GB2237439A

GB2237439A - Magnetic recording and reproducing apparatus

Info

Publication number: GB2237439A
Application number: GB9022167A
Authority: GB
Inventors: Yoshiaki Sato; Kohei Iketani; Nobuya Sakai
Original assignee: Asahi Kogaku Kogyo Co Ltd
Current assignee: Pentax Corp
Priority date: 1989-10-12
Filing date: 1990-10-12
Publication date: 1991-05-01
Also published as: FR2653586A1; JPH03127393A; DE4032310A1; GB9022167D0

Abstract

A magnetic recording and reproducing apparatus eg a still video camera includes a presearch performing device which presearches tracks of a magnetic disc loaded therein, a presearch cancelling switch which is provided in a body of the apparatus to cancel the presearch, and a presearch stopping device which stops the presearch by the presearch performing means in accordance with the operation of the presearch cancelling device.

Description

MAGNETIC RECORDING AND REPRODUCING APPARATUS

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a magnetic recording and reproducing apparatus. More precisely, it relates to a magnetic recording and reproducing apparatus having a presearching function for presearching a magnetic disc loaded therein.

2. Description of the Related Art

Recent magnetic recording and reproducing apparatuses for recording a still picture taken by a still video camera onto a magnetic disc or the like and for reproducing the recorded picture on a display usually has a presearching function in which the data recorded on the tracks of the magnetic disc is presearched and the data obtained by the presearch is stored in a memory.

The presearch, which usually requires about 10- 20 seconds, is performed each time the magnetic disc is loaded when the main power switch is made ON, or each time the main power switch is made OFF when the magnetic disc is loaded. However, even when only one frame of picture is viewed, a predetermined time (usually 10- 20 seconds) of presearch is carried out. This results in an increase of waiting time at the commencement of the operation, particularly when a large number of magnetic discs must be presearched.

Also, in the case of a battery-driven recording and reproducing apparatus, the increase of waiting time leads to an increase in power consumption, thus resulting In an accelerated decrease of the service life of the battery.

SUMMARY OF THE INVENTION

The primary object of the present invention is to provide a magnetic recording and reproducing apparatus in which the presearch is freely cancelled if unnecessary.

1 To achieve the object mentioned above, according to the present invention, there is provided a magnetic recording and reproducing apparatus comprising a presearch performing means for presearching the tracks of the magnetic disc loaded therein, a presearch cancelling switch which is actuated to cancel the presearch, and a stopping means for compulsively stopping the presearch by the presearch performing means in accordance with the operation of the presearch cancelling switch.

With this arrangement, when a magnetic disc is loaded, the presearch of the magnetic disc is optionally and selectively carried out in accordance with an operator's judgement. if the operator considers it no presearch is carried out, so that the the operation can be reduced, thus unnecessary, waiting time of resulting in a more effective operation.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described below in detail with reference to the accompanying drawings, in which:

Figure 1 is a block diagram of a magnetic recording and reproducing apparatus according to a firstembodiment of the present invention; Fig. 2 is a perspective view of a magnetic recording and reproducing apparatus shown in Fig. 1, according to the present invention; Fig. 3 is a flow chart of the operation of a magnetic recording and reproducing apparatus shown in Fig. 1, according to the present invention; and, Fig. 4 is a block diagram of a magnetic recording and reproducing apparatus according to a second embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In Fig. 2, which shows a generic magnetic recording and reproducing apparatus 1 according to the present -3invention, is provided on its front face 2 with a main power switch (POWER) 3, a disc loading portion 5, an ejecting button 6, an operating portion 7, and an LCD indicator 9. The operating portion 7 includes a reproducing button (PLAY) 10 for reproducing the recorded data, an erasing button (ERASE) 11 for erasing the recorded data, and a recording button (REC) 12 for performing the record, etc.

Fig. 1 shows a control system of the magnetic recording and reproducing apparatus 1. The magnetic control and reproducing apparatus 1 has a mechanical unit 13 and a microcomputer 15. To the microcomputer 15 are connected a sound recording circuit 30, a picture recording circuit 31, a sound reproducing circuit 32 and a picture reproducing circuit 33. A recording amplifier 35 is connected to the 15 sound recording circuit 30 and the picture recording circuit 31. A reproducing amplifier 36 is connected to the sound reproducing circuit 32 and the picture reproducing circuit 33.

The picture signal is input to the picture recording circuit 31 through a decoder 37. The picture reproducing circuit 33 outputs the picture signal through an encoder 39. A speaker 40 is connected to the sound reproducing circuit 32. The speaker 40 generates a sound in accordance with the sound signal output from the sound reproducing circuit 32.

