JP3144107B2 - Transmission method of recording / reproduction control signal and recording / reproduction control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for transmitting a recording / reproducing control signal for each head in a magnetic recording / reproducing apparatus having a rotating drum on which a number of magnetic heads are mounted, and more particularly to a digital VTR. It is suitable to be applied to.

[0002]

2. Description of the Related Art Conventionally, in a magnetic recording / reproducing apparatus provided with a rotating drum on which a magnetic head is mounted, a magnetic head provided on the rotating drum and a recording processing circuit or a reproducing processing circuit on a fixed substrate side are connected. In some cases, a recording amplifier, a reproduction amplifier, and the like are provided in a rotary drum in consideration of a reduction in transmission efficiency and frequency characteristics of a rotary transformer provided for transmitting a recording signal and a reproduction signal.

As described above, in a magnetic recording / reproducing apparatus in which a recording amplifier, a reproducing amplifier, and the like are provided in a rotating drum, switching control of a recording head provided in the rotating drum and control of recording current are performed from outside the rotating drum. In addition, it is necessary to perform switching control of the reproducing head and the like, and the recording / reproducing control signal control signal is transmitted using a slip ring or a rotary transformer.

Meanwhile, in a digital VTR or the like that has recently been used, it is necessary to record and reproduce high-density information, so that a large number of magnetic heads must be provided on a rotating drum as described later (FIG. 2). In addition, the number of recording and reproduction control signals to be transmitted increases, and the size of the slip ring and the rotary transformer becomes large. Therefore, a method of transmitting a recording / reproduction control signal for switching signals supplied to a large number of magnetic heads or signals output from these magnetic heads at a predetermined timing is devised, and the recording / reproduction control signal is multiplexed. This prevents slip rings and rotary transformers from becoming large.

[0005] An example of a conventional transmission method and apparatus for multiplexing and transmitting a recording / reproduction control signal will be described below with reference to FIGS. 11 to 13. The pulse waveform diagram shown in FIG.
The process of multiplexing the four recording / reproduction control signals shown in FIGS. A, b, c, and d supplied by one rotation of the rotating drum as shown in FIG. In FIG. 11, a '
3 shows a pulse output in which only the edge of the first recording / reproduction control signal a is detected. Similarly, the edge pulse output of the second recording / reproduction control signal b is denoted by b ′, the edge pulse output of the third recording / reproduction control signal c is denoted by c ′, and the edge of the fourth recording / reproduction control signal d is denoted by d ′. Shows pulse output.

When the edge pulse outputs a 'to d' are arranged on the time axis, they can be arranged as a serial pulse train as shown by E1 to E8 in FIG. As described above, the start code indicating the start of the recording / reproduction control signal for indicating the decoding timing is provided before the pulse sequence in the pulse train of the edge pulse output of the four recording / reproduction control signals serially arranged. Is added to the end of the pulse train to multiplex the four recording / playback control signals and transmit them to the rotating drum.

According to this transmission method, for example, information of four recording / reproduction control signals can be transmitted as a serially multiplexed pulse train to a rotating drum via one slip ring or one coil of a rotary transformer. become. In this transmission method, the information of the recording / reproduction control signal is mainly at the edge, the edges of the recording / reproduction control signal do not overlap each other, and each edge rises in order as shown in FIGS. And it was made by paying attention to falling.

Therefore, in order to return the serially multiplexed pulse train transmitted to the rotating drum to the original four recording / reproduction control signals in the rotating drum, attention is paid to the order of the pulses of the multiplexing pulse train. Decoding.

FIG. 12 schematically shows a conventional example of a decoder for decoding in this way. In FIG. 12, reference numeral 80 denotes an input terminal IN to which a recording / reproduction control signal, which is a transmitted serial multiplexed pulse train, is input; 81, a counter for counting each pulse of the multiplexed pulse train input to the input terminal 80;
Reference numeral 82 denotes a decoder for generating decode outputs D1 to D4 based on the count output of the counter 81, and reference numeral 83 denotes a start code detector for detecting the start of a recording / reproduction control signal of a multiplexed pulse train.

When the start code is detected from the serial multiplexed pulse train by the start code detector 83,
With this detection signal, the counter 81 is cleared to the initial value.
The counter 81 counts the multiplexed pulse train following the start code, that is, the edge pulse of the recording / reproduction control signal,
Each time the edge pulse is counted, the count value which is increased by one is applied to the decoder 82.

