KR910003212Y1 - Sub-sonic reduction circuit - Google Patents

Abstract

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Description

Ultra Bass Reduction Circuit

The accompanying drawings are ultra low noise circuit diagrams for the L-channel of a record player according to the present invention.

* Explanation of symbols for main parts of the drawings

1: phono lamp circuit 2: ultra-low filter circuit

3: audio output circuit 4: low pass filter for ultra low sound detection

5: Control signal generating circuit SWl: Analog switch

C _1, R ₁ : capacitors and resistors for ultra-low filtering

The present invention relates to a record player, and more particularly, to an ultra bass removing circuit for removing sub-sonic generated in a mono equalizer circuit for amplifying and reproducing an output signal of a record player.

In a phono equalizer circuit that amplifies and reproduces the output signal of a record player that plays a record record, mechanical vibrations, usually from the record player, affect the original playback sound and cause bad sound to the speaker during playback. In the conventional audio amplifier, the ultra low noise filter is used as a means for removing the low noise. However, since the operation is performed manually, the ultra low noise can be easily removed unless the user always pays attention. There was a problem that could not be.

Accordingly, an object of the present invention is to provide an ultra low noise removing circuit capable of listening to clear sound quality by automatically removing ultra low noise generated in a phono equalizer circuit in view of such circumstances.

The present invention for achieving this purpose will be described in detail with reference to the accompanying drawings.

1 is a schematic diagram of an ultra-low bass circuit according to the present invention, the present invention is a phono equalizer circuit (1) for receiving and amplifying a reproduction signal from a record player, and the ultra-bass output from the phono equalizer circuit (1) A first filter comprising a capacitor (1) for filtering and a resistor (R ₁ ) connected in parallel thereto, a filter ( ₂ ) consisting of resistors (R ₂ , R ₃ ) and a capacitor (C ₂ ) connected in series with the first filter; Bypass the output of the phono equalizer circuit (1) in the case of a third filter comprising a capacitor (C ₃ ) and a resistor (R ₄ ) connected in series to the filter and the first filter described above, and there is no ultra low sound. And an ultra low noise removing circuit of a record player having an ultra low filtering circuit (2) having an analog switch (SW ₁ ) for providing to the audio output circuit (3) through a second filter and a third filter. I added them.

That is, the low pass filter circuit 4 for detecting ultra low sound and the low pass filter circuit 4 for detecting ultra low sound when the ultra low sound occurs in the phono equalizer circuit 1 described above. Detects the AC signal level of ultra low noise, rectifies the above AC signal into DC voltage, compares the rectified DC voltage signal with the reference voltage, outputs a high state signal when there is ultra low sound, A control signal for operating the analog switch SW1 is generated by operating the signal of the state so that the ultra low sound is filtered by the first filter composed of the capacitor C ₁ and the resistor R ₁ . And a control signal generation circuit 5 for visually displaying the bass sound generation.

According to the present invention. Ultra-low noise detection low pass filter circuit (4) is composed of a resistor (R _{5 ~} R ₈ ), condensers (C _{4 ~} C ₆ ) and amplifier (OP ₁ ) to detect and control the ultra-low signal of 20HZ or less The signal generation circuit 5 includes an amplifier OP ₂ for detecting and amplifying the AC signal level of the ultra low sound output from the low pass filter circuit 4 for ultra low sound detection, and resistors R ₉ and VR ₁ . A non-inverting amplifier unit, a half-wave rectifying unit comprising a resistor (R ₁₀ ), a (R ₁₁ ) diode (D ₁ ), and a capacitor (c ₇ ) to convert the amplified ultra-low AC signal into a DC voltage, a half-wave of the rectified voltage signal, a resistance (R ₁₀₎ and compared with the reference voltage set by a diode (D ₂₎ if there are ultra-quiet comparator for outputting a signal of a high state (OP ₃₎ and the comparator (OP ₃₎ are turned on by an output signal as an input in the transfection for providing a control signal to a control terminal (C) of the analog switch (SW ₁₎ of the Consists of a requester (Q ₁₎ and, batgwang diode (LED) for visually warning when a second generation low turn-on of the transistor (Q _1).

In FIG. 1, only one of the right channel and the left channel is illustrated, and the remaining channels have the same configuration, which is omitted for simplicity of the specification and the drawings.

First, the output of the phono equalizer circuit 1, which receives and amplifies a reproduction signal from a record player (not shown), is input to the audio output circuit section 3 via an ultra bass filter circuit 2. The function of the bass filter circuit 2 is switched by an analog switch SW ₁ . Here, the control input terminal C of the analog switch SW ₁ performs an active low operation. When the control input terminal C is low, the output of the phono equalizer circuit 1 is a resistor ( R ₁₎ and via a capacitor (C ₁₎ switch (SW _1), without going through a resistance (R _2, R ₃₎ a condenser (C _2, C ₃₎ and via a resistor (R ₄₎ is provided to the audio output circuit .

However, when the control input terminal C of the analog switch SW ₁ is high, the switch SW ₁ is turned off so that the output signal of the phono equalizer circuit 1 is the resistor R ₁ and the capacitor C ₁ . By outputting through, it is possible to perform a role as an ultra low filter 2 having a frequency determined by the capacitors C ₁ -C ₃ and the resistors R ₁ -R ₄ . Therefore, the bass can be removed by directly adjusting the control input C provided to the analog switch SW ₁ , which will be described in detail.