A motor driving circuit microcomputer 15. A spindle motor driving circuit 41 to rotate the of the magnetic disc D which is 41 is connected to the 42 is driven by the motor magnetic disc D. The data read by a magnetic head H is sent to the sound reproducing circuit 32 and the picture reproducing circuit 33 through the reproducing amplifier 36. The data fed from the sound recording circuit 30 and the picture recording circuit 31 is recorded in the magnetic disc D through the recording amplifier 35 and the magnetic head H. The magnetic head H is driven by tracking motor 53.

The mechanical unit 13 of the apparatus 1 has various switches including a disc loading detecting switch 17, the main power switch 3 and a presearch cancelling circuit 18. The detecting switch 17 is mechanically actuated to be made ON when 'the magnetic disc is loaded on the disc loading portion 5.

The microcomputer 15 includes a disc loading judging means 19, a RAM 20, a presearch performing means 21, a ROM 23, and a presearch stopping means 24.

10, The disc loading judging means 19 judges if a new magnetic disc is loaded and if the magnetic disc exists, when the disc detecting switch 17 is made ON after the magnetic disc is loaded on the disc loading portion 5.

The presearch performing means 21 carries out the presearch in accordance with the judgement of the disc loading judging means 19. The data obtained by the presearch is stored in a RAM 20 of the microcomputer 15.

The presearch stopping means 24 operates to stop the presearch when the presearch cancelling switch 18 is made ON during the presearch or immediately before the presearch.

The microcomputer 15 has a Vcc terminal 22 to which a back-up power supply circuit 45 and a main power source 16 are connected through a switching means 50, such as a relay. When the main power switch 3 is made OFF, the switching means 50 selects the power supply from the back-up power supply circuit 45 in accordance with the command of the microcomputer 15. Conversely, when the main power switch 3 is made ON, the switching means 50 selects the power supply from the main power source 16 in accordance with the command of the microcomputer 15. As a result, the data obtained by the presearch and stored in the RAM 20 remains without being erased even if no power is supplied from the main power source, so that the loading (exchange) of the magnetic disc D can be checked.

The magnetic recording and reproducing apparatus as constructed above operates as follows (as shown in Fig. 3).

c Fig. 3 shows a main flow chart of the operation of the apparatus of the invention.

In the magnetic recording and reproducing apparatus 1 according to the present invention, the main power switch 3 is made ON to record the still picture input from an external device onto the magnetic disc D, or to reproduce the picture recorded on the magnetic disc. As a result, the switching means 50 establishes an electrical connection of the main power source 16 to the microcomputer 15 which has been, connected to the back-up power supply circuit 45, In accordance with the command of the microcomputer.

After the magnetic disc D is loaded on the loading portion 5 of the apparatus 1, when the command signal of the commencement of the presearch is output from the presearch performing means 21, the picture signal processing circuit, such as the picture reproducing circuit 33 is made ON (step S1).

Consequently, the spindle motor 42 is driven through the motor driving circuit 41 (step S2). At the same time, the track number variable Tr of the magnetic disc is read to be 50 (step S3) by the magnetic head H to drive the tracking motor 53(step S4). Thereafter, the control proceeds to step S5.

At step S5, whether the magnetic head H is placed on a predetermined track of the magnetic disc is checked. If the magnetic head is not placed on a predetermined track of the magnetic disc, the control is returned to step S4 to repeat the driving of the tracking motor 53. If the magnetic head H is correctly placed on a predetermined track, the control proceeds to step S6.

At step S6, whether the presearch cancelling switch 18 is made ON is checked. If the presearch cancelling switch 18 is made ON, the control proceeds to step S7 to stop the spindle motor 42. Thereafter, at step S8, the picture signal processing circuit is made OFF.

At step S6, if the presearch cancelling switch 18 is not made ON, the control proceeds to step S9 in which the picture is reproduced by the picture reproducing circuit 33.

Thereafter, whether there is a blank track is checked at step S10. If a blank track is found, the control proceeds to step S11. Conversely, if no blank track is found, the control proceeds to step S12.

At step S12, whether the track which is being searched is a track for picture is checked. If the track is a picture track, the control proceeds to step S14, and if the track is not a picture track, the control proceeds to step S13.

At step S14, the DPSK data which is a picture index is read, and then the blank track which is found at step S10 is stored in the RAM 20, for example at an address Tr thereof, and the DPSK data read out at step S14 is stored in the RAM 20, for example at an address Tr thereof (step Sil).

