JPH02128367A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To prevent the damage and the waste of a tape without missing a decisive moment, for example, with the application of a monitoring camera for preventing crimes by providing specified number of image memories and compensating recording in a delay time. CONSTITUTION:The image memories 11-13 are adopted and a video signal 9 is recorded in the image memories 11-13 at the same intervals as the rising period of an actual alarm REC(record, recording) when an alarm signal 28 rises. The alarm REC is not stopped immediately after the alarm signal 28 falls but is stopped after the recorded images of the image memories 11-13 are successively read out with a head switching signal 26 and recorded on the tape. Thus, the damage and the increase of the consumption of the tape and noises in a null recording spot, etc., are eliminated and recording is performed without missing the decisive moment at the time of inputting the alarm signal 28.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic recording/reproducing apparatus, and particularly to a magnetic recording/reproducing apparatus that performs recording only during a period in which a recording start signal (external trigger signal) is present.

[Background Art] With the recent progress in computer technology, the importance of magnetic recording and reproducing devices as external storage means has increased.

For example, home and industrial VTR devices, especially VTR devices for recording and playback.
TR devices are widely used, and are currently becoming more diverse and sophisticated.

VTR devices and the like that record and play back image information recorded on magnetic tape are widely used as magnetic recording and playback devices.

As is well known, in such a tape recording/reproducing apparatus, a magnetic head is brought into close contact with the magnetic recording surface of a magnetic tape that is continuously rotated at a constant speed, and image information is written and read by the magnetic head.

FIG. 3 shows a schematic configuration of the magnetic recording/reproducing device.

FIG. 3(a) is a principle diagram showing a conventional magnetic recording/reproducing apparatus, and this conventional example is an example of a magnetic recording/reproducing apparatus using a security camera.

In the figure, (1) is an alarm signal sent from, for example, an alarm operation in an emergency, (2) is a mechanism control microcomputer, (3) is a motor control unit, (4) is a motor, (
5) is a video signal control section, and (6) is a video head. (7) is an alarm REC (record) which is a period during which recording is actually performed after receiving the alarm signal (1) as a recording start signal.

record) indicates the period.

Next, the operation will be explained. When the alarm signal (1) is input manually, the mechanism control microcomputer (2) triggers the motor control section (3) and the video signal control section (5) to rotate the motor (4) and perform servo control. A recording current is also supplied to the video head (6) to record a desired video signal on the video tape.

[Problems to be Solved by the Invention] However, according to the conventional magnetic recording/reproducing device, an alarm signal (1) is input to start recording, but at this time, the alarm signal (1) as shown in FIG. 3(b) is input. Even if the alarm signal (1) rises so that the actual alarm REC (7)
In this case, recording starts with a delay of the time indicated by T in the figure. This T is usually several seconds, but the cause of the delay is
One example of this is that recording cannot be started until the tape is loaded from the standby state, the cylinder rotates, the servo is activated, and the tape travel becomes stable.

In addition, in order to shorten this delay time, there is a method that uses a deck mechanism with a configuration called full loading to load the tape into the cylinder head even in standby mode and maintain the state in which the cylinder head and tape are in contact. , unless the cylinder head is constantly rotated, no improvement can be expected to the extent that the delay time can be ignored.

However, if the cylinder head is rotating while the tape is in contact with the tape, the tape is likely to be damaged, so protective measures are taken to intermittently feed the tape a little while leaving blank recording, and to put it into standby mode. It is necessary to take the following steps. However, there are problems in that the amount of tape consumed increases and that blank recorded areas on the tape become noise during playback, making it unsightly.

Conventional magnetic recording devices are configured as described above, so even if an alarm signal is input, it takes several seconds to actually start recording. There was a serious problem that the exact moment was not recorded.

In addition, even if the full loading method is adopted, the purpose is to protect the tape from damage, so there is an increase in tape consumption due to the tape being fed intermittently and unnecessarily, and empty recording areas on the tape. The problem was unsightly noise.

The present invention has been made in order to solve the above-mentioned problems, and after eliminating problems such as damage to the tape, increase in tape consumption, and noise from blank recording areas, it is possible to eliminate the problem of tape damage, increase in tape consumption, and noise at blank recording locations, and to provide a decisive signal when an alarm signal is input. The object of the present invention is to obtain a magnetic recording/reproducing device capable of recording without missing a moment.

