JPS6256563B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a signal recording method, and in a magnetic recording/reproducing device, etc., if a control signal portion in which unnecessary signals are recorded is damaged, a control signal portion in which necessary control signals are recorded is detected. The purpose of the present invention is to provide a method that can multiplex record arbitrary signals without causing any interference.

In general, when a magnetic recording/reproducing device is in recording mode, a method for multiplexing another signal in addition to the normally recorded signal is to identify audio multiplexing by, for example, changing the position of the downward pulse of the control channel during recording. A method of multiplex recording signals, etc., and a method of multiplex recording a pilot signal such as an identification signal for audio multiplexing at a predetermined level at a frequency lower than the low frequency conversion color signal frequency are being considered. However, in these methods, signals are multiplexed during the recording mode of the magnetic recording/reproducing device, so they are not suitable for adding new information after the recording of signals is completed. Therefore, in the above method, it is not possible to erase or modify only the multiplexed signal, and the range of application is limited.

In addition, as a method for later writing or removing arbitrary information on a magnetic recording medium on which information has already been recorded, a dedicated track for recording arbitrary information as described above is provided on the same magnetic recording medium, and this method is used. A method of providing a head for a dedicated track is also considered, but such a method requires a new track (channel) on the recording medium and a head for this new track, so there are problems with recording standards and costs. This becomes a problem.

One way to utilize the recording function of a household magnetic recording/reproducing device (VTR) is to create a library by recording and collecting TV programs such as movies or concerts. Since the premise is to save the program, users usually do not want to record unnecessary parts such as commercials in the television program. In order to avoid recording such unnecessary parts, it is necessary to operate a pause switch that temporarily stops the recording operation of a magnetic recording/reproducing device (VTR) when recording a television program that is currently being broadcast. Furthermore, when so-called timer recording is performed, all information including unnecessary parts is recorded, so unnecessary parts cannot be removed unless dubbing editing is performed. Furthermore, expensive editing equipment is also required when taking pictures with a home television camera and removing unnecessary parts after the pictures are taken.

The present invention eliminates the above-mentioned drawbacks,
An embodiment thereof will be described with reference to FIG. 1 and the following figures.

FIG. 1 is a schematic block system diagram showing an embodiment in which the signal recording method of the present invention is applied to an automatic jump method that can substantially cut (erase) unnecessary signal portions in a magnetic recording/reproducing device or the like. be. First, the configuration of the block system of this embodiment will be explained. In the figure, the output of a 1/2 power supply voltage supply circuit 1 is connected to one terminal of a control head 2 and a non-inverting terminal of a differential amplifier 3. The other terminals of the control head 2 are connected via contacts 23 to the input side of the electronic switch 4 and to the output sides of the electronic switches 16, 17. The output side of the electronic switch 4 is connected to the differential amplifier 3 mentioned above.
The output terminal of the differential amplifier 3 is connected to the input terminals of the inverting amplifier 5 and the non-inverting amplifier 6 via a contact 24. Further, the output terminals of the inverting amplifier 5 and the non-inverting amplifier 6 are respectively connected to the input terminal of the peak detection comparator 7.
The output terminal of the peak detection comparator 7 is connected to the input side of the electronic switch 8 via a contact 33.

On the other hand, the logic circuit 15 has four electronic switch control signal output terminals, which are connected to the control signal input terminals of the electronic switches 4, 8, 16 and 17, respectively. The output terminal of the upward pulse detector 9 is connected via the contact 27 to the input terminals of the gate monostable multivibrator 10 and the waveform generation monostable multivibrator 11, and the output terminal of the monostable multivibrator 10 is connected to the above logic. It is connected to one input terminal of the circuit 15. The output terminal of the monostable multivibrator 11 is the contact 28
and the input terminals of the triangular wave generator 13 and the sawtooth wave generator 14 via the inverter 12 and the contact 29, and the output terminals of the triangular wave generator 13 and the sawtooth wave generator 14 are connected to the contacts 30 and 31, respectively.
It is connected to the input side of electronic switches 16 and 17 via. Further, the logic circuit 15 is connected to a display and switch section 18.

The input terminal of the upward pulse detector 9 and the output terminal of the inverting amplifier 5 are connected at a contact 25, and the output of the inverting amplifier 5 is the control reproduction signal 2.
It is 0. The output of the electronic switch 8 obtained through the contact 34 is a fast forward control signal 21, and 19 is a control recording signal.

