JP2002281452A - Magnetic recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic recording and reproducing device including a digital device capable of displaying normal onscreen display characters without depending upon the operation clock frequency of a microprocessor. SOLUTION: This magnetic recording and reproducing device has a tuner 4 for receiving television broadcasting, a digital device 1 for playing back a digitally recorded recording medium and outputting the reproduced data as an analog video signal, a signal detection circuit 5 for detecting a no-signal state of a video signal, an input switching circuit 7 for selecting a plurality of inputted video signals, and a microprocessor 11 for superimposing a character signal on the selectively switched video signal. When the signal detection circuit 5 detects the no-signal state, the digital device 1 generates video signals having prescribed horizontal frequency, vertical frequency and subcarrier signal according to a command of the microprocessor 11, and the input switching circuit 7 selectively switches the video signals.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conventional magnetic recording / reproducing apparatus capable of recording / reproducing an analog video signal, such as a DVD drive, a hard disk drive, etc., capable of recording or reproducing digital data (hereinafter referred to as digital equipment). The present invention relates to a magnetic recording / reproducing apparatus provided with a), and in particular, realizes a stable on-screen display by superimposing a character signal.

[0002]

2. Description of the Related Art A conventional magnetic recording / reproducing apparatus with a built-in digital device will be described with reference to FIG.

FIG. 4 is a block diagram of a magnetic recording / reproducing apparatus built in a digital device. In FIG.
Is converted into an analog video signal through a digital decoder circuit 2 and an analog conversion circuit 3,
The signal is supplied to an input switching circuit 7 built in the magnetic recording / reproducing signal processing circuit 6. The input switching circuit 7 converts the tuner video signal received by the tuner 4 and the external video signal externally input from the external input terminal a into the microprocessor 1.
Switching is selected by a command of 1. The selected video signal is supplied to a recording signal processing circuit 8 and also to an output switching circuit 10, and is selectively switched to a signal reproduced from a recorded medium through a reproduction signal processing circuit 9, and then the microprocessor 11 In the on-screen signal generation circuit 12 located inside, the generated character signal is superimposed. In other words, when only the on-screen character signal is displayed in the selected video signal, the OSD (on-screen display) switching circuit 13 is controlled to the through side, and the character character outline inside the character superimposition circuit 14 with outline is formed. The circuit 21 creates a border signal for adding a border to the character signal, and superimposes the character signal created by the character character creation circuit 22 on this border signal and outputs it. When displaying a full-screen colored character signal, the internal synchronization signal generation circuit 1
In step 5, a background signal having a predetermined synchronizing signal and a subcarrier signal is created, and after switching by the OSD switching circuit 13, a character signal to which a border is added is superimposed and output by a character superimposition circuit 14 with a border.

The microprocessor 11 oscillates in a crystal oscillation circuit 16 with a crystal oscillator of 14.31818 MHZ, which is four times the subcarrier frequency, and divides the frequency by a quarter frequency circuit 17 for an operation clock. A subcarrier for an internal synchronization signal is created from a clock of .579545 MHZ, and an internal synchronization signal is created from a clock of 15.734 KHz which is frequency-divided by a 910 frequency divider circuit.

Here, when the program recording screen of the magnetic recording / reproducing apparatus is shifted, when the tuner 4 is automatically selected, the tuner video signal selected by the tuner 4 and the input signal from the externally connected device are displayed as images. An on-screen display signal of a character signal with a full screen color is displayed when the signal detection circuit 5 detects the signal.

[0006]

However, the conventional circuit configuration has the following problems. When a chroma signal of a video signal reproduced from a recorded medium is converted into an R / G / B component signal in a signal processing circuit of a TV receiver (not shown), a sub signal synchronized with a burst signal of the TV signal is used. Since the frequency is converted based on the carrier signal, the frequency of the subcarrier signal is 3.579545 M
If the deviation from HZ is extremely large, the APC operation does not operate normally in the signal processing circuit in the TV receiver, the killer circuit operates, and the color of the video does not reach.

Therefore, in order to avoid such a coloring problem and to display an on-screen character signal with a full-screen background color, the oscillation frequency of the crystal oscillator used as the operation clock signal of the microprocessor is set to several tens. It is necessary to control with a variation of ppm or less.

