JPH0611627Y2 - Control device for digital signal selection circuit - Google Patents

Description

The present invention relates to a control device for a digital signal selection circuit that selects an audio signal to be input from audio signals supplied as digital signals from a digital audio device. .

(B) Prior Art The audio amplifier is configured such that audio signals obtained from various audio devices connected to the audio amplifier can be input, as disclosed in Japanese Utility Model Laid-Open No. 59-71495, for example. A speaker output selection circuit for selecting an audio signal to be supplied to the speaker is provided so that the speaker can be driven in accordance with a desired audio signal.

Further, the audio amplifier is, for example, the actual open circuit 61-528.
As shown in Japanese Patent Laid-Open No. 19, a recording output selection circuit is provided for selecting an audio signal in order to supply an audio signal obtained from another audio device as a recording source to an audio device having a recording function such as a tape recorder.
As the recording output selection circuit, there is one that also serves as the speaker output selection circuit described above. However, such a circuit can only emit sound from the speaker according to the audio signal selected as the recording source. Therefore, in recent audio amplifiers, the speaker output selection circuit and the recording output selection circuit are provided separately, and the audio signal for emitting sound from the speaker and the audio signal as the recording source are independent. Many of them are designed so that you can choose.

By the way, as an audio device, a CD player, a D
There are digital audio devices such as AT (digital audio tape recorder) and BS tuner (satellite broadcast receiving tuner) that handle audio signals as digital signals. Many of the digital audio devices mentioned above
The audio signal obtained by reproduction or the like can be output not only as an analog signal but also as a digital signal. Therefore, as the audio amplifier, a digital signal compatible audio amplifier which can directly input the digital signal from the digital audio device has been commercialized. Such a digital signal compatible audio amplifier has a built-in DA converter for converting a digital signal into an analog signal. The digital audio signal from the digital audio device is:
An analog audio signal is converted by the DA converter and supplied to the speaker output selection circuit and the recording output selection circuit. That is, a digital signal compatible audio amplifier to which a plurality of digital audio devices can be connected is provided with a digital signal selection circuit for selecting an audio signal of a digital signal input to a DA converter. The audio signal of the digital signal selected by the circuit is D
It is supplied as an analog signal to the speaker output selection circuit and the recording output selection circuit via the A converter.

(C) Problems to be Solved by the Invention By the way, in an audio amplifier compatible with digital signals, if the audio signal to be emitted from the speaker and the audio signal to be the recording source can be independently selected, the recording output When the audio signal from the DA converter is selected by the selection circuit, that is,
Depending on the audio signal of the digital signal obtained from the digital audio device other than the recording source, when the audio signal which is output as the digital signal from the predetermined digital audio device and converted into the analog signal by the DA converter is selected as the recording source. If the digital signal selection circuit is switched to cause the speaker to emit the generated sound, the recording source cannot be supplied to the audio device with the recording function, and the recording cannot be continued.

The present invention provides a controller for a digital signal selection circuit made in view of the above points.

(D) Means for Solving the Problems The present invention is directed to a digital signal selection circuit for selecting an audio signal to be input from among audio signals supplied as digital signals from a digital audio device, and selection by the digital signal selection circuit. DA for converting the converted digital audio signal to an analog audio signal
A converter, a speaker output selection circuit for selecting an audio signal output from the DA converter and an audio signal to be emitted from a speaker from audio signals supplied as analog signals from an audio device, and the speaker Speaker output switching control means for controlling switching between the output selection circuit and the digital signal selection circuit, and a recording function from an analog audio signal output from the DA converter and an audio signal supplied as an analog signal from an audio device. A recording output selection circuit for selecting an audio signal to be a recording source of an attached audio device, and a recording output switching control means for controlling switching between the recording output selection circuit and the digital signal selection circuit. Recording by means of When a force selecting circuit is made in the state of selecting the audio signal from the DA converter, a control signal for switching the digital signal selection circuit from said speaker output switching control means is in the manner not generated.

(E) Action The present invention is for supplying the recording source when the audio signal output from the digital audio device as a digital signal and converted into the analog signal by the DA converter is selected by the recording output selection circuit. When the DA converter incorporated in the audio amplifier is used, the audio signal of the digital signal selected by the digital signal selection circuit is controlled so that the control signal for switching the digital signal selection circuit is not generated from the speaker output switching control means. Prevent the signals from switching,
The DA converter is not used for the audio signal to be emitted from the speaker.

