close

Вход

Забыли?

вход по аккаунту

?

DESCRIPTION JPH09102997

код для вставкиСкачать
Patent Translate
Powered by EPO and Google
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 JPH09102997
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an
audio amplification apparatus for amplifying an audio signal.
[0002]
2. Description of the Related Art FIG. 3 is a block diagram of a conventional voice amplifying
apparatus. In the figure, 30 is a microphone for converting an audio signal into an electric signal,
31 is an amplifier for an electric signal, and 32 is a speaker for converting an electric signal into
an audio signal. The operation is described below.
[0003]
The input audio signal is converted into an electric signal by the microphone 30, amplified by the
amplifier 31, and then converted into an audio signal amplified by the speaker 32 again.
[0004]
However, in the system of the prior art described above, since the sound outputted from the
speaker 32 is inputted to the microphone 30, the feedback shown in FIG. 3 when the microphone
30 and the speaker 32 come close to each other. The path forms a positive feedback loop of the
15-04-2019
1
audio signal.
As a result, there is a problem that a howling occurs and the voice amplification function is
degraded.
[0005]
SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present
invention solves the above-mentioned problems by converting an input audio signal into an
electrical signal and then performing an arbitrary cycle provided between the input terminal and
the output terminal. It passes through a phase control circuit that performs phase control. As a
result, by generating a constant or arbitrary phase fluctuation in the phase between the amplified
audio signal and the input audio signal, it is possible to prevent the generation of howling due to
signal feedback between the microphone and the speaker.
[0006]
DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram of an audio
amplification apparatus according to the present invention. In FIG. 1, 1 is a microphone for
converting an audio signal into an electric signal, 2 is an amplifier for an electric signal, 3 is a
speaker for converting an electric signal into an audio signal, and the reference numerals 1, 2, 3
It is the same as 30, 31 and 32 of the code shown in 3). A phase control circuit 4 is shown in FIG.
Reference numeral 5 denotes an input terminal of the phase control circuit 4, and reference
numeral 6 denotes an output terminal, which correspond to reference numerals 20 and 21 in
FIG. An AC oscillator 8 oscillates at a constant frequency (f), and an output signal of the AC
oscillator 8 is connected to a phase control circuit 4 by a terminal 7.
[0007]
In FIG. 2, R is a voltage control variable resistor and C is a capacitor, and the phase difference
between the input 20 and the output 21 is approximately 180 ° under the condition of R ≠ 0.
Here, the condition for the approximation to be established is limited to the case where 2πfWCR
≧ 1 when the voice band is fW. Therefore, when R is varied in the range of r (Ω) where 0 ≦ r ≦
R, the phase difference between the input 20 and the output 21 is varied in the range of 0 degree
15-04-2019
2
to 180 degrees. The terminal 22 of FIG. 2 is connected to the AC oscillator 8 of FIG. 1, and as a
result, the phase difference between the input 5 and the output 6 of the phase control circuit 4 is
varied in the range of 0 degrees and 180 degrees in the cycle of the frequency f. It will be.
However, the phase control circuit shown in FIG. 2 is an example of the embodiment of the
present invention, and the phase control range and the like are not particularly limited as long as
the device can change the phase difference in the range of 0 degree to 180 degrees in the entire
voice band. .
[0008]
According to the configuration of the present invention described above, the audio signal input
by the microphone 1 is varied by the phase control circuit 4 with a period 1 / f within the range
of 0 degrees and 180 degrees, and then amplified by the amplifier 2. Output as an audio signal.
[0009]
As described above, according to the present invention, the input audio signal is amplified with a
period of 1 / f while the phase is varied between 0 degrees and 180 degrees, and output from
the speaker. The probability that the in-phase audio signal is fed back from the speaker to the
microphone is reduced.
[0010]
Therefore, it is possible to prevent the generation of the sounding (howling) caused by the signal
feedback of the microphone and the speaker in the audio amplification device, and it is possible
to realize an excellent audio amplification function.
[0011]
Brief description of the drawings
[0012]
1 is a block diagram of an audio amplification apparatus according to an embodiment of the
present invention
[0013]
2 phase control circuit diagram of the embodiment of the present invention
15-04-2019
3
[0014]
Fig. 3 A block diagram of the conventional audio amplification apparatus
[0015]
Explanation of sign
[0016]
Reference Signs List 1 microphone 2 amplifier 3 speaker 4 phase control circuit 5 input terminal
6, 7 output terminal 8 AC oscillator
15-04-2019
4
Документ
Категория
Без категории
Просмотров
0
Размер файла
10 Кб
Теги
description, jph09102997
1/--страниц
Пожаловаться на содержимое документа