US 3,968,514 A · Magnetic recording and/or reproducing apparatus

Abstract

In recording PAL television signals, the chrominance signal components of field intervals are recorded in successive parallel tracks on a record medium. The ends of the margins between the line intervals of each field are recorded in each of the tracks and are aligned, in the direction transverse to the lengths of the tracks, with the adjacent ends of such margins in the next adjacent tracks. Interference, or cross-talk, between signals recorded in adjacent tracks is reduced or eliminated during reproduction by converting the alternating polarity chrominance component into one of fixed polarity, similar to an NTSC signal, and then recording the information signals with different first and second carriers in the adjacent tracks, respectively. Such first and second carriers for signals recorded in adjacent tracks may be distinguished from each other by their respective frequency and/or polarity characteristics. When the signals recorded in a particular track are reproduced, the cross-talk signals from adjacent tracks can be conveniently suppressed or eliminated, for example, with the aid of a simple comb filter, by reason of the different frequency and/or polarity characteristics of the carriers of interfering signals. The signals are then reconverted to PAL form to be played back on apparatus designed to reproduce images in response to PAL signals.

Claims10

Dependent claims

In a recording system for recording PAL color television signals in a plurality of parallel tracks on a recording medium, the PAL signals being divided into line and field intervals and including a chrominance portion modulated on a PAL signal sub-carrier the phase of which is reversed for each line interval, and each of said tracks being divided into line interval areas, apparatus comprising:

A. a frequency converter, the chrominance signal portion of the PAL signal being applied to the frequency converter;
B. means to generate a first frequency converting sub-carrier at a first frequency equal to the sum of the sub-carrier frequency of the PAL color television signal plus a conversion sub-carrier frequency and a second frequency converting sub-carrier at a second frequency equal to the difference between the PAL color television sub-carrier frequency and a conversion sub-carrier frequency, the first and second frequencies differing from each other by an odd integral multiple of one-half the line repetition frequency of the PAL color television signal;
and
C. connecting means for applying the first and second frequency converting sub-carriers alternately, each for a line interval at a time, to the frequency converter to convert the PAL color television chrominance signal to an NTSC-type chrominance signal in a frequency band including the respective frequency converted chrominance sub-carrier frequency, said connecting means connecting the first and second frequency converting sub-carriers in one order during the recording of alternate ones of the tracks and in a different order during the remaining alternate tracks.

1 more element

In a playback system for reproducing color television signals recorded in a plurality of parallel tracks on a recording medium, the signals including a frequency converted NTSC-type chrominance portion modulated on a frequency converted subcarrier and being divided into line and field intervals, and each of said tracks being divided into line interval areas, apparatus comprising:

A. means to reproduce said recorded signals;
B. a frequency re-converter;
C. means to apply said reproduced signals to said frequency re-converter in predetermined polarity relationship;
D. means to generate a frequency re-converting carrier signal having a frequency that combines, in predetermined mathematical relationship, the PAL color television sub-carrier frequency converted sub-carrier frequency of the reproduced signal;
E. means to connect the frequency re-converting signal to said frequency re-converter to convert the carrier frequency of the reproduced chrominance portion to the PAL sub-carrier frequency;
F. a comb filter connected to said frequency re-converter to transmit desired chrominance signal harmonic frequency components and to attenuate cross-talk harmonic frequency components;
and
G. means connected to said comb filter to reconvert the output signal thereof to a PAL chrominance signal.

5 more elements

Dependencies are inferred from the claim text.

Magnetic recording and/or reproducing apparatus

Life of this patent

Magnetic recording and/or reproducing apparatus

Life of this patent

Abstract

Claims10