JPS5935099B2 - magnetic recording and reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic recording/reproducing device equipped with a recording canceller.

When performing an air check or the like with the above-mentioned magnetic recording/reproducing apparatus, that is, when recording an unknown source, we often encounter the following problems once the recording state has been established.

...I started recording thinking that it was the best source, but when I realized that this source was not what I expected, (2) I decided that the narration, commercials, etc. were over, and started recording my favorite source. When I started recording with this in mind, I ended up missing the first chance to record because of (3) ``live recording,'' etc. when it was followed by narration, commercials, etc., or when the source was completely disappointing. It's a time like this. In such a case as described above, it is desirable to quickly and efficiently rewind the magnetic tape to the recording start position on the magnetic tape, and then put the tape into the recording/pause state again in preparation for the next recording opportunity.

However, as described above, it is difficult to find the recording start position on the magnetic tape pattern. Furthermore, even if you are able to successfully find the above recording start position, you must immediately set the device's operation mode to record/pause, and you must perform these operations in a short period of time without losing the next recording opportunity. It requires considerable skill to do it properly. The present applicant has previously proposed a magnetic recording/reproducing device (see specification of Japanese Patent Application No. 162576/1983) which should deal with the above-mentioned situation.
The recording state is canceled based on a recording cancel operation, the rewinding operation is continued, and during this rewinding operation period, an unrecorded portion of the signal is detected from the state of magnetic flux distribution on the magnetic tape, We have proposed a magnetic recording and reproducing device that can determine this point as the recording start position on the magnetic tape, cancel the rewinding operation, and automatically set the recording/pause state to prepare for the next recording opportunity.

However, even with the magnetic recording/playback device described above, if you try to cancel the recording and return to the beginning of the recording (recording start position) even though the recording is only for a short time (about a few seconds), , the above operation is highly unstable. Furthermore, when cuing up after a short period of recording as described above, there is a good chance that the track will return to the previous track by mistake, which causes inconvenience. The present invention has been made in view of the above-mentioned circumstances, and provides a magnetic recording and reproducing device that can immediately respond to cancellation after even a short period of recording and can accurately locate the beginning within a short period of time. The purpose is to provide.

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

Generally, a method of detecting the intervals between songs on a magnetic tape is known as one means for performing so-called cue searching.

In order to detect the above-mentioned song interval, the above-mentioned magnetic tape is quickly wound and a pre-installed detection head (this detection head can also be used in combination with a playback head) is used.
The magnetic flux distribution on the magnetic tape is checked. Therefore, the above-mentioned song gaps are detected at a tape running speed several times higher than the normal playback speed. Figure 1 conceptually shows the state on the magnetic tape at this time; (a) shows the state of constant speed running during normal playback, and (b) shows the state of fast winding (constant speed running). In the diagram, TOytlyt2 and t2 represent time intervals, and a signal is recorded between TO and t2, and a signal is recorded between t1 and t1. Assume that no signal is recorded. Now, the fast winding speed during fast winding is (4.75XN
) In the case of CTIL/Sec, the output of the signal discrimination circuit T shown in FIG. 2, which is an embodiment of the present invention, must be driven by pulses, so that it is accurate even with the slightest recording error. In order to operate the signal discrimination circuit as described above, it is necessary to improve the responsiveness of the signal discrimination circuit described above. FIG. 2 is a block diagram showing an embodiment of a magnetic recording/reproducing apparatus equipped with a recording canceller according to the present invention.

Assume that the device is now in a recording state. Then, at the time when it is desired to cancel the recording, the user first operates the start switch SW to activate the start circuit 1. The start circuit 1 consists of a first flip-flop formed by a combination of NAND gates. Then, when the start switch Sw is operated to operate the start circuit 1, only when the previous memory state of the memory circuit 2 is the recording/playback mode, the RWD key is operated to enter the fast rewind mode. Make it. Note that, like the start circuit 1 described above, the memory circuit 2 is also composed of a second flip-flop formed by a combination of NAND gates. Therefore, only when the start switch SW is operated and the previous memory state of the memory circuit 2 stores the recording/reproducing mode, the RWD key is operated to enter the fast rewind state. The output of the start circuit 1 is supplied to a gate circuit 5 via an inverter 3 and an inverter 4, and drives the gate circuit 5 (shown as a NOR gate in the embodiment).

Further, the signal from the start circuit 1 via the inverter 3 is applied to the NA to which the signal from the gate circuit 5 is supplied.
A NAN to which signals from the memory circuit 2 composed of the ND gate 6 and the above-mentioned second flip-flop are supplied.
Each D gate is supplied. When the recording cancel operation (operating the start switch SW at the point in the recording state when you want to cancel) causes the fast rewind state as described above, the signal on the magnetic tape is detected by the detection head during this fast rewind period. An operation is performed to detect unrecorded portions.

