JPS5848832Y2 - CRT display device with horizontal phase correction circuit - Google Patents

Description

[Detailed description of the invention] The present invention relates to a CRT display device that displays character information, etc. as a computer terminal device (hereinafter referred to as a system).In the CRT display device, the signal applied to the CRT display device is a composite video signal. The present invention relates to the latter of the above three methods, that is, to a separate method CRT display device.

In the above-mentioned separation type CRT display device (hereinafter simply referred to as a CRT display device), the horizontal drive pulse H0D has a pulse width necessary for horizontal drive, such as a pulse width of 15 to 40 μs, and is applied directly to the horizontal output transistor. Since it is possible to apply pulses, there is no need to provide a horizontal oscillator. Therefore, the above CRT display device has a circuit configuration excluding the part surrounded by a dotted line as shown in FIG. The horizontal drive power H, D is applied to the cathode of the CRT through the horizontal drive circuit 4 to the horizontal output circuit 5.
The horizontal deflection output is applied to the deflection yoke 9 from the horizontal output circuit 5, while the vertical drive power V, D is applied to the vertical oscillator 7.
The output of the vertical oscillator 7 is taken out as a vertical deflection output through the vertical output circuit 8 and applied to the deflection yoke 9,
A part of the horizontal deflection output is applied to the high voltage circuit 6, and the rectified output from the high voltage circuit 6 is applied to the CRT 2.

However, a delay of about 2 to 6 μs occurs during the switching operation of the horizontal output transistor, and the delay during the switching operation causes a positional shift in the displayed image.

(If the horizontal scanning phase difference is 1 μs with respect to the video signal, 1
It is clear that in the case of a 2-in CRT, there will be an image blur of about 5 mm.

) The above positional deviation cannot be corrected in this type of device that does not use a horizontal oscillator because it cannot be corrected by adjusting the oscillator.

If a signal with a different input drive pulse width (scanning cycle is the same) is used, a positional shift in the image will naturally occur, and this positional shift cannot be corrected by adjusting the drive pulse width. It could not be used for devices with different types.

The present invention eliminates the above-mentioned drawbacks and provides a CRT display device in which the phase difference between the video signal and the horizontal drive pulse can be arbitrarily adjusted and the screen position shift can be corrected.

The configuration of the present invention will be explained below with reference to FIGS. 1 and 2.

In Fig. 2, NPN (or PNP) transistor Q1
There is a protective resistor R2 for the emitter of the transistor Q1.
(or a diode), a differentiating circuit consisting of a capacitor CI and a resistor R1 is inserted between the base and the input terminal 2, and a horizontal drive input is applied from the input terminal.

A variable parallel resonant circuit consisting of a variable coil L1 and a capacitor C2 is inserted between the collector and the power supply terminal (2).

On the other hand, the emitter of a PNP (or NPN) transistor Q2 is connected to the power supply terminal (2), and the base is connected to the collector of the transistor Q1 via a resistor R3.

Furthermore, a condenser C3 is inserted between the base and the power supply terminal (2).

A horizontal phase correction circuit is connected to the first
Horizontal drive input terminal and horizontal drive circuit 4 as shown in dotted line frame 3 in the figure
The CRT display device of the present invention is constructed by being inserted between the two.

Since the present invention is constructed in this way, when a horizontal drive signal such as waveform A in Fig. 3 is applied from the input terminal ①, the waveform B in Fig. 3 is generated by a differentiating circuit consisting of a capacitor C1 and a resistor R1. This is applied as a trigger signal to the base of transistor Q1.

A parallel resonant circuit consisting of a variable coil L1 and a capacitor C2 is inserted into the collector of the transistor Q1 as a load impedance, and a sinusoidal waveform (only the resonant component in the base human power pulse) as shown in waveform C in Fig. 3 appears. , further shapes the sine waveform through an integrating element including a resistor R3 and a capacitor C3, and applies it to the base of a transistor Q2.

In transistor Q2, the third
It is sliced along the ``2'' axis in the figure, becomes conductive at the level of the CC'C salt point, and the waveform shown in FIG.

In the above operating state, if one of the variable coil Ll and the capacitor C2 (for example, ) of the parallel resonant circuit, which is the load of the transistor Q1, is varied and enlarged, the waveform E in FIG. 3 is obtained.
and waveform F, and conversely, when it is made smaller, the waveform shown in Fig. 3 becomes waveform H, and by varying the coil L1, ±
Phase correction of about 10 μsec is possible.

The horizontal phase correction circuit is inserted between the horizontal drive input terminal and the horizontal drive circuit 4 as shown in FIG. Screen position shift due to the phase difference between the horizontal output (horizontal output delayed by the switching operation of the horizontal output transistor) and the case where signals with different input drive pulse widths (scanning period is the same) are used. The positional deviation of the screen is caused by the variable coil L of the horizontal phase correction circuit.
Correction is possible by varying 1.

Therefore, since the CRT display device of the present invention can arbitrarily adjust the screen position, it is possible to provide a CRT display device with a uniform screen, and even when the input drive pulses are different, it can be easily adjusted according to the input drive pulse. Since the position of the screen can be set, compatibility between systems is possible, the scope of use is very wide, and the value of use is extremely large.

[Brief explanation of drawings]

The parts other than the dotted line frame 3 in Figure 1 are commonly used CRs.
FIG. 3 is a circuit diagram of a T display device, FIG. 3 is a waveform diagram and a phase relationship diagram of each part of the present invention, and FIG. 2 is an embodiment of the present invention. Ql, Q2: transistor, C,, R,: differential element, R
2: Emitter resistance of Ql, Ll, C2: variable parallel resonant circuit, R3, C3: integrating element, R4: load resistance, ■: input terminal, ■: power supply terminal, ■: output terminal.

Claims (1)

[Scope of utility model registration request] Using an NPN (or PNP) transistor Q1 and a PNP/or NPN) transistor Q2, the emitter of the NPN (or PNP) transistor Q1 is connected to a protective resistor R2.
(or a diode is possible), and to its base, an input obtained by differentiating the horizontal drive signals H and D is added, and a variable parallel resonant element consisting of a coil and a capacitor C is inserted between the collector and the power supply, and on the other hand, a transistor Q2 The emitter is connected to the power supply, the collector is used as the output terminal, and a load resistor R4 is connected between the ground and the horizontal phase correction circuit is configured such that the collector output signal (sine wave) of the transistor Q1 is integrated and applied to the base. The horizontal phase correction circuit is inserted between the horizontal drive input terminal and the horizontal drive circuit, and the phase of the horizontal drive pulse is varied by varying the coil, thereby making it possible to correct the phase difference between the horizontal drive pulse and the video signal. A CRT display device equipped with a horizontal phase correction circuit.