JPH0673224B2 - Magnetic tape recorder - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic tape recording device having a rotary head.

2. Description of the Related Art In a magnetic recording / reproducing apparatus that digitizes an acoustic signal or an image signal and records / reproduces it on a recording medium such as a magnetic tape, in general, a digital signal has a wider frequency than an analog signal before being digitized. Bandwidth is needed. As one method of recording a digital signal having such a wide frequency band with high density, there is a magnetic tape recording / reproducing apparatus using a rotary head used in a home video tape recorder or the like.

Such a magnetic tape recording / reproducing apparatus is an A / D (analog / analog) that converts an input analog signal into a digital signal.
(Digital) converter, memory having a function of a buffer for temporarily storing the converted digital signal, a data format generation circuit for generating a predetermined data format from the digital signal stored in the memory, and a control unit for controlling these The output of the data format generation circuit is modulated and given to the rotary head and recorded on the magnetic tape wound around the rotary head.

The control unit is provided with a clock generation circuit for generating a plurality of clock signals having different frequencies, and the converter, the memory, the data format generation circuit, the motor for driving the rotary head, and the like respectively generate the clocks. The operation is controlled based on each clock signal generated from the circuit.

FIG. 7 is a block diagram showing an electrical configuration of a typical prior art clock generation circuit 1. Clock generation circuit 1
Is composed of a frequency divider 2 and two decoders 3 and 4, which are realized by, for example, an n-bit binary counter, and the frequency divider 2 has a plurality of frequency division periods based on the input reference clock signal. Two decoders for output
Give to 3,4.

The decoder 3 outputs the sampling clock signal B to the A / D converter, the decoder 4 outputs the slot clock signal C to the format generation circuit, and the read clock signal D to the memory. It is output respectively. An output having the minimum frequency division period of the frequency divider 2 is given to the motor as a synchronous clock signal A of the rotary head.

FIG. 4 is a diagram schematically showing a rotary head device 5 commonly used in the prior art and one embodiment of the present invention. Two
A magnetic tape 9 is wound at a winding angle α on a rotary drum 8 to which two magnetic heads 6 and 7 are attached with an interval of 180 °, and the magnetic tape 9 runs in the direction of arrow 51 at a speed Vt. On the other hand, the rotary drum 8 rotates in the arrow 52 direction at the rotation speed Vd. Since the tape running speed Vt is sufficiently smaller than the drum rotation speed Vd, the trace speed when the two magnetic heads 6 and 7 trace the magnetic tape 9 is substantially equal to the drum rotation speed Vd.

Here, when the diameter R0 of the rotary drum 8 is reduced, if the rotational speeds are kept the same, the magnetic tapes 9 of the magnetic heads 6 and 7 are
The trace speed for Therefore, if the winding angle α of the magnetic tape 9 is increased by the amount corresponding to the decrease in the tracing speed, for example, the distance over which the two magnetic heads 6 and 7 trace the magnetic tape 9 during one rotation of the rotating drum 8 is kept constant. Can be kept at However, since the trace speed of the magnetic heads 6 and 7 is low, it becomes impossible to record information on the magnetic tape 9 at the same density.

Therefore, the synchronous clock signals A and A / of the rotary head
When the sampling clock signal B of the D converter is not changed and the frequency of the slot clock signal C and the memory read clock signal D of the format generating circuit is lowered by the amount of the diameter R0 reduced, the diameter R0 is reduced. It is possible to record on the magnetic tape 9 in the same recording format as before.

That is, in this way, the read speed for reading data from the memory can be reduced while the rotation speed of the rotary drum 8 is kept constant, and the desired recording format can be generated by the changed slot clock signal C. it can. When it is desired to reduce the diameter R0 of the rotary drum 8 in this manner, the frequencies of the slot clock signal C and the memory read clock signal D are correspondingly changed to perform recording / reproduction in the same recording format. be able to.