[0008] For the same reason, when a signal reproduced from a recorded medium by a digital device is converted into an analog signal, strict frequency management is performed on the subcarrier signal.
It is necessary to perform color signal processing.

[0009]

In order to solve the above-mentioned problems, a magnetic recording / reproducing apparatus according to the present invention comprises a tuner for receiving a television broadcast and a digital for reproducing a digitally recorded recording medium and outputting an analog video signal. A device, a signal detection circuit for detecting a no-signal state of the video signal, an input switching circuit for selecting a plurality of input video signals, and a character signal for the video signal selected and switched by the input switching circuit When the signal detection circuit detects a no-signal state, the digital device generates a video signal having a predetermined horizontal frequency, a vertical frequency, and a subcarrier signal according to a command from the microprocessor. And the input switching circuit is selectively switched.

According to the present invention, by using a synchronization signal and a subcarrier signal based on a stable clock signal of a built-in digital device, the present invention does not depend on the frequency of a clock oscillation circuit of a microprocessor and has a problem of coloring. An on-screen display signal of a normal full-screen character signal without any can be displayed.

A magnetic recording and reproducing apparatus according to the present invention includes a tuner for receiving a television broadcast, a digital device for reproducing a digitally recorded recording medium and outputting an analog video signal, and detecting a no-signal state of the video signal. A signal detection circuit and a first signal for selecting a plurality of input video signals
Switching circuit, a video signal selected and switched by the first switching circuit, a second switching circuit for switching between a recorded video signal and a reproduced video signal of the magnetic recording / reproducing device, and a selective switching by the second switching circuit A third switching circuit for switching between the selected video signal and a predetermined video signal output from a digital device, and a microprocessor for creating and superimposing a character signal on the video signal selected and switched by the third switching circuit. When the signal detection circuit detects a no-signal state, a predetermined video signal is generated by a digital device in accordance with a command from the microprocessor, and the third switching circuit selectively switches the magnetic recording / reproducing device. A magnetic recording / reproducing apparatus can display a full-screen on-screen character signal even during recording. It is possible to provide a recording and reproducing apparatus.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(Embodiment 1) Embodiment 1 of the present invention will be described with reference to FIGS. Portions having the same configuration and operation and effect as those of the related art are denoted by the same reference numerals as those in FIG. 4, detailed description is omitted, and different portions will be mainly described.

The present embodiment is significantly different from the prior art shown in FIG. 4 in that the internal synchronization subcarrier generation circuit 15 in FIG. 4 is omitted. FIG. 1 shows a video signal reproduced by a digital device 1 built in a magnetic recording / reproducing apparatus, a tuner video signal received by a tuner 4 such as a terrestrial TV broadcast, a BS broadcast, and a video signal input from an external terminal a. And a reproduction signal reproduced by a reproduction signal processing circuit 9 from a recorded medium (not shown).
0, a character signal is superimposed on a video signal from the switching circuit 10 by a character superimposing circuit 14 with a border, and an on-screen character display is output to a display element medium such as a TV receiver (not shown). It is shown.

That is, in the magnetic recording / reproducing apparatus incorporating the digital device 1, when the full-screen on-screen display at the time of recording reservation or the full-screen blue-back display where the selected video signal is displayed when there is no signal, etc. After the digital device 1 creates a color background signal having a predetermined subcarrier signal based on a command from the processor 11,
The input switching circuit 7 is controlled to select a signal on the digital device 1 side, and a character signal can be inserted by the character superimposing circuit 14 with a border built in the microprocessor 11.

In FIG. 1, a tuner 4 transmits a desired channel (hereinafter referred to as C) via a receiving antenna (not shown).
(Referred to as H) in accordance with a command from the microprocessor 11 to select and receive a television broadcast signal, and output a baseband tuner video signal. The tuner video signal, a video signal (referred to as a LINE video signal) from an external device input from an external terminal a, and a digital decoder circuit 2 and an analog conversion circuit 3 built in the digital device 1 encode the analog NTSC signal. The video signal of the digital device 1 is switched and selected by the input switching circuit 7, and the reproduced video signal reproduced from the recording medium (not shown) through the reproduction signal processing circuit 9 and the switching circuit 10
Is selected and switched, and is input to the microprocessor 11.

