JPS632149A - Recording/reproducing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a recording/reproducing apparatus for recording and reproducing data such as audio information or video information on a recording medium.

The so-called digital audio tape recorder (DAT) records audio signals on magnetic tape, reproduces the signals, and performs signal processing using digital signals.
) records data on magnetic tape,
Alternatively, a pair of magnetic heads for reproducing data are provided on the outer peripheral surface of a rotating drum formed in a substantially cylindrical shape, in a straight line passing through the axial center of the drum.

A magnetic tape serving as a recording medium runs at a predetermined speed in sliding contact with a part of the outer peripheral surface of a rotating drum, and the rotating drum is driven to rotate at a predetermined speed faster than the running speed of the magnetic tape. The figure shows the state of sliding contact between the rotating drum 1 and the magnetic tape 2, and FIG. 6 shows the data recording area of the magnetic tape 2. The magnetic tape 2 has a substantially cylindrical pinch roller 3
and the capstan 4 is pressed against the capstan 4.
is rotationally driven in the direction of the fifth arrow A1 by a driving means (not shown). Therefore, the magnetic tape 2 runs in the direction of arrow A2 in FIG. Further, the rotating drum 1 is rotationally driven in the direction of arrow B1 by a driving means (not shown). Since the magnetic tape 2 runs at an angle of θ shown in FIG. 6 with respect to the rotational axis of the rotating drum 1, the sliding contact surface (data The storage area) will be in a state as shown in the PlfJG diagram. Region M1 in FIG. 6 is a recording region of the magnetic head 5,
Area M2 is a recording area of the magnetic herad 6.

When reproducing the recorded contents of the magnetic tape 2 that has been recorded as described above, the running speed of the magnetic tape 2 is different between normal playback, fast forward playback, and rewind playback. Adjustments must be made so that the relative speed between the traveling speed and the magnetic head 5.6 remains constant. The adjustment method is to record a control signal on the magnetic tape 2 at a position indicated by the reference numeral fjS6, and upon reproduction, process the signal by a processing circuit (not shown) to control the driving means (not shown) of the rotary drum 1.

Problems to be Solved by the Invention It is an object of the present invention to eliminate particles that adhere to the recording surface of the magnetic tape 2 when adjusting the relative speed of the magnetic tape 2 and the magnetic helads 5 and 6 as described above. The relative relationship between the recording medium and the recording/reading means can be adjusted without causing problems such as erroneous detection or non-detection of the control signal due to dust or dirt, etc., and the above-mentioned relative speed is different and the reproduced signal is disturbed. It is an object of the present invention to provide a recording/playback device that can keep the speed constant.

Means for Solving the Problems The present invention provides a method for reading a control signal when a control signal having a predetermined period is recorded on a recording medium at predetermined intervals and is read by a recording/reading head. Note 1: The relative speed between the recording/reading head and the recording medium is controlled to be constant according to the period of data! / In a reproducing device, read data of the control signal is given from the recording/reading head, and measuring means for measuring the period of the data a plurality of times, and comparing the plurality of measurement data obtained by the measuring means, respectively. and print its minimum value and perform such a comparison/
a first comparison means that repeats the output operation a plurality of times; and a first comparison means that is given the output of the first comparison hand Jffi, compares the outputs, outputs the maximum value, and performs such comparison/output operation a plurality of times. It is characterized by comprising a second comparison means for repeating the repetition, and a control means to which the output of the second comparison means is applied and controls the relative displacement speed between the recording medium and the recording/reading means to be constant. It is a recording/playback device.

Effect According to the present invention, a signal recorded on a recording medium and having a predetermined cycle is recorded/35! The reading means reads the cycle, the measuring means measures the period a plurality of times, and the outputs are compared by the first comparing means. Among the compared outputs, the one with the minimum value is given to the second comparing means. The above-mentioned operation is repeated a plurality of times, the second comparison means compares the given data, outputs the maximum value, and the output is given to the control means, which controls the recording medium and the recording/reading means. The relative displacement speed of is controlled to be constant.

Embodiment FIG. 1 is a block diagram showing the electrical configuration of a drum motor rotation control device 10 for a digital audio tape refugue (hereinafter abbreviated as DAT) according to an embodiment of the present invention. Referring to FIG. 1, the configuration of the DAT drum motor rotation control device 10 of this embodiment will be described below.

The drum motor rotation control device r No. 110 has a signal reading section No. 1.
and the first signal comparison section 12 and @2 signal ratio? Part 2 13 and
It is composed of a drum motor control section 14. The first signal reading section is equipped with a magnetic head 16 that reads control signals from the magnetic tape 15, and the signals read by the magnetic head 16 are amplified by a head amplifier 17, and supplied to a waveform shaping circuit 18 for waveform shaping. It is done.