Problems to be Solved by the Invention The two clock signals C and D are generated by dividing one reference clock signal CK as shown in FIG.
The ratio between the frequencies of the two clock signals C and D and the frequencies of the two clock signals A and B is always in an integral ratio relationship. Therefore, it is generally difficult to generate the clock signals C and D having a desired frequency only by changing the frequency division ratio in the frequency divider 2. Therefore, once a rotary drum with a specific diameter is designed and the circuit elements such as the clock generator circuit corresponding to this are integrated, the diameter of the rotary drum can be arbitrarily changed unless the circuit configuration is changed. It was impossible to do.

An object of the present invention is to solve the above-mentioned problems and to provide a magnetic tape recording apparatus capable of dealing with a rotary head having an arbitrary radius of rotation without newly changing the circuit configuration.

MEANS FOR SOLVING THE PROBLEMS In the present invention, (a) the magnetic tape 9 is wound around the rotary drum 8 with an inclination angle, and (b) the running speed Vt of the magnetic tape 9 is a predetermined constant value. If the diameter R0 of the rotary drum 8 has a predetermined first value, and the rotation speed Vd of the rotary head 5 is set sufficiently small, the magnetic tape 9 on the rotary drum 8 has a predetermined first value. Is wound with a wrap angle α of, and the diameter R0 has a second value smaller than the first value,
It is wound at a second winding angle larger than the first winding angle α, thereby keeping the distance traced by the magnetic heads 6 and 7 constant, and (d) generating the first reference clock signal CK1. A first reference clock signal generation source, and (e) the first reference clock signal CK1 from the first reference clock signal generation source is divided into a predetermined number n of frequency division periods to generate a clock signal, A first frequency divider 31 that outputs each clock signal from each of the first output terminals Q1 to Qn, and (f) a clock signal A1 from the output terminal Qn of the minimum frequency division period of the first frequency divider 31. Then, in response to the motor 19 that rotationally drives the rotary head 5, and (g) each clock signal output from the first output terminals Q1 to Qn of the first frequency divider 31, a continuous sampling clock signal B1 From the first decoder 35 for generating An analog / digital converter 14 for converting an analog signal to be recorded into a digital signal in response to the first sampling clock signal B1 and (i) a minimum frequency division period of the first frequency divider 31. A reset circuit 33 that generates a reset signal R for each period TA1 of one level of the minimum frequency division period clock signal A1 in response to the minimum frequency division period clock signal A1 from the output terminal Qn, and (j) is input. The reference clock signal is divided into frequency division cycles of the same number n as the frequency division cycle of the first frequency divider 31 and the same frequency division cycle to generate a clock signal, and each clock signal is generated by the second frequency division circuit. A second frequency divider 32 which outputs from each of the output terminals P1 to Pn, (k) a second reference clock signal CK2 is generated, and a period T1 of the first reference clock signal CK1 and a period T2 of the second reference clock signal CK2 And the ratio T1 / T2 is the minimum frequency division period of the first frequency divider 31. And the one period of the level TA1 locking signal A1, the second
The ratio TA1 / TF of the minimum frequency dividing period clock signal F of the frequency divider 32 to the period TF of the one level is equal to the period T2 of the second reference clock signal CK2 at each of the first and second winding angles α. The second reference clock signal generation source, which is defined correspondingly, and (l) the second reference clock signal CK2 from the second reference clock signal generation source A logic circuit 34 which is derived and given as the input reference clock signal CK of the second frequency divider 32 during the one-level period TF of the signal F, and cut off during the other-level period TF1, and (m) the second A second decoder 36 for generating a read clock signal D1 and a slot clock signal C1 in response to each clock signal output from the second output terminals P1 to Pn of the frequency divider 32, and (n) analog / digital conversion Write the digital signal from the device 14 and write it It reads the data clock signal D1
Memory 16 to be read in synchronism with, and (o) a data format is generated and added to the data read from the memory 16 in synchronism with the slot clock signal C1,
A magnetic tape recording apparatus comprising means 17 and 18 for giving to the rotary head 5 for recording.

