JPH04246905A - Reproducer - Google Patents

Abstract

PURPOSE:To output a reproducing signal corresponding to a signal level set by a user in a state in which an S/N ratio is not deteriorated. CONSTITUTION:A reproducer 20 which converts a digital signal S2 reproduced from a prescribed recording medium 3 through reproducing means 4 and 5, into an analog signal S22 by a digital/analog converting means 7, and adjusts the analog signal S22, to the prescribed signal level by an analog signal level adjusting means 9 and outputs it, is equipped with a digital signal level adjusting means 22 which adjusts the signal level of the digital signal S2 to the prescribed signal level, between the reproducing means 4 and 5, and the digital/analog converting means 7. Then, in a range where the signal level set by the user is larger than the prescribed level, the signal level is adjusted by the digital signal level adjusting means 22 while holding the adjustment level of the analog signal level adjusting means 9 to be the prescribed level.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a playback device, and is suitable for use, for example, in controlling the playback volume of a small rotary head type digital audio tape recorder.

0002

2. Description of the Related Art Conventionally, in this type of rotary head type digital audio tape recorder (DAT), a digitally converted audio signal is modulated into a recording signal by a predetermined recording means, and this is recorded on a magnetic tape. It is made to be.

[0003] Therefore, when reproducing a recorded signal recorded on the magnetic tape, the reproduced signal obtained from the magnetic tape is converted from digital to analog, and then adjusted to a predetermined signal level via an analog volume circuit. After that, this is outputted as an output audio signal.

That is, as shown in FIG. 3, the DAT 1 sends a reproduction signal S1 outputted from the magnetic tape 3 via the magnetic head 4 to the reproduction circuit 5.

[0005] The reproduction circuit 5 demodulates the reproduction signal S1 into a digital audio signal S2, and converts this into an analog audio signal S3 via a digital-to-analog conversion circuit 7.
The signal is sent via the amplifier circuit 8 to, for example, a variable resistance type analog volume circuit 9.

[0006] The analog volume circuit 9 adjusts the analog audio signal S3 to a volume value set by the user, and then amplifies the analog volume circuit output signal S5 in the output amplification circuit 11 to obtain an output audio signal S.
6 is obtained and this is output.

[0007]

However, when the analog audio signal obtained through the digital-to-analog conversion circuit 7 and the amplifier circuit 8 is adjusted to a volume value set by the user in the analog volume circuit 9 and outputted, Noise components generated in the signal processing circuits such as the digital-to-analog converter circuit 7 and the amplifier circuit 8 remain in the output audio signal S5, and when reproducing an audio signal recorded at a particularly low volume level, the analog volume circuit In the case where the set volume value of S5 is increased and the output audio signal S5 is played back, the noise components generated in the signal processing circuits such as the digital-to-analog conversion circuit 7 and the amplifier circuit 8 are amplified together with the audio signal. There was a problem that the S/N ratio deteriorated.

The present invention has been made in consideration of the above points, and it is an object of the present invention to propose a playback device that can prevent deterioration of the S/N ratio of an output audio signal.

[0009]

[Means for Solving the Problems] In order to solve this problem, in the present invention, a digital signal S2 reproduced from a predetermined recording medium 3 via reproduction means 4 and 5 is converted into a digital signal S2 by a digital-to-analog conversion means 7. In the reproducing device 20 which converts the analog signal S3 into an analog signal S3 and then adjusts the analog signal S3 to a predetermined signal level by the analog signal level adjusting means 9 and outputs the same, a A digital signal level adjusting means 22 for adjusting the signal level of the digital signal S2 to a predetermined signal level is provided.

0010

[Operation] In a range where the signal level set by the user is higher than a predetermined level, the digital signal level adjustment means 22 adjusts the signal level while maintaining the adjustment level of the analog signal level adjustment means 9 at a predetermined level. By doing so, it is possible to obtain a reproduced signal without increasing the noise generated in the analog signal processing circuits such as the digital-to-analog conversion means 7 and the analog signal level adjustment means 9.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

In FIG. 1, in which parts corresponding to those in FIG. 3 are denoted by the same reference numerals, a DAT 20 sends a reproduction signal S1 outputted from a magnetic tape 3 via a magnetic head 4 to a reproduction circuit 5, and converts it into a digital audio signal. After demodulating into S2, it is sent to the digital volume circuit 22.

