JP2000339858A - Recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recording and reproducing device without raising the cost of a system stereo and deteriorating sound quality, and capable of being used as the option of the system stereo or as a single use. SOLUTION: A system stereo 1 is connected to an MD deck 2 via an audio signal cable and a system control signal cable. When a micro-controller 8 confirms the connection to the system stereo 1, it changes over switches 11, 12 and sets the input level to 1 Vrms of the output level of the system stereo 1. In the case of a single use, a micro-controller 8 changes over the switches 11, 12 so that an attenuator 6 is inserted, and sets the input level of MD deck 2 to normal 2Vrms. In such a manner, the system stereo 1 eliminates the need for the amplifier for matching the input-output levels of the MD deck 2, and is reduced in cost, and prevented from deterioration in sound quality.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording / reproducing apparatus, and more particularly to a recording / reproducing apparatus for an audio signal in consideration of connection with a system stereo.

[0002]

2. Description of the Related Art A system stereo includes, for example, an amplifier section, a tuner section, a CD (Compact Disc) player section,
It is a system created by combining various components such as a D (Mini Disc) deck, a cassette deck, and a speaker. Such a system stereo is designed so that it can be efficiently systemized only within the system. For example, each component is functionally independent, but all components including the speaker unit or components other than the speaker unit are shared by a common housing, and the power supply circuit unit of each component is shared. By doing so, the number of housings and power supply circuits required by each component is reduced, and the cost is reduced. Functionally, it is only necessary to balance the entire system stereo, so the signal level setting between components has a relatively high degree of design freedom and can be determined to some extent. .

[0003] For this reason, in the system stereo, in order to reduce the cost, for example, the power supply unit is a power supply circuit for supplying a single voltage, and accordingly, the amplifier circuit of the amplifier unit is operated by a single power supply voltage. Composed of amplifiers,
2. Description of the Related Art An integrated circuit that operates at the same power supply voltage is used for various control circuits. Here, the input / output levels between the components are often set lower than in the case of a stereo configured by combining single components. This is because the input / output level between components depends on the power supply voltage, and the power supply voltage is often set to a relatively low voltage that is shared. This is no problem if the system stereo is used alone.

On the other hand, in a relatively high-end system stereo, the expandability of the system is considered, and an optional component can be additionally connected. If the basic system consists of, for example, an amplifier section, a CD player section, and a speaker section, for example, an MD deck can be connected to this system.
The amplifier unit is provided with input / output terminals for connection and a changeover switch for using the input / output terminals. When an additional MD deck is to be additionally connected to such a system stereo, an optional dedicated MD deck is normally used. In some cases, a general-purpose MD deck is connected and used. A connection example of this system stereo optional device is shown below.

FIG. 6 is a diagram showing a connection example and input / output levels of a conventional system stereo and optional equipment.
The system stereo 1 has an analog output terminal for connection to the MD deck 2, and the output terminal is connected to, for example, a selector 3 and an amplifier 4 for selecting a recording signal. Is performed. The MD deck 2 has an analog input terminal, and the input terminal is connected to an analog / digital converter 7 with a built-in low-pass filter via an attenuator 6. The control input of the analog / digital converter 7 is:
A microcontroller 8 is connected. The output terminal of the system stereo 1 is connected to the input terminal of the MD deck 2, and the microcontroller 5 of the system stereo 1 is connected to the M
It is interconnected with the microcontroller 8 of the D deck 2.

Here, the system input / output level of the system stereo 1 is lower than the input / output level of 2 Vrms, which is lower than the input / output level of a single component, due to the configuration of its power supply.
Vrms. The amplifier 4 amplifies the output of the selector 3 by 6 dB in order to match the output level of the system stereo 1 with the input level of the MD deck 2. In addition, the MD deck 2 is usually 2 Vrm in consideration of being combined with another single component stereo component.
It is designed to be able to input s signals, so that a 2 Vrms audio signal from the system stereo 1 can be directly input. As an arrangement of the MD deck 2, an attenuator 6 is provided at the input of the analog / digital converter 7, and this uses an analog / digital converter whose input voltage at the time of full bit conversion is 1 Vrms. When the input signal of 2Vrms is 1
It is for attenuating to Vrms.