As shown in FIG. 13, the decoder 82 raises the decode output D1 when the count value of the counter 81 becomes "1", and raises the decode output D2 when the count output becomes "2".
And decode output D3 when the count value becomes "3"
And decode output D4 when the count value becomes "4"
Start up. When the count value becomes "5", the decoder output D1 falls, when the count value becomes "6", the decoder output D2 falls, and when the count value becomes "7", the decoder output D3 falls, and the count value decreases. When it becomes "8", the decoder output D4 falls.

The multiplexed pulse train is transmitted at the timing of one rotation of the rotary head. As a result, the recording / reproducing control signal shown in FIG. 11e transmitted as a serial multiplexed pulse train becomes the decode output D1 as shown in FIG. 13b.
~ D4 to be decoded into the original recording and reproduction control signals.

[0013]

Conventionally, in such a multiplexed recording / reproduction control signal, the transmission means of the multiplexed recording / reproduction control signal can be reduced in size. There was a problem.

That is, the recording / reproducing control signal transmitted to the rotating drum is transmitted via a slip ring or a rotary transformer, but since the slip ring has a mechanical contact portion, noise is generated by the contact portion. In addition, when the rotary transformer is a coil, it tends to pick up pulse-like noise such as electrostatic noise generated in the VTR, so that the noise is superimposed on the transmitted serial pulse train. was there.

FIG. 14 shows how the decoder 82 operates when noise is superimposed on the serial multiplexed pulse train transmitted to the rotary head. In FIG. 14, a
Shows a serial multiplexed pulse train when noise is superimposed between the pulse of E2 and the pulse of E3, b shows the decode outputs D1 to D4 of the decoder 82 when the noise N is not superimposed, and c shows The decode outputs D1 'to D4' of the decoder 82 malfunctioning due to the noise N are shown.

Decoder 82 when noise is not superimposed
13 is as described above with reference to FIG. 13, and the output of the decoder 82 is as shown in FIG. However, when the noise N is superimposed, the counter 81 in FIG. 12 cannot determine whether or not the noise is noise, so that the counter 81 counts the noise N.

Then, since the decoder 82 performs decoding based on the count value of the counter 81, the counter 81 that has counted the E1 and E2 pulses is superimposed on the multiplexed pulse train as shown in FIG. When the noise N is counted,
The count value becomes "3", and the decoder 82 causes the decode output D3 to rise.

Therefore, the decoded output becomes a decoded output which rises at a timing earlier than the correct decoding result D3 as shown by D3 'in FIG. 14c. Further, not only the decode output D3 rises quickly, but also after counting the noise N, the count value of the counter 82 is always larger than the correct count value by "1". , The timing is advanced one by one, and the decoded output of the decoder 82 is the decoded output D1 'as shown in FIG.
~ D4 ', which is a recording / reproduction control signal having a different timing from the original recording / reproduction control signal.

That is, there is a problem that correct image information cannot be obtained even when the magnetic head is controlled at such timing to perform magnetic recording and reproduction. Also, once the counter 81
If the count value is incorrect, the multiplexed pulse train is transmitted only every rotation of the rotating drum, so the counter 81 is not cleared until the rotating drum makes one rotation, and the time required for the rotating drum to make one rotation (10 or more msec) While recording or reproducing erroneous data for a while, the data will be continued.

Further, since an error correction circuit that is put into practical use can deal with an error of only a few μsec, there is a problem that it is impossible to correct an error even if an error correction circuit is provided. . Further, FIGS.
According to the conventional transmission method described in (1), it is assumed that the rising edge and the falling edge of each recording / playback control signal come in order, so that each recording / playback control signal is not in order as in the case of performing an editing operation. There was also a problem that it could not be applied in some cases.

According to the present invention, in order to solve such a problem, information of each recording / reproduction control signal is transmitted as a serial multiplexed signal to the rotating drum every period much shorter than the period of the recording / reproduction control signal. Therefore, even if the serial multiplexed signal receives noise, the error caused by the noise can be completed in a short time, and the versatility that the rising and falling order of each recording / reproduction control signal can be controlled. An object of the present invention is to provide a recording / reproduction control signal transmission method and a recording / reproduction control signal device.

[0022]

In order to achieve the above-mentioned object, the present invention provides a timing signal obtained by dividing a clock signal by a predetermined number.
Temporally parallel each recording reproduction control signal by ring signal
Was simultaneously sampled, parallel based on parallel recording and reproduction control signals sampled with the clock signal - multiplexed by serial conversion, in the converted serial multiplexed signal that was to transmit to each of the sampling timing is there.

