JP3021809B2 - Index signal recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an index signal recording device used for a head of a video tape recorder (VTR) or the like.

[0002]

2. Description of the Related Art JP-A-62-229558 (G1)
1B15 / 087) shows a configuration in which a signal such as a horizontal synchronization signal is processed and recorded together with a video signal in order to realize cueing in a so-called 8 mm VTR.

[0003]

However, the above configuration has a disadvantage that the circuit configuration becomes complicated.

[0004]

Therefore, according to the present invention, in a recording / reproducing apparatus for recording a plurality of pilot signals having different frequencies in a predetermined order together with a video signal by two rotating heads when recording, one reference oscillation Two pilot signal generation circuits for generating the plurality of pilot signals from the output of the circuit are individually provided corresponding to the two rotary heads, and the video signal is recorded in a portion other than the recording period of the video signal. One of the plurality of pilot signals is recorded as an index signal by a rotating head different from the rotating head, regardless of the type of pilot signal recorded together with the video signal.

[0005]

That is, one of a plurality of pilot signals is recorded at the time of recording as an index signal independent of a pilot signal used for tracking control. Therefore, no special configuration is required, and the index recording device can be realized with a simple configuration.

[0006]

An embodiment will be described below with reference to the drawings. FIG.
FIG. 2 is a block diagram showing a configuration of an embodiment, FIG. 2 is an explanatory diagram for explaining recording of an index signal, FIG. 3 is an explanatory diagram for showing a timing of recording a pilot signal, and FIG. 4 is a processing timing of a reproduced pilot signal. FIG. 5 is an explanatory diagram illustrating reproduction of an index signal. FIG.
FIG. 3 is a block diagram for explaining the outline of the generation of a tracking error signal.

First, an outline of a tracking error signal using a pilot signal will be described with reference to FIG.
As shown in FIG. 2, pilot signals f1 to f4 are simultaneously recorded on the track where the video signal is recorded. The frequency of this pilot signal is f1
Is set to 102.5 KHz, f2 is set to 119.0 KHz, f3 is set to 165.2 KHz, and f4 is set to 148.7 KHz. Therefore, the difference between the frequencies of the pilot signals recorded on the adjacent tracks is f1−f2 of 16.5 KH.
z, f3-f2 is 46.2 KHz, f3-f4 is 16.
5KHz, f4-f1 becomes 46.2KHz.

That is, if the beat frequency with the pilot signal from the adjacent track being reproduced is 16 KHz,
The direction of the tracking shift can be determined by whether the frequency is 6 KHz, and the level of the shift can be determined by the level. In order to realize this, a configuration as shown in FIG. 6 may be used. That is, only the pilot signal is extracted from the reproduced signal by the low-pass filter 20, and the pilot signal recorded on the track currently being traced is mixed in the mixing circuit 21 as a reference.
As a result, the output of the mixing circuit 21 includes 16 KHz and 46 KHz.
A beat component of KHz is obtained.

The beat component is converted to a bandpass filter 2
2 and 23 are taken out, the levels are detected by detection circuits 24 and 25, and the magnitudes are compared by a comparison circuit 26 to generate a tracking error signal.

In FIG. 1, reference numeral 1 denotes a pilot signal reference oscillation circuit (crystal oscillation circuit), which creates a reference frequency for four pilot signals. The output of the reference oscillation circuit 1 is input to the pilot signal creation circuits 2 and 3 for the first channel and the second channel. The channels correspond to two 180 degree opposing rotating heads. Therefore, the pilot signal is created in association with the two heads.

Each of the pilot signal generating circuits 2, 3
Is controlled by the selection signals SEL1 and SEL2 and the RF switching pulse, which are generated based on the RF switching pulse and indicate the rotation phase of the rotary head. Specifically, the output of the reference oscillation circuit is divided by a predetermined frequency, and the frequency division ratio is sequentially switched by the RF switching pulse.

The outputs of the pilot signal generation circuits 2 and 3 are:
Each of them is combined with a video signal to be recorded in the adder circuits 4 and 5. Then, the data is supplied from the addition circuit to each head and recorded.

Here, the VTR to which the present invention is applied will be briefly described. The rotating head is arranged in a cylinder having a predetermined diameter, and the tape is spirally wound around the cylinder at a predetermined angle. The winding angle of the cylinder is slightly more than 210 degrees in the case of the embodiment, of which the video signal is 18 degrees.
Recorded in the 0 degree range. The remaining 30 degrees are PC
This area is defined for M audio signals. In the embodiment, the pilot signal is recorded in a different manner from the normal state without recording the PCM audio signal in this area.