[0007] System stereo 1 and MD deck 2
Are interconnected by a microcontroller 5 and a microcontroller 8, respectively, and can perform control in cooperation with each other via a system control signal.

[0008]

As described above, the input / output level of the system stereo is set low for reasons such as the configuration of the power supply. However, considering the connectivity with other components, the input / output level of the system stereo must be the same as the input / output level of the single component. And this amplifier requires 2
Since a power supply circuit for obtaining an output level of Vrms is also required, there is a problem that the cost increases as a system stereo. Also, the use of an amplifier is not a very desirable method because the passage of an audio signal through the amplifier causes deterioration of sound quality due to the audio signal.

[0009] The present invention has been made in view of such a point, and considerations have been given to both methods of using the system stereo as an option and cases of using the system stereo alone, resulting in an increase in the cost of the system stereo and a reduction in the cost. An object of the present invention is to provide a recording / reproducing device that does not cause sound quality deterioration.

[0010]

According to the present invention, in a recording / reproducing apparatus which considers both a case where the system stereo is used as an option and a case where the system stereo is used alone, a state of connection with the system stereo is detected. A recording / reproducing apparatus, comprising: a connection state detecting unit that performs a connection state detection; and a gain switching unit that switches an input / output gain according to a detection state of the connection state detection unit.

According to the above configuration, first, it is determined whether or not the connection state detecting means is connected as an option of the system stereo. Here, when the connection state detecting means detects the connection with the system stereo, the gain switching means switches the input / output gain to match the input / output level of the system stereo in response thereto. As a result, the system stereo does not require an amplifier for matching the input / output level with the recording / reproducing device used as an option, so that the manufacturing cost can be reduced and the sound quality can be prevented from deteriorating.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to an MD.
An example in which the present invention is applied to a deck will be described with reference to the drawings.

FIG. 1 is a diagram showing an example of connection of an MD deck to a system stereo and input / output levels. As shown in the figure, the system stereo 1 has an analog output terminal for connection to an MD deck 2, and a selector 3 for selecting a recording signal, for example, is directly connected to the output terminal. Is connected to a microcontroller 5 for controlling the switching between the two. The system stereo 1 has an internal input / output level equal to the input / output level of a single component for reasons such as the configuration of the power supply.
It is set to 1 Vrms, which is lower than Vrms.

The MD deck 2 has two switches 11, 1
2, an attenuator 6, and an analog /
It has a digital converter 7 and a microcontroller 8. In the switch 11, the fixed contact is connected to an input terminal for inputting an audio signal, the first movable contact is connected to the first movable contact of the switch 12, and the second movable contact is connected to the second movable contact.
Are connected to the input terminal of the attenuator 6. In the switch 12, the fixed contact is connected to the input terminal of the analog / digital converter 7, and the second movable contact is connected to the output terminal of the attenuator 6. The control terminals of the switches 11 and 12 are connected to a switching control signal output terminal of the microcontroller 8. The microcontroller 8 is also connected to the control terminal of the analog / digital converter 7 and further has a system stereo 1
It is also connected to the microcontroller 5 of the system stereo 1 in order to perform control in cooperation with.

Here, when the switches 11 and 12 are each switched to the first movable contact, the input terminal for the audio signal of the MD deck 2 is directly connected to the analog input terminal of the analog / digital converter 7. , Each second
When the switch is switched to the movable contact, the input terminal for the audio signal is connected to the analog input terminal of the analog / digital converter 7 via the attenuator 6. Attenuator 6
Has an attenuation of 6 dB, and the input voltage of the analog / digital converter 7 at the time of full bit conversion is 1 Vrms. Therefore, when the switches 11 and 12 are switched to the first movable contacts, respectively, Input level is 1Vrm
s, M when each is switched to the second movable contact
The input level of D deck 2 becomes 2 Vrms.