Operation According to the invention, when the diameter R0 of the rotary drum 8 has a second value smaller than the first value, the second reference clock signal CK2 is applied to the logic circuit 34, whereby the memory 16 is supplied. A read clock signal for reading is changed and given, and a slot clock signal C1 is changed and generated. In this way, even if the diameter R0 of the rotary drum 8 changes to the first value and the second value, the circuit configuration can be used with almost no change.

Further, according to the present invention, even if the diameter R0 of the rotary drum 8 changes, the first reference clock signal does not change, and therefore the rotation speed of the rotary head 5 does not change. At this time, the winding angle α is changed according to the change of the diameter R0 of the rotary drum 8,
This keeps the tracing distance of the magnetic heads 6 and 7 constant. Moreover, the running speed Vt of the magnetic tape 9 is a constant value and is set sufficiently smaller than the rotating speed Vb of the rotary head 5. Therefore, even if the diameter R0 of the rotary drum 8 changes, Can be written and recorded in the same manner.

Embodiment FIG. 3 is a block diagram showing the electrical construction of a magnetic tape recording / reproducing apparatus 11 which is an embodiment of the present invention. First of all
The recording system will be described with reference to the drawings. The analog signal to be recorded has a high-frequency component removed by a low-pass filter 12, is sampled by a sample hold circuit 13, and is applied to an analog / digital converter 14. In the converter 14, the sampled analog signal is a sampling clock signal which is the first type of control data output from the control unit 15.
It is converted into a digital signal in synchronization with B1, and this signal is written in the memory 16.

The memory 16 has a function as a buffer for time-compressing and storing digital signals continuously input from the converter 14 and outputting recording signals sequentially recorded on the magnetic tape 9. The data stored in the memory 16 is read based on the read clock signal D1 which is the second type of control data output from the control unit 15, that is, in synchronization.
The data read from the memory 16 is stored in the control information adding circuit 17
After being added with the control information and generated in a predetermined format, it is modulated by the modulation circuit 18 and recorded on the magnetic tape 9 through the rotary head device 5. In addition, memory 16
The control information addition circuit 17 constitutes a data format generation means.

The second information output from the control unit 15 is sent to the control information adding circuit 17.
The slot clock signal C1 which is the control data of the above type is given, and the above-mentioned format is formed based on the slot clock signal C1, that is, in synchronization. The slot clock signal C1 is output in synchronization with the read clock signal D1. On the other hand, a motor 19 that drives the rotary head 5
A synchronous clock signal A1 is given from the control unit 15, and the rotary head 5 rotates in synchronization with this clock signal A1.

Next, the reproducing system will be described. The signal read from the magnetic tape 9 by the rotary head 5 is demodulated by the demodulation circuit 20 into the format created at the time of recording, and the control information detection circuit 21 detects data including various control information and acoustic signals. , This data is written to the memory 16. The data written in the memory 16 is sequentially read by a clock signal synchronized with the sampling frequency, and reproduced as an analog signal through the digital / analog converter 22 and the low pass filter 23.

With reference to FIG. 4, as described above, the rotary drum 8 is an arrow.
The magnetic tape 9 is rotated in the 52-direction at a rotation speed Vd, and the magnetic tape 9 is wound around the rotating drum 8 at a winding angle α and travels in the 51-direction at a traveling speed Vt. The magnetic tape 9 is wound around the rotary drum 8 with an inclination angle θ with respect to the plane of FIG. The track pattern of the recording information recorded on the magnetic tape 9 by the rotary drum device 5 is shown in FIG.