[0023]

According to the present invention, as described above, even if the multiplexed serial multiplexed signal receives noise, the decoded recording / reproduction control signal is hardly affected by the noise. Even if the read / write control signal is erroneous, error correction can be performed because the error period is short.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a recording / reproduction control device according to the present invention.
In FIG. 1, reference numeral 1 denotes a rotary transformer for transmitting a digital recording signal, a digital reproduction signal, a head switching signal, and the like from a fixed substrate side A to a rotating drum side B; A recording amplifier having a switch function for selecting and switching a digital recording head, 6 a timing encoder for multiplexing a timing signal for switching the head, and 7 returning a pulse train multiplexed by the timing encoder 6 to a timing signal for switching the head. Timing decoders 8 and 9 are erase signal amplifiers having a switch function of selecting and switching a rotary erase head. 11 to 22 are reproduction signal amplifiers having a switch function of selecting and switching a read head. 31 to 34 are analog signals reproduced. Switches that are selectively switched between signals and digital signals, [REC A] to [REC D] are digital recording heads, [FE A] and [FE B] are rotary erasing heads, and [YA] and [Y B] are reproducing heads for analog-recorded luminance signals. , [CA], [C-
B] is a reproducing head for an analog-recorded chroma signal,
[ADV A] to [ADV D] are pre-read heads for reading recording signals in advance, [CNF A] to
[CNFD] is a reproducing head for digital recording signal confirmation.

Next, FIG. 2 shows an arrangement diagram of each head shown in FIG. 1 arranged around the rotary drum. In FIG. 2, digital recording heads [REC A] and [REC
C] and [REC B] and [REC D], and a reproducing head [CNF A] and [CNF
C] and [CNF B] and [CNF D], heads for rotation erasing [FE A] and [FE B], heads for advance reading [ADV A] and [ADV C], [ADV
B] and [ADV D], the analog luminance signal reproducing heads [YA] and [YB], and the analog chroma signal reproducing heads [CA] and [CB] are each opposed by 180 degrees. It is provided.

The digital recording heads [REC A] to [RECD] arranged as shown in FIG.
FIG. 6 shows an example of the track format recorded above. In FIG. 6, tracks A to D are digitally recorded by digital recording heads [REC A] to [RECD].

In FIG. 1, the digital recording signal [REC AC] on the fixed substrate A is amplified to a predetermined size by the REC driver 2 and transmitted to the recording amplifier 4 on the rotating drum B via the rotary transformer 1. Similarly, the digital recording signal [REC BD] on the fixed substrate A side is also R
The signal is amplified by the EC driver 3 and transmitted to the recording amplifier 5 on the rotary drum B side via the rotary transformer 1.

A switching signal for switching each head is multiplexed by a timing encoder 6 and transmitted to a timing decoder 7 on the rotating drum B side via a rotary transformer together with a clock signal.

At the time of digital recording, a digital recording head [using a switching signal decoded by the timing decoder 7] as follows so that recording is performed almost simultaneously on tracks A and B or C and D shown in FIG. REC
A] to [REC D] are selected.

First, a digital recording head [REC
A] and a selection signal [REC A] for selecting [REC C].
/ C] and the digital recording heads [REC A] and [R
ECC] and the digital recording head [REC
B] and [REC D].
/ D] and the digital recording heads [REC B] and [R
ECD], and one of the digital recording heads [REC A] or [REC C] is set to a selection signal [REC A EN] or [RE A].
C C EN] and select the digital recording head [R
EC B] or [REC D] is set to one of the selection signals [REC B EN] or [REC D E
N].

Since the winding angle of the magnetic tape 61 to be magnetically recorded on the rotating drum is substantially 180 degrees, the selection signal [R
The length of EC A EN] to [REC D EN] is set to the time required for the rotary drum to make about 1/2 rotation.

When reproducing an analog recorded signal,
A reproduction head [YA] from the timing encoder 6;
A signal for selecting [YB], [CA], or [CB] is multiplexed from the timing decoder 7 via the rotary transformer 1 and transmitted. The timing decoder 7 decodes the multiplexed signal. Reproduction signal amplifiers 11, 14, 1
7 and 20, the selection signal is applied to the reproducing head [Y
-A], the luminance signal reproduced by [Y-B] and the chroma signal reproduced by the reproducing heads [CA], [CB] are transmitted via the rotary transformer 1 to the switch 31 on the fixed substrate A side. ~ 34.