FIG. 2 shows a circuit diagram of the block system shown in FIG. In the figure, the same parts as in FIG. 1 are given the same reference numerals, and the explanation thereof will be omitted. In Figure 2,
_R1 to _R40 are resistors, C1 to C14 are capacitors, D
1 to D11 are diodes, 47 to 50 are inverters, X1 to X3 are transistors, 51 is an electronic switch, and 42 to 46 are operational amplifiers. FIG. 3 is a state transition diagram of the logic circuit 15.

Next, the operation of this embodiment will be explained with reference to FIG. 4 and the following figures. FIG. 4 shows recording waveforms in a mode for recording control signals. In the same figure, the control recording signal 19 shown at A is the signal at the contact point 22 of FIGS. 1 and 2, and
The control reproduction signal 20 shown in B is the signal at the contact 25. The recording waveform described above is generated by a servo circuit (not shown) in a magnetic recording/reproducing device (VTR), and has a waveform similar to that of a conventional waveform. Further, since power is supplied to the systems shown in FIGS. 1 and 2 only when the VTR is in the playback mode, the systems shown in FIGS. 1 and 2 do not perform any operation when the control signal is recorded.

FIG. 5 shows a timing chart during control signal regeneration (autojump off). The control head output signal shown at A is the signal at contact 23 in FIGS. 1 and 2, the control signal of the electronic switch 4 shown at B is the signal at contact 38, the differential amplifier output signal shown at C is the signal at contact 24, and the signal at D is the signal at contact 24. The control reproduction signal shown is the signal at contact 25. In the state shown in FIG. 5, the switch 3 in the display and switch section 18
5, 36, and 37 all correspond to the off state, and the operation is similar to that of a conventional servo circuit. Here, 1/2 power supply voltage supply circuit 1 shown in Figs.
Since the control head 2 supplies a relatively low impedance voltage of 1/2Vcc, which is half of the power supply voltage Vcc, to the conventionally grounded terminal, the voltage applied across the capacitor C4 changes when the electronic switch 4 is turned on and off. It is possible to suppress switching noise (switching noise) to a low level.
As shown in FIG. 3, when the autojump is off, the electronic switch 4 is in a high state (on), so the head output signal is supplied as is to the differential amplifier 3, and then to the inverting amplifier 5 as shown in FIG. 5D. After being inverted and amplified into a waveform like a control reproduction signal,
Supplied to a servo circuit (not shown). As is clear from FIG. 3, since the electronic switches 8, 16 and 17 are off when the auto jump is off, the fast forward control signal 21 is not output from the electronic switch 8 and no new signal is recorded.

FIG. 6 shows a timing chart when recording (in this case, obtaining new information by modifying the control signal) or erasing the jump signal while reproducing the control signal. When recording a jump signal while reproducing a control signal, in the display and switch section 18, switches 35 and 37 are off and switch 36 is on, as shown in FIG. Of the operating status displays 35a, 36a, and 37a using light emitting elements, etc., only the display 36a that displays the recording of the jump signal is lit.

The electronic switch 4 is supplied with the output gate signal of the monostable multivibrator 10 via the logic circuit 15. For example, if the time interval of control pulses is T, the time interval from the time when the control pulses start being supplied is about 0.9T.
The time control head 2 is separated from the differential amplifier 3. Therefore, the upward pulse of the control pulse is not turned off by the electronic switch 4, and only the portion including the other downward pulse is turned off, so that the control pulse as shown in FIG. 6B is turned off. A waveform differential amplifier output signal is obtained. Further, the control reproduction signal shown in FIG. 3C obtained from the inverting amplifier 5 is supplied to the servo circuit via the contact 25 to operate the servo system (not shown). Here, since the downward pulse does not transmit any information to the servo system, the presence or absence of this downward pulse has no effect on the operation. In addition, the resistance R in Figure 2
7 and the capacitor C15 constitute a low-pass filter, and suppress pulse noise such as switching noise caused by the electronic switch 4 to a low level.

The control reproduction signal thus obtained at contact 25 is then supplied to upward pulse detector 9, so that the waveform at contact 27 is similar to the upward pulse detector output signal shown in FIG. 6D. On the one hand, this upward pulse detector output signal is supplied to the logic circuit 15 via the gate monostable multivibrator 10 as a gate signal shown in FIG. The monostable multivibrator used in this example is of a type that is brought into a low state by an upward pulse of its input signal, and the second
It remains low for a time constant defined by capacitors C9 and C19 in the figure. The gate signal supplied to the logic circuit 15 is
5 to the control signal input terminal of the electronic switch 4 as an electronic switch control signal for the electronic switch 4 shown in FIG. 6A. Note that the time constant T1 of the gate signal is approximately 0.9T as described above.