At step S15, the track number which is to be stored in the RAM 20 is counted down. Whether or not the track number becomes M," is checked at step S16. If the track number becomes IT,", the control proceeds to step S7, and if the track number is not "0,", the control is returned to step S4 to repeat the driving of the tracking motor 53.

If the track which is being researched is not a picture track at step S12, the sound signal processing circuit, such as the sound recording circuit 30 is made ON at step S13. Thereafter, the control code which is a sound index is read (step S17), and then, the sound signal processing circuit is made OFF at step S18. Thereafter, the control proceeds to step S11.

Figure 4 shows a second embodiment of the present invention.

In the second embodiment, no additional presearch cancelling switch 18 in the first embodiment mentioned above is provided. Instead thereof, the existing operational buttons, such as the reproducing button (PLAY) 1 10, the erasing button (ERASE) 11, and the recording button (REC) 12 etc., are connected, as shown in Fig. 4. Namely, these buttons are connected to the respective actuators (e.g. motors) 45, 46, etc., which are driven by the respective operational buttons and are also connected to the presearch stopping means 24.

Consequently, for example if the reproducing button 10 is made ON after the presearch is done, the reproducing button 10 performs the routine function, so that the actuator (e.g. motor) 45 is driven to reproduce the recorded data of the magnetic disc. On the other hand, if the reproducing button 10 is made ON during the presearch or immediately before the presearch after the magnetic disc is loaded, the reproducing button 10 does not perform the routine operation as a reproducing button, but serves as a presearch cancelling switch, as mentioned above. Namely, the presearch stopping means 24 is activated by the operation of the reproducing button 10 to stop the presearch performing means 21.

Namely, if an operator considers the presearch unnecessary when the magnetic disc D is loaded on the loading portion 5 of the apparatus, when any one of the reproducing button 10, the erasing button 11 and the recording button 12, etc., is actuated before the presearch ends, no presearch is carried out from the beginning of the operation or the presearch which has been commenced is stopped upon the operation of the associated operational button.

1

Claims

CLAIMS:

1. A magnetic recording and reproducing apparatus comprising:

a presearch performing means for presearching tracks of a magnetic disc loaded therein; a presearch stopping means for compulsively stopping the presearch by the presearch performing means; and, a presearch cancelling switch for operating the presearch stopping means.

2. A magnetic recording and reproducing apparatus according to claim 1, wherein said presearch cancelling switch is a separate switch which is adapted only to stop the presearch.

3. A magnetic recording and reproducing apparatus according to claim 1, wherein said presearch cancelling switch is made of one of existing operational switches provided in the body of the apparatus.

4. A magnetic recording and reproducing apparatus according to claim 1, further comprising a disc loading judging means for judging whether the magnetic disc is loaded in the body, and wherein said presearch performing means operates in accordance with the judgement of the disc loading judging means. 25

5. A magnetic recording and reproducing apparatus according to claim 1, further comprising a microcomputer which includes a memory means for memorizing the data of the tracks of the magnetic disc obtained by the presearch.

6. A magnetic recording and reproducing apparatus according to claim 3, wherein said operational switches are connected to respective actuators which are to be driven thereby and said presearch stopping means.

7. A magnetic recording and reproducing apparatus according to claim 3, wherein orma. of said operational buttons which serves as the presearch cancelling switch Is an existing reproducing button which is actuated to c Q 1 -9reproduce the data recorded on the magnetic disc.

8. A magnetic recording and reproducing apparatus according to claim 3, wherein one of said operational buttons which serves as the presearch cancelling switch is an existing erasing button which is actuated to erase the data recorded on the magnetic disc.

9. A magnetic recording and reproducing apparatus according to claim 3, wherein one of said operational buttons which serves as the presearch cancelling switch is an existing recording button which is actuated to record the data on the magnetic disc.

10. A magnetic recording and reproducing apparatus according to claim 11, further comprising a backup power supply circuit and a main power source, so that said microcomputer is selectively connected to the back-up power supply circuit and the main power source.

11. A magnetic recording and reproducing apparatus according to claim 12, further comprising a switching means for switching the electrical connection of the microcomputer to the back-up power supply circuit and the main power source.

Published 1991 atThe Patent Office. State House.66/71 High Holborn, LondonIVC I R47?. Further copies maybe obWned from Sales Branch, Unit 6, Nine Mile Point, Cwmielinfach, Cross Keys, Newport. NP 1 7HZ. Printed by Multiplex techniques ltd, St Mary Cray, Kent.