JPH0237628B2 - DEIJITARUSHINGOKIROKUSAISEISOCHI - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is equipped with a so-called auto-reverse travel mechanism capable of recording and reproducing in both directions, as well as converting analog signals such as audio into digital signals. The present invention relates to a digital signal recording and reproducing device that records and reproduces signals on tape.

Conventional configurations and their problems In so-called general tape recorders that record and play back audio and other analog signals as they are, they can record and play back in both directions, in response to consumers' demands for long-term recording. Devices equipped with auto-reverse travel mechanisms are becoming increasingly popular. In the past, auto-reverse running mechanisms were often found in auto-reel type tape recorders, but in recent years compact cassette-type tape recorders have also been equipped with auto-reverse mechanisms. . Particularly recently, the time required to switch between forward and reverse rotation has been shortened, and many vehicles can switch running direction in less than one second. However, since it is necessary to mechanically switch the rotation mechanism of the reel stand, constant speed drive mechanism such as a capstan, etc., the time required for reversing the running cannot be completely eliminated. Therefore, when the tape reaches its end during continuous recording, a break in the sound occurs due to the mechanical switching time, which disturbs the continuity of musical tones. Therefore, even though the tape recorder has an auto-reverse function, the user must always pay attention to the remaining amount of tape and the recording time, which is one of the major drawbacks of current analog tape recorders.

On the other hand, in recent years, a digital signal recording and reproducing apparatus for converting an analog signal into a digital signal and recording and reproducing the digital signal on a tape has been proposed, and has already been realized as an open-reel type commercial machine. In order to enable long-time recording, these conventional digital signal recording and reproducing apparatuses employ methods such as slowing down the tape running speed and instead limiting the use of the tape to only one running direction. In digital recording and playback, tape precision determines the shortest recording wavelength (that is, recording density) of a digital signal that can be correctly recorded and played back, so when the tape running speed is slowed down, the tape running precision must be sufficiently high. Otherwise, it would not be possible to record and reproduce correctly at conventional recording wavelengths, resulting in the disadvantage that a great deal of cost would be required to improve the tape running accuracy.

Purpose of the Invention The present invention provides a digital signal recording and reproducing device that records and reproduces digital signals with a reciprocating and reversing traveling (auto-reverse) mechanism to completely prevent sound interruptions when switching between forward and reverse traveling directions. The object of the present invention is to provide a device that enables long-term recording of uninterrupted digital signals.

Structure of the Invention The present invention provides a first memory circuit in a signal path of a recording means for recording digital signals on a magnetic head, a second memory circuit in a signal path of a reproducing means, and This device is equipped with a circuit that detects the remaining amount and generates a reversal command signal.When a reversal command signal is generated during recording, reading of the first memory circuit is prohibited and the input signal during reversal operation is sent to the first memory circuit. Writing is performed sequentially, reading is resumed after the reversal is completed, and recording is performed without any gaps on the magnetic tape. During playback, writing to the second memory circuit is prohibited when the reversal command signal is generated, and during reversal operation, the second memory circuit is prohibited from writing. It is constructed to obtain uninterrupted playback output based on the readout signal from the memory circuit, and when recording and playing back digital signals, the running direction of the magnetic tape is reversed using an auto-reverse mechanism to avoid missing or missing data. This is a digital signal recording and reproducing device that is capable of recording and reproducing over a long period of time without any blank time.

DESCRIPTION OF EMBODIMENTS FIG. 1 is a configuration diagram of an embodiment of the present invention, FIG.
FIG. 3 is a state diagram for explaining the operations of the first and second memory circuits in this embodiment.

1 is an input terminal to which an analog signal is applied, and 2 is an analog-to-digital conversion circuit (hereinafter referred to as A/D) that converts the input analog signal into a digital signal.
(referred to as a D converter), 3 is a first memory circuit that inputs a digital signal that is the output of the A/D converter 2, and delays the digital signal in accordance with a control signal from a memory control circuit (to be described later); 4 is a first memory circuit; A modulation circuit inputs the output of the memory circuit 3 of No. 1, performs modulation suitable for recording, and further adds a predetermined error correction code, etc. A modulation circuit 5 amplifies the output of the modulation circuit and drives the recording head 6 to output the magnetic tape 7. This is a recording amplifier that performs recording on the top.

Reference numeral 8 represents a playback head for extracting signals from the magnetic tape 7, and reference numeral 9 represents a playback amplifier. 10 is a demodulation circuit that inputs the output of the reproduction amplifier and obtains the original digital signal; 11 is a second memory circuit that operates under the control of the memory control circuit during reproduction; and 12 inputs the output of the second memory circuit 11; This is a digital-to-analog conversion circuit (hereinafter referred to as a D/A converter) that converts it into an analog signal and outputs it to the output terminal 13.