The magnetic tape 9 runs at the running speed Vt in the direction indicated by the arrow C. The running speed Vt of this magnetic tape 9 is the rotating drum 8
Is set to be sufficiently smaller than the rotation speed Vd of. Therefore, the inclination of each track 40 formed on the magnetic tape 9 with respect to the running direction C of the magnetic tape 9 (track angle)
Is approximately equal to the inclination angle θ of the magnetic tape 9. Further, each track 40 on the magnetic tape 9 is sequentially and alternately recorded by the two magnetic heads 6 and 7 attached to the rotary drum 8.

Each track 40 is provided with a data area 41 in which digitized information is recorded. This digitized information is often recorded according to a certain format, and for example, the structure shown in FIG. 6 is used. The digital signal recorded on the track 24 is composed of a plurality of blocks, and each block is composed of a synchronization signal 25, an ID signal 26 and data 27. The synchronization signal 25 is located at the tip of each block and serves as a mark when reading the data 27, and the ID signal 26 identifies the data 27.

FIG. 1 is a block diagram showing an electrical configuration of a clock generating circuit 30 used in a magnetic tape recording / reproducing apparatus 11 which is an embodiment of the present invention. The clock generation circuit 30 is provided in the control unit 15 shown in FIG.

The clock generation circuit 30 includes two frequency dividers 31 and 32 realized by, for example, an n-bit binary counter, a reset circuit 33 that outputs a reset signal described later, and an OR circuit.
34 and two decoders 35 and 36.

The reference clock signal CK1 which is the first type of reference clock signal is input to the input terminal CK of the frequency divider 31, and based on the reference clock signal CK1, each of a plurality of predetermined n types of components is input. The clock signal divided in the cycle period is output to the decoder 35 from the n output terminals Q1 to Qn. The output from the output terminal Qn has a minimum frequency division period,
This is given to the motor 19 as the synchronous clock signal A1 of the rotary head 5 described above. The output of the decoder 35 is given to the converter 14 as a sampling clock signal B1 based on the output of the frequency divider 31.

On the other hand, the output from the output terminal Qn of the frequency divider 31 is input to the input terminal R of the frequency divider 32 via the reset circuit 33 including the delay circuit 37 and the exclusive OR circuit 38. The transfer clock signal CK2, which is the second type of reference clock signal, is input to the input terminal CK of the frequency divider 32 via the OR circuit 34. The outputs from the n output terminals P1 to Pn each have a predetermined frequency division period, which are supplied to the decoder 36. The output of the output terminal Pn has the minimum frequency division period, and is supplied to the decoder 36 and also input to one terminal of the OR circuit 34.

From the decoder 36, a slot clock signal C1 that is synchronized when the synchronizing signal and the ID signal are added in the control information adding circuit 17 and a memory read clock signal D1 that is synchronized when the data stored in the memory 16 is called. Is output.

FIG. 2 is a timing chart for explaining the operation of the clock oscillator circuit 30. When the reference clock signal CK1 as shown in FIG. 1A is input to the input terminal CK of the frequency divider 31, the output of the rotary drum as shown in FIG. 3C is output from the output terminal Qn based on the reference clock signal CK1. Synchronous clock signal
A1 is output. Further, the clock signal A1 is given to the frequency divider 31 as the reset signal R via the reset circuit 33 as described above. The reset signal R forms a falling pulse having a narrow width downward in synchronization with the clock signal A1 as shown in FIG. Further, the sampling clock signal B1 output to the converter 14
Outputs a continuous clock signal as shown in FIG.

Next, when the transfer clock signal CK2 having the cycle T2 as shown in FIG. 2B is input to the input terminal CK of the frequency divider 32,
The frequency divider 32 counts this up and outputs it to the decoder 36. As a result, the decoder 36 outputs the slot clock signal C1 and the memory read clock signal D1 as shown in FIGS. 7 (8) and 7 (8). The memory read clock signal D1 contains control information for addressing the memory 16 and the like. On the other hand, the frequency divider 32
The output F from the output terminal Pn becomes as shown in (4) of the figure based on the transfer clock signal CK2.