First, when the MD deck 2 is used as a part of a system stereo, as shown in FIG.
In addition to the audio signal cable, a system control signal cable is connected to the system stereo 1. With this system control interface, the microcontroller 8 of the MD deck 2 can communicate with the microcontroller 5 of the system stereo 1, and the microcontroller 8
12 is set to the illustrated state, that is, the state of the attenuation amount 0 dB where the first movable contacts are connected to each other. As a result, the input level of the MD deck 2 becomes 1 Vrms, which is the output level of the system stereo 1.

Next, a case where the MD deck 2 is used alone will be described. FIG. 2 is a diagram showing input / output levels of the MD deck when used alone. When the MD deck 2 is used alone, the system control signal cable is not connected to the system stereo 1. For this reason, since the microcontroller 8 of the MD deck 2 cannot communicate with any microcontroller, the microcontroller 8 connects the switches 11 and 12 in the state shown in FIG. , An attenuator 6 is inserted in series. As a result, the input level of the MD deck 2 becomes 2 Vrms, and a general source signal having a peak value of 2 Vrms can be directly input.

As described above, the microcontroller 8 of the MD deck 2 inserts and removes the attenuator 6 from the analog input terminal by switching the switches 11 and 12, and controls the timing of the switching control. An example is described below.

FIG. 3 is a diagram showing a first method for obtaining switch control timing. According to the illustrated example,
An insertion detection switch 13 is provided at a system control terminal for connecting a system control signal cable. The insertion detection switch 13 is configured to be turned on or off by mechanically detecting that a system control signal cable has been inserted into the system control terminal.

As a result, when the connector of the system control signal cable is inserted into the system control terminal, the insertion detection switch 13 operates in response to the insertion of the connector, and the microcontroller 8 switches the MD deck 2 from the system stereo 1 , And controls the switching of the switches 11 and 12, and inserts the attenuator 6 between the analog input terminal of the MD deck 2 and the analog / digital converter 7, and Set the input level to 2 Vrms.

FIG. 4 is a flowchart showing a second method for obtaining the switch control timing. First,
The microcontroller 8 monitors the system control signal cable to determine whether there is a connected device connected thereby (step S1). Here, when the microcontroller 8 cannot recognize the communication partner, the microcontroller 8 determines that the MD deck 2 is used alone, and switches the switches 11 and 12 to the attenuator 6 side, and Input level 2V
rms (step S2). If the microcontroller 8 is the microcontroller 5 of the system stereo 1
If the microcontroller 8 can use the MD deck 2 as an option of the system stereo 1, the switches 11 and 12 can be used.
To remove the attenuator 6 from the analog input terminal.
Set the input level of D deck 2 to 1 Vrms (step S
3).

In the above, the part of the circuit for switching the input level is constituted by the combination of the attenuator 6 and the switches 11 and 12. Next, another example of the constitution of the input level switching circuit will be described.

FIG. 5 is a diagram showing another example of the configuration of the input level switching circuit. According to the configuration of FIG. 5, the input level switching circuit includes two resistors R having the same value and the semiconductor switch 14.

If it is determined that the MD deck 2 is used alone, the microcontroller 8
Controls the semiconductor switch 14 to be off. This allows
Since the resistor R is simply connected in series between the analog input terminal of the MD deck 2 and the analog / digital converter 7, there is no signal level attenuation here.
Therefore, the input level of the MD deck 2 is analog /
This is set to 1 Vrms, which is the same as the allowable input voltage of the digital converter 7.

Next, the MD deck 2 is the system stereo 1
When it is determined that the semiconductor switch 14 is used while being connected, the microcontroller 8 turns on the semiconductor switch 14. Thereby, two resistors R are connected between the analog input terminal of the MD deck 2 and the analog / digital converter 7.
A voltage divider is constructed. Since the allowable input voltage of the analog / digital converter 7 is 1 Vrms and the attenuation of the voltage divider is -6 dB, the input level of the MD deck 2 is set to 2 Vrms.