Further, 14 and 15 are reel stands, 16 is a reel drive circuit that rotates the reel stands 14 and 15 in normal and reverse directions, and obtains information on the number of rotations of the reel stand; 17 is the number of rotations of the reel stand obtained by the reel drive circuit 16; This is a tape stage end detection circuit that detects the end of a magnetic tape from information. In this embodiment, the end of the tape is detected based on the detection of the rotational speed of the reel stand, but there are also other configurations in which a transparent leader tape is provided at the end of the magnetic tape and optical detection is performed.
Other means may be used, such as a configuration in which position signals are recorded on a magnetic tape and read.

A memory 18 receives the output of the tape end detection circuit 17 and generates a signal to control the first memory circuit 3 during recording and the second memory circuit 11 during playback before the head reaches the end of the magnetic tape. It is a control circuit. Reference numeral 19 denotes a capstan that can be rotated in forward and reverse directions, and 20 is a capstan drive circuit that is controlled by the output of the tape end detection circuit 17 and rotates the capstan 19 at a constant speed in either the forward or reverse direction.

Next, the operation of this embodiment will be explained. first,
The time when the magnetic tape is not near the end, that is, the normal time, will be explained in the order of recording and reproduction.

During normal recording, the state of the first memory circuit 3 is controlled so that the write address W slightly precedes the read address R, as shown in FIG. 2A. For this reason, the first
The delay time of the digital signal in the memory circuit 3 is {(write address) - (read address)}×
(address clock time), resulting in a very small amount of delay.

Therefore, during normal recording, an analog signal input to the input terminal 1 is converted into a digital signal by the A/D converter 2, and this digital signal is slightly delayed by the first memory circuit 3 as described above. The signal is modulated by a modulation circuit 4 and recorded on a magnetic tape via a recording amplifier 5 and a recording head 6.

Next, during normal playback, the second memory circuit 11
As shown in FIG. 3A, the write address W is controlled to be slightly delayed from the read address R. Therefore, the delay time of the digital signal in the second memory circuit 11 in the normal case is as follows: [Total memory capacity - {(Read address) - (Write address)}] x (Address clock time) The amount of delay is close to the capacity.

Therefore, during normal playback operation, the playback head 8
The reproduced signal passes through the reproduction amplifier 9, enters the demodulation circuit 10, is demodulated to the original digital signal, is delayed as described above in the second memory circuit 11, is input to the D/A converter 12, and is converted into an analog signal. It is converted and output to the output terminal 13.

Now, a case where the remaining amount of the running magnetic tape 7 becomes small and the tape running direction is reversed will be described below. It is now assumed that the magnetic tape 7 is running in the A direction and is reversed in the B direction when it reaches the end.

The reel drive circuit 16 drives each reel stand 14, 15, and at the same time obtains rotation speed information C, D from each reel stand 14, 15. E is rotation speed information input from the reel drive circuit 16 to the tape end detection circuit 17. When the magnetic tape 7 approaches the end, it is predicted from the rotation speed information E that the tape end will be reached, and the tape end detection circuit 17 A tape end command F is output.

When the tape end command F is output during the recording operation, the memory control circuit 18
Stop reading addresses from. For example, as shown in FIG.
decimal display, the same applies hereafter) address, write address W is
When the tape end detection circuit 17 outputs the tape end command F to the memory control circuit 18 at address CD02, the memory control circuit 18
The control signal is sent to 1 and the read address R is CD01.
The street address remains fixed. Therefore, recording on the magnetic tape is stopped, and the capstan drive circuit 20, which has received the tape end command F, reverses the capstan 17, and the magnetic tape running direction changes from A to B.

Even in this transient state of inversion operation, the input signal is of course continuously input to input terminal 1, and the analog
Since it is input to the first memory circuit 3 after being digitally converted, the write address W is updated sequentially as CD02→CD03→... even after the tape end command F is output, and passes through the final address FFFF. Then return to address 0000 again, and then 0001→0002→…
...changes. However, if the tape running direction is reversed before the write address W goes around and reaches the read address (address CD01) (for example, AD00) and reading from the first memory circuit 3 is resumed, then As shown in FIG. 1C, the relative positional relationship between the read address R and the write address W on the first memory circuit 3 is kept constant. From the point in time when the tape running direction is reversed and becomes the B direction, reading from the first memory circuit 3 is restarted, and the data is sequentially output from address CD01 and recorded on the magnetic tape 7. That is, on the magnetic tape 7, in the A direction, up to address CD00,
The tape is reversed in the B direction and recorded from address CD01, and all the signals input to the input terminal 1 during the tape running reversal operation are recorded without any loss.