In the microprocessor 11, a built-in on-screen signal creation circuit 12 creates a border signal in a character character border creation circuit 21, a character signal creation circuit 22 creates a character signal, and a selected video signal. A user signal is realized by superimposing a character signal and a border signal on the top and notifying the user using the CH information, the tape information, the time information, and the like.

Here, the tuner video signal selected by the control of the microprocessor 11 or the external terminal a
If the LINE video signal input from the microprocessor 11 is detected by the signal detection circuit 5 to be in a no-signal state, a normal horizontal and vertical synchronizing signal cannot be separated from the input signal, so that the character superimposition circuit 22 of the microprocessor 11 Therefore, even if the on-screen character signal is superimposed on the video signal, normal on-screen character display cannot be realized on the TV receiver. Note that, as described above, the non-signal state includes a video signal state in which a normal synchronization signal cannot be separated.

According to the present invention, the background signal generation command section 19 in the microprocessor 11
After instructing to create a colored background signal with a predetermined horizontal synchronization signal, vertical synchronization signal, and subcarrier signal,
When a video signal from the digital device 1 is selected by the input switching circuit 7, a colored background signal generated by the digital device 1 is output from the switching circuit 10 to the microprocessor 11. Then, an on-screen character signal having a luminance level between white characters and black characters created according to character information stored in advance in the microprocessor 11 is superimposed on the background signal in the character superimposition circuit 14 with a border. Even in a non-signal state, a normal full-screen on-screen character display can be realized on a TV receiver as a display element medium.

FIG. 2 shows the configuration and waveforms of the character superimposing circuit 14 with a border according to the present invention.
(A) is a block diagram of a character superimposing circuit 14 with a border, (B) is a full-screen background signal created by a digital device according to a command from the microprocessor 11,
(C) is a signal (referred to as a VOB signal) indicating a bordering period,
(D) shows a signal (referred to as a VOC signal) which becomes HIGH only during the character period, and (E) shows a character superimposed waveform.

In FIG. 2, the microprocessor 11
The full-screen background signal (B) created by the digital device 1 in response to the command from the controller is passed through the SYNC chip clamp circuit 20 so that the leading end of the synchronization signal is clamped to the DC voltage VA (V), and the character The character border creation circuit 21 switches the border DC voltage to 0.572 + VA (V) by the VOB signal (C) that is output HIGH only during the signal border period, so that the border signal is superimposed on the character signal.

Similarly, the background signal into which the character outline signal has been inserted is converted into the character DC voltage VA + 2.0 (V) by the character creation circuit 22 by the VOC signal (D) which is output HIGH only during the character signal period.
Is switched, the framed character signal is superimposed on the video signal as shown in the waveform (E).

The luminance levels of the black level and the white level of the character signal border can be changed by changing the border DC voltage and the character DC voltage supplied to the character border creation circuit 21 and the character creation circuit 22. Become.

(Embodiment 2) Embodiment 2 of the present invention will be described with reference to FIG. Portions having the same configuration and operation and effect as those of the related art are denoted by the same reference numerals as those in FIG. 4, detailed description is omitted, and different portions will be mainly described. FIG. 3 is different from FIG. 4 of the conventional embodiment in that an external switching circuit 23 is added, and a video signal from the digital device 1 and a video signal from the switching circuit 10 are switched in a stage preceding the microprocessor 11. Is a point.

In FIG. 3, the microprocessor 11
The external switching circuit 23 is additionally provided at the preceding stage of the digital device 1 during recording of the LINE video signal as the external input from the external terminal a or the tuner video signal from the tuner 4 in the magnetic recording / reproducing signal circuit 6. External switching circuit 23 for outputting analog video signal
By switching to and input to the microprocessor 11, a magnetic recording / reproducing apparatus capable of displaying a full-screen on-screen character signal even during recording is enabled.

It is apparent that the same can be realized in a magnetic recording / reproducing apparatus having an S terminal for outputting video signals as Y / C separated signals called luminance signals and chroma signals. Also, in this text, the NTSC broadcast signal has been described in the text, but other PAL / SECAM
The same can be realized for the broadcast signal of the system.