A signal A / D for selecting analog or digital is applied to the switches 31 to 34. In this case, since the analog is selected, the switches 31 to 34 are switched to analog, and the output terminal A Outputs an analog signal.

A digital recording confirmation head [CN
F A to [CNF D and head for pre-reading [A
A signal for selecting DV A] to [ADV D] is created on the fixed substrate A side as required, and this selection signal is multiplexed from the timing encoder 6 via the rotary transformer 1 to the timing decoder 7 on the rotating drum B side. The reproduction amplifiers 12, 13, 15, 16, 18, 19, 20, 2,
2 is selected and a desired selecting operation is performed.

FIG. 4 shows the configuration of the timing encoder 6 shown in FIG. 1, and the multiplexing operation of the encoder shown in FIG. 4 will be described with reference to FIG. In FIG. 3, a is a timing pulse for sampling the recording and reproduction control signals D1 to D4 of each magnetic head, b is an example of the recording and reproduction control signals D1 to D4 for selectively controlling each magnetic head, and c is serially multiplexed. The multiplex signal MPX, d indicates a multiplex format.

In FIG. 4, reference numeral 41 designates a parallel-to-serial conversion of the recording / reproduction control signals D1 to D4 at the timing of the supplied clock CK, and a start code and an end code added to the serially converted signal sequence. A parallel-to-serial converter for generating a multiplexed signal MPX, 42
Is a parity signal generator that receives the four recording / reproduction control signals D1 to D4 and generates a 1-bit parity signal. 43 is a sampling and holding circuit that samples the recording / reproduction control signals D1 to D4 with the divided output of the frequency divider 44. , 44 are frequency dividers that generate sampling pulses from the clock CK.
An encoder 45 converts the multiplexed signal MPX into a code having no DC component.

In FIG. 4, a sampling and holding circuit 43 simultaneously samples each of the recording / reproduction control signals D1 to D4 with a sampling pulse (see FIG. 3a) which is a frequency division output of a frequency divider 44, and holds the sampling output. The sampled and held signal becomes a parallel 4-bit signal.

The contents of the parallel 4-bit signal will be described. As shown in FIG. 3, when sampling is performed with a sampling pulse of T1, at the timing of T1, D1
Is "1", D2 is "0", D3 is "0", D4 is "0"
Therefore, the contents of the parallel signals sampled and held are "1000". Similarly, "1100" when sampling with the sampling pulse of T2, "1100" when sampling with the sampling pulse of T3,
When sampling with the sampling pulse of T4, "11
Sampling with a sampling pulse of "01" and T5 results in a 4-bit signal having the content of "1111".

The sampled and held parallel 4
The bit signal is applied to the parallel-serial converter 41 and is converted into a serial 4-bit signal (see FIG. 3D) at the timing of the supplied clock CK. Further, a start code ST is added before the 4-bit serial signal serially converted by the parallel-serial converter 41, and the 1-bit parity signal PARI and end code END generated by the parity generator 42 are added after the start code ST. Is added to obtain a multiplexed signal MPX having a format of one frame as shown in FIG. 3D.

4D in the multiplexed signal MPX shown in FIG.
Since the bit signals D1 to D4 are signals sampled at the timing of T3, the 4-bit signals D1 to D4
The content of D4 is "1101" as described above.
A multiplexed signal MP multiplexed in such a format
X is sent from the parallel-to-serial converter 41 at each of the sampled timings as shown in FIG. 3c.

Here, if the period of the timing pulse is set to, for example, several μsec, one frame of the multiplexed signal MPX is transmitted every several μsec. However, since the multiplexed signal MPX thus multiplexed contains a DC component, there is a possibility that the multiplexed signal MPX cannot be transmitted by the rotary transformer.

Therefore, in this embodiment, the parallel-serial converter 4
By converting the multiplexed signal MPX into a code having no DC component by the encoder 45 connected to 1, the multiplexed signal MPX can be transmitted via the rotary transformer.

There are many known encoding systems for performing coding without DC component, and an example thereof is shown in FIGS.
This will be described with reference to FIG. In FIG. 7, reference numeral 45 denotes an encoder that encodes a code having no DC component, and is configured by an EX-OR circuit. A multiplexed signal MPX and a clock synchronized with the multiplexed signal MPX are applied to two input terminals of the EX-OR circuit 45, respectively.

Assuming that the multiplexed signal MPX is “10011” as shown in FIG. 8A, the EX-OR output becomes “0110100101” as shown in FIG. 8C from the truth table of the EX-OR circuit. Can be understood. That is, when the multiplexed signal MPX is “1”, it is coded to “01”, and when the multiplexed signal MPX is “0”, it is coded to “10”. No longer contains a DC component. Such encoding is called phase encoding.

