KR100261444B1 - Noise eliminating circuit of color picture tube - Google Patents

Abstract

PURPOSE: An apparatus for removing a spurious electric field noise of the front of a Braun tube is provided to effectively cut off a spurious electric field noise of the front of a Braun tube by sensing the spurious electric field noise from a Braun tube band, and by providing a noise waveform inversed and amplified to a lead wire of the front of the Braun tube. CONSTITUTION: A horizontal pulse generation unit(11) generates a horizontal pulse according to a horizontal driving signal. A high-voltage generation unit(12) generates a high voltage according to the pulse generated from the horizontal pulse generation unit(11) and provides the voltage to an anode of a Braun tube(13). An inversion amplification unit(14) applies a subordinate pulse to a lead wire of the front of the Braun tube(13).

Description

Unnecessary radiation field noise removing device in front of CRT

The present invention senses and amplifies the full-length radiation noise induced on the CRT surface in order to remove the full-length radiation noise induced on the CRT surface during normal operation so as to feed back to the front of the CRT tube to remove or offset unnecessary radiation field noise. will be.

Referring to FIG. 1, a configuration of a circuit for eliminating unnecessary radiated electric field noise of a conventional CRT front surface is as follows.

First, the horizontal pulse generator 1 receives a horizontal drive drive signal and outputs the horizontal pulse to the high voltage generator 2, and the horizontal pulse generated by the horizontal pulse generator 1 is boosted to the secondary side. High-pressure generating unit (FBT) 2 for supplying the high pressure to the added gap of the CRT and resistors for dividing the polarized deflection output waveform induced in the high-pressure generating unit 2 to adjust the level (R1, R2) and a resistor (R3) and capacitor (C2) for waveform correction of the polarized deflection output waveform divided to be level adjusted by the resistors (R1, R2), and the resistor (R3) and capacitor (C2). The resistor R4 and the capacitor C3 for removing the spike-like noise of the reverse polarity deflection output waveform corrected by the waveform, and the resistance R1 being wound around the CPT by one turn (1Turn) in a closed loop. ) And polarized deflection output waveform with spike noise removed by capacitor (C2) To only the constant voltage applied to the CPT consists of a wire (L1) to remove the unnecessary radiation wave on the CPT,

The horizontal pulse generator 1 includes a deflection coil DY for generating a deflection output waveform, a capacitor C11 for charging and discharging a deflection output waveform generated in the deflection coil DY, and a deflection coil DY. And transistor Q1 that performs on / off switching operation according to the deflection output waveform generated by the "

Reference numeral D1 denotes a diode and C4 denotes a capacitor.

Referring to FIG. 1, the operation of the unnecessary radiation removing circuit in the present invention CPT configured as described above is as follows.

First, when the power supply is applied to the primary side of the flyback transformer FBT of the high voltage generator 2, the horizontal transistor Q1 connected to the primary side of the flyback transformer performs on / off switching operation. ,

According to the on / off switching operation of the transistor Q1, the deflection output waveform is generated in the deflection coil DY to which the diode D1 and the capacitor C4 are connected.

In addition, the deflection output waveform generated by the deflection coil DY is charged and discharged by the capacitor C1 and is induced on the primary side of the flyback transformer according to the on / off switching operation of the transistor Q1. The high pressure induced on the secondary side of the flyback transformer is applied to the anode gap of the CRT 3.

The deflection output waveform Va of the reverse polarity (negative pulse) induced on the secondary side is shown in Equation 1,

[Equation 1]

B⁺

부펄스

B ⁺

Bupulse

As described above, the voltage is adjusted while being divided by a constant voltage (B ⁺ ) and the resistor (R1) (R2),

The reverse polarity deflection output waveform divided by the resistors R1 and R2 and level-adjusted is waveform-corrected by the resistor R3 and the capacitor C2.

Here, the pulse and amplitude of the deflection output waveform and the direct current (DC) level can be adjusted according to the actual values of the resistors R1 and R2.

Accordingly, the reverse polarity deflection output waveform corrected by the resistor R3 and the capacitor C2 passes through the resistor R4 and the capacitor C3, and the waveforms are generated by the resistor R4 and the capacitor C3. The spiked noise of the corrected reverse polarized deflection output waveform is removed.

At this time, the wire L1 wound on the CPT phase (e.g., the front part or the rear part) by one rotation (1Turn) in a non-circulating state is one of the reverse polarized deflection output waveforms in which the spike noise is removed. By applying only a constant voltage to the CPT phase (eg, the front or rear) without applying a component of the current, the unwanted radiation wave generated in the CPT phase (eg, the front or the rear) is removed.

Conventionally, there is a problem in that it is not possible to completely block unnecessary radiation field noise generated in the front side of the CRT while blocking the unnecessary radiation field noise applied without providing a means for detecting unnecessary radiation field noise induced on the front surface of the CRT.

The present invention is connected to sense the band around the front of the front of the tube to detect unnecessary radiation generated on the front surface of the CRT, so as to generate and apply a waveform having the same amplitude and opposite phase as the unnecessary radiation of the front of the CRT, The circuit is configured to effectively block unwanted radiation.