The recommendation for this detection operation is as follows, centering on the signal discrimination circuit T shown below. During the fast rewinding period in the above state, changes in the magnetic flux distribution on the magnetic tape are detected by the detection head 8 (of course, the reproducing head may also serve as this). The pickup output from this detection head 8 is sent to a saturation amplifier 9.
The signal is amplified by the detector circuit 10, further rectified by the detection circuit 10, and held in a capacitor (not shown) of the integration circuit 11. The integrated output of the above integrating circuit 11 is input to the non-inverting input terminal (4) of the next comparator 12. Further, the reference voltage VI is connected to the inverting input terminal (to) of the comparator 12.
N is applied. The comparator 12 compares the integral output (pickup output from the detection head 8) with the reference voltage VIN. When the detection head 8 comes to a part of the magnetic tape where no signal is recorded, the pickup output from the detection head 8 rapidly decreases to zero, so that the charge in the capacitor in the integration circuit 11 described above is discharged. Accordingly, the terminal voltage of the non-inverting input terminal (4) of the comparator 12 decreases. The output of the comparator 12 is inverted when the terminal voltage of the non-inverting input terminal (a) becomes lower than the reference voltage applied to the inverting input terminal (g), and this inverted signal is used as a no-signal detection signal. The above-mentioned no-signal detection signal is supplied to the gate circuit 5.

As mentioned above, upon detection of no signal, an end signal (reset pulse) is applied to the memory circuit 2, and the fast rewinding state is canceled. In addition, the output of the NAND circuit 6 causes the PLA
When the Y key is activated, the output of the NAND circuit 7 activates the REC key and the PAUSE key. In other words, when the recording cancel operation is performed in the recording state, the device shown in Fig. 2 is rewound to the recording start position by a fast rewind operation, and then waits in the recording/pause state at this recording start position. The series of operations described above will then be performed automatically and reliably.

In the above embodiment, the example is shown as recording cancel → rewind → record/play → record/pause, but it is also possible to do this as recording cancel → rewind → stop → record/pause. Needless to say.

FIG. 3 shows an embodiment of the signal discrimination circuit T shown in FIG.

As mentioned above, this signal discrimination circuit must have good responsiveness and detects the unrecorded portion of the signal from the magnetic flux distribution on the magnetic tape. Next, we will briefly explain its operation. . During the fast winding operation (FF and REW), the output of the comparator is inverted when the detection head 8 outputs a signal from the magnetic tape.

From equation (1), t is found as follows.

Therefore, the VCC-
After VINV, CR・? (Sec) inverts the output of the comparator VINV.

That is, the above-mentioned discharge time constant (CXRl) serves as a reference value for determining how many seconds it takes to determine a no-signal portion. Note that since this is also related to the applied voltage VcO, sufficient consideration must also be given to the setting of Vcc. for example,
Let us consider the case where a C-60 (for 60 minute round trip) tape is used.

The fast winding speed at the time of detecting between songs is NXν (however, ν-4
．． 75CTrL/Sec), and if it is determined that there is no signal after TO seconds, then equation (2) is obtained.

From equation (3), we obtain.

That is, the time constant in the signal discrimination circuit described above is (4
), and it can be seen that this time constant can be determined according to N. Note that the signal obtained as the output of the signal discrimination circuit is a signal that plays an important role in subsequent processing.

When determining the recording start position, do you start from the part of the magnetic tape where signals are recorded, as shown in Figure 4, or start from the no-signal part (where no signals are recorded)? The processing of the above-mentioned signals differs depending on the situation. (b) shows the comparator output, in which τ1 indicates a delay due to the discharging time constant, and τ2 indicates a delay due to the charging time constant. As described above, the processing of the output signal from the signal discrimination circuit differs depending on the recording start position, and it is necessary to perform pulse driving or perform pulse processing in later processing. adopts the pulse drive of the above, and uses a negative edge. As described above, according to the present invention, it is possible to provide a magnetic recording/reproducing device that can perform operations from recording cancellation to recording/pause reliably with a single touch.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the concept of running speed on a magnetic tape, FIG. 2 is a block diagram of an apparatus showing an embodiment of the present invention,
FIG. 3 is a circuit diagram showing one embodiment of the signal discrimination circuit, and FIG. 4 is an explanatory diagram for explaining the present invention in more detail. 1: Start circuit, 2: Memory circuit, 5: Gate circuit, 6
, 7: NAND circuit, 8z detection head, SW: start switch, T: signal discrimination circuit.

Claims (1)

[Claims] 1. In a magnetic recording/reproducing device equipped with a recording canceller, a start circuit comprising a first flip-flop activated based on a recording canceling operation;
A storage circuit consisting of a second flip-flop that stores the operating mode of the device before the recording cancellation described above, and a detection head during the rewinding period to the recording start position on the magnetic tape based on the recording cancellation operation described above. a signal discrimination circuit that detects a non-signal portion on the magnetic tape based on the presence or absence of a pickup output; a gate circuit to which signals from the signal discrimination circuit and the start circuit are supplied; and a signal from the gate circuit and the signal from the start circuit; A first NAND circuit is supplied with a signal from the start circuit and operates the PLAY key, and a second NAND circuit is supplied with signals from the start circuit and the memory circuit and operates the REC key and the PAUSE key. By driving the start circuit, the rewind operation is performed only when the memory mode of the memory circuit is in the recording/playback mode, and the memory circuit is reset by the no-signal detection signal from the signal discrimination circuit. A magnetic recording/reproducing device characterized in that a pulse is supplied to terminate the rewinding operation and automatically enter a recording/pause state.