The multiplexed signal MPX phase-encoded in this way is transmitted to the rotary drum B via the rotary transformer 1, and the original recording / reproduction control signals D1 to D4 in the timing decoder shown in FIG.
Is decoded.

In FIG. 5, reference numeral 51 denotes a multiplexed signal MPX based on the phase-encoded multiplexed signal MPX.
A decoder for decoding into X, 52 is a serial-parallel converter composed of a shift register for returning a multiplexed serial signal to an original parallel signal, 53 is a rewritable state by an enable signal of a detector 55 The register 54 holds the parallel converted recording / reproduction control signals D1 to D4 and the parity signal. The register 54 stores the recording / reproduction control signals D1 to D4 which can be rewritten when the parity check circuit 56 does not detect an error. A holding register, 55 is a detector that detects a start code and an end code and applies an enable signal to the register 53, and 56 performs a parity check of the transmitted signal and applies an enable signal to the register 54 when there is no error. This is a parity check circuit.

The phase-encoded multiplexed signal MPX received by the rotating drum is decoded by the decoder 51 into an original multiplexed signal MPX having a DC component. The decoder 51 is composed of an EX-OR circuit as shown in FIG. 9, and a multiplexed signal MPX subjected to phase encoding and a clock synchronized with the multiplexed signal MPX are applied to two input terminals of the EX-OR circuit.

Then, as can be easily understood from the truth table of the EX-OR circuit, as shown in FIG.
When the phase-encoded input data to be input to “1” is “0110100101”, the output is
As shown in FIG. 8, "10011" is output, so that the decoder 51 decodes the signal into the original multiplexed signal MPX, as can be seen from FIG. 8A.

The multiplexed signal M decoded by the decoder 51
The PX is converted into a parallel signal by a serial-parallel converter 52. Of the converted parallel signals, the recording / reproduction control signals D1 to D4 and a parity signal are stored in a register 53, and a start code and an end code are detected as a start / end code. Applied to the vessel 55. When the start code is detected by the start / end code detector 55, the start of the frame of the multiplexed signal is recognized, and the register 53 stores the recording / reproduction control signals D1 to D
4 and a parity signal are prepared.

The recording / reproduction control signals D1 to D
When the parity signal 4 and the parity signal are held, the recording / reproduction control signals D1 to D4 of the held output are applied to the register 54 and the parity signal is applied to the parity check circuit 56. The parity check circuit 56 checks odd parity or even parity. When no error is detected as a result of the parity check, the recording / reproduction control signals D1 to D4 are held in the register 54. At this time, the enable signal output from the parity check circuit 56 is applied to the register 54.

If an error is detected as a result of the parity check, the parity check circuit 56 does not output an enable signal, and the register 54 does not enter a rewritable state. ＤD4 is not held, and the correct recording / reproduction control signals D1 to D4 of the immediately preceding frame which are already held are continuously output.

When an error is detected in this manner, the data of that frame is discarded, and the data of the immediately preceding frame is output as data of an erroneous frame. For this reason, it is possible to prevent a large error from occurring in the recording / reproduction control signal. The error is generated due to the superimposition of noise as described above. Since the noise is generated at random, the erroneous frame is rarely continued.
Since the frame is as short as several μsec, the time during which the error lasts is short.

Therefore, even if there is an error in the reproduced digital signal as a result of using the recording / reproduction control signal one frame before, this error can be corrected by providing an error correction circuit for the digital signal. Become. In the above description, the number of recording / reproduction control signals is four. However, when as many as 18 heads are arranged around the rotating drum as shown in FIG. It does not matter at all.

The coding for removing the direct current component is not limited to the phase encoding, and any coding that can remove the direct current component may be used. The multiplexed signal may be transmitted using a slip ring instead of the rotary transformer.

[0055]

According to the recording / reproducing control signal transmission method and recording / reproducing control device of the present invention, an arbitrary number and an arbitrary mode of recording / reproducing control signals can be transmitted, and the number of heads differs. There is versatility that it can be used for other systems.

Further, when a parity check is performed at the time of decoding a multiplexed signal and an error is detected, the previous decoded output is output. Therefore, even if noise or the like is superimposed on the multiplexed signal, an erroneous decoded output is output. It is difficult to output. Further, since the time of one frame of the multiplexed signal can be shortened, even if the decoded output is erroneous, it can be returned to the normal state in a short time.