The two frequency dividers 31, 32 have the same configuration. As a result, the ratio between the falling period TA1 of the synchronous clock signal A1 shown in FIG. 3C and the falling period TF of the output F is the same as the period T1 of the reference clock signal CK1 shown in FIG. 2) Equal to the ratio of the illustrated transfer clock signal CK2 to the period T2. Since the reset signal R synchronized with the synchronous clock signal A1 is input to the frequency divider 32 as described above, the rising period of the output F is also at the L level in synchronization with the reset signal R.

When such an output F is input to one terminal of the OR circuit 34, the frequency divider 32 is prohibited from counting up the transfer clock signal CK2 during the rising period TF1 of the output F.
Therefore, the transfer clock signal CK2 is counted up only in the falling period TF of the output F, and the slot clock signal C is also counted only in the falling period TF1.
1 and the memory read clock signal D1 are counted up. As a result, the period t during which the recording signal E is recorded on the magnetic tape 9 is determined. That is, the transfer clock signal CK2 is used during the recording period t.
Is determined by the period T2 of. The two frequency dividers 31 and 32 have the same configuration as described above, and further two decoders 35 and 36
And the period T2 of the transfer clock signal CK2 is selected to be half the period T1 of the reference clock signal CK1, the recording period t of the recording signal E becomes 1/4 period of the synchronous clock signal A1. In this state, the winding angle α of the magnetic tape 9 with respect to the rotary drum 8 is selected to be 90 °.

Here, if the diameter R0 of the rotary drum 8 is reduced, the trace speed Vd is reduced as described in the section of the prior art. Therefore, the winding angle α of the magnetic tape 9 may be increased by the amount that the diameter R0 is decreased, and the period T2 of the transfer clock signal CK2 may be increased correspondingly. As a result, the recording period t can be lengthened without changing the number of blocks in one frame in the recording area recorded on the magnetic tape 9, and the winding angle α of the magnetic tape 9 is increased by the lengthened length. This corresponds to the decrease in the diameter R0 of the rotary drum 8.

Even if the diameter of the rotary drum 8 is changed in this way, the winding angle α of the magnetic tape 9 is changed correspondingly, and the cycle T2 of the transfer clock CK2 is changed. Data can be recorded in the same format. Therefore, even if the diameter of the rotary drum 8 is changed, it is not necessary to newly provide a circuit configuration corresponding to the diameter, and it is possible to record on the magnetic tape in the same format. The same thing can be done during playback.

Therefore, in the present invention, since the recording track length T on the magnetic tape 9 is fixed, the diameter R0 of the rotary magnetic heads 6 and 7 is
The wrapping angle α becomes smaller as is increased. That is, (1) Here, since the traveling speed Vt of the magnetic tape 9 is a constant value and the number of rotations of the rotary drum 8 is constant, when the winding angle α becomes small, the time to write on the magnetic tape 9 becomes short. . That is, the relative speed between the magnetic heads 6 and 7 and the magnetic tape 9 increases. Therefore, in the present invention, the second clock frequency is increased.

Effect As described above, according to the present invention, when the diameter R0 of the rotary drum 8 changes, the magnetic tape 9 can always be written in the same manner by using the second reference clock signal CK2. In this way, even if the diameter R0 of the rotary drum 8 changes, it can be used without significantly changing the circuit configuration.

