JPS5810202Y2 - Recording/playback device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a recording/reproducing apparatus capable of recording a cue signal indicating a desired position on a recording medium onto the recording medium.

In a VTR that records video signals on a magnetic tape and plays them back, a cue signal (or cue signal) indicating the position of a required scene is sometimes recorded on the tape.

Such a cue signal is, for example, a control signal (hereinafter referred to as a CTL signal) that serves as a reference for tracking servo.
Control head (CTL head) for recording
However, even if such a cue signal can be recorded when recording a video signal, at the time of playback, it is necessary to obtain a playback CTL signal from the CTL head, so cue No. 1 is used. could not be recorded.

The present invention has been devised in view of the above-mentioned problems, and is designed so that a cue signal can be recorded using a CTL head during playback.

Embodiments of the present invention will be described below with reference to the drawings. ○Figure 1 is a circuit diagram of a CTL/Cue recording/reproducing circuit showing an embodiment of the present invention, and Figure 2 shows the various parts of Figure 1. FIG. 3 is a waveform diagram showing waveforms.

The circuit shown in Figure 1 includes a circuit for recording and reproducing a control signal (CTL signal) in order to correctly track the recording track formed on the tape during playback, and a circuit for recording and reproducing a control signal (CTL signal) for locating the beginning of a necessary scene (hereinafter referred to as a cue signal). ) and a recording/reproducing circuit.

As shown in FIG. 1, the CTL/Cue recording and reproducing circuit mainly consists of a cue signal forming circuit 1, a recording amplifier 2, a compression amplifier 3, a reproducing amplifier 4, and a cue signal detecting circuit 5.

At the time of automatic recording, a 30 Hz CTL recording signal shown in FIG. Ru.

This recording amplifier 2 is a direct-coupled amplifier connected to transistors T1 and T2, and the collector output of transistor T2 is passed through a limiter consisting of diodes DI and D2 to CT.
It is supplied to the L head 6.

As a result, a CTL signal is recorded on the CTL rack of the tape corresponding to the position of each recording track.

Note that during recording, the cue switch γ of the cue signal forming circuit 1
When the CTL) is operated, a cue signal is recorded on the CTL rack in the same way as during playback, which will be described later.

Next, to explain the time of playback, during playback, the playback CTL signal detected by the CTL head 6 (FIG. 2B)
is supplied to a drum servo circuit (not shown) via the compression amplifier 3 and reproduction amplifier 4, and tracking is performed based on this reproduction CTL signal.

Then, when the cue switch 7 of the cue signal forming circuit 1 is pressed in the desired scene while watching the playback screen, the cue signal is supplied to the CTL head 6 and the cue signal is changed to CTL).
It is now recorded on the rack.

In FIG. 1, the positive pulse of the reproduced CTL signal (FIG. 2B) is amplified and waveform-shaped by the CTL reproduction amplifier 4 to form the reproduced CTL signal Sc shown in FIG. 2C.

This reproduced CTL signal S. is supplied to the monomulti 19 of the cue signal forming circuit 1 via the non-game) G1.

The monomulti 19 synchronizes with the rise of the reproduced CTL signal and outputs a low level pulse width, for example 1rrLSe, as shown in the second figure.
A pulse SD of C is formed.

This pulse SD is supplied to the monomulti 8, and similarly, in synchronization with the rise of the pulse SD, a low level cue signal SE having a pulse width of 1@sec, for example, as shown in FIG. 2E, is formed.

On the other hand, when the cue switch 7 is pressed, the mono multi 9 is triggered, and from the output of this mono multi 9, for example, 3QQ7r
A pulse P is obtained which is at a low level during LSeC.

Since this pulse P is supplied to the NOR gate G2, the cue signal SE passes through the NOR gate G2 during the low level period (300 msec) of the pulse P, and the cue signal SF (FIG. 2 F) whose polarity is inverted is generated. can get.

The output of this NOAH game) G2 is supplied to the recording amplifier 2 as a cue signal of the same polarity as that shown in FIG. 2E via a NOAH game) G3.

Note that the other input terminal of the Noah Game (G3) is at a low level during playback.

As a result, the recording amplifier 2
The transistors TI and T2 are turned on, a recording current flows through the CTL head 6 from the ground potential to the -V power supply, and the cue signal is recorded on the CTL rack.

Note that as shown in Figure 2, the position where the cue signal is recorded on the CTL rack is in a part other than the part where the CTL signal is recorded, so it may be recorded overlapping with the already recorded CTL signal. There isn't.

During playback, the playback CT is transmitted from the CTL head 6 as described above.
Since the L signal is obtained and the cue signal is supplied to the CTL head 6 when the cue switch 7 is pressed, the C
The voltage waveform at terminal A of the TL head 6 is as shown in FIG. 2G.

