JP2001119597A - Phase controller for horizontal drive pulse - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize countermeasures for the requirement of phase control of a horizontal drive pulse by changing phase change sensitivity with respect to a control voltage when a gradient of a reference sawtooth wave is made steep for horizontal jitter countermeasures in a phase controller of the horizontal drive pulse. SOLUTION: The phase controller is provided with a control pulse generator generating a reference pulse, a sawtooth wave generator that generates a sawtooth wave required to decide a start point of the horizontal drive pulse, a control voltage generator that compares a phase of an output of the control pulse generator with a phase of a horizontal deflection pulse and that converts the phase result into voltage, a gain control means that controls a gain of an output voltage of the control voltage generator, a comparator that compares an output of the sawtooth generator with a voltage of an output of the gain control means, and a drive pulse width adjustment device that decides the width of the horizontal drive pulse.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a phase control device for a horizontal drive pulse input to a horizontal deflection circuit in a television receiver.

[0002]

2. Description of the Related Art In recent years, the age of BS digital broadcasting has been approached.
The development of functions that can support various inputs corresponding to multimedia has also been emphasized in television receivers. Hereinafter, a conventional horizontal drive pulse phase control device will be described.

FIG. 3 shows a block diagram of a horizontal position correction circuit proposed in Japanese Patent Application Laid-Open No. 7-46427. In FIG. 3, a VCO 31 and a phase comparison 33
A pulse synchronized with the horizontal synchronizing signal is generated by a block including the horizontal countdown 32, and the phase of the pulse is compared with that of the FBP by the phase comparator 34. A capacitor 3 for smoothing and holding the phase-compared signal
The voltage is converted into a voltage in 6 and is compared with the sawtooth wave generated by the sawtooth wave generation 35 by the comparator 40. The output of the comparator 40 is shaped by the frequency divider 41 and input to the horizontal deflection coil 42. The horizontal position is adjusted by controlling the switch 37 with the control 39 only during the burst gate period.

[0004]

However, the above configuration has the following problems. In other words, when the phase of the FBP and the reference signal generated from the horizontal synchronization signal are compared to adjust the phase of the horizontal drive pulse based on the comparison result, which is a phase error, the amount of phase change with respect to the detection voltage of the comparator is fixed. However, the above configuration cannot cope with the case where it is desired to change the amount of phase change with respect to the detection voltage, or the case where the amount of phase change is desired to be changed when the slope of the sawtooth wave is changed in order to prevent jitter.

[0005]

In order to solve the above problems, a phase control apparatus for a horizontal drive pulse according to a first aspect of the present invention generates a control pulse for generating a reference pulse necessary for generating a horizontal drive pulse. A device, a sawtooth wave generator that generates a sawtooth wave required to determine the start point of the horizontal drive pulse based on the output of the control pulse generator, and an output different from the above output of the control pulse generator. A control voltage generator for performing phase comparison with a horizontal deflection pulse to convert the phase result into a voltage, gain control means for performing gain control on an output voltage of the control voltage generator with respect to a reference voltage, and generating the sawtooth wave A comparator for comparing the voltage value of the output of the device with the voltage value of the output of the gain control means and outputting a comparison result; A drive pulse width adjustment device for determining the drive pulse width of the pulse, and a horizontal deflection circuit for performing horizontal deflection based on the output of the drive pulse width adjustment device, wherein the phase control amount of the horizontal drive pulse is controlled by the gain control means. Can be controlled.

According to the above invention, since the amount of phase change with respect to the detection voltage of the comparator can be changed, the amount of phase change can be changed even when the slope of the sawtooth wave is changed for measures such as jitter, and accurate horizontal phase control can be performed. It becomes possible.

[0007]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment) FIG. 1 is a block diagram of a horizontal drive pulse phase control device according to a first embodiment of the present invention.

In FIG. 1, a control pulse generator 1 includes:
This is a device that creates a pulse necessary to generate a horizontal drive pulse based on the horizontal synchronization signal A. The sawtooth wave generator 2 is a device that generates a sawtooth wave necessary for determining the start point of the horizontal drive pulse based on the output of the control pulse generator 1. The control voltage generator 3 is a device for detecting the phase difference between the output of the control pulse generator 1 and the horizontal deflection pulse and converting the phase difference into a voltage.

