JPS6032895B2 - magnetic recording and reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic recording and reproducing device that can automatically detect the position on a tape, and in particular, when recording several types of content on one tape, Regarding a device that is configured to provide a no-signal portion in the system, detect this no-signal portion later in a high-speed playback state such as cue or review, and automatically stop or shift to the playback state, the purpose thereof is: If the constant tape running speed during playback and recording can be changed to 2.4 arc/sec, 4.8 arc/sec, 9.5 arc/sec, etc., the above non-signal portion The purpose is to prevent the failure to detect a non-signal portion in a high-speed playback state due to a change in length.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an overall configuration diagram of the device according to the present embodiment, and 1 indicates the operations represented by six keyboard switches for inputting operation commands such as play, recording, pause, fast forward, rewind, and stop. A switch 2 is a logic circuit that receives an operation command from the switch 1. This logic circuit 2 not only stores each operation command but also has the function of processing multiple inputs and determining the priority order of commands, such as outputting a stop command when it receives a fast forward command and a rewind command at the same time, and has a flip-flop function. It consists of circuits and various gate circuits. Reference numeral 3 denotes a mechanism control circuit for receiving command output from the logic circuit 2 and executing the command, and is composed of transistor switches, relays, etc. The suction and reel motors of the various plungers constituting the pump are controlled in forward and reverse directions so that an operating mode can be obtained according to a command from the switch 1.

Next, 5 is a recording mute switch for forming a no-signal portion for a certain period of time on the tape, and 6 is a recording mute control circuit.

This control circuit 6 immediately applies a signal to the muting circuit 8 interposed in the output line of the recording amplifier 7 in the recording mode only when the recording mute switch 5 is closed in the recording mute and recording pause modes. A muting operation is performed to suppress the recording signal to the recording/reproducing head 9, and after a certain period of time, the muting operation is automatically canceled and a recording pause mode is set. Figure 2 shows the main circuitry of the device of this embodiment, where la, lb, and lc are keyboard switches for input commands for play, pause, and recording, and when these are closed even momentarily, the corresponding flip-flops are switched. pull circuit 2a, 2
b and 2c are set, and their output changes from “L” to “
It is designed to be reversed to "H".

It goes without saying that all flip-flop circuits are reset by instantaneously closing a stop switch (not shown). The recording mute control circuit 6 includes a monostable multipipulator including transistors Q, Q2, etc., which is triggered by closing the recording mute switch 5.

And if there is no trigger input above, transistor Q
, is conductive and transistor Q2 is non-conductive and stable. However, when the recording mute switch 5 is closed and a trigger input is given to the monostable multipipulator, the transistor Q , becomes a negative potential, so that the capacitor C
An "L" output is obtained on the collector side (point B) of the transistor Q2 for a time determined by the time constant of the resistor R4 and one of the switches 3 to C5 selected by the switch 1. 11 is an inverter that inverts the "L" output of the monostable multipipulator to "H", shapes the waveform, and sends it to the meeting output terminal 12; 13 is the "L" output of the above inverter 1;
This is an inverter that receives an output change from "H" to "L" via a differentiator circuit consisting of a resistor R and a capacitor C6, inverts it, shapes the waveform, and sends it to one input terminal of the NAND gate circuit 14.

The NAND gate circuit 14 is for setting the temporary stop command storage flip-flop circuit 2b, and receives the output from the recording command storage flip-flop circuit 2c at its other terminal. The switch 10 is a switch that is linked to a constant tape running speed switch (not shown), and the contacts a, b, and c are 2.4 skin/sec, 4.8 skin/sec,
It corresponds to a speed position of 9.5 skin/sec.

Figure 3 is a waveform diagram of the main part of the circuit in Figure 2. Figure 3 (F) is the waveform accompanying the opening and closing of switch 5, (A) is the potential waveform at point A, (C) is the potential waveform at point B, and The potential waveform at point C, O shows the output waveform of the inverter 13, and O shows the output waveform of the flip-flop circuit 2b for storing the temporary stop command.

FIG. 4 is a specific circuit diagram of the muting circuit 8, in which a transistor Q whose conduction and non-conduction are controlled by the signal from the muting output terminal 12 of FIG. 2 is interposed between the recording signal line and the ground. configuring the switching circuit 8.

The operation of the above embodiment will now be explained.