The digital volume circuit 22 has a so-called multiplier configuration with a gain of 1 or more, and changes the volume value of the digital audio signal S2 to a predetermined volume value by changing coefficients based on playback volume data set by the user. After the adjustment, the digital volume circuit output signal S21 is sent to the digital-to-analog conversion circuit 7.
Send to.

The digital-to-analog conversion circuit 7 obtains an analog audio signal S22 by digital-to-analog conversion of the digital volume circuit output signal S21, and sends this to, for example, a variable resistance type analog volume circuit 9.

The analog volume circuit 9 adjusts the volume value (that is, signal level) of the analog audio signal S22 by changing the resistance value based on reproduction volume data set by the user, and outputs the analog volume circuit output signal S23. After being amplified to a predetermined level via the amplifier circuit 11, this is output as an output audio signal S24.

Here, the digital volume circuit 22 and the analog volume circuit 9 adjust the digital audio signal S2 and the analog audio signal S22 to predetermined volumes, respectively, based on volume data set by the user operating the reproduction volume controller 24. It is possible to control the value.

That is, the plus volume key 24A or the minus volume key 2 of the playback volume operator 24
When 4B is turned on, the input control circuit 25 receives this and sends a volume control signal S26 to the subsequent volume control circuit 26 to increase or decrease the volume value.

The volume control circuit 26 sends a digital volume control signal S27 to the digital volume circuit 22 based on the volume control signal S26, and also sends an analog volume control signal S28 to the analog volume circuit 9, thereby controlling the digital volume circuit. 22 and the analog audio signal (S23) obtained through the analog volume circuit 9, the volume value of the analog audio signal (S23) is controlled to the volume value set by the user using the reproduction volume operator 24.

That is, as shown in FIG. 2B, in the digital volume circuit 22, the volume data set by the user (in this embodiment, the minimum volume data corresponding to the minimum volume value is set to level 0, and the maximum volume value The maximum volume data corresponding to level 3
0) is controlled to maintain a predetermined volume value between levels 0 and 24, and is controlled to change in proportion to the volume data set by the user between levels 24 and 30. being done.

On the other hand, in the analog volume circuit 9, the volume data set by the user changes in proportion to the volume data set by the user between level 0 and level 24, as shown in FIG. 2(A). It is controlled to maintain the maximum volume value between levels 24 and 30.

Therefore, for example, when the user turns on the plus volume key 24A of the recording volume controller 24 to continuously increase the set volume value, when the volume data is between level 0 and level 24, the digital volume The set volume value VOL2 of the circuit 22 maintains a predetermined value, and the set volume value VOL1 of the analog volume circuit 9 increases from the minimum volume value to the maximum volume value.

[0022] Also at this time, the volume data is level 2.
4 to level 30, the set volume value VOL2 of the digital volume circuit 22 increases from a predetermined value to the maximum volume value according to the volume data set by the user, and the set volume value of the analog volume circuit 9 increases. VOL1 maintains the maximum volume value.

In this way, the analog volume circuit 9
In the range in which the set volume value changes continuously from the minimum value to the maximum value (that is, the playback volume data set by the user is from level 0 to level 24), the setting in the digital volume circuit 22 The volume value is held at a predetermined value other than 0 level, and the reproduction volume data (level 24
) When the above data is set by the user, the set volume value of the analog volume circuit 9 is maintained at the maximum value while the digital volume circuit 22 is set.
By increasing the set digital volume value, the predetermined volume data (level 24) is changed from 0 level.
Until then, the digital volume circuit output signal S21 output from the digital volume circuit 22
Analog volume circuit 9 with a volume level range of
At the same time, the volume value of the output audio signal is adjusted to the volume value set by the user, and in the volume data range larger than the predetermined volume data (level 24), the set volume value of the digital volume circuit 22 is set by the user. The volume is increased according to the volume data.

