System for recording and reproducing picture signals into which character signals can be inserted

Claim 1

A system (1) for recording and reproducing picture signals comprising a phase-modulated or frequency-modulated picture colour signal on and from a magnetic tape (2) in adjacent tracks which are inclined relative to the longitudinal direction of the tape, which picture signals can be recorded and reproduced in a first recording mode and in a first reproduction mode with a first tape speed and in a second recording mode and in a second reproduction mode with a second tape speed which is preferably a submultiple of the first tape speed, the video signals recorded in the first recording mode being additionally reproducible in at least one first further reproduction mode with at least one first further tape speed which differs from the first tape speed, and the video signals recorded in the second recording mode being additionally reproducible in at least one second further reproduction mode with at least one second further tape speed which differs from the second tape speed, modulated character signals, which comprise a phase-modulated or a frequency-modulated character colour signal, being insertable into at least the reproduced picture signals, the system having a conversion stage (70) for reconverting a reproduced picture colour signal (F) to an original frequency range, which conversion stage supplies the reconverted picture colour signal to an output (71), having a detection stage (73) which is arranged behind the output (71) of the conversion stage (70) and which in the case of a phase-modulated picture colour signal is constructed as a phase detection stage for detecting the phase of the burst signal in the reconverted picture colour signal and in the case of a frequency-modulated picture colour signal is constructed as a frequency detection stage for detecting the frequency of the non-modulated colour subcarrier signals in the reconverted picture colour signal, which detection stage supplies a detection signal of half the line frequency to an output (76), having a first switching device (82) arranged behind the output (71) of the conversion stage (70) and controllable by means of a control device (17), which first switching device is set to a first switch position by the control device (17) in the second further reproduction mode of the system (1), in which first switch position a first delay device (84) of the system (1) with a delay time of one line period is arranged in series with the first switching device (82) and the reconverted picture colour signal supplied to the output (71) of the conversion stage (70) is transferred with a delay of one line period to a further signal-processing stage (67) of the system (1), and which is set to a second switch position by the control device (17) in all the other reproduction modes of the system (1), in which second switch position the first delay device (84) is bypassed and the reconverted picture colour signal supplied to the output (71) of the conversion stage (70) is transferred without a delay to the further signal-processing stage (67), and having a character generator (37) for the generation of non-modulated character signals and a modulator (36) which is connected to the character generator (37) and which enables the non-modulated character signals to be converted into modulated character signals to be inserted, and having a character insertion stage (33) which is connected to the further signal processing stage (67) and to the modulator (36) and which is adapted to insert the modulated character signals at least into the reproduced picture signals, the modulator (36) comprising a control input (36b) to which a control signal (S2) of half the line frequency is applied, which control signal is phase-locked to a detection signal of half the line frequency supplied to the output (76) of the detection stage (73), in order to achieve that the reproduced picture colour signals and the character colour signals to be inserted are locked in phase in the case of a phase-modulated picture colour signal and are locked in frequency in the case of a frequency-modulated picture colour signal, characterized in that the control input (36b) of the modulator (36) is preceded by a second switching device (93) which can be controlled by the control device (17) in the same way as the first switching device (82) and which is set to a first switch position by the control device (17) in the second further reproduction mode of the system (1), in which first switch position a second delay device (94) of the system (1) with a delay time of one line period is arranged in series with the second switching device (93) and the control signal (S2) applied to the control input (36b) of the modulator (36) is transferred with a delay of one line period to the control input (36b) of the modulator (36), and which is set to a second switch position by the control device (17) in all the other reproduction modes of the system (1), in which second switch position the second delay device (84) is bypassed and the control signal applied to the control input (36b) of the modulator (36) is transferred without a delay to the control input (36b) of the modulator (36).