JPH0724086B2 - Magnetic recording / reproducing device - Google Patents

Description

The present invention relates to a multi-channel magnetic recording / reproducing apparatus such as a multi-channel tape deck.

[Prior Art] A conventional analog multi-channel tape deck is provided with a system control circuit that controls the entire system, and controls the operation changeover switch of the recording / reproducing circuit of each channel based on the output of this system control circuit. It is configured.

[Problems to be Solved by the Invention] By the way, if a dedicated signal line for switching recording / reproducing, erasing current on / off, muting, and dbx on / off in each recording / reproducing circuit is provided, The total number of signal lines in the channel is considerably large. For example, if four signal lines are required for each channel in a 16-channel tape deck, then 64 signal lines are required.

Therefore, an object of the present invention is to provide a magnetic recording / reproducing circuit capable of connecting the main control circuit and the recording / reproducing circuit of each channel with a small number of signal lines.

[Means for Solving the Problems] The present invention for achieving the above object provides a plurality of recordings arranged to perform recording or reproduction on a plurality of tracks of a magnetic tape provided corresponding to a plurality of channels. A reproducing magnetic head, a plurality of erasing heads arranged on the plurality of tracks, a plurality of recording circuits provided corresponding to the plurality of channels, and a plurality of reproduction provided corresponding to the plurality of channels. A circuit, an erase signal supply circuit, a plurality of recording / reproducing changeover switches for selectively connecting the recording / reproducing magnetic head to the recording circuit and the reproducing circuit in each of the plurality of channels, and the plurality of channels. A plurality of erase switches for selectively connecting the erase head to an erase signal supply circuit in each of the A main control circuit for sending command data for controlling the recording / reproducing changeover switch and the erasing switch on a channel-by-channel basis in a time division manner, and a common control circuit connected to the main control circuit for transmitting the instruction data in a time division manner. A signal line and a common signal line, each of which is connected to the common signal line, is provided for each of the plurality of channels, and extracts the command data of its own channel to set the recording / reproducing changeover switch and the erase switch of its own channel. The present invention relates to a magnetic recording / reproducing apparatus including a plurality of sub-control circuits configured to control.

The sub control circuits are, for example, the microcomputers 8a to 8c shown in the embodiments.

[Operation and Effect] The present invention has the following operation and effect.

(A) Since the command for controlling the recording / reproducing changeover switch of each channel and the erasing head is sent through the common signal line, the number of signal lines can be significantly reduced.

(B) Since a method of executing recording / reproduction of a plurality of channels based on command data of the main control circuit is adopted, control of recording / reproduction of a plurality of channels can be easily achieved.

[Embodiment] Next, a multi-channel magnetic tape recording / reproducing apparatus according to an embodiment of the present invention will be described with reference to FIGS.

FIG. 1 shows the structure of three channels of a 16-channel magnetic tape recording / reproducing apparatus. The recording medium magnetic tape 1 has a plurality of tracks 2a, 2b, 2c, and recording / reproducing magnetic heads 3a, 3b, 3c and erasing heads 4a, 4b, 4c are provided corresponding to the respective tracks 2a, 2b, 2c. ing. The recording / reproducing magnetic heads 3a, 3b, 3c and the erasing heads 4a, 4b, 4c are configured as a composite head.

Reference numerals 5a, 5b, and 5c denote recording / reproducing circuits provided for each channel, and the recording / reproducing magnetic heads 3a-
3c, erasing heads 4a to 4c, recording signal input terminals 6a to 6c, and reproduction output terminals 7a to 7c are respectively connected. Each of the recording / reproducing circuits 5a to 5c has a built-in microcomputer 8a to 8c for digitally switching the operation.

The main control circuit 9 centrally controls the operation switching of the recording / reproducing circuits 5a to 5c of each channel, and includes one common signal line 10, a CPU synchronization signal line (clock signal line) 11, and a system. The clock lines 12 and channel designation lines 13a to 13c corresponding to the channel lines are connected to the recording / reproducing circuits 5a to 5c of the respective channels.

