KR19980041423A - Device for discriminating circuit error in video cassette recorder - Google Patents

Abstract

The present invention provides an apparatus for determining a circuit abnormality in a video cassette recorder for determining whether or not an abnormality of a series of image processing circuits or video heads is reproduced based on an image signal read out from a video head. A video cassette recorder comprising: a video head for reading out a video signal from a magnetic tape; and a video signal reproducing processor for reproducing and processing a video signal read out from the video head into a video signal in an output form; A frequency detector for detecting a frequency level of the video signal read out from the video head and outputting a high level result signal when the frequency level is lower than a predetermined level; and a synchronization signal from the video signal output from the video signal reproduction processor. When the level is detected and the level of the synchronization signal is lower than or equal to a predetermined level, a synchronization signal detector for outputting a high level result signal, a caption data storage unit for storing predetermined caption data, and an OSD signal based on a predetermined control signal. An OSD generator for outputting a signal, a mixer for mixing an OSD signal input from the OSD generator, and a video signal input from the video signal reproducing processor, and a high level from the frequency detector or the sync signal detector during tape playback. When a signal is inputted, the corresponding subtitle data is recalled. And a control unit for the film read out from the data, and outputs the OSD signal to the OSD control unit generated on the basis of the subtitle data, it is characterized in that configured.

Description

Device for discriminating circuit error in video cassette recorder

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video cassette recorder, and more particularly, to a video cassette capable of determining whether or not an abnormality of a series of image processing circuits or video heads which reproduce a video signal based on a video signal read out from a video head is detected. The present invention relates to a device for determining a circuit error in a recorder.

Magnetic tapes currently used in video cassette tapes (hereinafter referred to as tapes) are capable of recording information by magnetizing a thin film uniformly coated with a magnetic material with a contracted electromagnetic signal. It is intended to be read.

Fig. 1 is a block diagram showing the configuration of a general video cassette recorder using the above video cassette tape.

In the drawing, reference numeral 1 is a remote control device for remotely controlling the overall device, 2 is a receiving unit for receiving an infrared signal transmitted from the remote control device 1 and converting it into an electrical code signal, and 3 is a receiving unit 2 A microprocessor as a control unit for controlling the operation of the overall apparatus based on the code signal output from the ().

In addition, reference numeral 4 is a supply reel for conveying the tape wound while rotating in a constant direction, 5 is a rewind reel to rewind the tape supplied from the supply reel (4), 6 is from the microprocessor (3) A video head which writes a video signal to a tape conveyed from the supply reel 4 or reads out a recorded video signal in accordance with a predetermined control signal, 7 denotes a video head drive unit for driving control of the video head 6; 8 is a switching unit that performs switching switching according to the execution of the recording or reproducing operation on the basis of a predetermined control signal from the microprocessor 3.

On the other hand, reference numeral P _in denotes a video signal input terminal for receiving a video signal output from a television receiver or camcorder connected to a video cassette recorder, and reference numeral 9 denotes an internal portion of the apparatus through this video signal input terminal P _in . YC separation section for dividing and outputting the video signal applied to the luminance signal (Y) and the color tone signal (C), 10 is a frequency modulation circuit for frequency modulating the luminance signal (Y) output from the YC separation section (9) 11 denotes a frequency low pass conversion circuit for converting the color tone signal C output from the YC separation unit 9 into a low band frequency signal and outputting the low frequency signal, and 12 denotes the frequency modulation circuit 10 and the frequency low pass conversion circuit 11. Mixer (Mixer) for mixing the luminance signal (Y) and the color tone signal (C) respectively output from the (), 13 amplifies the video signal output from the mixer 12 to a predetermined level of the switching unit (8) It is an amplifying unit to be supplied to the recording terminal R. .

Reference numeral HD2 denotes an audio head for recording and reading a voice signal, reference numeral 14 denotes an amplifier for amplifying and outputting a voice signal read out from the audio head HD2, and 22 denotes the switching unit ( And a preamplifier for amplifying and outputting a video reproduction signal input from the reproduction terminal P side of FIG.

Reference numeral 16 denotes a high pass filter for detecting only the luminance signal Y from the reproduction signal output from the preamplifier 22, and 17 denotes a high pass filter 16. A frequency demodulation circuit for demodulating the luminance signal outputted therein, 18 is a low pass filter for detecting only the hue signal C from the reproduction signal output from the preamplifier 22; A frequency high frequency conversion circuit for converting the color tone signal output from the low pass filter 18 into a high frequency signal of a predetermined frequency band, 20 is a luminance signal Y output from the frequency demodulation circuit 17 and the frequency high frequency conversion. A mixer 21 for synthesizing the hue signal C outputted from the circuit 19, 21 is an amplifier which amplifies the video reproduction signal synthesized by this mixer 20 to a predetermined level, and P _out is an amplifier 21. Amplified video playback signal from the TV An output terminal for outputting to an image output apparatus such as a receiver.