The pulse detector output signal is also supplied to the monostable multivibrator 11 for waveform generation, so that the waveform at the contact 28 becomes the multivibrator output signal shown in FIG. 6F.
The time constant T2 of the multivibrator output signal shown in Figure F is approximately 0.6T, and the inverter 1
An inverter output signal such as G obtained through 2 is on the one hand supplied to a triangular wave generating circuit 13,
Resistors R21 and R22 in this triangular wave generation circuit 13
A triangular wave whose lower end is approximately half the power supply voltage is generated in an integrating circuit composed of capacitor C11 and capacitor C11, and its impedance is converted by transistor X2. The circuit consisting of the diode D3 and the electronic switch 51 is configured to forcibly prevent a voltage higher than half of the power supply voltage from being supplied to the electronic switch 16 when the electronic switch 4 is in the on state due to constant errors, temperature changes, changes over time, etc. This circuit regulates the voltage and can be omitted.

When recording the jump signal, the electronic switch 16 is in the on state as shown in FIG. 3, so the output signal of the triangular wave generator 13 as shown in FIG. . In this case, since electronic switch 17 is in the off state, the signal at contact 32 is the output signal of electronic switch 16. The output signal at contact 32 at this time is shown in FIG. 6J. In order to DC (direct current) erase the portion of the waveform obtained in this way other than the portion where the upward pulse is equal to the control pulse, the control channel to which this waveform is added is changed so that its reproduced wave becomes as shown in FIG. 6L.

Next, the operation when canceling the jump signal will be explained. When the jump signal is erased, the switches 35 and 36 are on and the switch 37 is off, as shown in FIG. 3, and the erase display 37a is lit as a status display. The difference from when recording a jump signal is that the electronic switch 16 that was on when recording the jump signal is turned off, and the electronic switch 17 that was off when recording the jump signal is turned on. Therefore, when canceling the jump signal, the output as shown in FIG. 6I of the sawtooth wave generator 14 shown in FIGS. 1 and 2 is output to the contact 32.
via the control head 2 as the signal shown in FIG. 6K.
is supplied to As is clear from FIG. 2, this sawtooth wave generator 14 is basically a differential circuit.
A diode D5 in the circuit outputs a downward pulse portion which is a waveform portion less than half of the power supply voltage.

Therefore, when the downward pulse portion of the waveform is recorded in the control channel, the signal has a reproduced waveform as shown in FIG. 6M, and the downward pulse is restored, so that the jump signal is erased. Further, the sawtooth wave generator 14 may also be provided with a circuit composed of a diode and an electronic switch (corresponding to the diode D3 and the electronic switch 51 of the triangular wave generator 13), similarly to the triangular wave generator 13. However, it is omitted in this embodiment.

Next, timing charts in a playback state with the autojump function turned on are shown in FIGS. 7 and 8. In such a reproduction state, in the display and switch section 18, the switch 35 is on and the switches 36 and 37 are off, as shown in FIG.
Only the light emitting element 35a, which indicates that the autojump function is on, is lit. In this case, the electronic switch control signal for the electronic switch 4 is in a high state, so the electronic switch 4 is in an on state.
The reproduction signal shown in FIG. 7A of the control head 2 is supplied to the differential amplifier 3. Therefore, the waveforms of the signals at contacts 25 and 26 are as shown in the inverting amplifier output signal shown in FIG. 7B and the non-inverting amplifier output signal shown in FIG. 7C, respectively. Here, since the amplification factor of the non-inverting amplifier 6 is set larger than that of the inverting amplifier 5, when there is a downward pulse, the amplitude P of the inverting amplifier output signal is
1 becomes smaller than the amplitude P2 of the non-inverting amplifier output signal, and the output of the peak detection comparator 7 becomes low as shown in FIG. 7D. At this time, electronic switch 8
is in the on state as shown in Figure 3, but contact 3
Since the output of the peak detection comparator 7 at 3 is in the low state as described above, the signal at the contact 34 is in the low state, and the output signal of the electronic switch 8 is in the low state as shown in FIG. 7E. Since the fast-forward control signal 21 is in a low state, the magnetic recording/reproducing device (VTR) does not enter the fast-forward state.