[0027]

As described above, according to the magnetic recording / reproducing apparatus incorporating the digital device of the present invention, at the time of a reservation screen, at the time of no signal reception, etc., the digital device creates a full-screen colored background signal. By superimposing only the character signal by the microprocessor 11 which performs recording / reproduction control,
Strict frequency control of the crystal oscillator for the microprocessor is no longer required, and the microprocessor 1
It is not necessary to equip the internal synchronization signal generation circuit and the subcarrier generation circuit inside 1, and the circuit can be simplified. As a background signal created by a digital device, a black screen having no color can be realized with a similar circuit configuration.

In addition, for the character display of the on-screen character, the software resources of the conventional on-screen character screen can be utilized, and the product development can be shortened.

[Brief description of the drawings]

FIG. 1 is a block diagram of a magnetic recording and reproducing device according to a first embodiment of the present invention.

FIG. 2 is a diagram for explaining the configuration of main parts of a character superimposing circuit with a border in the recording / reproducing apparatus of the present invention and waveforms thereof;

FIG. 3 is a block diagram of a magnetic recording and reproducing apparatus according to a second embodiment of the present invention.

FIG. 4 is a block diagram of a magnetic recording / reproducing apparatus according to a conventional embodiment.

[Explanation of symbols]

 Reference Signs List 1 digital equipment 2 digital decoder circuit 3 analog conversion circuit 4 tuner 5 video signal detection circuit 6 magnetic recording / reproduction signal processing circuit 7 input switching circuit 8 recording signal processing circuit 9 reproduction signal processing circuit 10 output switching circuit 11 microprocessor 12 on-screen signal Creation circuit 13 OSD switching circuit 14 Character superimposition circuit with border 16 Crystal oscillation circuit 19 Background signal creation command unit 20 SYNC chip clamp circuit 21 Character border creation circuit 22 Character creation circuit 23 External switching circuit

Claims (6)

[Claims] 1. A magnetic recording / reproducing apparatus, comprising: a tuner for receiving a television broadcast; and a digital device for reproducing a digital signal from a digitally recorded recording medium, converting the digital signal into an analog signal, and outputting an analog video signal. When,
A signal detection circuit for detecting a no-signal state of a video signal, an input switching circuit for selecting a plurality of input video signals, and a text signal created and superimposed on the video signal selected and switched by the input switching circuit When the signal detection circuit detects a no-signal state, by the instruction of the microprocessor, the digital device generates a predetermined horizontal frequency, a vertical frequency, a video signal having a subcarrier signal, A magnetic recording / reproducing device, wherein selection is switched by an input switching circuit. 2. The magnetic recording / reproducing apparatus according to claim 1, wherein when the signal detection circuit detects a no-signal state, an on-screen character signal is created and superimposed on the predetermined video signal. 3. The magnetic recording / reproducing apparatus according to claim 2, further comprising a border creating means for superimposing a border signal on the on-screen character signal. 4. A magnetic recording / reproducing apparatus, comprising: a tuner for receiving a television broadcast; a digital device for reproducing a digitally recorded recording medium and outputting an analog video signal; and a signal for detecting a no-signal state of the video signal. A detection circuit;
A first switching circuit for selecting a plurality of input video signals, and a second switching circuit for switching between the video signal selected and switched by the first switching circuit and the recording video signal and the reproduced video signal of the magnetic recording / reproducing apparatus. Switching circuit, a third switching circuit for switching between the video signal selectively switched by the second switching circuit and a predetermined video signal output from the digital device, and a selection switching by the third switching circuit. Having a microprocessor that creates and superimposes a character signal on the video signal, and when the signal detection circuit detects a no-signal state, a command of the microprocessor causes the digital device to generate a predetermined video signal,
A magnetic recording / reproducing apparatus, wherein the selection is switched by the third switching circuit. 5. The magnetic recording / reproducing apparatus according to claim 4, wherein when the signal detection circuit detects a no-signal state, an on-screen character signal is created and superimposed on the predetermined video signal. 6. The magnetic recording / reproducing apparatus according to claim 5, further comprising a border creating means for superimposing a border signal on the on-screen character signal.