JP3043014B2 - Magnetic recording / reproducing device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing apparatus having a time code generation processing function.

Conventional technology According to IEC461, longitudinal time code (Longitudin
al Time-and-control Code) is determined to be simultaneous with the period of the television frame. The relationship between the frame of the video signal and the phase of the color subcarrier has a phase difference of 180 ° per frame in the NTSC system and 270 ° in the PAL system. Therefore, the complete cycle of the video signal is NTSC
In the system, every two frames, and in the PAL system, every four frames. These frame units are called color frames,
In order to completely perform video editing, it is necessary to perform editing in units of color frames. For this reason, IEC-TC60 SC60B
In CO-62, when the time code value has a predetermined relationship with the color frame, it is said that the color is locked, and a color lock ID, that is, color frame information is set in the time code. In the color frame information, NTSC is information indicating a phase in a two-frame cycle, and PAL is information indicating a phase in a four-frame cycle.

The conventional magnetic recording / reproducing apparatus has a configuration shown in FIG. 3 to introduce a function of synchronizing the time code with a television frame or the color lock operation. A frame pulse is generated by a frame detection circuit 2 from the video signal generated by the video signal generation circuit 1, and a time code generation circuit 3 generates a longitudinal time code in synchronization with the frame pulse. Further, a color frame pulse is generated by the color frame detection circuit 4 from the video signal generated by the video signal generation circuit 1, and the value is adjusted so that the time code value is color-locked by the color frame pulse. The circuit 3 can generate a color locked time code.

However, in the above-described conventional configuration, the power of the video signal generation circuit 1 is turned off after the time code is color-locked (frame locked), and then the video signal generation circuit 1 is turned on again. ODD of the input video signal
When the phase of the (odd field), the EVEN (even field) or the color subcarrier is not continuous with that before the video signal generating circuit 1 is turned off, the time code is color-locked (frame-locked) to the input video signal again.
For example, when the time code generation circuit 3 is in the FREE-RUN mode and the time code value is constantly increasing, when the power of the video signal generation circuit 1 is turned off (OFF) and on (ON), a maximum of one frame is set in the NTSC system. In the PAL system, a shift of up to two frames (or up to one frame when only frame locking is performed) occurs.
It is added each time F or ON. For this reason, this method alone has a problem that the time code value gradually shifts from the real time. The problem is that when a plurality of magnetic recording / reproducing devices as shown in FIG. 3 are used, the video signal generators 1 are turned off, Due to the difference in the ON frequency, different time code values are recorded even in the same real time, and there has been a problem that precise time adjustment cannot be performed.

An object of the present invention is to provide a magnetic recording / reproducing apparatus in which a difference between a time code value and a real time is not accumulated by turning off and on a power supply of a video signal generating circuit.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a time code generation circuit which runs independently of a color frame of a video signal to generate a time code signal including color frame information; A color frame pulse generation circuit that generates a color frame pulse locked by
A video signal generating circuit for adjusting the position timing of the color sub-transport of the video signal by the color frame pulse when power is supplied.

According to the above configuration, when the video signal generation circuit is turned on again, the color frame pulse generation circuit uses the color code information of the time code signal of the time code generation circuit which is generated independently regardless of the color frame of the video signal. A color frame pulse is generated, and the video signal generation circuit adjusts the phase timing of the color subcarrier of the video signal with the pulse. Therefore, the time code value does not shift when the power of the video signal generating circuit is turned on and off.

Embodiments The present invention focuses on the fact that when a time code value is color-locked (frame locked), a color frame pulse (frame pulse) can be generated from the time code value, and a color generated from the time code value can be generated. The generation timing of the video signal and the phase timing of the color subcarrier are adjusted by the frame pulse (frame pulse).

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a main block diagram of a magnetic recording / reproducing apparatus showing one embodiment of the present invention.

Time code generation circuit 11 that generates a time code signal
Is configured to be switchable between FREE-RUN mode and REC-RUN mode.When FREE-RUN mode is selected, if there is a video signal, the time code value is increased by the frame pulse signal, and if there is no video signal. , The time code value is incremented by itself for each 1 / frame frequency, and when the REC-RUN mode is selected, the time code value is incremented only when the video signal is being recorded. When the time code signal generated by the time code generation circuit 11 selected in the FREE-RUN mode is in a color lock (frame lock) state,
Based on the time code value and the output timing, the pulse generation circuit 12 generates a color frame pulse (frame pulse) subjected to reverse color lock (reverse frame lock) and outputs it to the video signal generation circuit 13. Even if the power of the video signal generating circuit 13 is turned off, if the power is supplied to the time code generating circuit 11 and the pulse generating circuit 12 in which the FREE-RUN mode is selected, the NT signal is supplied regardless of the color frame of the video signal.
The time code including color frame information of 2 frame cycles in SC and 4 frame cycles in PAL continues to be generated from the time code generator 11. And the pulse generation circuit 12
The color frame pulse locked to the color frame information is continuously generated. When the power of the video signal generation circuit 13 is turned on again, the video signal generation circuit 13 adjusts the generation timing of the video signal and the position timing of the color subcarrier by the color frame pulse (frame pulse). Reference numeral 13 denotes a reverse color lock (reverse frame lock), and a color frame pulse (frame pulse) detected from the video signal output from the video signal generation circuit 13 is a color frame generated by the time code generation circuit 11 and the pulse generation circuit 12. Coincides with the pulse (frame pulse).

