JPH0217850B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an endless tape recording and reproducing apparatus that sets a plurality of reference points used as recording and reproducing points along the longitudinal direction of the endless tape.

The use of endless tapes as a means of recording video signals and various data has been considered. That is, while the tape is driven to run endlessly, the head mechanism is set in a fixed position, and the recording/reproducing head in this head mechanism is moved in the width direction of the tape to extend in the width direction of the tape and in its longitudinal direction. It is designed to form a large number of recording tracks; for example, it is being considered to form as many as 300 tracks on a 1/2 inch wide tape.

Endless tape used in this way has a seam to make it endless. For example, this seam can be used to form a tape mark with reflective tape, and this tape mark can be optically By detecting
One revolution of the tape can be detected. This tape mark can be used as a reference point for an endless tape, and is used as a reference point for signal recording and playback. It is also possible to make the tracks consecutive.

In this way, when a large number of tracks are formed in the width direction of the tape, accessing any track can be performed very quickly by controlling the movement of the recording/reproducing head in the tape width direction using the head mechanism. Therefore, playback operations from arbitrary tracks as well as recording operations to arbitrary tracks can be effectively executed.

However, when using such tape marks, the minimum recording or playback unit is the length of one tape round, and even if 300 tracks are formed as described above, up to 300 types of information can be stored. All I can do is record.

In reality, even if the tape is made endless, it can be set to a length of 100 meters or more per circumference, and even more types of digital information can be stored on one track. It is possible to record and set the following data. but,
At a position other than the tape mark on the endless tape,
Furthermore, in order to set multiple recording and playback points, a means such as recording a reference period signal on the tape is required, which not only complicates the control circuit, but also causes problems with the length of one circumference of the tape. In the current situation where there is an error in the length of each tape, its control becomes more complicated.

This invention was made in view of the above points, and by setting multiple reference points for recording and playback in addition to the tape mark position on an endless tape, it is possible to create a wider variety of tapes. An object of the present invention is to provide an endless tape recording and reproducing apparatus that can record and reproduce signals based on simple access operations.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows its construction, and tape marks 12 made of reflective tape are attached to an endless tape 11 corresponding to its seams. An optical detection mechanism consisting of a light source 13a and a light detection element 13b is provided in the running path of the tape 11, and each time the tape 11 runs once, an optical detection mechanism is provided, as shown in FIG. A reference signal as shown in A is detected.

This detected reference signal is supplied to a phase comparison circuit 14, and the phase comparison signal from this circuit 14 is passed through a filter circuit 15 to a clock oscillator 1 which is a voltage controlled variable frequency oscillator VCO.
6 as a control drive signal. The clock signal from the clock oscillator 16 is frequency-divided by a counter 17, and the frequency-divided signal from the counter 17 is supplied to the phase comparison circuit 14 as a comparison signal.

That is, the phase comparison circuit 14, clock oscillator 16, and counter 17 constitute a PLL circuit, and the reference signal is detected once while the reference signal is detected, that is, while the tape 11 runs one revolution. A frequency-divided signal is generated from the counter 17 in synchronization with . For example, if the counter 17 is a 1/N frequency divider circuit, the oscillation frequency of the oscillator 16 is controlled so that the clock oscillator 16 generates N clock signals while the tape 11 runs one revolution. B and C in FIG. 2 show the states of the oscillation signal of the oscillator 16 and the frequency-divided output of the counter 17 in this state.

Therefore, in this state, the counter 17 is incremented at the point in time when the running time of one round of the tape 11 is divided into N equal parts, and the counted value is counted at a position on the tape 11 corresponding to, for example, a recording/reproducing head. It comes to represent the classification range of . That is, the comparison circuit 19 compares the counted value of the counter 17 with the setting information of the setting circuit 18 that sets the classification range of the purpose to be accessed, and by detecting the matching EQ, the result is calculated as shown in D in FIG. Thus, it becomes possible to obtain the desired section position detection output of the tape 11.

Here, when dividing the running time of one round of the tape 11 into N equal parts, the frequency division ratio in the counter 17 is set to "N".
×α” (where α is a positive integer), and
The clock oscillator 16 can be controlled so that "N×α" clock signals are oscillated during one revolution of the tape 11. In this case, the count value of the counter 17 is divided by 1/α. The signal may be supplied to the comparison circuit 19.

FIG. 3 shows another embodiment of the present invention, in which a detection signal from the light detection element 13b of the tape mark 12 is supplied to a differentiating circuit 20. The differentiating circuit 20 generates differential pulses corresponding to the leading edge and the trailing edge as shown in B and C in FIG. Generate a signal. Then, the flip-flop circuit 21 is reset by a pulse signal corresponding to the leading edge from the differentiating circuit 20, and the counter 17 is also reset. Further, the flip-flop circuit 21 is set by a differential pulse corresponding to the trailing edge following this reset pulse, and when this circuit 21 is set, a gate signal is given to the AND circuit 22. This AND circuit 22 has
A clock signal from the clock oscillator 16 whose frequency is controlled as described above is supplied, and the counter 17 is controlled by the output clock signal from the AND circuit 22.

That is, the counter 17 is initialized for each reference signal for detecting the tape mark 12 from the running endless tape 11, and the AND circuit 22 is controlled during the initial setting. As mentioned above, 1 of tape 11
A count signal representing the point in time when the circulation time is divided into N equal parts is obtained, and this count signal is supplied to the comparator circuit 19.

Here, if the information from the recording or playback start position setting circuit 23 and end position setting circuit 24 is supplied to the comparison circuit 19 as comparison information, the comparison circuit 19 can perform a comparison corresponding to the set start position and end position. A position detection output is obtained from the circuit 19,
A time range for recording or reproducing as shown in F in FIG. 4 is set corresponding to the running of the tape 11.

As described above, according to the present invention, reference points for recording and playback are set in a state where one round running time of an endless tape is divided into sections, and access control of various types of information is easily and reliably performed. This allows recording to be performed on an endless tape in any condition possible, and the range of applications for endless tapes is significantly expanded.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram illustrating a recording/reproducing apparatus according to an embodiment of the present invention, FIG. 2 is a signal diagram illustrating the above embodiment, and FIG. 3 is a configuration diagram illustrating another embodiment of the invention. FIG. 4 is a signal diagram showing the same operation. 11...Tape, 12...Tape mark, 13a...
Light source, 13b... Photodetection element, 14... Phase comparison circuit, 16... Clock oscillator (variable frequency), 17
...Counter, 18, 23, 24...Setting circuit, 19
...comparison circuit.

Claims (1)

[Claims] 1. means for detecting a reference signal corresponding to one revolution of the endless tape; a counter for dividing the clock signal from a variable frequency clock oscillator; and comparing the phase of the divided output from the counter with the detection signal; a phase comparator whose output also controls the oscillation frequency of the clock oscillator;
and means for dividing the time required for one round of the tape into N equal parts based on the detected signal and the count value of the counter, and using the dividing time point of the divided into N equal parts as a recording and playback standard. An endless tape recording and reproducing device characterized in that the endless tape is used as a point.