That is, as shown in FIG. 2A, in the video (video) area, f1, f2,
The pilot signals f3 and f4 are superimposed and recorded on the video signal in this order. On the other hand, in the PCM area, unlike the related art (conventionally, a common pilot signal has been supplied to two heads), in a normal state, a pilot signal having a frequency of f3 is always recorded. When the index signal is recorded, the pilot signal to be recorded in the PCM area is recorded as the f1 signal facing the f3 signal. The recording time is a fixed period of, for example, 600 fields or more.

Here, "opposite" means the relationship between the frequency of the pilot signal recorded on the adjacent track and the pilot signal of a different frequency in the recording pattern of the pilot signal in a normal state. For example, f3
And f1 are opposed to each other (the tracks adjacent to the track where the pilot signal of f1 is recorded are f2 and f1).
4 pilot signals are recorded). Also, the signals of f1 and f3 are examples, and pilot signals of f2 and f4 may be used.

FIG. 3 shows a pilot signal in each head. For comparison, the conventional case is also shown. That is, conventionally, a pilot signal is supplied to the first channel c and the second channel d in accordance with the recording sequence a of the pilot signal. On the other hand, in this embodiment, when the index signal is not recorded, the pilot signal is supplied to each head as shown by e and f. When recording an index signal, a pilot signal is supplied as shown in g and h.

Next, the configuration and operation during reproduction will be described. The signals reproduced from the respective heads are mixed in the mixing circuits 6 and 7 with reference signals (signals corresponding to respective channels) at the time of reproduction in consideration of index reproduction. The results are sampled using the switches 8 and 9, respectively, then synthesized and supplied to a circuit for generating a tracking error signal (for example, the BPF 22 and the BPF 22 in FIG. 6).
23). The sampling timing is shown in FIG.
Is performed at the center of the PCM area as shown in FIG. In addition, for normal servo, at the timing of C in FIG.
Sampling must be performed. However, switches used for servo are not shown.

The sampling pulse is generated by a sampling pulse generation circuit 10 using an RF switching pulse.
Is output by It should be noted that the selection signal is also R
It is created based on the F switching pulse.

At the time of reproduction, the reference signal is generated in the order of f1, f2, f3 and f4 in the video area as in the prior art. On the other hand, in the PCM area, it is fixed to f2 (normally f3, when the index signal is f1). These relationships are shown in FIG.

Therefore, in a normal case where the index signal is not recorded, the comparison circuit (for example, 26 in FIG. 6)
Goes high, and when the index signal is recorded, the output of the comparison circuit goes low. This is because if f1 of the index signal is recorded, f1
This is because the beat component at 16 KHz, which is the difference from 2, becomes large. That is, as shown in FIG. 5, the result of integrating the level of the result of comparing the beat components of the sampling outputs from the switches 8 and 9 becomes as shown in FIG. 5B, and becomes like C after waveform shaping. . Therefore, it is possible to detect the index signal based on the level of the signal C.

[0021]

As described above, according to the present invention, by providing two pilot signal generation circuits for generating a plurality of pilot signals from the output of one reference oscillation circuit, the structure is not complicated. The index signal can be recorded independently of the pilot signal used for the tracking control, and the effect is obtained that the index signal can be detected without affecting the tracking control at all.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment.

FIG. 2 is an explanatory diagram showing writing of an index signal.

FIG. 3 is a waveform diagram showing recording timing of a pilot signal.

FIG. 4 is an explanatory diagram showing sampling of an ATF error signal.

FIG. 5 is an explanatory diagram illustrating reproduction of an index signal.

FIG. 6 is a block diagram of a configuration for creating a tracking error signal.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 pilot signal reference oscillation circuit 2 pilot signal creation circuit (for first channel) 3 pilot signal creation circuit (for second channel) 8 sampling switch (for first channel) 9 sampling switch (for second channel) 10 sampling pulse Generator circuit

Continuation of front page (56) References JP-A-2-240852 (JP, A) JP-A-60-214494 (JP, A) JP-A-2-276048 (JP, A) JP-A-1-166355 (JP) JP-A-59-168959 (JP, A) JP-A-61-144701 (JP, A) JP-A-4-243304 (JP, A) JP-A-61-48436 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) G11B 15/087 101 G11B 15/467

Claims (1)

(57) [Claims] 1. A recording / reproducing apparatus for recording a plurality of pilot signals having different frequencies in a predetermined order together with a video signal by two rotating heads, wherein the plurality of pilot signals are output from one reference oscillation circuit. Each of the two pilot signal generation circuits to be generated is individually provided corresponding to the two rotary heads, and a rotary head different from the rotary head recording the video signal in a portion other than the recording period of the video signal. And recording one of the plurality of pilot signals as an index signal irrespective of the type of pilot signal recorded together with the video signal.