DE1258449B - Arrangement for generating a color circle according to the PAL standard for a so-called rainbow generator - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. CL:

H04n

German: 21 al -34/31

Number:
File number:
Registration date:
Display day:

P 38190 VIII a / 21 al
November 25, 1965
January 11, 1968

The invention relates to an arrangement for generating test signals for continuous running of the color wheel according to the PAL standard for a so-called rainbow generator.

It is already known to generate such signals in color television systems according to the NTSC standard. In this so-called rainbow generator, a color carrier oscillator is used which supplies a frequency / which corresponds to the difference jj ~ j _n or the sum f _T + fn , where f _{T is} the color carrier frequency and f _{H is} the line frequency.

Substantial and different from the NTSC standard is that with the PAL standard, a test signal must be made available that alternates from Runs through the color wheel line to line in the opposite direction.

The aim of the invention is now to show a way to use the rainbow generators known for NTC signals can also be used for PAL signals.

This is done according to the invention in that, in addition to the known color subcarrier oscillator with the frequency f _T ± f _H, a further color subcarrier _{oscillator with the frequency / 2} = f _T + f _{H is} provided and the output signals of both oscillators both a phase-dependent rectifier for coupling with the clock frequency and can be fed to the receiver via an electronic switch controlled at the horizontal frequency.

The figure shows a block diagram of the arrangement according to the invention. Therein 1 is a color subcarrier oscillator of a known type, which z. B. provides a frequency Z ₁ - fr - fii . In addition, a second color carrier oscillator 2 is now provided, the output frequency of which is J ₂ = fT + fti . The chrominance signals U _fl and U _f2 are available at the outputs of these oscillators 1, 2. These are fed to a phase-dependent rectifier 3 on the one hand and to an electronic switch 4 on the other. At the output of the rectifier 3, double the horizontal frequency is now available which, after appropriate divisions, results in the horizontal frequency f _H = 15 625 Hz and the vertical frequency f _v = 50 Hz. In the rectifier 3 takes place through the phase arrangement for generating a color wheel
according to the PAL standard for a so-called
Rainbow generator

Applicant:

Philips Patent Administration G. m. B. H.,

2000 Hamburg 1, Mönckebergstr. 7th

Named as inventor:

Waldemar Hartwich, 2000 Hamburg

dependent rectification, a so-called off-server coupling of the frequencies Z ₁ and / ₂ with the horizontal frequency takes place.

In addition, the horizontal frequency f _{H is used} to control the electronic switch 4, which switches the signals Uf ₁ and U _{f 2} coming from the two color subcarrier oscillators 1 and 2 in the rhythm of the horizontal frequency and feeds them to the receiver. In this way, it is possible to run through the color wheel in the opposite direction from line to line, which is required for the PAL standard.

Claims (1)

Claim: Arrangement for generating color circles according to the PAL standard for a so-called rainbow generator by means of a frequency J ₁ = f _T ± f. _H delivering color subcarrier oscillator, where f _{T is} the color subcarrier frequency and / # is the line frequency, characterized in that, in addition to this known color subcarrier oscillator (1), a further color subcarrier oscillator (2) with the frequency f ₂ = f _T + f _{H is} provided and the output signals U _fv U _{f2 of} both oscillators are fed to the receiver both to a phase-dependent rectifier (3) for coupling with the clock generator frequency and via an electronic switch (4) controlled with the horizontal frequency. 1 sheet of drawings