That is, at the terminal A, reproduction CTL signals a and a' with a relatively low level are generated, and a negative pulse b with a considerably high level is generated due to the recording current of the cue signal.

If such a terminal voltage of the CTL head 6 is directly supplied to the reproduction amplifier 4, there is a risk that the reproduction amplifier 4 will be saturated for a predetermined period due to the high-level negative pulse bK, making it impossible to obtain the reproduction CTL signals a and a'. be.

This is because the reproduction amplifier 4 is generally configured as an AC amplifier and has a predetermined time constant due to its coupling capacitor and the like.

Therefore, as shown in FIG. 1, the output signal of the CTL head 6 is supplied to the reproduction amplifier 4 via the compression amplifier 3.

The compression amplifier 3 includes a differential amplifier consisting of transistors T4 and T6 for compressing and amplifying the output of the CTL head 6, and a limiter transistor T8 connected to the output of this differential amplifier. T9 and an emitter follower transistor T7 that receives the output of the differential amplifier.

The emitters of the transistors T4, T6 of the differential amplifier are connected to diodes D3, . It is connected to the transistor T5 via D4, and since a constant voltage is supplied to the base of the transistor T5, the differential amplifier is driven with a constant current.

The collector of the ordinary transistor T6 is the transistor T3.
An active load consisting of is connected.

When the reproduced outputs a and a' of the CTL head 6 are supplied to the base of the transistor T4 of the differential amplifier, a reproduced CTL signal amplified to a predetermined level is obtained from the collector of the transistor T6 of the differential amplifier.

This reproduced CTL signal is supplied to the attenuator 10 through the follower stage of the transistor TI, where it is adjusted to a predetermined level and then supplied to the reproduction amplifier 4.

The output of the reproduction amplifier 4 is supplied to a drum servo circuit (not shown).

Also, the differential pulse b generated by the recording current of the cue signal
, b' are supplied to the CTL head 6, the negative pulse b causes the collector current of one transistor T4 of the differential amplifier to decrease and the collector current of the other transistor T6 to increase.

Therefore, since the collector potential of the transistor T6 decreases, the base potential of the transistor T3 also decreases, and the bias of the transistor T3 becomes deeper.

As a result, the impedance of the transistor T3 decreases, and the decrease in the collector potential of the transistor T6 is compensated for.

On the other hand, the collector of the transistor T6 is connected to the common emitter of the transistors T8 and T9 constituting the limiter, and is also connected to the common base via a CR circuit with a large time constant.

Therefore, the base potentials of the transistors T8 and T9 are always kept at a constant potential, and the base potential and emitter potential are almost equal to each other.
．． T9 are each turned off.

When the collector potential of the transistor T6 of the differential amplifier decreases due to the negative pulse bK generated by the cue signal, a forward bias is applied between the base and emitter of the transistor T8, making the transistor T8 conductive and lowering its impedance.

Therefore, this compensates for the drop in collector potential of transistor T6.

In this way, the excessive current and voltage levels at the negative pulse b of the cue signal are compressed by the compression amplifier 3, so that the signal obtained from the emitter of the transistor T7 becomes as shown in FIG. The reproduction amplifier 4 in the stage does not become saturated.

Next, the cueing operation in the playback mode will be explained. In the portion where the cue signal is recorded, the playback signal sI shown in Figure 2 is obtained from the CTL head 6.

This reproduction signal sI is obtained as positive and negative differential pulses of the rising and falling positions of the CTL signal and the cue signal, respectively.

After these differential pulses are amplified by the compression amplifier 3,
The signal is supplied to the TL reproduction amplifier 4 and sent to the drum servo circuit as a reproduction CTL signal.

Note that this reproduced CTL signal includes a cue signal (differential pulse).
However, since the cue signal is within the servo insensitive area within a width of 10 m5ec from the reproduced CTL signal, there is no possibility that a tracking error will occur due to the cue signal.

The output of the compression amplifier 3 is also supplied to a waveform shaping circuit 13 via a low-pass filter 11.

From this waveform shaping circuit 13, a pulse signal S as shown in FIG. 2J is obtained corresponding to the position of the positive differential pulse of the reproduced signal sI.

This pulse signal S includes a reproduction CTL signal C and a reproduction queue signal d, and the interval between them is 5277Lse.
c.

The output S of the waveform shaping circuit 13 is supplied to the cue signal detection circuit 5.

This cue signal detection circuit extracts only the reproduced cue signal d from the pulse signal S, and the pulse signal S is supplied to the monomulti 14 via the inverter 1.

The monomulti 14 generates a pulse SK (K in FIG. 2) having a pulse width of 17 FLsec in synchronization with the rise of the pulse signal SJ.

This pulse SK is supplied to the monomulti 15, and the pulse S
An example of synchronizing with the rising edge of K is Ha5? A pulse SL (L in FIG. 2) with a pulse width of n8ee is formed.

