JP3348728B2 - Horizontal deflection circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a horizontal phase correction circuit suitable for correcting image distortion of a television receiver.

[0002]

2. Description of the Related Art In a horizontal synchronization process of a television receiver, as can be understood from FIG. 2, a composite video signal is input to a synchronization separation circuit 10 to separate a horizontal synchronization signal. The signal is input to the horizontal oscillation circuit 20. The circuit 20 is provided with an oscillator, the oscillation frequency of which is adjusted to the input horizontal synchronization signal, and the deflection phase is locked to the signal phase.

[0005] An output signal (horizontal timing signal) of the circuit 20 is input to a horizontal drive circuit 30, and a pulse for driving a horizontal output transistor is generated from the timing signal and input to a horizontal deflection circuit 40.

In this case, a process for matching the phase of the horizontal synchronizing signal with the phase of the deflection circuit 40 is required, and the process is performed by the circuit shown in FIG.

[0005] In FIG. 3, a horizontal synchronizing signal is a PLL composed of a phase comparator 1 , a filter 3 and a VCO 5.
The phase is input to the circuit (first loop circuit), and the phase of the VCO 5 (oscillator) is locked to the horizontal synchronization signal.

The second loop circuit comprising the phase comparator 7, the integrator 9, the variable phase shifter 11, the horizontal drive circuit 13, and the horizontal deflection circuit 15 is locked by the phase waveform generated by the VCO 5.

[0007] In FIG. 3, reference numeral 100 denotes an IC part.

When such a circuit configuration is adopted, image distortion,
In particular, orthogonal distortion (parallelogram distortion) and vertical bow distortion occur in the deflection yoke and the deflection circuit 15.

Therefore, when correcting these distortions, the first
A correction waveform is externally added to the filter 3 of the loop,
The horizontal phase is changed by the vertical synchronization signal.

[0010]

However, the first loop circuit needs to be designed in consideration of the pull-in response characteristics and noise resistance.
Since the constant is set, the correction cannot follow when the response is fast.

In addition, since a correction waveform is added to the filter 3, the frequency is modulated, and when the loop gain is switched, the correction changes together with the response characteristic of the frequency.

It is an object of the present invention to provide a horizontal phase correction circuit which does not affect the pull-in response characteristics and can follow a sudden change in the correction waveform.

[0013]

The horizontal deflection circuit according to the present invention comprises, for example, a horizontal oscillator 5 as shown in FIGS.
And a phase comparator 1 for comparing the phase of the oscillation output of the horizontal oscillator 5 with the phase of the horizontal synchronizing signal of the input video signal and outputting a control signal to the horizontal oscillator 5. A first loop circuit for obtaining an output signal locked to a horizontal synchronizing signal of a signal; a horizontal deflection pulse being input; comparing the phase of the horizontal deflection pulse with the output signal of the first loop circuit; And a charge amount corresponding to the result of comparison of the phase between the horizontal deflection pulse and the output signal of the first loop circuit is changed by the correction waveform of the vertical period image distortion correction. Means A (Q1, Q2, Q3, Q4, Q5, Q
6, C, etc.), and a variable phase shifter 11 that changes the phase relationship between the horizontal deflection pulse and the output signal of the first loop circuit by an output signal based on the charge amount of the phase modulation means A; A horizontal deflection driving means 15 driven by an output signal from the variable phase shifter 11; an output signal of the horizontal deflection driving means 15 is input to the phase modulation means A as a horizontal deflection pulse; This horizontal deflection driving means 1 corresponds to the output signal and this correction waveform.
And a second loop circuit in which the phase of the output signal is locked.

[0014]

In the horizontal deflection circuit according to the present invention, the amount of charge in accordance with the result of comparing the phase between the horizontal deflection pulse from the horizontal deflection driving means and the output signal of the first loop circuit is corrected for vertical period image distortion correction. The phase modulation means that changes according to the waveform
It is provided in a loop circuit, and is corrected by a synchronous loop for phase matching in the second loop circuit.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the horizontal phase correction circuit according to the present invention will be described below with reference to the drawings.