The first signal comparison section 12 is equipped with a slice circuit 19 that converts the first output of the signal reading section into a digital signal and an envelope detection circuit 20, and each output is A
The signal is applied to the rising edge detection circuit 22 via the ND date circuit 21. The output of the rising edge detection circuit 22 is given to a rising latch pulse generation circuit 24 of a counter 23 . The output of the envelope detection circuit 20 is also applied to the AND date circuit 2 in relation to the 0 interval pulse generation circuit 25 and the latch pulse generation circuit 24 which are applied to the interval pulse generation circuit 25.
6.27 is provided. The output of the counter 23 is supplied to a latch circuit 28 and a comparison circuit 29.

The second signal comparator 13 includes a latch circuit 30 that holds the output of the first signal comparator 12, a latch pulse generation circuit 31 that provides a latch signal to the latch circuit 30, and a value held by the latch circuit 30. A comparator circuit 32 for comparing the input signal and the input signal is also provided. The counter 33, the inverting circuit 34, and the latch circuit 35 are used to take out and hold the output of the output circuit 30 at predetermined intervals.

The drum motor control unit 14 includes a drum servo circuit 37 that controls the rotation of the drum motor 36 based on the output from the second signal comparison unit 13, a low-pass filter (hereinafter abbreviated as LPF) 38, a drive circuit 39, and a drive circuit 39 for controlling the drum motor 36. It is comprised of a phase detection element 40 that detects the number of rotations, a phase signal amplification circuit 41 and a phase signal two-prong detection circuit 42 that process the output of the phase detection element 40. The operation of the drum motor rotation control II device 10 having the above configuration will be described below.

FIG. 2 is a timing chart showing the electrical timing of the drum motor rotation control device 10. As explained in the background art section, the magnetic tape 15 is run by a drive means (not shown), and the magnetic head 16 and another magnetic head (not shown) rotate the magnetic tape 15 as the rotating drum rotates.
5, data recording/reproduction is performed. Here, in order to make the explanation easier to understand, only the magnetic head 16 will be explained. Control signal data having a constant cycle for controlling a drum motor 36 that drives a rotating drum is recorded in advance on the magnetic tape 15.

During high-speed playback and high-speed rewinding, the magnetic tape 15 is run at high speed by a drive means different from the drive means described above. Here, the operation during high-speed running will be explained.

The data recorded on the magnetic tape 15 is transferred to the magnetic head 1
6 and converted into an electrical signal. The signal is amplified by head amplifier 17.

ff52 (1) shows a simplified signal waveform diagram of the output of the head amplifier 17, and this signal is an analog signal containing data such as audio information. This signal is given to the waveform shaping circuit 18, and the waveform shaping circuit 18
Only the control signal data described above is extracted. Second
FIG. (2) shows the output waveform of the waveform shaping circuit 18. The signal is transmitted to the slice circuit 19 and the envelope detection circuit 2.
2 (3) and 2 (4), respectively.
) is converted into a digital signal as shown in The signal shown in PIS2 diagram (3) is a repetitive pulse signal with a duty ratio of 50%. The respective outputs of the slice circuit 19 and the envelope detection circuit 20 are connected to an AND date circuit 21.
The signal passes through the rising edge detection circuit 22, becomes a waveform as shown in FIG. 2 (5), and is applied to the counter 23. This signal performs counting control in the counter 23 as will be described later. ? Figure tS3 is an enlarged view of Figure 2 in the horizontal direction (time axis), and the waveform shown in Figure 3 (1) is Pt52.
The waveform shown in FIG. 2(5) corresponds to the waveform shown in FIG. 2(5), and the waveform shown in FIG. 2(5) corresponds to the waveform shown in FIG. f53
FIG. 3(3) shows a basic clock pulse, which is generated by a pulse generation circuit (not shown) and supplied to the counter 23. In the counter 23, when the basic clock pulse rises while the control signal shown in FIG. 3(2) is at the word level, the counter 23 starts counting the basic clock pulse,
The period until the control signal becomes low level again (Pt
Counting is performed during the period indicated by reference numerals in Figure S3).

In addition, the output of the envelope detection circuit 20 (Fig. 2 (4)
) is given to the interval pulse generation circuit 25, and the interval pulse generation circuit 25 and the AND date circuit 26
As a result, a signal as shown in FIG. 2 (6) is output.

This signal is supplied to one input of the AND date circuit 27 and controls the latch pulse generation circuit 24. That is, if the signal is at a low level, the latch pulse generation circuit 2
4 does not operate, and if it is at a high level, it becomes operational.

The maximum value is held in the latch circuit 28 in advance, and when the counter 23 executes counting as described above, the count value is supplied to the terminal A of the comparison circuit 29, and the value held in the latch circuit 28 is is supplied to terminal B,
When the count value applied to terminal A is smaller than the holding value applied to terminal A, comparison circuit 29 supplies a high level signal to one input of AND date circuit 27.