A part of the phono equalizer circuit 1 is provided to the ultra low pass filter circuit 2, and the other part is composed of a resistor R ₅ to R ₈ , a capacitor C _{4 to} C ₆ , and an amplifier OP ₁ . The low-pass filter circuit 4 for ultra low noise detection is provided, and the frequency output from the low-pass filter circuit 4 is determined by the resistors R ₅ to R ₈ and the capacitors C _{4 to} C ₆ . 20HZ.

The 20HZ frequency signal generated in this way, that is, the ultra low frequency signal, is applied to the non-inverting input terminal of the amplifier OP ₂ in the control signal generating circuit 5 and amplified. The gain of the amplifier OP ₂ is a variable resistor VR _1. Can be varied by The AC ultra low signal output to the amplifier OP ₂ is rectified as a DC component through the diode D ₁ , the capacitor C ₇ , and the resistor R ₁₁ constituting the half-wave rectification via the resistor R ₁₀ . And the non-inverting input terminal of the comparator OP ₃ .

The inverting input terminal of the comparator (OP _3), the diode (D ₂₎ and the input voltage is the reference voltage of the resistor (R ₁₆₎ a comparator (OP ₃₎ due to the bar, if the generation of the second bass in that the reference voltage is set by When larger, the comparator OP ₃ outputs a high state signal to turn on the transistor Q ₁ through the resistor R ₁₂ .

Transistor (Q ₁₎ that when the turn-on voltage (B ⁺⁾ through the resistor (R ₁₃₎ is the collector of the transistor (Q ₁₎ - by way of the emitter to cause the bias voltage due to the resistor (R ₁₁₎ light emitting diode ( LED) lights up to visually indicate that ultra low sound is being generated.

At the same time, a high-state signal is applied to the control input terminal c of the analog switch SW ₁ due to the turn-on operation of the transistor Q ₁ , but the analog switch SW ₁ is turned off, so that the phono equalizer circuit 1 Is generated by the capacitor C ₁ and the resistor R ₁ so that the audio output circuit 3 can be provided with only a pure record signal having no ultra bass.

On the other hand, when the signal output from the phono equalizer circuit (1) does not contain an ultra-low component, there is no signal from the amplifier OP ₂ because there is no ultra-low signal from the low pass filter circuit (4), Accordingly, the comparator OP ₃ outputs a low state signal. As the comparator OP ₃ outputs a low signal, the transistor Q ₁ is turned off, the light emitting diode LED is not turned on, and a low signal is applied to the control input terminal of the analog switch SW ₁ .

At this time, the analog signal SW ₁ is operated and the record signal output from the phono equalizer circuit ₁ is bypassed to the switch SW ₁ without passing through the condenser C ₁ and the resistor R ₁ . 3) can be provided.

As described above, the operation of the ultra low noise filter circuit for removing ultra low noise has been manually switched, so that it is very inconvenient for a user to use. However, the ultra low noise elimination circuit of the present invention automatically switches the operation of the ultra low noise filter circuit. It has a feature that can provide convenience to the user.

Claims (2)

Phono equalizer circuit (1) for receiving and amplifying a reproduction signal from a record player, a capacitor (C ₁ ) for filtering ultra low sound output from the phono equalizer circuit (1), and a resistor (R) connected in parallel thereto. ₁ ) a first filter, a second filter consisting of resistors R _{2 and} R ₃ connected in series with the first filter and a capacitor C ₂ , a capacitor C ₃ connected in series with the second filter, and a resistor (R _A ) is connected in parallel with the first filter and the first filter and operate according to a predetermined control signal, and when ultra low noise is generated, ultra low noise is filtered by the first filter and there is no ultra low noise. In the case of an ultra low pass filter circuit 2 having an analog switch SW ₁ for bypassing the output of the phono equalizer circuit 1 and providing it to the audio output circuit 3 via the second and third filters. In the super bass cancellation circuit of a record player having: Ultra low bass detection low pass filter circuit 4 for detecting the low bass sound and ultra low bass detection low pass filter circuit 4 for detecting the low AC signal is rectified to DC voltage, compared with the reference DC voltage signal, and if there is an ultra low sound, it outputs a high state signal and operates by the high state signal according to the above ultra low sound. A control signal for generating a control signal for operating (SW ₁ ) so that the ultra low sound is filtered by the first filter including the capacitor C ₁ and the resistor R ₁ , and a control signal for visually displaying the ultra low sound generation. Ultra-low noise removing circuit, characterized in that consisting of a generator circuit (5). 2. The control signal generating circuit (5) according to claim 1, wherein the control signal generating circuit (5) comprises: an amplifier (OP ₂ ) for detecting and amplifying the level of the ultra low AC signal output from the low pass filter circuit (4) for detecting the ultra low sound; A non-inverting amplifier consisting of resistors R ₉ and VR ₁ , and resistors R ₁₀ , R ₁₁ diodes D ₁ , and capacitors C to convert the amplified ultra-low AC signals into DC voltages. ₇ ) a comparator (OP) for outputting a high state signal when there is an ultra low noise by comparing the half-wave rectified part and the half-wave rectified voltage signal with the reference voltage set by the resistor (R ₁₆ ) and the diode (D ₂ ). ₃ ) and a transistor Q ₁ for turning on the input signal output from the comparator OP ₃ to provide a control signal to the control terminal C of the analog switch SW ₁ ; With a light emitting diode (LED) for visually alarming the occurrence of ultra low sound when the transistor Q ₁ is turned on. Ultra low noise removing circuit, characterized in that configured.