When it is determined whether or not the attenuator 6 is to be operated by using the communication of the microcontroller, the information to be attenuated is transmitted from the communication partner on the connected side.
The amount of attenuation may be determined accordingly. In this case, the received information may be not only information on the amount of attenuation but also information on a connected device, and the MD deck may determine the amount of attenuation based on the information. In such a case, since these attenuators are controlled by the microcontroller 8, they may be used for muting to reduce noise when power is turned on or when power is turned off.

In the above-described embodiment, the amount of attenuation at the analog input terminal of the MD deck is controlled on the basis of whether or not the system stereo 1 is connected. It is preferable to perform the same control. That is, the MD deck amplifies the analog signal output from the digital / analog converter and outputs the amplified signal to the analog output terminal. When the amplification factor is made variable and the MD deck is connected to the system stereo 1, the microcontroller is activated. If it is determined, the amplification factor is reduced, the output level is set to 1 Vrms, and M
If the microcontroller determines that the D deck is used alone, increase the amplification and increase the output level to 2 Vrms.
To

[0028]

As described above, according to the present invention, the input / output level is made variable according to the connection state with the system stereo. This eliminates the need for an amplifier to adjust the input / output level in consideration of the connection with optional equipment that can be used independently, thus simplifying the circuit configuration and simplifying the circuit configuration, reducing material costs and manufacturing costs. Since the number of components can be reduced, the reliability can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a connection example of an MD deck with a system stereo and input / output levels.

FIG. 2 is a diagram showing input / output levels of an MD deck when used alone.

FIG. 3 is a diagram illustrating a first example of obtaining a switching control timing of a switch.
It is a figure showing the method of.

FIG. 4 is a diagram showing a second example of obtaining switch control timing.
9 is a flowchart showing the method.

FIG. 5 is a diagram showing another configuration example of the input level switching circuit.

FIG. 6 is a diagram showing a connection example and input / output levels of a conventional system stereo and optional devices.

[Explanation of symbols]

1 ... system stereo, 2 ... MD deck, 3 ... selector, 5 ... microcontroller, 6 ... attenuator,
7 ... A / D converter, 8 ... Microcontroller, 11 ... Switch, 12 ... Switch, 1
3 ... insertion detection switch, 14 ... semiconductor switch.

Claims (6)

[Claims] 1. A recording / reproducing apparatus considering both a case where the system stereo is used as an option and a case where the system stereo is used alone, a connection state detecting means for detecting a connection state with the system stereo, and the connection state A recording / reproducing apparatus, comprising: gain switching means for switching an input gain according to a detection state of a detection means. 2. The connection state detection means includes: switch means for mechanically detecting connection of a control line to the system stereo; and gain control means in response to detection of connection of the control line by the switch means. 2. The recording / reproducing apparatus according to claim 1, further comprising: switching control means for switching to match the output level of the system stereo. 3. A communication partner detection unit for determining whether communication with the system stereo is possible via a control line, and a connection state detection unit responsive to a communication partner detection by the communication partner detection unit. 2. The recording / reproducing apparatus according to claim 1, further comprising: switching control means for switching a gain switching means to match an output level of the system stereo. 4. The attenuating means for setting the input level to a first level when used as an option of the system stereo and a second level when used alone, and the connection state detection. 2. The recording / reproducing apparatus according to claim 1, further comprising: level switching means for switching the attenuation means to the first level in response to detecting the connection with the system stereo. 5. The apparatus according to claim 1, wherein said gain switching means includes an attenuation means having a variable attenuation amount, and an attenuation amount determining means for determining an attenuation amount of said attenuation means based on information from said connection state detecting means. The recording / reproducing apparatus according to claim 1, wherein 6. A recording / reproducing method for a recording / reproducing apparatus that considers both a case where the system stereo is used as an option and a case where the system stereo is used alone, comprising: detecting a connection state with the system stereo; Recording / reproducing is performed by switching an input gain according to the output level of the system stereo when the detection is performed, wherein the recording / reproducing method is performed.