First, the play switch la and the recording switch lc are momentarily closed to put the device into recording mode and record information. When the recording is finished, the recording mute switch 5 is momentarily closed, and the monostable multipipulator consisting of transistors Q, , Q2, etc. is operated for a certain period of time, and the muting transistor Q is made conductive for this certain period of time. As a result, a no-signal portion for a certain period of time is formed on the magnetic tape. At the same time as the monostable multipipulator stops operating, the muting transistor Q becomes non-conductive, and the NAND gate circuit 14
An "H" signal is applied to one input terminal of the . At this time,
Since the other input terminal of the NAND gate circuit 14 is given the "H" output from the recording command storage flip-flop circuit 2c, the output of the NAND gate circuit 14 immediately becomes "H".
With this "L" output, the flip-flop circuit 2b for storing the pause command is set, and the device enters the recording pause mode. Then, this pause mode is released and the next information is recorded. In this way, a no-signal portion for a certain period of time T is created between adjacent recorded portions.

This fixed time T can be changed depending on the tape speed. For example, when a monostable multipipelator is operated for 3 seconds at a speed of 4.8 skins/second, and when a monostable multipipelator is operated for 3 seconds at a speed of 2.4 skins/second, If the length of the no-signal part on the tape is 4.8 skin/second, it will be 1, and if it is 2.4 skin/second, it will be 1/2, but in this embodiment, the switch 10 switches the capacitors C3 to C5. is selected and the operating time of the monostable multipipelator is varied so that the shape growth of the non-signal portion on the tape is approximately the same even if the tape speed is changed. Since this is done, if you try to automatically detect the position of a tape that has finished recording,
Can perform reliable operations.

In other words, if you try to detect a no-signal part through the head 9 by performing fast-forward playback (cue) or rewind playback (review), no matter what the tape speed at the time of recording, the no-signal part during the above-mentioned high-speed forward playback will be detected. The head transit times of the signal portions are approximately equal, and detection errors will no longer occur. When a no-signal portion is detected, the apparatus is automatically stopped or switched to a playback mode, thereby locating the beginning of the recorded portion. Note that since the regeneration system is already well known, further explanation will be omitted. As described above, in the apparatus of this embodiment, when the tape speed during recording is slow, the operation time of the no-signal portion forming means is lengthened, and when the speed is fast, the operation time is set short, and no signal on the tape is set. The aim is to keep the shape and growth of the parts almost constant. That is, the queue,
With a device that uses the head output during review to detect a non-signal area on the tape and "cue" it, the fast forward speed is as fast as about 15 to 3 notes during playback, and it changes quickly, so there is no error. It is very difficult to detect the signal part.

Or, with a device configured to switch the speed during play and recording, as mentioned above, a 3-second blank section is created when the speed is 4.8 cm/sec, and a 3-second blank section is also created when the speed is 2.4 cm/sec. In this case, the actual blank area on the tape is only half the length of the former, and the cue and review speeds are the same, so it is difficult to correctly detect the blank area created with the latter, but the apparatus of this embodiment According to this method, this drawback can be overcome with a simple construction. As explained above, according to the magnetic recording and reproducing apparatus of the present invention, the operating time of the no-signal portion forming means is changed in response to switching of the tape speed, so that a no-signal portion of approximately constant length is formed on the tape. Therefore, no matter what tape speed the tape is recorded at, the no-signal portion can be detected without error during high-speed playback, and reliable cueing can be performed.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a magnetic recording/reproducing apparatus according to an embodiment of the present invention, Fig. 2 is a circuit diagram of its main parts, and Fig. 3 shows a second
FIG. 4 is a waveform diagram of the main parts of the circuit shown in the figure, and FIG. 4 is a circuit diagram showing the muting circuit portion. 1... Operation switch, 2... Logic circuit, 5... Recording mute switch, 6...
...Control circuit, 7...Recording amplifier, 8...
...Muting circuit, 9... Recording/playback head. Figure 1 Figure 4 Figure 2 Figure 3

Claims (1)

[Claims] 1. When recording on a tape, by operating a specific switch, a no-signal portion forming means is automatically activated for a predetermined period of time to form a no-signal portion on the tape, and the tape is played back at high speed while playing back signals from the tape. In a magnetic recording and reproducing apparatus, the magnetic recording and reproducing apparatus is equipped with a control means for detecting a non-signal portion on the tape by a magnetic head in a high-speed feed reproducing state in which the tape is being run, and automatically stopping or shifting to a normal reproducing state upon detection of the non-signal portion. tape constant running speed switching means for switching the constant tape running speed during playback and recording; and the above-mentioned non-signal portion forming means in response to switching of the tape speed by the tape constant running speed switching means when recording on the tape. 1. A magnetic recording and reproducing apparatus characterized in that a means for changing the operating time of the magnetic recording and reproducing apparatus is provided so that a non-signal portion of approximately constant length is formed on the tape regardless of the tape speed during recording.