FIG. 1 shows a circuit configuration diagram (phase modulation means) provided in the block A portion (second loop circuit) of FIG. 3, and this circuit includes multipliers Q _{1 to} Q _4.
Is provided.

The output signal (phase pulse) from the first loop is input to the multiplier Q _1, and the H pulse is input as a deflection timing from the horizontal deflection circuit 15 to the multiplier Q ₃ to perform phase comparison. It is.

In the comparison period, the transistor
The potential charged in the capacitor C (integrator) is determined by the time ratio of the currents I ₁ and I ₂ flowing through Q ₁ and Q ₂ .

Further, the collector terminals of the multipliers Q1 and Q2 are connected to transistors Q5,
Q6 collector terminal of are respectively connected, transistor
The current flowing through the Q5 and Q6 changes with the AFC correction waveform Vs.
In response, the charge amount of the capacitor C changes.
Become

Then, two inputted pulses (the phase pulse and the H pulse) so as to cancel the change
As a result, the horizontal phase is adjusted by the correction waveform signal VS.

Note that the second loop circuit is a loop that matches only the phase regardless of the frequency, and the loop time constant is set sufficiently faster than the time constant of the first loop circuit.

As described above, in this embodiment, the second
Since the phase modulation means A is provided in the loop circuit, the phase relationship between the two pulses input from the first loop circuit and the horizontal deflection circuit 15 is changed. As a result, the horizontal phase is changed by the correction waveform.

Therefore, the circuit is not affected by the pull-in response characteristic, can follow a rapid change in the correction waveform, and can easily be integrated into a circuit.

It is also preferable that the phase pulse generated by the first loop circuit is phase-modulated with a correction waveform, and the second loop circuit is locked to the modulated pulse.

[0025]

As can be understood from the above description, the horizontal deflection circuit according to the present invention responds to the comparison result of the phase between the horizontal deflection pulse from the horizontal deflection driving means and the output signal of the first loop circuit. Phase modulation means in which the amount of charge changes according to the correction waveform of the vertical period image distortion correction is provided in the second loop circuit.

That is, since the correction is performed in the synchronous loop of the phase matching in the second loop circuit, there is no influence on the pull-in response characteristic.

Further, it is possible to follow a sudden change of the correction waveform, and it is suitable for circuit integration.

[Brief description of the drawings]

FIG. 1 is a circuit configuration diagram of a preferred embodiment of a horizontal phase correction circuit according to the present invention.

FIG. 2 is a block diagram of a circuit that performs horizontal synchronization processing of the television receiver.

FIG. 3 is a circuit configuration diagram of a conventional example.

[Explanation of symbols]

5 VCO 11 Variable phase shifter 15 Horizontal deflection circuit A Phase modulation means Q _{1 to} Q ₄ Multiplier C Capacitor (integrator) Q _{5 to} Q ₈ Transistor

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Takahiko Tamura 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Inventor Satoshi Miura 6-35-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Sony Corporation

Claims (1)

(57) [Claims] 1. A horizontal oscillator, comprising: a horizontal oscillator; and a phase comparison circuit for comparing a phase of an oscillation output of the horizontal oscillator with a phase of a horizontal synchronization signal of an input video signal and outputting a control signal to the horizontal oscillator. A first loop circuit for obtaining an output signal locked to a horizontal synchronization signal of an input video signal; and a horizontal deflection pulse being input, and comparing the phase of the horizontal deflection pulse with the output signal of the first loop circuit. In addition to charging the electric charge according to the comparison result, the charge amount according to the comparison result of the phase between the horizontal deflection pulse and the output signal of the first loop circuit is changed by the correction waveform of the vertical period image distortion correction. A phase relationship between the horizontal deflection pulse and an output signal of the first loop circuit can be changed by an output signal based on the charged amount of charge of the phase modulation unit. And phase shifter composed of a horizontal deflection drive means driven by the output signal from the variable phase shifter, the output signal of the horizontal deflection drive means is inputted to said phase modulation means as said horizontal deflection pulse, said first loop A horizontal deflection circuit, comprising: a second loop circuit in which the phase of the output signal of the horizontal deflection driving means is locked in accordance with the output signal of the circuit and the correction waveform.