On the other hand, in the tape, an audio signal is recorded at the upper end of the track, a control signal is recorded at the lower end of the track, and a video signal is recorded at the middle of the track. When a play command signal is input using a predetermined input means such as a control signal recorded at the lower end of the tape, the data is read out from the upper end and the stop of the tape as a reference signal, and then restored to the video and audio signals. Output to image output means and audio output means. When the recording command signal is input from the user, the video and audio signals are applied to the tape as magnetic data in the reverse order to the above reproducing operation.

However, if the video screen is bad while the tape is playing, the user may clean the video head by using a head cleaner. As a result, the current video signal is not reproduced clearly and the video signal is read from the track of the tape. This may be a problem of the video head, but there may be a problem with a series of image processing circuits for reproducing the video signal read out from the video head as the original video signal. There is a problem of continuing the head cleaning.

Accordingly, the present invention was created in view of the above circumstances, and judges the RF level of the video signal read out from the video head, and also determines the synchronization signal from the video playback signal after the video playback process. It is an object of the present invention to provide an apparatus for determining a circuit abnormality in a video cassette recorder which determines whether an abnormality of a video head or a series of image reproduction processing circuits is output based on the OSD screen.

1 is a block diagram showing the configuration of a conventional video cassette recorder.

Figure 2 is a block diagram showing the configuration of the circuit abnormality discrimination apparatus in the video cassette recorder according to an embodiment of the present invention.

* Explanation of symbols for main parts of the drawings

1: remote control unit 2: receiver

3, 30: microprocessor 4: supply reel

5: rewind 6: video head

7: video head drive unit 8: switching unit

9: Y-C separation unit 10: FM modulation circuit

11: frequency low frequency conversion circuit 12, 20, 35: mixer

13, 14, 21: amplifier 15: audio head drive unit

16: High Pass Filter 17: FM Demodulation Circuit

18: Low Pass Filter 19: Frequency High Frequency Conversion Circuit

22: preamplifier 31: RF level detector

32: sync signal detector 33: caption data storage

34: OSD generator HD2: audio head

In the video cassette recorder according to the present invention for realizing the above object, an apparatus for determining a circuit abnormality reproduces a video head for reading a video signal from a magnetic tape and a video signal read out from the video head as an output video signal. A video cassette recorder having a video signal reproduction processing section for processing; A frequency detector for detecting a frequency level of the video signal read out from the video head and outputting a high level result signal when the frequency level is lower than a predetermined level; and a synchronization signal from the video signal output from the video signal reproduction processor. When the level is detected and the level of the synchronization signal is lower than or equal to a predetermined level, a synchronization signal detector for outputting a high level result signal, a caption data storage unit for storing predetermined caption data, and an OSD signal based on a predetermined control signal. An OSD generator for outputting a signal, a mixer for mixing an OSD signal input from the OSD generator, and a video signal input from the video signal reproducing processor, and a high level from the frequency detector or the sync signal detector during tape playback. When a signal is inputted, the corresponding subtitle data is recalled. And a control unit for the film read out from the data, and outputs the OSD signal to the OSD control unit generated on the basis of the subtitle data, it is characterized in that configured.

That is, according to the present invention having the above-described configuration, the video head or the series of image reproduction processing circuits are judged to be abnormal and output them to the OSD screen.

Hereinafter, with reference to the accompanying drawings will be described an embodiment according to the present invention.

FIG. 2 is a block diagram showing the configuration of an apparatus for determining a circuit abnormality in a video cassette recorder according to an exemplary embodiment of the present invention, wherein like reference numerals are used to designate components which perform the same functions as those of FIG. Omit.

In FIG. 2, reference numeral 30 denotes a microprocessor as a controller for performing overall control of the apparatus, and 31 denotes a frequency level from an image signal read out from the video head 6, and the detected frequency level is below a predetermined level. In this case, for example, the RF level detection unit for outputting a high level result signal to the microprocessor 30, 32 is the level of the synchronization signal detected by detecting the synchronization signal from the image reproduction signal output from the mixer 20 When the level is below a certain level, for example, the synchronization signal detector outputs a high level result signal.

