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JPH0549091

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Notice
This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or
financial decisions, should not be based on machine-translation output.
DESCRIPTION JPH0549091
[0001]
The present invention will be described in the following order. Industrial application field
Conventional technology (FIG. 4) Problem to be solved by the invention (FIG. 5) Means for
solving the problem (FIG. 1) (1) Configuration of the embodiment (FIG. 1 to 3) (2) ) Operation of
the embodiment (3) Effects of the embodiment (4) Other embodiments
[0002]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
reproduction apparatus and can be applied to, for example, a portable tape recorder.
[0003]
2. Description of the Related Art Conventionally, among portable tape recorders, there are some
which are made to enjoy music personally using earphones.
[0004]
In such a tape recorder, as shown in FIG. 4, the sound leakage from the earphone is prevented by
suppressing the high sound.
[0005]
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1
However, as shown in FIG. 4, when only the high-pitched sound is suppressed, the sound quality
deterioration can not be avoided, and there is a problem that the music and the like become hard
to hear.
In addition, if the volume is raised too much, there is a problem that the part of the sound is
leaked.
[0006]
As one method of solving this problem, as shown in FIG. 5, a method of detecting a volume and
suppressing a large volume part is also conceivable.
However, even in this case, the sound leakage can not be completely prevented, and there has
been a problem that the sound leakage can not be avoided if the volume is increased on the main
body side.
[0007]
The present invention has been made in consideration of the above points, and an object of the
present invention is to propose a reproduction apparatus capable of preventing sound
deterioration and effectively avoiding sound leakage.
[0008]
SUMMARY OF THE INVENTION In order to solve the problems, in the present invention,
amplification circuits 12, 14, 16, 18, 20, 22, 24, which amplify a reproduction signal output from
a predetermined recording medium 6, are provided. 26 and a signal for detecting the signal level
of medium to high sound for the earphones 28 and 30 reproducing the output signals of the
amplification circuits 12, 14, 16, 18, 20, 22, 24 and 26 and the earphones 28 and 30 Level
detection circuits 32, 34, 36, 38, 40, 42, 43, 44, 46, 50, 52, 54, 58 and signal level detection
circuits 32, 34, 36, 38, 40, 42, 43, 44, Gain control circuits 56, 60, 62, 64, 66 that control the
gains of the amplifier circuits 12, 14, 16, 18, 20, 22, 24, 26 based on the detection results of the
circuits 46, 50, 52, 54, 58. And For example, when the treble of the volume in the input signal is
greater, to suppress the signal level of the input signal.
[0009]
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[Function] With regard to the input signals of the earphones 28, 30, the signal level of medium to
high tone is detected, and when the volume of the medium to high tone is large based on the
detection result, the sound level deterioration is effectively avoided by suppressing the signal
level. Sound leakage can be prevented.
[0010]
An embodiment of the present invention will be described in detail with reference to the
drawings.
[0011]
(1) Configuration of Embodiment In FIG. 1, reference numeral 1 generally indicates a tape
recorder, and operates the controller 4 connected to the tape recorder main body 2 to switch the
operation of the tape recorder 1.
[0012]
That is, in the tape recorder main body 2, the magnetic tape 6 is caused to travel at a
predetermined speed, and the audio signal recorded on the magnetic tape 6 is reproduced.
For this reason, in the tape recorder main body 2, after reproducing signals output from the
magnetic heads 8 and 10 are amplified by the preamplification circuits 12 and 14, they are
output to the amplification circuits 20 and 22 through volume adjustment volumes 16 and 18,
respectively. Here, it is amplified by a predetermined gain and output to the controller 4.
[0013]
The controller 4 outputs the output signals of the amplifier circuits 20 and 22 to the stereotype
earphones 28 and 30 via the sub-volume adjustment volumes 24 and 26.
As a result, in the tape recorder 1, the volume adjustment volumes 16 and 18 are adjusted to
enjoy music and the like at a desired volume, and if necessary, the volume adjustment volumes
24 and 26 of the controller 4 are added. It is designed to be able to easily adjust the volume by
operating.
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[0014]
Further, in the controller 4, after the input signals of the earphones 28 and 30 are added through
the resistors 32 and 34, the signals are output to the contact a of the slide switch 36.
Here, the slide switch 36 is configured to switch the contacts in three steps by sliding the
operation element, and connects the contacts a and b with a resistor 38, and connects the
contacts c and d, and the contact e It is designed to be grounded.
[0015]
By this, the slide switch 36 outputs the output signal of the contact c to the tape recorder main
body 1 to hold the signal level of the output signal at the 0 level in a state where the contacts c
and e are shorted, but the contact b And d are fed back through the resistors 32, 34, 38 to feed
back the input signals of the earphones 28 and 30, respectively.
[0016]
Furthermore, the slide switch 36 feeds back the input signals of the earphones 28 and 30 to the
tape recorder body 2 via the resistors 32 and 34 with the contacts a and c shorted.
Thereby, in the tape recorder 1, the signal level of the input signals of the earphones 28 and 30
can be detected directly, and the slide switch 36 can be operated to switch the detection level.
[0017]
In the tape recorder body 2, the output signal of the slide switch 36 is output to the transistor 42
via the capacitor 40 to suppress and input the low frequency band.
Here, the transistor 42 is constituted by an emitter grounding circuit having an emitter resistor
43, and the collector and the base are connected by the resistor 44, and the power supply VCC is
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4
supplied through the collector resistor 46.
[0018]
On the other hand, the transistor 50 suppresses the low band through the capacitor 52 to receive
the collector output of the transistor 42, and the diode 54 connected between the base emitters
performs double wave rectification of the collector output.