The gain control means 4 is a means for amplifying the output voltage of the control voltage generator 3 with respect to the reference voltage to control the gain of the voltage. Comparator 5
Is a block for comparing the sawtooth wave output from the sawtooth wave generator 2 with the output voltage of the gain control means 4 and outputting the comparison result. The start point of the output waveform of the comparator 5 changes according to the change in the phase difference between the horizontal deflection pulse and the horizontal synchronization signal, and coincides with the start point of the horizontal drive pulse. The drive pulse width adjusting device 6 adjusts the drive pulse width and determines the width from the start point. The horizontal deflection circuit 7 is a circuit for performing horizontal deflection by the drive pulse. A horizontal deflection pulse, which is an output, is input to the control voltage generator 3.

The operation of the horizontal drive pulse phase control device configured as described above will be described with reference to FIG. FIG. 2 is a waveform diagram of a signal output from each section of the horizontal drive pulse phase control device according to the present invention.

In FIG. 2, a reference signal B is a signal for determining a start point of a sawtooth wave C generated from the horizontal synchronization signal A. A sawtooth wave is generated only when the reference signal B is low, and the output waveform is low during a high period.
Fixed to The reference waveform D is for comparing the phase with the horizontal deflection pulse E. Horizontal deflection pulse E is Hig
During the period h, the phase is compared with the reference waveform D, and the phase comparison result is converted into the voltage F. Voltage F is a gain control means 4
Are amplified with respect to the reference DC, become a converted voltage G, are compared with the sawtooth wave C by the comparator 5, and an output waveform H is created.

Here, for example, by changing the gain of the gain control means 4, the output waveforms H when the converted voltages become G1 and G2 become H1 and H2, respectively, and the start point of the drive pulse changes. Next, the horizontal drive pulses after the pulse width is adjusted by the drive pulse width adjusting device 6 become I1 and I2, respectively, and the phase of the horizontal drive pulse can be changed by changing the gain of the gain control means 4. In addition, the sawtooth wave generator 2
The cases where the slope of the sawtooth wave is changed are C1 and C2,
The waveforms corresponding to the output waveform H at this time are H31,
H32.

Also in this case, the start point of the drive pulse can be changed. Here, when the two inputs of the comparator 5 include a jitter component that causes horizontal jitter, the steeper the slope of the sawtooth wave C, the smaller the jitter component (the amount of phase change with respect to time) of the horizontal drive pulse. However, if the inclination of the sawtooth wave C is steep, the phase change sensitivity becomes small, and sufficient phase correction cannot be performed. In such a case, gain control is performed using the gain control means 4 to control the conversion voltage G, and accurate horizontal phase control can be performed while keeping the slope of the sawtooth wave C steep.

As described above in detail, according to the horizontal drive pulse phase control apparatus of the present invention, the amount of phase change with respect to the detection voltage of the comparator can be changed. In this case, the phase change amount can be changed, and accurate horizontal phase control can be performed.

[0016]

As described above, according to the horizontal drive pulse phase control device of the present invention, the amount of phase change with respect to the detection voltage of the comparator can be changed. However, the phase change amount can be changed, and accurate horizontal phase control can be performed.

[Brief description of the drawings]

FIG. 1 is a block diagram of a horizontal drive pulse phase control device according to a first embodiment of the present invention;

FIG. 2 is a waveform chart showing the operation of each part of the phase control device of the horizontal drive pulse of the present invention.

FIG. 3 is a block diagram of a conventional horizontal drive pulse phase control device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Control pulse generator 2 Sawtooth wave generator 3 Control voltage generator 4 Gain control means 5 Comparator 6 Drive pulse width adjusting device 7 Horizontal deflection circuit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hisao Morita 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. 72) Inventor Hitoshi Ando 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. BA08 BA23 HA03

Claims (2)

[Claims] 1. A phase control device for a horizontal drive pulse input to a horizontal deflection circuit, comprising: a control pulse generator for generating a reference pulse necessary for generating a horizontal drive pulse; A sawtooth wave generator that generates a sawtooth wave required to determine the start point of the horizontal drive pulse based on the output, and a different output from the above control pulse generator and a horizontal deflection pulse and phase comparison. A control voltage generator for converting the phase result into a voltage, gain control means for performing gain control on an output voltage of the control voltage generator with respect to a reference voltage, and an output of the sawtooth wave generator and the gain control means. The comparator that compares the output voltage value and outputs the comparison result and the drive pulse width of the horizontal drive pulse A drive pulse width adjusting device for adjusting the horizontal drive pulse, and a horizontal deflection circuit for performing horizontal deflection based on the output of the drive pulse width adjusting device. A phase control device for a horizontal drive pulse. 2. The sawtooth wave generator can change the slope of the sawtooth wave, and by controlling the slope of the sawtooth wave and the gain of the gain control means simultaneously, accurate horizontal phase control and jitter amount can be achieved. 2. The phase control device for horizontal drive pulses according to claim 1, wherein both reductions can be achieved.