[Brief description of drawings]

FIG. 1 shows a magnetic tape recording / reproducing apparatus according to an embodiment of the present invention.
11 is a block diagram showing an electrical configuration of the clock generating circuit 30 used in FIG. 11, FIG. 2 is a timing chart for explaining the operation of the clock generating circuit 30, and FIG. 3 is an electrical configuration of the magnetic tape recording / reproducing apparatus 11. FIG. 4 is a schematic diagram of the vicinity of the rotary head device 5, FIG. 5 is a diagram showing an example of a track pattern recorded on the magnetic tape 9,
FIG. 6 is a diagram showing an example of the format of the information recorded on the magnetic tape 9, and FIG. 7 is a block diagram showing the electrical configuration of a typical prior art clock generation circuit 1. 5 ... rotary head, 6, 7 ... magnetic head, 8 ... rotary drum, 9 ... magnetic tape, 11 ... magnetic tape recording / reproducing device, 14, 22 ... converter, 15 ... control unit, 16 ... Memory, 17 ... Control information addition circuit, 19 ... Motor, 30 ... Clock generation circuit, 31,32 ... Frequency divider, 33 ... Reset circuit, 34 ... OR circuit, 35,36 ... Decoder, 37 Delay circuit, 38 Exclusive OR circuit

Claims (1)

[Claims] 1. A magnetic tape 9 is wound around a rotary drum 8 at an inclination angle, and a running speed Vt of the magnetic tape 9 is a predetermined constant value and the rotary head 5 has When the diameter R0 of the rotary drum 8 has a first predetermined value, the magnetic tape 9 is wound around the rotary drum 8 at a predetermined first winding angle α. Attached, and when the diameter R0 has a second value that is less than the first value,
It is wound at a second winding angle larger than the first winding angle α, thereby keeping the distance traced by the magnetic heads 6 and 7 constant, and (d) generating the first reference clock signal CK1. A first reference clock signal generation source, and (e) the first reference clock signal CK1 from the first reference clock signal generation source is divided into a predetermined number n of frequency division periods to generate a clock signal, A first frequency divider 31 that outputs each clock signal from each of the first output terminals Q1 to Qn, and (f) a clock signal A1 from the output terminal Qn of the minimum frequency division period of the first frequency divider 31. Then, in response to the motor 19 that rotationally drives the rotary head 5, and (g) each clock signal output from the first output terminals Q1 to Qn of the first frequency divider 31, a continuous sampling clock signal B1 From the first decoder 35 for generating An analog / digital converter 14 for converting an analog signal to be recorded into a digital signal in response to the first sampling clock signal B1 and (i) a minimum frequency division period of the first frequency divider 31. A reset circuit 33 that generates a reset signal R for each period TA1 of one level of the minimum frequency division period clock signal A1 in response to the minimum frequency division period clock signal A1 from the output terminal Qn, and (j) is input. The reference clock signal is divided into frequency division cycles of the same number n as the frequency division cycle of the first frequency divider 31 and the same frequency division cycle to generate a clock signal, and each clock signal is generated by the second frequency division circuit. A second frequency divider 32 which outputs from each of the output terminals P1 to Pn, (k) a second reference clock signal CK2 is generated, and a period T1 of the first reference clock signal CK1 and a period T2 of the second reference clock signal CK2 And the ratio T1 / T2 is the minimum frequency division period of the first frequency divider 31. And the one period of the level TA1 locking signal A1, the second
The ratio TA1 / TF of the minimum frequency dividing period clock signal F of the frequency divider 32 to the period TF of the one level is equal to the period T2 of the second reference clock signal CK2 at each of the first and second winding angles α. The second reference clock signal generation source, which is defined correspondingly, and (l) the second reference clock signal CK2 from the second reference clock signal generation source A logic circuit 34 which is derived and given as the input reference clock signal CK of the second frequency divider 32 during the one-level period TF of the signal F, and cut off during the other-level period TF1, and (m) the second A second decoder 36 for generating a read clock signal D1 and a slot clock signal C1 in response to each clock signal output from the second output terminals P1 to Pn of the frequency divider 32, and (n) analog / digital conversion Write the digital signal from the device 14 and write it It reads the data clock signal D1
Memory 16 to be read in synchronism with, and (o) a data format is generated and added to the data read from the memory 16 in synchronism with the slot clock signal C1,
A magnetic tape recording apparatus comprising means 17, 18 for giving to the rotary head 5 for recording.