Thereby, in the transistor 50, the signal level of the input signals of the earphones 28 and 30 is
detected centering on the middle high region.
[0019]
The transistor 56 inputs the collector output of the transistor 50 to the base, and the base is
grounded by the capacitor 58.
Further, the transistor 56 is connected to ground the emitter and to connect the collectors to the
transistors 64 and 66 via the resistors 60 and 62.
[0020]
Here, the transistors 64 and 66 are connected to the volume control volumes 16 and 18 so that
the signal levels of the output signals of the volume control volumes 16 and 18 can be varied in
response to changes in the base voltage. ing. Thus, in the tape recorder 1, when the contacts c
and e are selected by the slide switch 36, the earphones 28 and 30 are driven at signal levels
determined by the volume adjustment volumes 16 and 18 and the secondary volume adjustment
volumes 24 and 26. It is made to be done.
[0021]
On the other hand, when the contacts b and e are selected by the slide switch 36, the input
signals of the earphones 28 and 30 are fed back by the feedback amount determined by the
resistors 32, 34 and 38, and the transistors 64 and 66 By being controlled, the volume of the
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earphones 28 and 30 is suppressed according to the volume of the middle and high range of the
reproduction signal.
[0022]
Furthermore, when the contacts a and c are selected by the slide switch 36, in this case, the input
signals of the earphones 28 and 30 are fed back by the feedback amount determined by the
resistors 32 and 34 compared to when the contacts b and e are selected. Thus, the volume of the
earphones 28 and 30 is further suppressed.
[0023]
As a result, in the tape recorder 1, the contact of the slide switch 36 can be selected to effectively
avoid the sound leakage of the earphones 28 and 30.
[0024]
At this time, in the embodiment, by directly detecting the signal level of the input signals of the
earphones 28 and 30, the volume suppression operation can be maintained even when the
volumes 16 and 18 on the main body 1 side are operated, Sound leakage can be reliably
prevented.
Further, with the prevention of sound leakage, the occurrence of hearing loss and the like can be
effectively avoided.
[0025]
Further, at this time, by controlling the transistors 64 and 66, the sound volume can be
suppressed without deteriorating the frequency characteristic of the reproduction signal, and the
sound quality deterioration of the tape recorder 1 can be effectively avoided.
[0026]
At this time, by detecting the signal level of middle to high tone and suppressing the volume of
the input signals of the earphones 28 and 30 at this time, even if the bass is emphasized and
reproduced, the volume is reliably suppressed only when necessary. The usability of the tape
recorder 1 can be improved accordingly.
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[0027]
As shown in FIG. 2 and FIG. 3, according to the experiment, even when the volume was reduced
by operating the slide switch 36, it was confirmed that the sound volume deterioration could be
effectively avoided and the volume reduced. .
[0028]
Furthermore, in this embodiment, by providing the slide switch 36 for volume suppression in the
controller 4, the switch operation can be performed easily at hand as required, and the usability
of the tape recorder 1 can be improved accordingly.
[0029]
Further, in the tape recorder main body 1, the output signal of the slide switch 36 is applied to
the transistor 72 through the resistor 70 and the capacitor 71, whereby switching information of
the slide switch 36 is output to the control circuit 74 through the transistor 72.
[0030]
The control circuit 74 switches and controls the operation of the entire tape recorder 1 in
response to the operation of an operation element (not shown) such as reproduction, and is
provided in the controller 4 based on switching information of the slide switch 36. The liquid
crystal display unit 75 is driven.
As a result, in the tape recorder 1, the state of the volume reduction operation can be visually
checked via the controller 4, and the usability of the tape recorder 1 can be improved.
[0031]
(2) Operation of the embodiment In the above configuration, the reproduction signals output
from the magnetic heads 8 and 10 are adjusted to the predetermined volume by the volume
adjustment volumes 16 and 18 through the amplification circuits 12 and 14, respectively. The
signal is output to the earphones 28 and 30 via the amplification circuits 20 and 22 and the
auxiliary volume adjustment volumes 24 and 26.
[0032]
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At this time, the input signal of the earphones 28 and 30 is output to the transistor 42 through
the resistors 32 and 34 and the slide switch 36, and after the low band is suppressed here, both
waves are rectified by the diode 54 to The signal level of middle to high tone is detected via
[0033]
The signal level detection result is output to the transistors 64 and 66 through the transistor 56,
whereby the volume of the reproduction signal is suppressed.
[0034]
(3) Effects of the Embodiment According to the above configuration, the signal level of middle to
high tone is directly detected for the input signals of the earphones 28 and 30, and the signal
level of the input signal is suppressed based on the detection result. The sound quality
deterioration can be effectively avoided to suppress the volume reliably.
[0035]
(4) Other Embodiments In the above embodiment, the present invention is applied to a tape
recorder provided with a controller, but the present invention is not limited to this, and the
volume etc. is adjusted only on the main body side. It can be widely applied to tape recorders
designed to be obtained.
[0036]
Furthermore, in the above-described embodiment, the case of simply suppressing the signal level
has been described, but the present invention is not limited to this and the frequency
characteristic may be corrected together.
[0037]
Furthermore, in the above-mentioned embodiment, although the case where the present
invention was applied to a tape recorder was described, the present invention is not limited to a
tape recorder, but can be widely applied to a reproduction apparatus designed to listen to by
earphone.
[0038]
As described above, according to the present invention, the signal level of medium to high tone is
directly detected for the input signal of the earphone, and the sound quality deterioration is
effectively performed by suppressing the signal level based on the detection result. It is possible
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to obtain a playback device that can avoid and prevent sound leakage.
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