JPH11266491A - Acoustic reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the S/N and a noise in the acoustic reproducing device that uses a USB digital input and an analog input in common. SOLUTION: The acoustic reproducing device is provided with a USB signal input section 1, an analog signal input section 3, a USB interface section 2 that demodulates a USB signal into a reproduction signal, a signal processing section 4 that processes the demodulated USB reproduction signal and an analog signal, a power amplifier 5 that amplifies power of the processed signal, a speaker 6 that reproduces a sound, and a control section 7 that controls the operation of the signal processing section and the power amplifier in response to a state of the signal input section of the USB signal and the analog signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound reproducing apparatus.

[0002]

2. Description of the Related Art Hitherto, a speaker with a built-in amplifier as an accessory device for a personal computer has been compatible with only an analog input. However, in recent years, the operating system OS has started to support connection to USB digital bus type peripheral devices, and speakers as peripheral devices have also become U.S.A.
There is a need to support SB connection, and by providing a USB digital input in addition to an analog input, analog and digital are used together for the time being switching to digital for the time being.

[0003]

However, it is disadvantageous, such as S / N, if only the input is mixed and reproduced.
When the input connection portion is disconnected and inserted, there is a problem that unnecessary signal disturbance is generated and noise is generated.

[0004]

SUMMARY OF THE INVENTION In order to solve this problem, the present invention detects the connection state of USB digital input and analog input, and performs optimum operation control by prioritizing two inputs and taking logic. This is to improve the signal S / N and the noise at the time of connection / disconnection.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention comprises a USB signal input section, an analog signal input section, a USB interface section for demodulating a USB signal into a reproduction signal,
A signal processing unit that processes the demodulated USB reproduction signal and the analog signal, a power amplifier that power-amplifies the processed signal, a speaker that performs sound reproduction, and a state of each signal input unit of the USB signal and the analog signal. A sound reproducing apparatus comprising a signal processing unit and a control unit for controlling the operation of a power amplifier in response to the signal processing unit, and has an effect of improving S / N and noise of the apparatus.

According to a second aspect of the present invention, in the first aspect of the invention, when the control unit detects the connection to the analog signal input unit, the control unit suspends the power amplifier even in the USB suspend state. This is a sound reproducing device that is configured not to be applied, and has the effect of improving the S / N and noise of the device.

According to a third aspect of the present invention, in the second aspect of the invention, the connection detecting means is a sound reproducing apparatus configured to detect mechanically, and the S / N and noise of the apparatus are controlled. It has the effect of improving.

According to a fourth aspect of the present invention, in the second aspect of the present invention, the connection detecting means is an audio reproducing apparatus configured to detect electrically, and the S / N and noise of the apparatus are controlled. It has the effect of improving.

According to a fifth aspect of the present invention, in the fourth aspect of the present invention, the connection detecting means is a sound reproducing apparatus configured to detect by an electric impedance looking out from the connecting portion. S / N and noise can be improved.

According to a sixth aspect of the present invention, in the fourth aspect of the present invention, the connection detecting means is a sound reproducing apparatus configured to detect by an electric signal input from the connecting section. / N and noise can be improved.

According to a seventh aspect of the present invention, in the first aspect of the present invention, the control section mutes the corresponding signal path in the signal processing section when there is no connection to the signal input section. This is a configured sound reproducing device, and has an effect of improving S / N and noise of the device.

According to an eighth aspect of the present invention, in the seventh aspect of the invention, the connection detecting means is a sound reproducing apparatus configured to detect mechanically, and the S / N and noise of the apparatus are controlled. It has the effect of improving.

According to a ninth aspect of the present invention, in the sound reproducing apparatus according to the seventh aspect, the connection detecting means is configured to detect the electric connection electrically. It has the effect of improving.

According to a tenth aspect of the present invention, in the ninth aspect of the present invention, the connection detecting means is a sound reproducing apparatus configured to detect by an electric impedance looking out from the connecting portion. It has the effect of improving S / N and noise.

According to an eleventh aspect of the present invention, in the ninth aspect of the present invention, the connection detecting means is a sound reproducing apparatus configured to detect by an electric signal input from the connecting portion. / N and noise can be improved.

According to a twelfth aspect of the present invention, in the first aspect of the present invention, a main volume adjuster or a sound quality adjuster for adjusting a reproduced signal between the signal processing unit and the power amplifier or both of them. This is a sound reproducing apparatus characterized by adding a symbol, and has an effect of improving S / N and noise of the apparatus.

An embodiment of the present invention will be described below with reference to FIGS. (Embodiment 1) FIG. 1 is a block diagram of a sound reproducing apparatus according to Embodiment 1 of the present invention. In FIG. 1, a signal from a USB signal input unit 1 is connected to a USB interface unit 2, and a signal from the USB interface unit 2 is connected to a signal processing unit 4.

The signal from the analog signal input unit 3 is also connected to the signal processing unit 4. The signal from the signal processing unit 4 is connected to a power amplifier 5, and the signal from the power amplifier 5 is connected to a speaker 6. The control unit 7 is USB
Connection detection means 1A, 3 provided in each of the signal input unit 1, the analog signal input unit 3, and the USB interface unit 2.
Signals from A and 2A are received, and a control signal from the control unit 7 is connected to the signal processing unit 4 and the power amplifier 5.