1 is a view showing an unnecessary radiation field noise removing circuit of a conventional CRT front part

Figure 2 is a circuit diagram showing an unwanted radiation field noise removing device of the present invention CRT

Figure 3 is the output waveform diagram of each part of the unnecessary radiation field noise removing device of the present invention CRT

The configuration of the apparatus for eliminating unnecessary radiation field noise in front of the CRT of the present invention will be described with reference to FIG. 2.

High voltage generation to generate a high pressure by the horizontal pulse generator 11 for generating a horizontal pulse by the horizontal drive drive signal and the pulse generated by the horizontal pulse generator 11 to supply to the anode of the CRT 13 A negative (FBT) 12 and the inverted amplification part 14 which is connected to the vicinity of the front part band (CDT BAND) of the CRT 13 and applies a negative pulse to the lead wire L11 of the CRT 13 front part. Is composed,

The inverting amplifier 14 allows the unwanted radiated field noise waveform detected around the CRT band to be input through the capacitor C11 and the resistor R11, and includes the resistors R13 and R12 and the power supply voltage. It consists of Vcc1) and transistor (Q12) to sense only AC component to stabilize the bias, and it is composed of power supply voltage (Vcc2), resistor (R15) (R14), capacitor (C12) and transistor (Q13) to operate as an amplifier circuit. The inverted waveform of the amplified unnecessary radiation field noise composed of the diode D11, the resistors R16 (R17) and the transistors Q14 (Q15) is applied to the lead wire L11.

Reference numeral C13 denotes a capacitor and D12 denotes a diode.

Referring to Figures 2 and 3 with respect to the action of the unnecessary radiation field noise removing circuit of the present invention, the front tube C tube configured as described above are as follows.

The horizontal transistor Q11 of the horizontal pulse generator 11 is driven to be switched on / off through the capacitor C13 and the diode D12 by the horizontal drive driving signal, and the high voltage generator is switched on by the on / off switching. A horizontal pulse as shown in FIG. 3A is applied to (12).

The high pressure generator 12 boosts the applied horizontal pulse to apply a high pressure (about 25 KV, V1 is several tens to several hundred V) as shown in FIG. 3B to the anode gap of the CRT.

At this time, the applied high pressure is a constant high voltage is always supplied when the capacity value of the internal high-pressure capacitor (C _HV ) of the flyback transformer of the high-pressure generator 12 is infinite, but the capacity value of the actual capacitor (C _HV ) is 3000PF or 4500PF The high pressure containing the high pressure ripple voltage as shown in FIG. 3B is supplied to the CRT 13.

In the waveform, undesired radiated field noise of several hundred mw to several V (V2) as shown in FIG. 3C is generated on the surface of the CRT by the internal capacitor and the internal resistance of the CRT.

At this time, the unwanted radiated field noise on the surface of the CRT 13 is sensed by the inverted amplifier 14 from the vicinity of the CRT band, and the sensed unwanted radiated field noise waveform is the condenser of the inverted amplifier 14. When input through C11) and resistor R11, only the AC component of the radiated field noise waveform generated by the power supply voltage Vcc1, resistor R13 (R14), and transistor Q12 which is composed of a buffer circuit to stabilize the bias is provided. Sense to stabilize the bias.

Then, the power supply voltage Vcc2 connected to the collector of the transistor Q13 is applied through the resistor R15, and the transistor Q13 is connected by the capacitor C12 and the resistor R14 connected to the emitter of the transistor 12. Switching amplification. The amplification degree (several times several hundred times) at this time is determined by the resistor R15 and the resistor R14.

When the amplified waveform is applied to the base of the transistor Q15 through the transistor Q14 and the diode D11, the lead wire L11 positioned between the bracket 13 and the bracket connected to the resistors R16 and R17. The inverted waveform of the unwanted radiated field noise amplified by the waveform is supplied as a waveform (V3 is several tens to hundreds of volts) as shown in FIG.

The unnecessary radiation field noise sensed as described above is inverted and amplified by several tens to several hundred times, and then supplied to the lead wire L11 of the front side of the CRT 13 to suppress or cancel the unnecessary radiation field noise.

As described above, the unwanted radiated field noise of the CRT surface is sensed from the CRT band and inverted and amplified by several tens or hundreds of times to supply the lead wire of the CRT front face so as to effectively block the unnecessary radiated field noise of the CRT front face.

Claims (2)

Switching operation is performed in accordance with the horizontal pulse applied to generate a high pressure, connected to the high-pressure generating unit (FBT) 12 supplied to the anode of the CPT (13) and the front band (CPT BAND) around the CPT (13) Detects and extracts the electric field noise generated by the CPT (13), and inverts and amplifies the extracted electric field noise waveform to apply to the lead wire (L11) mounted on the front part of the CPT (13) to cancel the unnecessary radiation field noise generated. The unnecessary radiation field noise removing device of the front portion of the CRT, characterized in that it comprises a reverse amplifier circuit (14). The capacitor amplifier (C11), resistors (R11 to R13), and transistors according to claim 1, wherein the inverting amplifier circuit 14 receives an unwanted radiated field noise waveform detected from the CPT band and senses only an AC component to stabilize the bias. An amplifier comprising a stabilizer including Q12, a transistor Q13 for amplifying the electric field noise waveform input from the stabilizer, and resistors R14 and R15 for determining the amplification degree of the transistor Q13; And an inverting portion including transistors (Q14, Q15) for inverting the field noise waveform amplified through the supply line to the lead wire (L11).

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