JPS6374291A - Pal-ntsc signal converter - Google Patents

Abstract

PURPOSE:To constitute the device simply and inexpensively by synthesizing a burst signal extracted by a 1st switch means, a burst signal extracted from a phase-locked oscillator and a signal extracted from the 1st adder at a 2nd adder. CONSTITUTION:A burst gate signal inputted from an input terminal 2 is fed to a flip-flop 5 to form a switch control signal inverted at each 1H. On the other hand, a PAL system chrominance carrier signal is inputted from an input terminal 1 and fed to the 1st switch 3. Then the signal is separated into a burst signal and a chrominance signal by the burst gate signal inputted from the input terminal 2. A chrominance signal from an adder 9 fed to an adder 11 and the burst signal from a phase shifter 10 are added and the result is outputted from an output terminal 12. Since the chrominance signal is identical at each 1H in the NTSC signal formed in this way, the quantity of information is half to the normal NTSC signal.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention is a PA used in video tape recorders, etc.
The present invention relates to an L-NTSC signal conversion device.

Conventional technology Conventionally, PAL-NTSC signal conversion devices used in consumer video tape recorders demodulate PAL carrier color signals into color difference signals, and modulate the color difference signals into NTSC carrier color signals. This is what I used.

Problems to be Solved by the Invention However, in the above configuration, the PAL carrier color signal is demodulated and the signal is modulated into the NTSC carrier color signal, so a demodulator and a carrier signal modulator are required, and the configuration is complicated. The problem was that it was very complicated and expensive.

Means for Solving the Problems In order to solve the above problems, the PAL-NTSC of the present invention
The signal converter converts the burst gate signal into one horizontal scan (
A flip-flop circuit that generates a signal that is inverted every period (hereinafter referred to as 1H), a first switch means that separates a PAL carrier color signal into a burst signal and a color signal using a burst gate signal, and a burst signal is removed. a second switch means for extracting the carrier color signal every 1H period by the output of the flip-flop circuit; a first adder for adding the signal from the second switch means every 1H; and the first switch. A second adder is provided for combining the burst signal taken out from the oscillator, which is phase-synchronized with the burst signal taken out by the means, and the signal taken out from the first adder.

Effect of the Invention The present invention allows a PAL-NTSG signal conversion device to be constructed easily and inexpensively by the above-described configuration.

Embodiments Hereinafter, embodiments of the PAL-NTSO signal conversion apparatus of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of one embodiment of the present invention.

In FIG. 1, 1 is a PAL color carrier color signal input terminal;
2 is the burst gate input terminal, 3 is the first switch, 4
is the second switch, 5 is the flip-flop circuit, 6 is the phase comparator, 7 is the oscillator, 8 is the third switch, and 9 is the first switch.
10 is a phase shifter, 11 is a second adder, and 12 is an output terminal.

The operation of the PAL-NTSC signal converter of this embodiment configured as described above will be explained below with reference to FIGS. 1 and 2.

The burst gate signal inputted from the input terminal 2 is sent to the flip-flop 5, and a switch control signal that is inverted every 1H period is generated.

On the other hand, the PAL carrier color signal is input from the input terminal 1 and sent to the first switch 3. The PAL carrier color signal sent to the first switch 3 is divided into a burst signal and a color signal by a burst gate signal inputted from the input terminal 2. The carrier color signal from which the burst signal produced by the first switch 3 has been removed is sent to the second switch 4,
It is removed every 1H period by a switch control signal generated by the flip-flop circuit 6. Said second switch 4
The carrier color signal for each 1H period generated by The carrier color signal is added every 1H.

On the other hand, the burst signal taken out by the first switch 3 is sent to the phase comparator 6. The phase comparator 6 controls the phase of the oscillator 7 to synchronize with the burst signal, and controls the flip-flop circuit 5 to synchronize with the polarity of the burst every 1H. The signal taken out from the oscillator 7 is filtered out during the burst gate period by the third switch 8 , phase shifted by -(BY) by the phase shifter 10 to become a burst signal, and sent to the adder 11 . The color signals from the adder 9 sent to the adder 11 and the burst signal from the phase shifter 1° are added together and outputted from the output terminal 12.

In the apparatus configured as described above, the phase of each burst signal of the PAL carrier color signal, such as the person shown in FIG.
It looks like this. The phase of the carrier color signal is like C. If this signal is supplied to input terminal 1, output terminal 1
2, a signal as shown in D in Fig. 2 is output, the phase of each burst signal is as shown in E in Fig. 2, and the phase of the carrier color signal is F as shown in Fig. 2.
become that way. In this way, the PAL-NTSC of this embodiment
The NTSO signal created by the signal converter has the same color signal every 1H period, so the amount of information is normal NTSC.
The signal is half.

Effects of the Invention As described above, according to the present invention, a PAL-NTSC signal converter can be obtained more easily and at a lower cost than the conventional one.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of a PAL-NTSC signal converter according to the present invention, and FIG. 2 is a signal waveform diagram of each part in the embodiment. 1...PAL carrier color signal input terminal, 2...
...Burst gate signal input terminal, 3...1st
switch, 4... Second switch, 5...
...Flip-flop, 6...Phase comparator,
7... Oscillator, 8... Third switch, 9... First adder, 10... Phase shifter, 11... ...Second adder, 12...
Output terminal.

Claims (1)

[Claims] A flip-flop circuit obtains a signal that is inverted every horizontal scanning period from the burst gate signal, a first switch means separates the PAL carrier color signal into the burst signal and the color signal using the burst gate signal, and a second switch means for extracting the removed carrier color signal every horizontal scanning period by the output of the flip-flop circuit; and a first addition means for adding the signal from the second switch means for every horizontal scanning period. a second adder for synthesizing the burst signal taken out from the oscillator which is phase-synchronized with the burst signal and the signal taken out from the first adder;
A PAL-NTSC signal conversion device characterized by comprising an adder.