(F) Embodiment FIG. 1 is a circuit diagram showing a speaker output selection circuit and a recording output selection circuit part in a digital signal compatible audio amplifier. (1) shows a digital signal audio signal reproduced by a CD player. The supplied first digital input terminal (2) can output an audio signal as a digital signal and is a second terminal provided as a spare terminal for supplying a digital signal of a digital audio device which cannot be connected to a predetermined connection point. Digital input terminal, (3) is the first
And a first selector for selecting an audio signal supplied to the second digital input terminals (1) and (2), and (4) is a DAT digital recording system circuit for recording an audio signal as a digital signal. A digital output terminal which is connected to (not shown) and to which the audio signal selected by the first selector (3) is supplied, and (5) is supplied with the audio signal of the digital signal reproduced by the DAT. A third digital input terminal, (6) a second selector for selecting an audio signal supplied to the first selector (3) and the third digital input terminal (5), and (7) a second selector. An input circuit for performing demodulation and signal processing of various digital signals selected by the selector (6) and matching with the circuit of the next stage, (8) is an analog circuit for digital signals obtained from the input circuit (7) DA converter to convert to signal (9) supplies a first analog input audio signal of the analog signal received by the tuner is supplied, the audio signal of the digital signal (10) said first digital input terminal (9) C
The second analog input terminal to which the analog audio signal reproduced by the D player is supplied, and (11) is provided as a spare terminal for supplying the analog audio signal of the audio device which cannot be connected to the predetermined connection point. A third analog input terminal (12) is a DA for supplying a digital audio signal to the third digital input terminal (5).
A fourth analog input terminal to which an audio signal of an analog signal reproduced by T is supplied, (13) is the DA converter
From the audio signal output from (8) and the audio signals supplied to the first to fourth analog input terminals (9) to (12), an audio signal output from a speaker (not shown) is output. A third selector for selecting, (14) a fourth selector for selecting an audio signal supplied to the DA converter (8) and the first to third analog input terminals (9) to (11) , (15) is connected to an analog recording system circuit (not shown) of the DAT for recording an analog audio signal, and the audio signal selected by the fourth selector (14) is gated ( 16)
It is an analog output terminal supplied via.

In the circuit of FIG. 1, by switching the first and second selectors (3) and (6), the first digital input terminal (1),
The digital signal supplied to the second digital input terminal (2) or the third digital input terminal (5) is input to the input circuit (7). Here, the digital signal input to the input circuit (7) is demodulated and signal-processed by the input circuit (7) and input to the DA converter (8). Therefore, an audio signal obtained by converting a digital signal supplied from the DA converter (8) to any of the first, second and third digital input terminals (1), (2) and (5) into an analog signal. The signal is output.

The audio signal output from the DA converter (8) is supplied to the third selector (13). The third selector (13) includes first to fourth analog input terminals (9) to (9) to audio signals from the DA converter (8).
The audio signals from (12) are respectively supplied, and the audio signal to be emitted from the speaker can be selected by the third selector (13). Therefore, by switching the third selector (13), the DA converter (8) outputs From the audio signal and the audio signals from the first to fourth analog input terminals (9) to (12), the sound corresponding to the desired audio signal can be emitted from the speaker.

Therefore, a CD player that is input with a digital signal,
Audio signal from the digital audio device and DAT connected to the second digital input terminal (2), a tuner, a CD player that is input as an analog signal, an audio device and DAT connected to the third analog input terminal (11)
The sound to be emitted by the speaker can be freely selected from the audio signals from.

On the other hand, the audio signal output from the DA converter (8) is supplied to the fourth selector (14). The fourth selector (14) has first to third analog input terminals (9) to (9) to audio signals from the DA converter (8).
The audio signals from (11) are supplied respectively. Also, the audio signal selected by the fourth selector (14) is output to the gate (1) when the gate (16) is closed.
It is supplied to the analog output terminal (15) via 6). Therefore, when the gate (16) is closed, the audio signal from the DA converter (8) and the first to third analog input terminals are switched by switching the fourth selector (14).
A desired audio signal among the audio signals from (9) to (11) can be recorded as an analog signal by DAT.

Therefore, it is input as a digital signal and the DA converter
The audio signal from the digital audio device connected to the CD player and the second digital input terminal (2) converted into the analog signal by (8), and the tuner, the CD player and the third analog input terminal which are input by the analog signal The audio signal to be recorded as an analog signal by DAT can be freely selected from the audio signals from the audio device connected to (11).

Also, the audio signal of the digital signal from the CD player or the digital audio device connected to the second digital input terminal (2) is not converted into an analog signal and is output to the digital output terminal (4) via the first selector (3). ), The audio signal from the CD player and the digital audio device can be recorded as a digital signal by the DAT.

At present, it is prohibited to record the audio signal from the CD player as a digital signal,
Since the circuit of the DAT digital recording system does not support the digital signal from the CD player, the audio signal from the CD player cannot be recorded as a digital signal.

By the way, the first selector (3), the second selector (6), the third selector (13), the fourth selector (14) and the gate (16).
As shown in FIG. 2, switching control is performed by the control circuit (18) which operates according to the operating state of the key switch (17). The control circuit (18) is composed of a microcomputer, monitors the operation state of the key switch (17),
Switch input means that operates according to the operated switch
A control signal is generated according to the switch (19) and a switch detected to be operated by the switch input means (19), and a first selector (3) and a second selector, respectively.
(6), a first selector control unit (20), a second selector control unit (21), and a third selector control that generate a control signal for switching and controlling the third selector (13) and the fourth selector (14) Section (22) and fourth selector control section (23), and the second
And a gate according to the fourth selector control unit (21) and (23)
A gate controller (24) for generating a control signal for switching control of (16) is provided.