The first memory circuit 3 needs only have a capacity sufficient to store input digital signals for the time required for the tape running direction to be reversed.

As described above, during recording, all of the input signals are recorded on the magnetic tape, so during playback, as described below, the second memory circuit is used to output all the information on the magnetic tape without interruption. do it.

Next, the reversing operation during reproduction will be explained.
When the tape end detection signal F is generated during playback, the memory control circuit 18 stops writing addresses to the second memory circuit 11. For example, as shown in FIG. 3B, which shows the state of the second memory circuit 11 during an inversion transition, when the write address W is DE11 and the read address R is DE12, the tape end command F is used to control the memory in the same way as above. When output to the circuit 18 and the capstan drive circuit, the write address W is fixed at address DE11, the capstan 17 is reversed, and the tape running direction changes from A to B.

In this second memory circuit 11, the write address W is driven to be slightly delayed from the read address R, so when the write address W is fixed at address DE11 and enters the transient state of inversion operation, The read address R is
The final address changes as DE12→DE13→...
Pass through address FFFF, return to address 0000, and then return to address 0001
It changes sequentially as →0002→... Therefore, the output signal converted from digital to analog and outputted to the output terminal 13 is continuously outputted from the second memory 11 even during the inversion transition period. When the read address R is BE01, when the tape running direction is completely reversed, writing to the second memory circuit 11 is resumed.
From then on, write address W is written as shown in Fig. 3C.
The relative positional relationship between the read address R and the read address R on the second memory 11 is kept constant. In this case the second
Similarly to the recording system, the capacity of the memory 11 may be sufficient as long as it can store digital signals for the time required for reversing the tape running direction.

As described above, according to the configuration of this embodiment, during recording, the first memory circuit 3 stores the input signal for the time required to reverse the tape running direction, thereby recording the input signal on the magnetic tape without any omission. During playback, the signal stored in the second memory circuit 11 can be read out and the signal can be continuously sent to the output terminal during the time required to reverse the tape running direction.

Next, a configuration will be described in which recording and reproduction are performed by continuously repeating forward rotation and reverse rotation many times. Basically, it is the same as shown in FIG. 1, but the reel drive circuit 1
6 and the capstan drive circuit 20, and the running speed of the magnetic tape can be changed depending on the driving state of the first or second memory circuit.

That is, during recording, after the reversal of the tape running direction is completed by the mechanism, the reading speed of the first memory circuit 3 is made faster than the writing speed at that time. This can be easily achieved by increasing the read clock frequency from the memory control circuit 18. On the other hand, by using the read clock frequency of the memory control circuit as a control input for the reel stand drive circuit 16 and the capstan drive circuit 20, the reel stand and Increase the rotation speed of the capstan, that is, increase the tape running speed. Therefore, since the signal (recorded signal) read from the first memory circuit 3 is high speed and the tape running speed is also high, the state of the recorded magnetic tape is the same as the previously recorded state.

When the read speed from the first memory circuit 3 is increased as described above, the read address R will catch up with the write address W to the first memory circuit 3 after a while, and the normal recording shown in FIG. Therefore, by returning the read speed to the same as the write speed at this time, the first memory circuit 3 thereafter remains in the same recording state as before inversion.

At this point, the read speed returns to the normal speed, and at the same time, the memory control circuit 18 causes the reel drive circuit 1 to
6. The capstan drive circuit 20 is controlled, and the tape running speed during high-speed running is reduced to return to normal speed.

On the other hand, during playback, after the reversal of the tape running direction is completed, the writing speed of the second memory circuit 11 is made faster than the reading speed, and after a while the writing address W catches up with the reading address R, so the writing speed is increased. If the speed is set to the normal speed, the operating state of the second memory circuit 11 becomes the normal reproduction state shown in FIG. 3A. At this time, if the reel drive circuit 16 and capstan drive circuit 20 are controlled to run at high speed only while the writing speed is increasing, writing to the second memory circuit 11 will be performed correctly. There is no inconvenience.

With the above configuration, even if the tape running direction is repeatedly reversed, the first and second memory circuits 3 and 11 will not overflow, and recording and playback can be performed without any sound dropouts. It is.

Effects of the Invention The present invention performs reading with a slight delay from writing in the first memory circuit during recording,
The read signal is recorded on the magnetic tape, the magnetic tape is reversed near the end of the magnetic tape, and reading is prohibited at the same time. During the reversal operation, only the above writing is performed, and after the reversal is completed, the first
By restarting reading from the first memory circuit and recording the signal, the analog signal input during the reversing operation can be stored and maintained in the first memory circuit. In some cases, it is possible to record all input signals on a magnetic tape without any omissions.