[Brief description of the drawings]

FIG. 1 is a block diagram of a recording / reproducing system of a digital VTR.

FIG. 2 is a diagram showing a head arrangement of a rotary drum of a digital VTR.

FIG. 3 is a timing chart illustrating the principle of multiplexing in the present invention.

FIG. 4 is a block diagram illustrating a configuration of a timing encoder.

FIG. 5 is a block diagram illustrating a configuration of a timing decoder.

FIG. 6 is a diagram showing a recording format of a magnetic tape.

FIG. 7 is a diagram showing an encoder circuit for phase encoding.

FIG. 8 is an operation waveform diagram of the phase encoding encoder.

FIG. 9 is a diagram illustrating a decoder circuit that decodes a phase-encoded code.

FIG. 10 is an operation waveform diagram of the phase encoding decoder.

FIG. 11 is a timing chart for explaining conventional multiplexing.

FIG. 12 is a block diagram of a conventional decoder.

FIG. 13 is an operation timing chart of a conventional decoder.

FIG. 14 is a timing chart illustrating a problem of conventional multiplexing.

[Explanation of symbols]

 Reference Signs List 1 rotary transformer 2, 3 driver for amplifying digital recording signal 4, 5 recording amplifier 6 timing encoder 7 timing decoder 8, 9 erasing signal amplifier 11-22 reproduction signal amplifier 31-34 switch 41 parallel-serial converter 42 parity generator 43 Sampling and holding circuit 44 Frequency divider 45 Encoder 51 Decoder 52 Serial-parallel converter 53, 54 Register 55 Start / end code detector 56 Parity check circuit 81 Counter 82 Decoder 83 Start code detector

Claims (6)

(57) [Claims] 1. A method for transmitting a recording / reproduction control signal of each magnetic head to a rotating drum having a plurality of magnetic heads for performing recording / reproduction, wherein the timing signal is obtained by dividing a clock signal by a predetermined number.
Ri, simultaneously sampling the reproduction control signal temporally parallel, parallel based recording and reproduction control signals sampled parallel to the clock signal - converted into a serial multiplexed signal by serial conversion, conversion are multiplexed signal transmitted to the rotary drum through a rotary transformer for each of said timing signal, and decodes the multiplexed signals transmitted in the rotary drum to the recording and reproduction control signal of the original parallel, each magnetic head A method for transmitting a recording / reproduction control signal, comprising: 2. A parity signal is added to the multiplexed signal transmitted to the rotary drum via the rotary transformer, and the multiplexed signal is transmitted. When the transmitted multiplexed signal is decoded, a parity check based on the parity signal is performed. 2. The recording / reproducing apparatus according to claim 1, wherein when the transmitted recording / reproducing control signal is erroneous, the erroneous recording / reproducing control signal is replaced with an already transmitted correct recording / reproducing control signal. Transmission method of control signal. 3. The transmission of a recording / reproduction control signal according to claim 1, wherein the multiplexed signal transmitted to the rotary drum via the rotary transformer is converted into a code having no DC component and transmitted. Method. 4. A recording / reproducing control device for transmitting recording / reproducing control signals of respective magnetic heads to a rotating drum on which a number of magnetic heads for performing recording / reproducing are mounted. at the same time the sampling means, means for generating a timing signal for sampling the reproduction control signal of the parallel by dividing the clock signal by a predetermined number, the recording and reproduction control signal of the parallel with the timing signal for means for the recording and reproduction control signals sampled parallel the
An encoder including a parallel-serial converter for converting a multiplexed signal into a serial multiplexed signal based on a clock signal; a rotary transformer to which the encoder output is input and transmitting the multiplexed signal to a rotating drum; A decoder for inputting and re-converting the multiplexed signal into an original parallel recording / reproduction control signal; and controlling the plurality of magnetic heads with each of the recording / reproduction control signals re-converted by the decoder. Recording and playback control device. 5. The encoder includes means for adding a parity bit to a multiplexed signal, the decoder includes means for performing a parity check using the parity bit, and further, rewriting is performed according to an output of the parity check means. 5. The recording / reproducing control device according to claim 4, further comprising a register that holds the output of the decoder to be controlled, wherein the parity check unit outputs a rewrite signal to the register only when no error is detected. 6. An encoder for converting the output of the encoder into a code having no DC component is provided between the encoder and the rotary transformer, and the code having no DC component is also provided between the rotary transformer and the decoder. 6. The recording / reproduction control device according to claim 4, further comprising a decoder for re-converting the signal into the following signals.