However, if the downward pulse is erased as shown in Figure 8A, then B and C in the same figure
As is clearer, the amplitude P3 of the inverting amplifier output signal
is larger than the amplitude P4 of the non-inverting amplifier output signal, and the output of the peak detection comparator 7 at the contact point 33 is in a high state as shown in D in the figure, so the output signal of the electronic switch 8 shown in E is in a high state. Therefore, the fast forward control signal 21 via the contact 34 becomes high. As a result, the tape running of the magnetic recording/reproducing apparatus (VTR) becomes a fast-forward mode, and the time interval t of the control signals becomes narrower. Furthermore, since the reproduction frequency also increases, the levels of amplitudes P3 and P4 both increase, but since the inequality P3>P4 holds true, the fast-forward mode continues until this lower equation is reversed in a portion where there is a downward pulse.

Fast forwarding allows the tape to run at about 20 times the normal speed, so it is possible to skip (pass) an unnecessary portion of about 3 minutes in less than 10 seconds. Furthermore, during this fast-forwarding, it is also possible to mute the image signal and the audio signal by using the fast-forwarding control signal.

In the above embodiment, information is recorded depending on the presence or absence of a downward pulse, but as shown in FIG. 6, when the electronic switch 17 is turned on, the downward It is also relatively easy to record information using the number of pulses. Information can also be recorded based on the position of the downward pulse.

Further, in the above embodiment, the newly recorded signal is a jump signal, and this jump signal is used to perform a fast-forward operation to substantially erase unnecessary signal portions, but it is also possible to record signals other than the jump signal. It may also be configured to perform other operations.

As described above, according to the signal recording method of the present invention, a new signal can be recorded in the playback mode without providing a new recording channel or a new recording head. If a jump signal indicating the unnecessary signal part is recorded in the unnecessary signal part, this jump signal is used to fast-forward only the unnecessary part, thereby effectively cutting (erasing) the unnecessary part.
It is also possible to erase only the information added later using the new signal without causing any disturbance to the control pulses necessary for the servo circuit in the magnetic recording/reproducing device (VTR). Furthermore, by using a method of recording information based on the presence or absence of pulses that have no effect on the operation of the servo circuit inside the VTR, it has the advantage of simplifying the circuit configuration of the recording system and preventing malfunctions. It is.

[Brief explanation of the drawing]

FIG. 1 is a schematic block system diagram showing one embodiment of the signal recording method according to the present invention, FIG. 2 is a specific circuit diagram of the embodiment shown in FIG. 1, and FIG. The state transition diagram of the logic circuit in the figure, Figure 4 is the signal timing chart when recording the control signal,
Fig. 5 is a signal timing chart when reproducing a control signal (auto jump off), Fig. 6 is a signal timing chart when reproducing a control signal (when recording or erasing a jump signal), and Fig. 7 is a signal timing chart when reproducing a control signal (when recording or erasing a jump signal). FIG. 8 is a signal timing chart when the downward pulse is eliminated and the control signal is regenerated (when the autojump is on). 1...1/2 power supply voltage supply circuit, 4, 8, 16,
17, 51...Electronic switch, 2...Control head, 3...Differential amplifier, 5...Inverting amplifier, 6...
...Non-inverting amplifier, 7...Peak detection comparator, 9...
...Upward pulse detector, 10, 11... Monostable multivibrator, 12, 47-50... Inverter, 13... Triangular wave generator, 14... Sawtooth wave generator, 15... Logic circuit, 18... Display and switch section, 19... Control recording signal, 20... Control reproduction signal, 21... Fast forward control signal, 22-3
4, 38-41...Contact, 35-37...Switch, 35a, 36a, 37a...Light emitting element, 42
~46...Operation amplifier, R1-R40...Resistor,
C1-C14... Capacitor, D1-D11...
Diode, X1-X3...transistor.

Claims (1)

[Scope of Claims] 1. In a magnetic recording and reproducing device having a control head for recording and reproducing control signals such as tape running speed and phase control in a control channel, the control signals recorded in the control channel in the signal reproduction mode. a signal state modification means for modifying the signal state of a predetermined signal portion that is not involved in the operation of the servo system in the magnetic recording/reproducing device; A signal recording method characterized by having a discriminating means for obtaining a signal. 2. The signal state modification means includes head control means that alternately uses the control head as a reproduction head for reproducing the control signal and as a recording head for recording a signal for modifying the predetermined signal portion in a signal reproduction mode. A signal recording method according to claim 1, characterized in that: 3. The signal recording system according to claim 1, further comprising means for substantially returning the predetermined signal portion whose signal state has been altered to its original signal state. 4. The signal recording system according to claim 1, wherein the signal state modification means erases the predetermined signal portion.