JPH01175500A - Image expanding circuit - Google Patents

Abstract

PURPOSE:To expand an image at a whole frequency band regardless of the more or less of the same phase component of a right and left input signal by adding a pseudo reverberation signal generated by a non-limit delaying loop and a low pass filter to an original signal and a right left difference signal. CONSTITUTION:The branch signal of the input original signal of a right and left channel is made into a reverse phase by phase inverters 1 and 11 and the difference signal of (L-R) and (R-L) is generated by adders 2 and 12. On the other hand, one more branching signal of the input original signal of a right and left channel is inputted to a non-limit delaying loop composed of delaying circuits 4 and 14, variable resistors 5 and 15 and adders 6 and 16, a pseudo reverberation signal is outputted, the difference in (L-R) or (R-L) through variable resistors 3 and 13 is added by adders 8 and 18, after the signal passes through variable resistors 9 and 19 and thereafter, the signal is added respectively to right and left input original signals by adders 10 and 20 and the right and left output signals are generated. Thus, the image can be expanded at the whole frequency band regardless of the more or less of the same phase component of the right and left input signals.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a tone magnification circuit for magnifying a sound image in music reproduction in a small or medium-sized space.

Conventional technology Figure 2 shows a conventional sound image enlarging circuit (published utility model 1986-
146097). 22nd ・＼−
7 In figure 22. Reference numeral 23 denotes left and right speakers, the ten terminals of which are respectively connected to the ten terminals of the speaker terminal 21 of the amplifier. Left and right speakers 22. 23 are commonly connected, and are connected to one terminal of the speaker terminal 21 of the amplifier via a circuit 24 having frequency characteristics. As shown in FIG. 3, the circuit 24 has a configuration in which a resistor R2 is connected in series to a parallel circuit of an inductance L and a resistor R.

Next, the operation of the above embodiment will be explained. In Figures 2 and 3, the left and right input original signals are from speaker terminal 2 of the amplifier.
1, the signal is sent from the ten terminals to the left and right speakers, and from the one terminal to the circuit 24. In the circuit 24, the output level up to the treble range is set by the resistor R1, and the output level is set to the same level by the resistor R2 (L-Ft).

The (RL) component is enhanced.

In addition, because the impedance in the bass range is lowered by the inductance L even if the left and right signals are in phase, the left channel output other than the (L-R) and (R-L) components set by the resistor R2 will be output from the right channel.゛ is not output, and similarly, the right channel output is 3.\-7 and the left channel is not output.

Furthermore, in the high frequency range, the impedance of the inductance L becomes narrower, and the outputs from the left and right speakers become (L-R) and (R-L) signals, respectively, giving a sense of spaciousness.

In this way, even with the conventional sound image expansion circuit described above, the effect of tone expansion can be obtained when there are few in-phase components in the left and right input signals or in the high frequency range.

Problems to be Solved by the Invention However, in the conventional sound image enlarging circuit described above, the sense of expansion is given only by the left and right difference signals, so when there are many in-phase components in the left and right input signals, or in the low frequency range, the sound image enlarging effect cannot be achieved. The problem was that it became smaller. The present invention solves these conventional problems, and aims to provide an excellent sound image enlarging circuit capable of enlarging a sound image in all frequency bands, regardless of the amount of in-phase components of left and right input signals. This is the purpose.

Means for Solving the Problems In order to achieve the above object, the present invention includes, in addition to an adder for left and right difference signals, an infinite delay loop for creating a pseudo-reverberation signal and a low-pass filter. .

Therefore, according to the present invention, by adding the pseudo-reverberation signal created by the infinite delay loop and the low-pass filter to the original signal and the left-right difference signal, the signal can be reverberated regardless of the amount of in-phase components of the left and right input signals. , it has the effect that it is possible to expand the sound image in all frequency bands.

Example FIG. 1 shows the configuration of an embodiment of the present invention.

In FIG. 1, 1 and 11 are phase inverters, respectively.
The adders 2 and 12 perform addition with original signals of other channels, and are connected to variable resistors 3 and 13. 4.1
4 is a delay circuit, which includes variable resistors 5, 15 and an adder 6.
, 16 constitute an infinite delay loop. 7,17
is a low-pass filter that cuts off the high frequency range of the output of the infinite delay loop, and is connected to variable resistors 3. through adders 8 and 18.
] Connected with 3 and 5 \.

It is. Variable resistors 9 and 19 are connected to adders 10 and 20.

Next, the operation of the above embodiment will be explained. In the above embodiment, the branch signals of the input original signals of the left and right channels have opposite phases in the phase inverters 1 and 11, and the difference signals of (L-R) and (R-L) are created by the adders 2 and 12. .

On the other hand, another branch signal of the input original signal of the left and right channels is input to an infinite delay loop composed of delay circuits 4, 14, variable resistors 5, 15, and adders 6, 16, and a pseudo reverberation signal is generated. Output. The pseudo-reverberation signal passes through a low-pass filter 7.17, and the high frequency range is cut off. To this signal, adders 8 and 18 add the (L-R) or (R-L) difference signal that has passed through variable resistors 3 and 13, and after passing through variable resistors 9 and 19, the adder 10.20, the left and right input original signals are added to each other to create left and right output signals.

In this way, according to the above embodiment, the left and right input original signals are
In addition to the difference signals of (L-4%) and (R, -L) created using phase inverters 1 and 11, delays 6 and -7 circuits 4 and 14, variable resistors 5 and 15, and adders 9, 1
By adding the pseudo-reverberation signal created by the infinite delay loop configured by 9, the sound image can be enlarged in the entire frequency band, regardless of the in-phase components of the left and right input signals.

Effects of the Invention As is clear from the above embodiments, the present invention combines the difference signals of (L-R) and (R-4,) created from the left and right input original signals and the pseudo-reverberation signal created from an infinite delay loop into left and right signals. This is added to the input original signal, and has the effect of enlarging the sound image in all frequency bands, regardless of the amount of in-phase components of the left and right input original signals.

[Brief explanation of the drawing]

FIG. 1 is a schematic block diagram of a sound image enlarging circuit according to an embodiment of the present invention, FIG. 2 is a schematic block diagram of a conventional sound image enlarging circuit, and FIG. 3 is a detailed diagram of the circuit 24 in FIG. 2. 1.11...Phase inverter, 4.14-Delay circuit, 7,1
7.Low pass filter, 3.5.9.13.1.5.1
9-Variable resistor, 2.6.8, 10.12.16.18
．． 20 Adder.

Claims (1)

[Claims] The left and right channel input signals are input to an infinite delay loop composed of a delay circuit and a variable resistor, and the output is passed through a low-pass filter to create left and right pseudo-reverberation signals. The (L-R) difference signal obtained by the phase inverter and adder is added to the right channel, and the (R-L) difference signal is added to the right channel by the adder, which is then added to the left and right original signals by the adder, respectively. A sound image enlargement circuit that outputs in addition to.