As described above, according to the present embodiment, by providing the pulse generation circuit 12 reverse-locked to the time code and the video signal generation circuit 13 reverse-locked to the pulse generated by the pulse generation circuit 12, the time code generation circuit 11 The generated time code does not shift every time the power of the video signal generating circuit 13 is turned off and on, and the time code value and the real time can be matched with high accuracy.

FIG. 2 is a main block diagram of a magnetic recording / reproducing apparatus showing a second embodiment of the present invention. In the figure, components having the same functions as those of the components of FIG. 1 and FIG. 3 of the conventional example are denoted by the same reference numerals, and description thereof will be omitted.

In the embodiment shown in FIG. 1, when the time code value does not advance in the REC-RUN mode, the pulse generation circuit 12 does not generate a pulse. Therefore, only after the recording is started and the time code generation circuit 11 advances the time code, the pulse generation circuit 12 starts the color frame pulse (frame pulse).
After receiving this pulse, the video signal generation circuit 13 performs reverse color lock (reverse frame lock), and the video signal is disturbed during recording. To avoid this, input the FREE-RUN /
A control circuit 14 for inputting an identification signal of the REC-RUN mode is provided, and the control circuit 14 determines and controls which of the time code generation circuit 11 and the video signal generation circuit 13 controls which according to the input mode. . That is, the control circuit
Reference numeral 14 denotes a time code generation circuit that controls the time code generation circuit 11 to lock the video signal output from the video signal generation circuit 13 to the color frame pulse (frame pulse) generated by the color frame detection circuit 4 in the REC-RUN mode. In the case of FREE-RUN, on the other hand, a color frame pulse (frame pulse) obtained by reverse color locking (reverse frame locking) to the time code value generated in the pulse generating circuit 12 is supplied to the video generating circuit 13 to generate a time code. The circuit 11 is controlled not to lock on the color information (frame information) of the video signal detected by the video signal generation circuit 13.

As described above, according to the second embodiment, in addition to the configuration of the first embodiment, the control circuit 14 that determines which of the time code generation circuit 11 and the video signal generation circuit 13 controls which is controlled. The time code generation circuit 11 controls the video signal generation circuit 13 only when time alignment between the time code value and the real time is necessary, and the video signal generation circuit 13 controls the video signal generation circuit 13 as in the REC-RUN mode. When the continuity of the generated video signal is more important, the video signal generation circuit 13 can generate a continuous video signal regardless of the time code value.

Advantageous Effects of the Invention As described above, according to the present invention, a color frame pulse locked with color frame information is generated from a time code signal of a time code generation circuit which is generated independently regardless of a color frame of a video signal, By reverse color-locking the video signal generation circuit with the color frame pulse, it is possible to prevent the time code value from being shifted by turning on and off the power supply of the video signal generation circuit.
Therefore, the time code value can be matched with real time with high accuracy, and the practical effect is large.

[Brief description of the drawings]

FIG. 1 is a main block diagram of a magnetic recording / reproducing apparatus showing one embodiment of the present invention, FIG. 2 is a main block diagram of a magnetic recording / reproducing apparatus showing a second embodiment of the present invention, and FIG. FIG. 11 is a block diagram of a main part of a conventional magnetic recording / reproducing apparatus in which a time code generation circuit performs color lock (frame lock). 2 ... frame detection circuit, 4 ... color frame detection circuit, 11 ... time code generation circuit, 12 ... pulse generation circuit, 13 ... video signal generation circuit, 14 ... control circuit, 15 ...
... Input terminal.

Claims (2)

(57) [Claims] 1. A time code generation circuit for generating a time code signal including color frame information by running independently of a color frame of a video signal, and a color frame pulse generating a color frame pulse locked by the color frame information. A magnetic recording / reproducing apparatus, comprising: a circuit; and a video signal generating circuit for adjusting a position timing of a color sub-transport of a video signal by the color frame pulse when power is supplied. 2. A time code generating circuit having an operation state in which a time code signal is generated by self-running independently of a color frame of a video signal, and an operation state lockable by a color frame of a video signal, The magnetic recording / reproducing apparatus according to claim 1, further comprising a control circuit capable of controlling an operation state of the time code generation circuit.