[Means for Solving the Problems] In order to achieve the above object, the present invention loads a tape into a magnetic head in response to a recording start signal, and sends a recording start signal to a magnetic recording and reproducing device that records a video signal from a video camera on the tape. an image memory for storing a video signal for a period from the rising edge of the signal until the video signal is recorded on the tape; and an image memory for recording the video signal stored in the image memory and a predetermined video signal from the video camera on the tape. It has a switch circuit for switching control, stores the video signal in the image memory, controls recording on the tape, and operates the switch circuit to read out the video signal stored in the image memory when a predetermined recording is completed. , is characterized by being recorded on tape.

[Function] The magnetic recording/reproducing device according to the present invention employs an image memory, and records video signals in the image memory at equal time intervals during the actual rising edge of the alarm REC when the alarm signal rises. Instead of immediately stopping the alarm REC after the alarm REC has dropped, the recorded images in the image memory are sequentially read out using a head switch signal and recorded on the tape, and then the alarm REC is finally ended.

Therefore, the switch circuit controls switching so that the video signal is stored in the image memory or recorded on the tape, so when the recording of a predetermined video signal is completed, the video signal stored in the image memory is read out and recorded on the tape. can do. This eliminates blank recording on the tape during the loading time from the rising edge of the alarm signal to the rising edge of the alarm signal, and it becomes possible to record the video signal from the rising edge of the alarm signal.

[Embodiment] An embodiment of the present invention will be described below with reference to a block diagram of a magnetic recording/reproducing apparatus shown in FIG. 1 and a timing chart shown in FIG. 2. In FIG. 1, (9) is a video signal, (1
0) is an A/D converter, (11), (12),
(13) is an image memory for recording images in a field memory or frame memory; (14) is a flip-flop; and (15).

(16) is a ring counter that sequentially outputs Q1 . Q2. Pulses are output in the order of Q3.

(17) is a clock pulse generator, (18) is an AND gate, (19) is a NOR gate, (20), (21)
), (22) is an inverter, (23) is a D/A converter, (2
4) is a switch as a switch circuit, and (25) is a signal recording section.

In the timing chart of FIG. 2, (26) is the head switch signal, (27) is the delay-alarm RE
C period, (28) is an alarm signal as a recording start signal, (29) is a clock pulse generator output pulse signal, (
30) is the alarm RFC period, (31) is the output QA of the ring counter (16), QI3. Qc timing, (
32) is the output Q1. of the ring counter (15). Q2. Q
This is a waveform showing the timing of No. 3.

As is clear from the above configuration, the difference between the present invention and the conventional one is mainly that an image memory and a switch circuit are provided. ), it is possible to store video signals even in one hour, which was not possible in the past.

With this, image memory (11), (12)
.

Switch (2) is used to record the video signal stored in (13) or the video signal from a video camera onto a tape.
4), the video signal stored in the image memory is read out and recorded on tape by controlling the switching.

Next, regarding the operation of this embodiment, Fig. 1, Fig. 2(a),
This will be explained using (b).

In FIG. 1, a switch (24) is normally connected to the a terminal, and a video signal (9), which is an image signal from a video camera or the like, is supplied to a signal recording section (25).

However, no video signal is recorded on the magnetic tape unless the alarm signal (28) is input to the signal recording section (25).

Here, when an alarm signal (28), which is a recording start signal for starting recording, is manually input to the signal recording section (25), it enters a recording preparation state, and the alarm signal (28) is sent to the clock pulse generator (17). is triggered, a clock pulse (29) at a predetermined timing is output, and an AND gate (1
8) is input to one input terminal. The other input terminal of the AND gate (18) is connected to the NOR gate (19).
) is input.

Further, the ring counter (16) is triggered by the output signal of this AND gate (18), and the ring counter (16) is triggered by the output signal of this AND gate (18).
QA and QB sequentially at the timing (31) shown in b)
, Qc pulses are output.

The output of these ring counters (16), QA.

The pulses of QB and Qc are stored in the image memory (13), (12),
(11) is applied to the write (WRITE) input, and immediately after the alarm signal (28) rises, QA, QB, Q
At timing o, the video signal (9) is sent to the A/D converter (1
0) is converted into a digital image signal and stored in the image memory (13
), (12).