2 shows the main control circuit 9 in detail, and FIG. 3 shows the state of each part of FIG. The input device 14 shown in FIG. 2 has an operation switch for designating the mode of each channel and designates a desired operation, and is connected to the CPU 15. The input device 14 can be wirelessly coupled to the CPU as a remote control unit.

The CPU 15 forms data for switching the operation of the recording / reproducing circuits 5a-5c of each channel based on the information given from the input device 14 as shown in FIG.
The signal is sent to the common signal line 10 via the circuit 16 and the channel designating data is supplied to the interface 18 by the 8-bit parallel transmission line 17. Further, the synchronizing signal (clock) shown in FIG. Sync signal line 11 through 19
To be sent to.

The interface 18 decodes the designated channel on the basis of the 8-bit channel designation data, and designates the selected channel designation lines 13a to 13n as an analog channel designated by the high level and the low level shown in FIG. 3 (A). It supplies a signal.

The system clock generator 20 is connected to the common clock line 12 via the NOT circuit 21, and supplies a common clock signal to each of the recording / reproducing circuits 5a-5c.

In this embodiment, the data sent from the CPU 15 to the signal line 10 is data consisting of 8 bits B0 to B7 and is serially transferred within the channel designation period t1 to t2. Since there is only one signal line 10, it is used in a time-divisional manner for multiple channels.

Since the recording / reproducing circuits 5a-5c of each channel have the same configuration, only the recording / reproducing circuit 5a of the first channel is shown in FIG. 4, and the description of the recording / reproducing circuits 5b, 5c of the other channels is omitted. The recording / reproducing circuit 5a has a recording circuit 22 including a recording amplifier connected to the recording input terminal 6a and a reproducing circuit 23 connected to the reproducing output terminal 7a. The recording circuit 22 is connected to the recording / reproducing magnetic head 3a via a bias trap circuit 24 and a recording / reproducing changeover switch 25. Playback circuit 23
Is also connected to a recording / reproducing magnetic head 3a via a recording / reproducing switching switch 25. Bias oscillator (not shown)
The high-frequency bias signal line 26 of 145 kHz connected to is connected to the recording / reproducing magnetic head 3a via the voltage control amplifier 26a and the changeover switch 25, and also via the voltage control amplifier 27 and the erase switch 28. It is connected to the erasing head 4a.

The microcomputer 8a includes a common signal line 10 and a synchronization signal line.
11, the system clock line 12, the input terminal A1, A2, A3, A4 to which the channel designation line 13a is connected, and the recording bias period designation signal output terminal B1, the recording period designation signal output terminal B2,
Erase bias control signal output terminal B3, erase period designation signal output terminal B4, input / tape signal output terminal B5, erase stop signal output terminal B6, high / low instruction signal output terminal B7, muting control output terminal B8, dbx on / It has an off instruction signal output terminal B9.

As shown in FIG. 5A, a recording bias engine designating signal is output from the output terminal B1 in correspondence with the recording period, and is input to the recording bias control integrating circuit 30. The integrating circuit 30 generates the control voltage shown in FIG. 5 (B) in response to the signal shown in FIG. 5 (A). That is, a voltage having a slope and rising and a slope and falling is generated. As a result, the amplitude of the AC bias signal obtained at the output of the voltage controlled amplifier 26a does not change sharply at the rising and falling but gradually changes, and noise recording is prevented. Output terminal B2 of microcomputer 8a
A high-level recording period designating signal is output at the timing shown in FIG. 5 (C), and the transistor 32 connected in series to the relay 31 is driven on. When the transistor 32 is turned on, the switch 31 is turned on at the connection point a by the relay 31, and the recording current and the bias signal are supplied to the magnetic head 3a.