Reference numeral 33 denotes a caption data storage unit for storing predetermined caption data according to, for example, abnormality of a series of image reproduction processing circuits or abnormality of a video head, and 34 denotes a control from the microprocessor 30. An OSD generator for generating and outputting a predetermined OSD signal based on the signal, and 34 denotes a synchronization signal detected from a video reproduction signal output from the mixer 20 when the level of the detected synchronization signal is below a predetermined level, for example. The synchronization signal detector 35 outputs a high level result signal, and the mixer 35 is a mixer for mixing an image reproduction signal input from the mixer 20 and an OSD signal input from the OSD generator 34.

That is, in the above-described configuration, the microprocessor 30 drives the OSD generator 33 to drive and control the OSD generator 33 when a high level signal is input from the RF level detector 31 while the tape is playing. Clean the video head to output an OSD screen, and when the high-level signal is input from the synchronization signal detector 34, for example, the OSD generator 33 is driven to control the image reproduction processing circuit. This will control the OSD screen to be displayed.

Next, the operation of the device having the above configuration will be described in more detail.

First, when a user inserts a tape, the microprocessor 30 controls to seat the tape in the deck. Subsequently, when a predetermined playback command signal is input from the remote control device 1, the tape is loaded to bring the tape track into close contact with the video head 6, the audio head HD2 and the control head (not shown).

In addition, the microprocessor 30 controls the video head driver 7, the audio head driver 15, and the control head driver (not shown) to read out the video signal audio signal control signal. Subsequently, the microprocessor 30 performs a series of playback processes on the video signal and the audio signal based on the control signal read out from the control head.

Meanwhile, while the tape is playing, the RF level detecting unit 31 and the synchronizing signal detecting unit 32 detect the level of the RF signal and the synchronizing signal from the video signal, respectively, and output the resultant signal to the microprocessor 30. do.

Thereafter, the microprocessor 30 reads the subtitle data corresponding to the abnormality of the video head, for example, from the RF level detection unit 31, for example, a high level result signal from the subtitle data storage unit 33. The OSD generating unit 34 is driven and controlled based on the caption data so as to output an OSD screen, for example, clean the video head. Further, the microprocessor 30 reads the subtitle data corresponding to the abnormality of a series of image reproduction processing units from the synchronous signal detection unit 32, for example, a high level result signal from the subtitle data storage unit 33, for example. The OSD generation unit 34 is driven and controlled based on the read caption data so as to output an OSD screen, for example, that the image reproduction processing circuit is not normally operated.

On the other hand, when the microprocessor 30 receives a high level result signal from the RF level detector 31 and the synchronization signal detector 32 at the same time, the microprocessor 30 responds to the abnormality from the caption data storage 33. The subtitle data is read out and a predetermined 0SD screen is output based on the read data. That is, the microprocessor 30 controls to output a caption signal, for example, that there is an error in the video head and the image reproduction processing circuit.

That is, according to the above embodiment, the video cassette recorder according to the present invention determines whether the video head or the series of image reproduction processing circuits are abnormal and outputs it to the OSD screen.

The present invention is not limited to the above embodiments and can be variously modified within the scope not departing from the technical gist of the present invention.

As described above, according to the present invention, the RF level of the video signal read out from the video head is judged, and the synchronization signal from the video playback signal after the video playback processing is judged, and the abnormality of the video head based on the two determination results. Alternatively, it is possible to realize a circuit abnormality determination device in a video cassette recorder which determines whether or not a series of image reproduction processing circuits are abnormal and outputs them to an OSD screen.

Claims (1)

A video cassette recorder comprising: a video head for reading out a video signal from a magnetic tape; and a video signal reproducing processor for reproducing and processing a video signal read out from the video head into a video signal in an output form; A frequency detector for detecting a frequency level of the video signal read out from the video head and outputting a high level result signal when the frequency level is below a predetermined level; A synchronization signal detection unit for detecting a level of the synchronization signal from the video signal output from the video signal reproduction processing unit and outputting a high level result signal when the level of the synchronization signal is lower than a predetermined level; A caption data storage unit for storing predetermined caption data; An OSD generator for outputting an OSD signal based on a predetermined control signal, A mixer for mixing the OSD signal input from the OSD generator and the video signal input from the video signal reproduction processor; If a high level signal is input from the frequency detector or the sync signal detector while the tape is playing, the caption data corresponding thereto is read out from the caption data, and the OSD generator is controlled based on the caption data to output the OSD signal. Apparatus for determining a circuit abnormality in the video cassette recorder, characterized in that it comprises a control unit to.