In FIG. 1, when there is no connection to the USB signal input unit 1, the signal S1 from the connection detecting means 1A becomes low. If there is no connection to the analog signal input unit 3, the signal S2 from the connection detection unit 3A becomes low. When the USB audio signal to the USB interface unit 2 is interrupted for a predetermined time, the USB interface unit 2 changes the signal S3 from the connection detection unit 2A to low in response to the USB suspend (standby) state.

The control section 7 uses the signals S1 to S3 to mute the signal line in the signal processing section 4 corresponding to the input without the detection signal by the control signal S4. Further, the control signal S6 is set to low to send the power amplifier 5 to the energy saving state (standby) in response to the USB suspend detection, and is sent.

However, since it is necessary to be able to reproduce when there is an analog input, the control unit 7 takes the logic of the suspend detection signal S3 and the analog connection detection signal S2, sets the control signal S6 high with priority on the S2 signal, and sends the power amplifier. Release the standby of 5.

For this reason, the control section 7 takes the logic of the signal S1 and the signal S2 by the OR gate 7A, takes the logic of the signal S2 and the signal S3 by the OR gate 7B, and uses the both gates by the AND gate 7C.
The logic of the output of the R gates 7A and 7B is taken.

By muting in accordance with the condition of each signal in this manner, unnecessary signal line noise can be suppressed, and analog input is also considered for USB suspend.

FIG. 2 shows an example of connection detection means. FIG. 2A shows an example of mechanical detection of analog input. A detection signal is transmitted to a switch which opens and closes according to a mechanical connection inside the connector 11. By connecting the power supply + B via the resistor 12 as shown in the figure, it is possible to set high when connected and low when not connected.

FIG. 2B shows an example of electrical detection of an analog input. The audio signal is passed through a charge / discharge circuit 13 having a time constant, and the output voltage is compared with a threshold voltage Vth by a comparator 14. Thus, when there is a signal, the detection signal can be made high.

FIG. 2C shows an example of USB input detection.
By detecting a bus power supply voltage due to the connection of the USB bus line in the USB receptacle 15, a detection signal can be generated through a buffer 16 such as a comparator.

FIG. 2D shows an example of electrical detection. Since the impedance changes when the signal line is connected and when it is not connected, the signal is used as a detection signal, and a three-terminal bridge circuit is used. Balance condition Z1 + Z2 + Z4 + Z1
A deviation from a desired value can be known from × Z2 / Z3 = 0.

FIG. 2E shows an example in which a photo interrupter 18 is used, in which a detection electric signal is obtained optically in accordance with the presence or absence of the connector 17, which is considered to be an example of electric detection widely.

With the above arrangement, it is possible to mute according to the conditions of each signal, it becomes difficult to receive unnecessary signal line noise, and it is possible to reduce pop noise generated at the time of insertion and removal. In addition, since analog input is also considered for USB suspend,
This has the effect of avoiding the inconvenience that analog playback cannot be performed during the B suspend.

It is needless to say that the logic in the embodiment can be constituted by a combination of AND, OR, etc. other than this example.

[0031]

As described above, according to the present invention, unnecessary signals are muted, so that the signal-to-noise ratio (S / N) and the noise at the time of insertion / removal are improved, and the analog input is also considered for USB suspend. As a result, it is possible to improve the operation in which the inconvenience of being unable to perform analog reproduction during USB suspension is avoided, and the effect is great.

[Brief description of the drawings]

FIG. 1 is a block diagram of a sound reproducing device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing an example of connection detection means used in the device.

[Explanation of symbols]

 Reference Signs List 1 USB signal input unit 2 USB interface unit 3 Analog signal input unit 4 Signal processing unit 5 Power amplifier 6 Speaker 7 Control unit

Claims (12)

[Claims] 1. A USB signal input section, an analog signal input section, a USB interface section for demodulating a USB signal to a reproduction signal, a signal processing section for processing the demodulated USB reproduction signal and an analog signal, and A power amplifier for power amplification, a speaker for sound reproduction, and the US
An audio reproducing apparatus comprising: the signal processing unit; and a control unit that controls an operation of a power amplifier according to a state of each signal input unit of a B signal and an analog signal. 2. The control unit detects a connection state by connection detection means for detecting connection to the analog signal input unit.
2. The sound reproducing apparatus according to claim 1, wherein the power amplifier is not put on standby even in the B suspend state. 3. The sound reproducing apparatus according to claim 2, wherein the connection detecting means is configured to detect mechanically. 4. The sound reproducing apparatus according to claim 2, wherein the connection detecting means is configured to detect electrically. 5. The sound reproducing apparatus according to claim 4, wherein said connection detecting means is configured to detect the electric impedance based on an electric impedance seen from a connecting portion. 6. The sound reproducing apparatus according to claim 4, wherein the connection detecting means is configured to detect based on an input electric signal from the connection section. 7. The control unit according to claim 1, wherein when a connection state is detected by connection detection means for detecting that there is no connection to the signal input unit, the signal processing unit mutes the corresponding signal path. The sound reproducing device according to claim 1. 8. The sound reproducing apparatus according to claim 7, wherein the connection detecting means is configured to detect mechanically. 9. The sound reproducing apparatus according to claim 7, wherein said connection detecting means is configured to detect electrically. 10. The connection detecting means is configured to detect by an electric impedance looking out from the connection part.
The sound reproducing device according to claim 1. 11. The sound reproducing apparatus according to claim 9, wherein said connection detecting means is configured to detect by an electric signal input from said connecting portion. 12. The sound reproducing apparatus according to claim 1, further comprising a main volume adjuster and / or a sound quality adjuster for adjusting a reproduced signal between the signal processing unit and the power amplifier.