.
The input signal is supplied to the power amplifier 6 via the volume 10 through the switch 9c of the changeover switch array 9 via the switch 9c.
Switches between inputting the input signal passing through the tone amplifier 13 to the power amplifier 6 and cutting off the input signal. Further, the input terminals 1 to 5 are connected to the respective switches 14a, 14a,
The other output paths 15, 15a are connected via 14b, 14c, 14d, and 14e, and the output paths 15, 15a include, for example, an output terminal 16 to a tape recorder and an output terminal 17 to a DAT recorder, respectively. It is provided. However, the third changeover switch 14 is
Switch 14 for selecting different input terminals
The portion excluding b and the portion of the switch 14b are collectively illustrated. Each of the switches 9, 11 and 14 is controlled by a microcomputer 18 as control means.
Receives information for control from a key matrix 19 as an external input means. The microcomputer 18 includes a first and a second, as described later.
Switching control according to the mode is also performed. In the figure, reference numeral 20 denotes a power supply circuit for the power amplifier 6 and the tone amplifier 13. When the switch 9a is selected and turned on by the key matrix 19 in the first mode, for example, by a specific key switch meaning "direct line", the microcomputer 18 switches the switches 9b and 9c. And turning off another input signal path or an output path that loads the direct input signal path 7 in which the input signal is supplied to the power amplifier 6 by the selection of the switch 9a. Turn off all 14 switches. Therefore, the power amplifier 6 is not affected by the input impedance of the tone amplifier 13 and the influence of the input impedance from an external device via the output path 15 is avoided. If the switch 9b is selected by pressing a specific key switch indicating "direct line" of the signal of the input terminal 2 by the key matrix 19, the microcomputer 18 turns on the switch 9b, and the direct input signal path 8
Supplies the input signal to the power amplifier 6. Also in this case, the switches 9a and 9c are off and the other changeover switch train 1
Turn off all switches 1 and 14. Further, for example, similarly, the switch 9c of the changeover switch row 9 is turned on by the key switch selection of the key matrix 19, and
When the other switches 9a and 9b are turned off, when the switch 11a or 11b of the changeover switch array 11 is turned on, the tone amplifier 13 is turned off.
The input signal is supplied to the power amplifier 6 and the signal-processed input signal is supplied to the power amplifier 6. At this time, the microcomputer 18 can cut off the influence of the input impedance of the external device introduced into the input signal path 12 via the output path 15 by turning off the other changeover switch rows. However,
If the key selection of the key matrix 19 requires the output to the output terminal 16 as the second mode, the changeover switch array 14 naturally operates. In the above embodiment, the changeover switch rows 9, 11, and 14
Is controlled by the microcomputer 18 using an electronic switch such as an FET having an isolator. However, it is needless to say that the switch used here may be configured by a mechanical switch. In this case, using a relay switch for the switch is convenient on computer control. The present invention has been described above in detail. When a direct input signal path for directly supplying a signal of an input terminal to a power amplifier is passed by a switch operation, an electric signal is input from another input signal path or an output path. It is possible to prevent a bad influence from being exerted. For example, when sound is reproduced, a pure sound is obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a block diagram for explaining a conventional mode. 1 to 5: input terminal, 6: power amplifier, 7, 8: input signal path, 9: changeover switch row, 10: volume,
11 ...... Changeover switch row, 12 ...... Input signal path, 3 ...... Tone amplifier, 14 ...... Changeover switch row, 15 ...... Output path,
16,17 …… Output terminal, 18 …… Microcomputer, 19
... key matrix, 20 ... power supply circuit.

Claims (1)

(57) [Claims] 1. A plurality of input terminals, a first changeover switch connected to some of the input terminals as inputs, a signal processing circuit to which an output of the first changeover switch is input, and the input terminal And an output of the signal processing circuit are connected as inputs, a second selector switch for selecting one of the inputs and supplying the selected input to a power amplifier, and a second switch connected to some of the input terminals as inputs. A third switch, an output terminal for outputting the output of the third switch, input means for inputting a signal switching instruction, and the first to third signals in response to a signal switching instruction from the input means. And control means for controlling the changeover of the changeover switch, wherein one of the input terminals to be selected by the signal changeover instruction is selected.
A first mode in which all signal paths from one to the power amplifier are formed by at least the second changeover switch, and the other signal paths are completely cut off by the first to third changeover switches; And a second mode in which one of the input terminals is selected by the third changeover switch and is also output to the output terminal.