(11) are stored in the order.

While Q^, QB, and Qc of the ring counter (16) are sequentially outputting pulses, that is, until a predetermined number of images have been stored in the memory, the memory operation will not continue even if the next alarm signal (28) is input. The output of the NOR gate (19) is input to the other terminal of the input of the AND gate (18) so as not to cause any trouble.

Then, when the clock pulse generator (17) stops outputting the clock pulse (29), the image memory (1
3), (12), and (11) continue to hold the stored image memories, respectively.

Next, as shown in FIG. 2(a), the alarm REC
When the period (30) starts, a normal video signal is recorded on the tape without going through the memory during the t1 period (tl is shown compressed in the figure).

Also, at the start of this alarm REC period (30),
The head switch signal (26) also rises.

When the alarm signal (28) rises, the delay-alarm RFC signal (27) rises, and the switch (24) is connected to the b side.

Here, the head switch signal (26) is the alarm RE
It is output at the start of the C period (30) and is output to the flip-flop (14). This flip-flop (14) generates mH" pulses at both the rise and fall of the input pulse of the head switch signal (26).Then, the Q output of the flip-flop (14) generates mH" pulses.
The ring counter (15) sequentially outputs Q1 . Q2. Q3 is output, and the previously stored video signal is transferred to the image memory (13
) , (12) , and (11) are read out in this order and converted into an analog image signal by a D/A converter (23). Then, the D/A converted video signal is input to the signal recording section (25) via the switch (24) and is recorded on the tape.

Here, the delay-alarm REC period (27) is supplied to the inverters (20), (21), (22), and the image memories (13), (12),
The image memory is prevented from malfunctioning when reading (11). As shown in FIG. 2, this delay-alarm REC period (27) is a period t2 in which the image signal in the memory is recorded on the tape, and (27) the image signal in the memory is recorded on the tape.
When 7) ends, the alarm REC period (30) also ends, and the recording end message B) waits for the next alarm signal (28) to be input (wait message!).

As described above, in the T period of the alarm REC period (3o), the image memories (13) and (12) are stored in the image memories (13) and (12).

A video signal is stored in (11), and a normal video signal from a video camera or the like is recorded on the tape during the t1 period.
During period t2, the output from the image memory is recorded on tape.

In order to simplify the explanation, the image memory (13) is connected to the "H" IIL of the head switch signal.

Although the signal outputs (12) and (11) correspond to each other, they may correspond to every several tens of cycles of the head switch signal.

Furthermore, although this embodiment has been described with respect to a magnetic recording/reproducing device such as a security camera, the present invention can also be applied to a commonly used video camera.

[Effects of the Invention] As explained above, the magnetic recording/reproducing device of the present invention sequentially records video signals in a predetermined image memory using clock pulses triggered by an alarm signal, and switches the head switch at the falling edge of the alarm signal. This method employs a method in which data is sequentially read out using pulses and recorded on a tape via a video head.

As described above, according to the present invention, a predetermined number of image memories are provided and the recording of the delay time is compensated for, so that the critical moment is not missed in applications such as security cameras, etc. This has the effect of preventing tape damage and waste.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a magnetic recording/reproducing apparatus according to an embodiment of the present invention, FIGS. 2(a) and 2(b) are timing chart diagrams showing signal timing in the same embodiment, and FIG. 3(a) ) and (b) are explanatory diagrams showing a conventional magnetic recording/reproducing device. In the figure, (9) is a video signal, (10) is an A/D converter, (11), (12), (13) are image memories, (15), (16) are ring counters, and (23) is D/A wheat changer, (24) is a switch, (2
6) is a head switch signal, and (28) is an alarm signal. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] In a magnetic recording and reproducing device that loads a tape into a magnetic head in response to a recording start signal and records a video signal from a video camera on the tape, the video signal is recorded on the tape from the rising edge of the recording start signal. an image memory for storing video signals for a period of up to 30 seconds; a switch circuit for switching and controlling the video signals stored in the image memory and a predetermined video signal from the video camera to be recorded on tape; A magnetic recording/reproducing device characterized in that storage in a memory and recording on a tape are controlled, and when a predetermined recording is completed, the switch circuit is operated to read out the video signal stored in the image memory and record it on the tape. Device.