EP0094194A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Magnetic recording and reproduction system
Assignee: Panasonic Holdings Corp
•
Filing: 1983-05-04
•
Granted: —
•
Expires: 2003-05-04
Abstract
Abstract A magnetic recording and reproduction system of helical scan type is disclosed. During the recording process, pilot signals (f,p, f 2 p, f 3 p, f 4 p) for reproduction tracking control are sequentially recorded by the rotary magnetic head in recording tracks in proximity to each other in superimposed relation with the television signal to be recorded. During the normal reproduction process, from the level difference between the crosstalk signals of the pilot signals reproduced from the recording tracks to be reproduced, a tracking error is detected to control the relative positions of the recording track and the reproduction scanning traces of the reproduction magnetic head. During the reproduction process at a speed different from that for recording, on the other hand, a pulse signal is produced at a time point when the crosstalk levels of the pilot signals reproduced from the tracks adjacent to the recording track to be reproduced coincide with each other. This pulse signal is used to maintain a predetermined positional relation between the recording track and the reproduction scanning traces of the reproduction magnetic head thereby to produce a superior reproduced image.
Inventors
- 👤 Koichi Yamada
- 👤 Kanji Kubo
- 👤 Yasuo Nishitani
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 09:31
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/76; H04N5/91; H04N5/92; H04N5/93; G; G11; G11B; G11B15/00; G11B15/18; G11B15/1808; G11B5/00; G11B5/48; G11B5/58; G11B5/584; G11B5/588
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
254 words
In a magnetic recording and reproducing system of helical scan type, wherein during the recording process, four types of pilot signals (f 1p , f 2P , f 3p and f 4P ) of different frequencies are sequentially recorded by a rotary head one for each field of a television signal to be recorded, in superimposed relation with said television signal on a magnetic tape, in such a manner that the television signal of each field forms one recording track, and during the normal reproduction process involving the same tape speed as for the recording, first and second frequency signals are generated representing the frequency difference between the reference signals and the pilot signals reproduced-from the adjacent recording tracks on both sides of the main recording track to be reproduced, the relative positions of the recording track and the reproduction scanning traces of the rotary head being controlled by a tracking error signal corresponding to the level difference between said first and second frequency signals: the improvement wherein during the reproduction process when the magnetic tape is fed at a speed different from that for recording, a pulse signal is generated at the time point when the levels of said first and second frequency signals coincide with each other, said pulse signal being used as a signal indicating that said rotary head has reproduced a predetermined position of the recording track pattern on the magnetic tape, thus controlling the relative positions of the reproduction scanning traces of said rotary head and the recording track.
Claim 2
Dependent Claim
254 words
In a magnetic recording and reproducing system of helical scan type, wherein during the recording process, four types of pilot signals (f 1p , f 2P , f 3p and f 4P ) of different frequencies are sequentially recorded by a rotary head one for each field of a television signal to be recorded, in superimposed relation with said television signal on a magnetic tape, in such a manner that the television signal of each field forms one recording track, and during the normal reproduction process involving the same tape speed as for the recording, first and second frequency signals are generated representing the frequency difference between the reference signals and the pilot signals reproduced-from the adjacent recording tracks on both sides of the main recording track to be reproduced, the relative positions of the recording track and the reproduction scanning traces of the rotary head being controlled by a tracking error signal corresponding to the level difference between said first and second frequency signals: the improvement wherein during the reproduction process when the magnetic tape is fed at a speed different from that for recording, a pulse signal is generated at the time point when the levels of said first and second frequency signals coincide with each other, said pulse signal being used as a signal indicating that said rotary head has reproduced a predetermined position of the recording track pattern on the magnetic tape, thus controlling the relative positions of the reproduction scanning traces of said rotary head and the recording track.
Claim 3
Dependent Claim
52 words
A magnetic recording and reproducing system according to Claim 1, wherein the frequency of one of said four pilot signals (f 1p , f 2 p 1 f 3P , f 4P ) is set, and the feed of the magnetic tape'is stopped in response to the generation of said pulse signal.
Claim 4
Dependent Claim
62 words
A magnetic recording and reproducing system according to Claim 1, wherein during the reproduction process when the tape is fed in the same direction as at the time of recording at a speed N times higher than for recording, the four pilot signals are supplied as reference signals in a sequence reverse to that for recording thereby to produce a pulse signal.
Claim 5
Dependent Claim
79 words
A magnetic recording and reproducing system according to Claim 1, wherein during the reproduction process when the magnetic tape is fed in the direction opposite to that for recording at a speed N times higher than for recording to produce a reproduced image, said four pilot signals (f 1P , f 2p , f 3 p 1 f 4P ) are supplied as reference signals in a sequence reverse to that for recording thereby to produce a pulse signal.
Claim 6
Dependent Claim
101 words
A magnetic recording and reproducing system according to Claim 1, comprising a pseudo control signal generator circuit including a Schmitt circuit (34), a trapezoidal wave generator circuit (35) supplied with an output of said Schmitt circuit, a waveform shaping circuit (36) supplied with an output of said trapezoidal wave generator circuit, and an exclusive OR circuit (37) supplied with an output of said waveform shaping circuit and an output of said Schmitt circuit, said Schmitt circuit being supplied with a tracking error signal so that the tracking control is effected by use of a pulse produced from said exclusive OR circuit.
Claim 7
Dependent Claim
89 words
A magnetic recording and reproducing system according to Claim 5, wherein during the reproduction process when the magnetic tape is fed in forward direction at a speed N times higher than for recording to produce a reproduced image, the four pilot signals (f 1p , f 2p , f 3p , f 4p ) are supplied as reference signals in a sequence reverse to that for recording, the output pulse of said pseudo control signal generator circuit being frequency-divided to 1/(N-1), said frequency-divided signal being used for tracking control.
Claim 8
Dependent Claim
89 words
A magnetic recording and reproducing system according to Claim 5, wherein during the reproduction process when the magnetic tape is fed in reverse direction at a speed N times higher than that for recording to produce a reproduced image, the four pilot signals (f 1p , f 2p , f 3P' f 4P ) are supplied as reference signals in a sequence reverse to that for recording, the output pulse of said pseudo control signal generator circuit being frequency-divided into 1/(N-1), the frequency-divided signal being used for tracking control.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.