The gate controller (24) is driven by the fourth selector (14)
When the audio signal from the A converter (8) is selected and the audio signal from the DAT supplied to the third digital input terminal (5) is selected by the second selector (6), the gate (16) is opened. It is controlled so that it will be in the state
The audio signal from T is controlled so as not to be input to the DAT.

The first and second selector control units (20) and (21) are configured so that the control signal generated according to the fourth selector control unit (23) is restricted. That is, the fourth selector control unit (23) transfers the fourth selector (14) to the DA converter (8).
When controlling to select the audio signal supplied from, it is output as a digital signal from a digital audio device other than the recording source, and a DA converter (8)
The key switch (17) is used to cause the speaker to emit the sound corresponding to the audio signal converted to the analog signal by the
The first and second selector control units (20)
The control signals generated from (21) and (21) do not change. On the other hand, when the fourth selector control unit (23) controls the fourth selector (14) to select an audio signal other than the audio signal supplied from the DA converter (8),
The first and second selector control units (20) and (21) respectively switch the audio signal to be emitted from the speaker by the key switch (17) to the digital audio signal from the digital audio device. A control signal for switching the first and second selectors (3) and (6) is generated.

Therefore, it is input as a digital signal and the DA converter
The audio signal from the digital audio device converted into the analog signal by (8) is selected by the fourth selector (14), and the audio signal is supplied to the analog output terminal (15) as a recording source. Then, the operation of the key switch that switches the audio signal to output from the speaker is the first and second selector (3)
Even if the switching of (6) and (6) is required, the state before the operation of the first and second selectors (3) and (6) is continued. Therefore, even if the key switch corresponding to the digital audio device other than the recording source is operated in order to emit the sound corresponding to the audio signal of the digital signal obtained from the digital audio device other than the recording source, from the speaker The audio signal for emitting sound is not switched, and the state in which the audio signal serving as the recording source can be recorded is continued. On the other hand, when the audio signal input from the audio device as an analog signal is selected by the fourth selector (14) and the audio signal is supplied to the analog output terminal (15) as a recording source, the speaker If the operation of the key switch for switching the audio signal for emitting the sound from the first switch requires switching of the first and second selectors (3) and (6), the first and second selectors are operated according to the operation of the key switch. The selection states of the second selectors (3) and (6) are switched. Therefore, the sound corresponding to the audio signal of the digital signal obtained from the desired digital audio device can be emitted from the speaker by operating the key switch.

In the state where the audio signal of the digital signal from the digital audio device is selected as the recording source, a digital signal from a digital audio device other than the digital audio device and capable of selecting the same audio signal as a digital signal and an analog signal. When the audio signal of is selected as the audio signal to be emitted from the speaker, the third selector (13) is switched so that the analog audio signal of the digital audio device is selected. Although there is a difference in sound quality depending on whether the input is made by inputting or by an analog signal, desired music can be emitted from the speaker. For example, the second digital input terminal
From the CD player input to the first digital input terminal (1) while the audio signal input to (2) as a digital signal and converted to an analog signal by the DA converter (8) is selected as the recording source. Second analog input terminal when the audio signal of the digital signal of is selected as the audio signal for emitting sound from the speaker.
The analog audio signal from the CD player input to (10) is selected as the audio signal to be emitted from the speaker.

(G) Effect of the Invention As described above, the present invention, when the audio signal output from the digital audio device as a digital signal and converted into an analog signal by the DA converter is selected as the recording source by the recording output selection circuit. , The digital signal selection circuit does not switch even if an operation for emitting an audio signal of a digital signal obtained from a digital audio device other than the digital audio device is performed from the speaker. It has the advantage that recording can be continued.

[Brief description of drawings]

1 and 2 show an embodiment of the present invention, FIG. 1 is a circuit diagram showing a speaker output selection circuit and a recording output selection circuit portion in a digital signal compatible audio amplifier, and FIG. It is a circuit block diagram which shows the control apparatus which controls the circuit of the figure. Description of main drawing numbers (3) (6) (13) (14) …… Selector, (1) (2) (5) …… Digital input terminal, (9) (10) (11) (12)… … Analog input terminal,
(8) …… DA converter, (18) …… Control circuit, (20) (21)
(22) (23) …… Selector controller.

Claims (1)

[Scope of utility model registration request] 1. A digital signal selection circuit for selecting an input audio signal from audio signals supplied as digital signals from a digital audio device, and an analog audio signal of the digital signal selected by the digital signal selection circuit. DA to convert to other audio signals
A converter, a speaker output selection circuit for selecting an audio signal output from the DA converter and an audio signal to be emitted from a speaker from audio signals supplied as analog signals from an audio device, and the speaker Speaker output switching control means for controlling switching between the output selection circuit and the digital signal selection circuit, and a recording function from an analog audio signal output from the DA converter and an audio signal supplied as an analog signal from an audio device. A recording output selection circuit for selecting an audio signal to be a recording source of an attached audio device, and a recording output switching control means for controlling switching between the recording output selection circuit and the digital signal selection circuit. Recording by means of When the force selection circuit is in a state of selecting the audio signal from the DA converter, a control signal for switching the digital signal selection circuit is not generated from the speaker output switching control means. Control device for signal selection circuit.