Also, during playback, the signal from the magnetic tape is
The magnetic tape is written in a memory circuit, and the data slightly before the writing is read and output.The magnetic tape is reversed near the end of the magnetic tape, and writing is prohibited at the same time, and only the above-mentioned reading is performed during the reversal operation. By restarting writing from the magnetic tape to the second memory circuit after the reversal is completed, reproduction output is generated by the signal read from the second memory circuit during the reversal operation. This enables uninterrupted playback of recorded sounds. As described above, the present invention can provide an excellent digital recording and reproducing apparatus that enables continuous reciprocating recording and reproducing of a magnetic tape using an auto-reverse mechanism in digital recording and reproducing.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.
FIG. 2 is a state diagram for explaining the operation of the first memory circuit, and FIG. 3 is a state diagram for explaining the operation of the second memory circuit. 2...Analog-digital conversion circuit, 3...
First memory circuit, 6... Recording head, 7... Magnetic tape, 8... Playback head, 11... Second memory circuit, 12... Digital-to-analog conversion circuit, 16... Reel drive circuit, 17 ...Tape end detection circuit, 18...Memory control circuit, 20...
Capstan drive circuit.

Claims (1)

[Scope of Claims] 1. An auto-reverse tape running system that can record and play back the magnetic tape in the forward and reverse directions, and a magnetic head that converts analog signals such as audio into analog-digital signals. a first memory circuit which is inserted in the middle of a digital signal path of the recording means, and includes a recording means for recording with a magnetic head; and a reproduction means for converting the digital signal obtained by the magnetic head into an analog signal and outputting the analog signal; and,
A second memory circuit inserted in the digital signal path of the reproducing means, a tape remaining amount detection circuit that detects the remaining tape amount based on the number of rotations of the reel stand, and a command signal from this tape remaining amount detection circuit, A control circuit is provided to control writing and reading of the first and second memory circuits, and during recording, a remaining tape detecting circuit detects that the end of the tape is approaching and outputs the digital signal from the first memory circuit. Reading is prohibited, and only digital signals are written in accordance with the input during reversal of the tape running direction, and reading of digital signals from the first memory circuit is started again after the tape running direction is reversed. None. During playback, the tape remaining amount detection circuit detects that the end of the tape is approaching and prohibits writing of digital signals to the second memory circuit. During reversal of the tape running direction, the digital signal for playback output is disabled. After continuing to read the signal and reversing the tape running direction, writing of the digital signal to the second memory circuit is started again, and during recording, the digital signal input to the first memory during the reversing operation is A digital device characterized in that the signal is accumulated so that the recorded signal on the magnetic tape is not lost, and during playback, the playback digital signal is sent out from the second memory during the reversal operation so that the playback output is not interrupted. Signal recording and reproducing device. 2. An auto-reverse tape running system that can record and play back in the forward and reverse directions of the magnetic tape, and a recording device that records digital signals obtained by converting analog signals such as audio into analog-to-digital via a magnetic head. a first memory circuit which is inserted in the middle of the digital signal path of the recording means, and includes a reproducing means for converting the digital signal obtained by the magnetic head into an analog signal and outputting the analog signal;
A second memory circuit inserted in the digital signal path of the reproducing means, a tape remaining amount detection circuit that detects the remaining tape amount based on the number of rotations of the reel stand, and a command signal from this tape remaining amount detection circuit, the above-mentioned A control circuit that controls writing and reading of the first and second memory circuits is provided, and during recording, a remaining tape amount detection circuit detects that the end of the tape is approaching and reads out digital signals from the first memory circuit. During the reversal operation of the tape running direction, only digital signals are written in accordance with the input, and after the tape running direction is reversed, reading of digital signals from the first memory circuit is started again, and the first The read speed of the first memory circuit and the tape running speed are synchronized and accelerated until the difference between the read address and the write address of the first memory circuit matches the difference before inversion, and during playback, the remaining tape amount detection circuit detects that the end of the tape is approaching and prohibits writing of digital signals to the second memory circuit, and while the tape running direction is being reversed, reading out digital signals for playback output is continued, and the tape running direction is After the is reversed,
Start writing digital signals to the second memory circuit again, and increase the writing speed to the second memory circuit until the difference between the read address and the write address of the second memory circuit matches the difference before inversion. The speed is synchronized with the running speed so that digital signals can be transmitted even during the reversal operation, and after the reversal operation, the difference between the read address and write address of each memory circuit is restored to the original value and the tape is repeatedly stored. A digital signal recording and reproducing device characterized in that it is configured to reverse the running direction.