The output terminal B3 is connected to the voltage control amplifier 27 through the erase bias control integrating circuit 33. Output terminal B3 to 5th
When the low level signal shown in FIG.
In response to this, 33 generates an erase bias control voltage having a rising and falling slope as shown in FIG. 5 (E). As a result, the voltage-controlled amplifier 27 obtains an erase bias signal whose amplitude gradually changes at rising and falling. The output terminal B4 is connected to the base of a transistor 35 to which a relay 34 is connected in series. When the erase period designation signal shown in FIG. 5 (F) is generated from the output terminal B4 and the transistor 35 is turned on, the relay 34 causes the switch 28
Is controlled to be turned on, and an erase bias signal is given to the erase head 4a. The output terminal B5 outputs a signal indicating permission of the input signal as shown in FIG.

When the channel designation signal shown in FIG. 3A is input to the input terminal A3 of the microcomputer 8a and the operation switching data is input to the input terminal A1 at the same time, the data is read by the synchronizing signal of the input terminal A2. The microcomputer 8a forms a signal for setting a desired mode based on the data and outputs a control signal as shown in FIG. 5 to the output terminals B1 to B5, for example.

It is necessary to send various control signals with a time difference from the output terminals B1 to B5, but since this time difference is digitally set in the microcomputer 8a, analog signals are generated using a conventional time constant circuit. The accuracy is higher than those that are set manually.

Further, since the signal line 10 is shared by a plurality of channels, not only the recording / reproducing circuit 5a of the first channel,
The data necessary for the recording / reproducing circuits 5b and 5c of the other channels are also transmitted. However, when the data of other channels is being transmitted, the specified number of channels of its own channel is 13a.
Since the channel designating signal of FIG. 3 (A) is not given to, the data of other channels will not be read by mistake.

[Modification] The present invention is not limited to the above-described embodiments, and the following modifications are possible, for example.

(1) One signal line may be added for communication from each of the recording / reproducing circuits 5a-5c toward the main control circuit 9.

(2) Instead of providing the channel designation lines 13a to 13c, an address may be attached to the data transmitted by the signal line 10 so that only the microcomputer of the channel designated by the address reads the data.

[Brief description of drawings]

FIG. 1 is a block diagram showing a magnetic tape recording / reproducing apparatus according to an embodiment of the present invention, FIG. 2 is a block diagram showing the main control circuit of FIG. 1 in detail, and FIG. 3 shows the state of each part of FIG. FIG. 4 is a block diagram showing the recording / reproducing circuit of FIG. 1, and FIG. 5 is a voltage waveform diagram showing the state of each part of FIG. 1 ... Magnetic tape, 3a-3c ... Magnetic head for recording / reproducing, 5a-5b ... Recording / reproducing circuit, 8a-8c ... Microcomputer, 9 ... Main control circuit, 10 ... Common signal line, 11 ...
… Synchronization signal line, 13a-13c …… Channel designation line.

Claims (1)

[Claims] 1. A plurality of recording / reproducing magnetic heads arranged to record or reproduce on a plurality of tracks of a magnetic tape provided corresponding to a plurality of channels, and a plurality of magnetic heads arranged on the plurality of tracks. An erasing head, a plurality of recording circuits provided corresponding to the plurality of channels, a plurality of reproducing circuits provided corresponding to the plurality of channels, an erasing signal supply circuit, and each of the plurality of channels At a plurality of recording / reproducing changeover switches for selectively connecting the recording / reproducing magnetic head to the recording circuit and the reproducing circuit, and in each of the plurality of channels, the erasing head is selectively connected to an erasing signal supply circuit. Controlling a plurality of erase switches for connection, the recording / reproducing changeover switch and the erase switch of the plurality of channels A main control circuit for sending command data for each channel in time division, a common signal line connected to the main control circuit for transmitting the command data in time division, and to the common signal line. A plurality of sub-devices connected to each other and provided for each of the plurality of channels, and configured to extract the command data of its own channel to control the recording / reproducing changeover switch and the erase switch of its own channel. A magnetic recording / reproducing apparatus equipped with a control circuit.