JPS5830278Y2 - Control signal recording device for magnetic recording and playback devices - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a rotating head type magnetic recording and reproducing device (hereinafter referred to as VTR). , the control signal is constructed so as to provide continuity of the control signal.

Conventionally, in a VTR, in order to control tracking during reproduction, a signal corresponding to the rotational phase of a rotary head during recording is recorded on a magnetic tape as a control signal.

During reproduction, tracking is obtained by controlling the rotary head or capstan using this reproduction control signal as a reference signal.

Therefore, during tape editing, if the phase of the control signal changes in the continuation portion of the signal, tracking for a certain period will be disturbed.

On the other hand, a recording system for control signals during tape editing in a conventional VTR having a tape editing function has the configuration shown in FIG.

That is, G is a frequency dividing circuit to which a constant frequency signal obtained by a frequency generator from a motor that rotationally drives a rotary head is applied from terminal 2, and the output is a frame frequency (30 Hz) with a duty of 50-50. It is configured to obtain a rectangular wave output.

Further, this frequency dividing circuit 1 is configured to be reset by a signal applied from a terminal 3.

Therefore, if a playback control signal (A in Figure 2) is applied from terminal 3 during the playback mode during editing, the output of frequency divider circuit 1 will be 30Hz phase-synchronized with the playback control signal as shown in B in Figure 2. The output is obtained.

In this state, when the editing start command signal (C in Figure 2) is input to switch from the playback mode to the record mode, the playback control signal A disappears because the mode changes to the record mode. A rectangular wave signal B is obtained.

This signal B is applied to the base of the transistor 4 from the terminal 7, and the editing start command signal C is also applied to this base from the terminal 5, and the signal B and the editing start command signal are applied to the collector of the transistor 4. The configuration is such that an AND output with C can be obtained.

As for the timing at which this command signal C is generated, there are two possible cases, a and b, as shown in FIG. 2C.

A indicates a case where a command is received at a High portion of the rectangular wave signal B, and b indicates a case where a command is received at a Low portion.

The collector waveform of transistor 4 in case a is D in Figure 2.
Therefore, the recording waveform recorded on the magnetic tape by the control head 6 is as shown in E of FIG.

Therefore, if a positive signal is used as the control signal, there is no problem since it is possible to record at regular intervals including the previously recorded control signals such as C→d-, )e.

Similarly, in the case of b, the collector waveform is F in FIG. 2, and its reproduced waveform is G.

Therefore, the control signal is recorded as c-I-d-+e-I-f, but the interval from C to d is different from the regular interval, which is a problem.

Therefore, when a tape recorded with timing b is played back, servo disturbance occurs at the editing point, resulting in screen disturbance.

The present invention aims to solve this problem, and the main part of one embodiment thereof is shown in FIG.

The output terminal 8 in FIG. 3 is connected to the terminal 5 in FIG. 1.

A part of the output B of the frequency divider circuit 1 in FIG. 1, which is a rectangular wave with a duty of 50-50, is applied to the input terminal 9 in FIG. .

From this signal H, only the negative pulse is extracted by the inverting circuit 11 and the polarity is inverted, and the signal H is converted into a NAND signal.
It is input to one input terminal of the circuit 12.

On the other hand, a command signal C is applied to the input terminal 13 and guided to the other input terminal of the NAND circuit 12 and the reset terminal R of the RSS flip-flop circuit 14.

According to this configuration, the command signal C is generated at a position a.

Regardless of b, the output of the NAND circuit 12 is as shown in FIG.

This signal ■' is applied as a set signal to the set terminal S of the RS flip-flop 14, and the output of the RS flip-flop 14 becomes as shown in FIG. 4J.

Needless to say, when the command signal C becomes Low level, the output of the RS flip-flop 14 is reset and returns to Low level.

If a signal K is obtained by inverting the phase of the signal J by the phase inverting circuit 15 and is applied as a command signal to the terminal 5 in FIG. 1, the collector waveform of the transistor 4 becomes L, and the recorded control signal is Like M, regardless of the generation position a s b of the command signal C, it is always recorded as d and e that are approximately continuous with the recorded control signal C.

As described above, according to the present invention, the continuity of the control signal that is valid during tape editing can always be obtained, and there is no screen disturbance when playing back the edited tape.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing a conventional control signal recording system, Fig. 2 is a waveform diagram explaining the same operation, Fig. 3 is a main part configuration diagram showing an embodiment of the present invention, and Fig. 4 is a waveform diagram explaining the same operation. It is a diagram. 1... Frequency dividing circuit, 6... Control head, 10
...Differential circuit, 12...NAND circuit, 14...
RSS flip flora circuit.

Claims (1)

[Scope of utility model registration request] A continuous signal of a predetermined frequency that is applied continuously from the playback mode to the recording mode during tape editing.
It is applied to a frequency divider that is forcibly reset by the playback control signal only when the button is pressed in the playback mode, and the divider keeps the phase synchronized with the playback control signal in the playback mode, so that even if the switch is switched to the record mode, playback will not occur. A first logic that generates a 30 Hz rectangular wave signal that is continuous in phase with the output in the mode, and combines the rising edge or falling edge of the rectangular signal and the editing authority signal for switching from the reproduction mode to the recording mode. Create a product output, drive the RSS flip-flop circuit with the first AND output, and
A magnetic recording characterized in that a second AND output is created between the output of the flip-flora circuit and the rectangular wave signal, and the second AND output is recorded on a magnetic tape as a control signal in the recording mode. Control signal recording device for playback equipment.