In the above configuration, when the DAT 20 attempts to output an audio signal with a volume value greater than or equal to the maximum volume value that can be set by the analog volume circuit 9, the DAT 20 sets the set volume value of the analog volume circuit 9 to the maximum value. By increasing the set volume value of the digital volume circuit 22 while maintaining the same value, the volume variable range of the output audio signal S24 can be expanded, and noise components in the signal processing circuits such as the digital-to-analog conversion circuit 7 and the analog volume circuit 9 can be increased. The output audio signal S24 having the volume value set by the user can be obtained without increasing the volume value.

[0025] Therefore, for example, when trying to play back audio recorded at a low level by increasing the volume,
By increasing the set volume value on the digital volume circuit 22 side, this can be reproduced while avoiding deterioration of the S/N ratio.

Furthermore, the digital volume circuit 22 is constructed with an overflow limiter, so that even if a signal of a large level is suddenly input, this can be clipped at a predetermined value.

According to the above configuration, the digital volume circuit 22 at the front stage and the analog volume circuit 9 at the rear stage
In addition, by separately controlling the reproduction volume values of the digital volume circuit 22 and the analog volume circuit 9 according to the reproduction volume level set by one volume operation, the reproduction volume level set by the user can be controlled separately. In a range where the reproduced volume level is higher than a predetermined volume level, the volume level can be adjusted by the digital volume circuit 22 while maintaining the volume level of the analog volume circuit 9 at the maximum level, and thereby the output audio signal Deterioration of the S/N ratio in S24 can be avoided.

In the above-described embodiment, the case was described in which the set volume values in the digital volume circuit 22 and the analog volume circuit 9 were controlled so that they became values as shown in FIG. 2 in accordance with the user's set volume data. However, the present invention is not limited to this, and the point is that the volume value may be controlled on the digital volume circuit 22 side when the volume value is equal to or greater than predetermined set volume data.

Further, in the above-described embodiment, a case was described in which a variable resistance type was used as the analog volume circuit 9, but the present invention is not limited to this. You may also use it.

Furthermore, in the above-described embodiments, a case has been described in which the present invention is applied to a digital audio tape recorder, but the present invention is not limited to this and can be applied to various digital audio recorders.

Furthermore, in the above-described embodiments, the present invention is applied to a playback device designed to play back audio signals, but the present invention is not limited to this, and can also be applied to playback other signals. It can be widely applied to made playback devices.

[0032]

As described above, according to the present invention, the digital signal level adjustment means is provided at the front stage with the digital to analog conversion means in between, and the analog signal level adjustment means is provided at the rear stage, so that the set playback signal level can be adjusted to a predetermined level. By adjusting the signal level by the digital signal level adjusting means while maintaining the set signal level of the analog signal level adjusting means at a predetermined level in a range larger than the level of , deterioration of the S/N ratio can be prevented. It is possible to realize a playback device that can obtain a playback signal according to the playback signal level set by the user while avoiding the playback signal level set by the user.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a reproducing apparatus according to the present invention.

FIG. 2 is a characteristic curve diagram showing volume control states of an analog volume circuit and a digital volume circuit according to a set volume level.

FIG. 3 is a block diagram showing a conventional playback device.

[Explanation of symbols]

1, 20...DAT, 3...Magnetic tape, 5...Reproduction circuit, 7...Digital-to-analog conversion circuit, 9...Analog volume circuit, 22...Digital volume circuit, 24...Reproduction volume operator, 26 ...Volume control circuit.

Claims (1)

[Claims] Claims: 1. After converting a digital signal reproduced from a predetermined recording medium via a reproducing means into an analog signal by a digital-to-analog converting means, the analog signal is converted to a predetermined level by an analog signal level adjusting means. A playback device for adjusting and outputting a signal level, characterized in that a digital signal level adjustment means for adjusting the signal level of the digital signal to a predetermined signal level is provided between the playback means and the digital-to-analog conversion means. playback device.