JPH04214252A - Device for detecting termination of recording information locus - Google Patents

Abstract

PURPOSE:To more accurately detect the termination of recording information locus recorded on a magnetic tape without receiving the effect of a tape speed at the time of recording and at the time of detecting in a rotary head type magnetic recording and reproducing device. CONSTITUTION:At the time of detecting the termination, a control signal is reproduced by a head 1 for a control signal, and the cycle of the reproduced control signal is detected by an up-counter 6 and compared with the cycle of the next reproduced control signal by a down-counter 8, then the termination of the recording information locus is detected when a difference is found for a period which is equal to or longer than the previously set period.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a detection device for detecting the end of a track of recorded information recorded on a magnetic tape by a rotary head type magnetic recording/reproducing device.

0002

2. Description of the Related Art Conventionally, in a rotary head type magnetic recording and reproducing apparatus that sequentially records and reproduces information signals as a recording trajectory inclined with respect to the longitudinal direction of a magnetic tape using a rotary head, in order to obtain tracking during reproduction, During recording, an alternating current (for example, 30H) synchronized with the rotational phase of the rotating head is used.
z) is recorded as a control signal along the edge of the magnetic tape by a fixed control signal head.

That is, as shown in FIG. 3, in the control signal track corresponding to section A in which the information signal is recorded,
S and N poles are recorded alternately, and the control signal track corresponding to section B in which no information signal is recorded is in a magnetic field-free state.

In such a rotary head type magnetic recording/reproducing device, as a method for detecting the end of the recorded information trajectory, a control signal head consisting of a wire-wound head arranged to scan the control signal track is used to detect the end of the recorded information trajectory. A method has been considered in which a signal is reproduced, and if the reproduction control signal does not last for a certain period of time, it is determined that a non-recorded section is being scanned, and the end of the recorded information trajectory is detected.

In FIG. 2, numeral 1 indicates a control signal head made of a wire-wound head, and 2 is an operational amplifier that amplifies the output waveform (C in FIG. 3) detected by the control signal head 1. 3 is the operational amplifier 2
This is a flip-flop whose input is the output of Reference numeral 5 denotes a system controller of the rotary head type magnetic reproducing device, which receives the output of the flip-flop 3 (D in FIG. 3) and converts the value of predetermined fixed period data 10 into a down counter in synchronization with the rising edge of the output. Set as the initial value of 8. The down counter 8 receives the basic clock 9 and sequentially counts down the initialized value. If the down counter 8 overflows before receiving the next rising edge of the output D of the flip-flop 3, it is determined that the end of the recorded information trajectory has been detected.

[0006]

According to the conventional example described above, in order to detect the end of a recorded information trajectory, a non-recorded section while the magnetic tape is running is obtained from a wire-wound head that is running in a recorded section. It must last longer than the longest period of the effective control signal, and it can be detected even in fast-forward conditions, where the tape speed is 50 times faster than the tape speed during normal recording and playback.Also, taking into account malfunctions due to tape scratches, etc.
It was necessary to set the value of the fixed cycle data 10 so that when approximately 1000 cycles of the control signal are missing, it is determined that the recorded information trajectory has reached its end. Therefore, it has not been effective in detecting the end of a recorded information trajectory for the purpose of searching for a small non-recorded section that occurs at the recording end point when re-recording is performed on a tape that has been previously recorded.

[0007]

[Means for Solving the Problems] The recorded information trajectory end detection device of the present invention detects the end of the recorded information trajectory recorded on a tape. The control signal is reproduced, the period of the reproduction control signal is sequentially detected, and when there is a difference of more than a predetermined period between detection periods close to each other, it is determined that the recording trajectory is at the end.

[0008]

[Operation] According to the above configuration, when detecting the end of the recording information trajectory recorded on the tape, the control signal recorded at the time of recording is reproduced at a predetermined constant cycle, and the cycle of the reproduction control signal is adjusted. Since the configuration is such that detection is performed sequentially and based on differences in the playback cycles of adjacent playback control signals, the end of the recorded information trajectory can be detected with high accuracy regardless of the tape speed at the time of recording and the tape speed at the time of detection. This makes detection possible.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 indicates a control signal head consisting of a wire-wound head, and 2 an operational amplifier for amplifying the output waveform detected by the control signal head 1. 3 is a flip-flop that receives the output of the operational amplifier 2 as an input, and 4 is a 30-pulse counter that sequentially counts the output a of the flip-flop 3 and generates an output b every time it counts 30 pulses. 6 is an up counter that is reset every time the output b of the 30 pulse counter 4 is applied, inputs the basic clock 9, sequentially counts up, and sequentially outputs the counted value at the time of reset to the multiplier 7. The count value at this reset is proportional to the cycle of the reproduction control signal. The multiplier 7 multiplies the data transferred from the up counter 6 by four times, for example, and sets it as the initial value of the down counter 8.

The down counter 8 receives the basic clock 9 and sequentially counts down from the initially set value. If the down counter 8 overflows before the next initial value is set by the multiplier 7 (before receiving the output b of the 30 pulse counter 4), an output is generated and the end of the recorded information trajectory is detected. This is what we judge. That is, in the case of this embodiment, the difference between the sum of the periods of 30 reproduction control signal groups whose number is set in advance by the 30 pulse counter 4 and the sum of the periods of the next 30 reproduction control signal groups is 4 times ( If there is a difference in the number of multipliers (multiplier), it is determined that the terminal has reached the end.

0012

As described above, according to the present invention, when detecting the end of a recorded information trajectory, the cycle of the reproduction control signal is detected, and detection cycles that are close to each other are detected to have a difference of more than a predetermined period. By configuring the system to determine that it is the end of the recorded information trajectory when there is a trace of recorded information, accurate detection is possible without being affected by the tape speed at the time of recording or detection. This also makes it possible to search for a small unrecorded section that occurs at consecutive recording points when recording is performed again.

[Brief explanation of the drawing]

FIG. 1 is a system block diagram showing the main parts of a recording information trajectory end detection device according to an embodiment of the present invention.

[Fig. 2] System block diagram showing the main parts of a conventional recording information trajectory end detection device

[Figure 3] Output waveform diagram of the conventional example

[Explanation of symbols]

1 Wire-wound head 2 Operational amplifier 3 Flip-flop 4 30 pulse counter 5 System controller 6 Up counter 7 Multiplier 8 Down counter 9 Basic clock 10 Fixed cycle data

Claims (1)

[Claims] 1. When detecting the end of a recording information trajectory recorded on a tape, a control signal recorded at a predetermined constant cycle during recording is reproduced, and the cycles of the reproduction control signal are sequentially detected. An end detection device for a recorded information trajectory, characterized in that it is determined that the recording trajectory is the end when there is a difference of more than a predetermined period in the detection cycles of reproduction control signals that are close to each other.