This pulse SL and pulse signal S. Toga Nando Game) G4
Therefore, from this Nantes gate G4, the second
As shown in FIG. M, a signal S containing only the polarity inverted signal of the reproduction cue signal is obtained separately.

This signal SM is supplied to the monomulti 18 via a NAND gate G6, an inverter 2, and a NOR gate G7, and a signal SN that is at a high level for, for example, 1 sec from the reproduction cue signal is obtained from the Q terminal of the monomulti.

In response to this signal SN, the transistor Tll is turned on, and the light emitting diode D5 connected to its collector is lit to indicate that the beginning of the playback has been found.

Note that the other input terminal of the gate circuit G6 is supplied with a signal SP that becomes high level when the reproduction mode is set.

Furthermore, the polarity-inverted signal SN obtained from the q terminal of the monomulti 18 is supplied to a NOR gate G8, and the signal SP is supplied to the other input terminal of this NOR gate G8.

Therefore, the transistor T10 is turned on for approximately 1 sec corresponding to the signal SN, and the transistor T10 is turned on for approximately 1 sec corresponding to the signal SN.
A solenoid (not shown) for stopping the VTR connected to the VTR 10 is energized, and the VTR enters the stop mode with the required recording scene cued.

Also, when the VTR is placed in fast forward mode (FF) or rewind mode (REW), a cue signal is detected in the same manner as described above, and a necessary scene is cued.

That is, in the FF mode or REV mode, the reproduced signal SI/, which is almost the same as that in Figure 2 although the time axis is different, is
The signal S obtained from the TL head 6 is supplied to a circuit consisting of monomultis 16 and 17 of the cue signal detection circuit 5, and only the reproduced cue signal is separated in the same manner as described above.

Then, in response to this playback cue signal, the light emitting diode D5
is lit for a predetermined period of time, the stop solenoid is activated, and the VTR is placed in stop mode.

Furthermore, when a cue signal is detected, the VTR is turned to FF”/RE.
The W mode may be automatically switched to the playback mode.

In the above explanation, a cue signal can be recorded during playback to locate the beginning of a necessary scene, but the above-mentioned cue signal can be recorded at the end of a necessary scene to perform end detection. Good too.

Further, in the above embodiment, only the cue signal is extracted from the reproduction signal of the CTL head 6, but the CTL signal is extracted from the reproduction signal and the already recorded cue signal is erased based on this CTL signal. It is also possible to form an erasing signal for this purpose.

Note that the cue signal is partially magnetized, for example, in the S-pole direction in the section of the CTL signal, which is magnetized, for example, in the N-pole direction, in the CTL rack.

In the FF mode or the REW mode, the reproduced cue signal is obtained as a relatively wide undifferentiated pulse, so it is possible to separate this cue signal using a low-pass filter.

Also, without using a low-pass filter, FF mode or
In the modes, the band of the CTL reproduction amplifier may be switched so that the cue signal can be obtained from the CTL reproduction amplifier in these modes.

In the above-described embodiment in which the CTL signal is
Although several cue signals are inserted into one section of the CTL signal, several cue signals may be inserted into one section of the CTL signal.

In this case, by encoding the cue signal, different cue signals can be recorded for each of a plurality of scenes recorded on the same tape, and each scene can be reproduced in a distinct manner.

Further, in the above embodiment, the compression amplifier 3 is used to prevent the recording cue signal from being directly supplied to the CTL reproduction amplifier 4, but in the pulse width section of the recording cue signal, the CTL head 6 and the reproduction amplifier By using a circuit (for example, a switch circuit, etc.) that cuts off the signal between
It may be configured so that it is supplied to the TL reproduction amplifier 4.

As described above, the present invention supplies a cue signal to the control head during playback and records this cue signal, and at this time, a leg circuit is provided to compress or block the cue signal superimposed on the playback control signal. The playback control signal can be obtained through the

Therefore, during playback, the cue signal can be recorded using the control head without interfering with the tracking servo operation based on the playback control signal.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a CTL/Cue recording/reproducing circuit showing an embodiment of the present invention, and FIG. 2 is a waveform diagram showing waveforms at various parts in FIG. In addition, in the symbols used in the drawings, 1...
・Cue signal forming circuit, 3... Compression amplifier, 6
...It is a CTL head.

Claims (1)

[Scope of utility model registration request] In a recording and reproducing apparatus equipped with a control head for recording and reproducing a control signal serving as a reference for tracking servo on a recording medium, the control head is connected to the control bed and transmits a cue signal indicating a desired position on the recording medium. and a control circuit that is connected to the control head and compresses or blocks the cue signal from the cue signal forming circuit that is superimposed on the reproduction control signal obtained from the control head. . A recording and reproducing apparatus, wherein when recording the cue signal during reproduction, the tracking servo can be performed using the output signal of the control circuit.