US 5,347,317 A · Horizontal oscillation control circuit for a cathode-ray tube

Abstract

The present invention relates to a horizontal oscillation circuit for generating horizontal drive pulses to be used for a cathode-ray tube. A microcomputer measures the frequency or the period of an input horizontal synchronizing signal, takes out a target value corresponding to the measured frequency or the period from an EEPROM, and gives a set value corresponding to the target value to a first D-A converter. The microcomputer also gives a set value corresponding to 1/2 of a period of the input horizontal signal to a second D-A converter. A first monostable multivibrator outputs a pulse signal having pulse widths corresponding to the output voltage of the first D-A converter. A second monostable multivibrator outputs a horizontal drive pulse signal having pulse widths corresponding to the output voltage of the second D-A converter. Furthermore, the microcomputer compares the output pulse width of the first monostable multivibrator output from a first counter with a latch with a target value, and gives a set value to the first D-A converter to make the output pulse width of the first monostable multivibrator approach the target value. The microcomputer also compares the output pulse width of the second monostable multivibrator output from the second counter with a latch with 1/2 of a period of the input horizontal signal and gives a set value to the second D-A converter to make the output pulse width of the second monostable multivibrator approach 1/2 of a period of the input horizontal signal.

Claims11

Dependent claims

A horizontal oscillation circuit comprising:

a first pulse generator section for generating a pulse signal having a pulse width corresponding to a first set value and for setting a picture display position using an input horizontal synchronizing signal as trigger pulses;
a second pulse generator section for generating a horizontal drive pulse signal having a pulse width corresponding to a second set value using the trailing edges of the pulse signal output from said first pulse generator section;
a first measurement section for measuring the pulse width of the pulse signal output from said first pulse generator section;
a second measurement section for measuring the pulse width of said horizontal drive pulse signal;
and a control section for outputting the first set value and the second set value such that a difference between an output of said first measurement section and a first target value is dissolved, and a difference between an output of said second measurement section and a second target value is dissolved.

2 more elements

A horizontal oscillation circuit comprising:

a first pulse generator section for outputting a pulse signal for roughly setting a picture display position, a pulse signal having pulse widths corresponding to the first set value, using an input horizontal synchronizing signal as trigger pulses;
a second pulse signal generator section for generating a horizontal drive pulse signal having pulse widths corresponding to the second set value using trailing edges of a pulse signal output from a third pulse generator section;
the third pulse signal generator section for generating a pulse signal for finely setting a picture display position, a pulse signal having pulse widths corresponding to a third set value using trailing edges of a pulse signal output from the first pulse generator section as trigger pulses;
a first measurement section for measuring the pulse widths of a pulse signal output from said first pulse signal generator section;
a second measurement section for measuring the pulse widths of said horizontal drive pulse signal;
a third measurement section for measuring the pulse widths of a pulse signal output from said third pulse generator section;
and a control section for inputting the third set value corresponding to the difference between the output from said first measurement section and the first target value to said third pulse generator section and outputting the first set value, the second set value and the third set value such that a difference between the sum of the output value of said first measurement section and the output value of said third measurement section, and the first target value is dissolved, and a difference between the output of said second measurement section and the second target value is dissolved.

4 more elements

Dependencies are inferred from the claim text.

Horizontal oscillation control circuit for a cathode-ray tube

Life of this patent

Horizontal oscillation control circuit for a cathode-ray tube

Life of this patent

Abstract

Claims11