If the input on the other side of the AND date circuit 27 is at a high level, the output of the AND5'-) circuit 27 is at a high level, and the latch pulse generating circuit 24 generates a latch pulse as shown in FIG. 3 (4). The launch circuit 28 holds the count value. In this way, the latch circuit 28 has
The minimum quant value will be retained.

A phase detection element 40 provided near the outer peripheral surface of the rotating shaft of the drum motor 36 generates a phase signal corresponding to the rotation of the drum motor 36, and its output is given to a phase signal amplification circuit 41 for amplification and waveform processing. Plastic surgery is performed. ff14 is a diagram in which the left-right direction (time axis) of FIG. 2 is degenerated, and both FIG. 4 (1) and FIG. This output is given to the phase signal edge detection circuit 42. The phase signal edge detection circuit 42 outputs a signal as shown in FIG. 152 (7), and supplies this output to the latch circuit 28. When this signal supplied to the latch circuit 28 is at a high level, the latch circuit 28
8 becomes operational and its value is reset when it goes low.

The minimum value of the count values thus held in the launch circuit 28 is given to the latch circuit 30 of the second signal comparator 13, and the value is held in the latch circuit 30.

The comparison circuit 32 compares the value held in the latch circuit 30 with the value input to the latch circuit 30, and if the input value is larger, it gives a signal (not shown) to the latch pulse generation circuit 31, and outputs a signal (not shown) to the latch pulse generation circuit 31. A latch pulse as shown in Figure (2) is generated. The launch circuit 30 is supplied with a latch pulse and holds the input value. In this way, the latch circuit 3
The maximum input value is held in 0. counter 3
3 and the inversion circuit 34, fjS every predetermined period.
4 (3) and 4 (4), and the latch circuit 30 is given the signal shown in FIG. 4 (4) to reset the held data to the minimum value, Further, a latch pulse as shown in FIG.

By repeatedly performing the above-described comparison operation, an averaged value of the count values is output from the latch circuit 35, and erroneous detection due to errors in reading control signals or dust attached to the magnetic tape is eliminated. can.

The output of the latch circuit 35 is given to the drum servo circuit 37 as data indicating the rotational speed of the drum motor 36, and only low frequency components are extracted from the output of the drum servo circuit 37 by the LPF 38 and given to three drive circuits. The drive circuit 39 drives the drum motor 3 according to the supplied signal.
Controls the rotation speed of 6.

In this way, the relative speed between the magnetic tape 15 and the spinning drum is controlled to be constant.

Effects According to the present invention as described above, the control signal recorded on the recording medium is read by the recording/reading means, the first comparison means outputs the minimum value of the data read multiple times, and the second comparison By outputting the maximum value of the output of the first comparison means, an averaged signal output can be obtained, and the signal may not be detected or be erroneously detected due to dust or dirt attached to the recording surface of the recording medium. Even if there is a detection, it is possible to control the relative speed between the recording/reading means and the recording medium to be kept constant without causing any shadow.

[Brief explanation of the drawing]

Fig. fiS1 is a block diagram showing the electrical configuration of a drum motor rotation control device f10 according to an embodiment of the present invention, and Fig. 2 is a timing chart diagram of the drum motor rotation control device 10.
Figure 3 is P! FIG. 4 is a diagram in which the time axis of FIG. S2 is expanded, FIG. 4 is a diagram in which the time axis of FIG. 2 is a diagram showing a data recording area of a magnetic tape 2. FIG. 10...Drum motor rotation control device, 1st...signal reading section, 12...1jSl signal comparison section, 13...@
2 signal comparison section, 14... drum motor control section, 15.
...Magnetic tape, 16...Magnetic head, 17...Head amplifier, 18...Waveform shaping circuit, one...Slice circuit, 20...Envelope detection circuit, 21.2
6.27...AND date circuit, 22...Rise detection circuit, 23,33...Counter, 24.31...
Latch pulse generation circuit, 25... section pulse generation circuit, 28, 30. 35... drum motor, 37... drum servo circuit, 38... LPF, 39... drive circuit, 40... Phase detection element, 41... Phase signal amplification circuit, 42... Phase signal Esso detection circuit

Claims (1)

[Claims] When a control signal having a predetermined cycle is recorded on a recording medium at predetermined intervals and is read by a recording/reading head, the read data of the control signal is recorded/read according to the cycle. In a recording/reproducing device configured to control a relative speed between a reading head and the recording medium to a constant value, read data of the control signal is given from the recording/reading head, and the period of the data is measured a plurality of times. A measuring means and a plurality of measurement data obtained by the measuring means are compared respectively, and the minimum value thereof is outputted, and such comparison/
a first comparison means for repeating an output operation a plurality of times; and a first comparison means for receiving the output of the first comparison means, comparing the outputs, outputting the maximum value thereof, and repeating such comparison/output operation for a plurality of times. 2 comparing means, and a control means to which the output of the second comparing means is applied and controls the relative displacement speed between the recording medium and the recording/reading means to be constant. playback device.