JP3109648B2 - Video signal recording device with on-screen display function - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video signal recorder having an on-screen display (hereinafter abbreviated as OSD) function suitable for use in a home video tape recorder (hereinafter abbreviated as VTR) or the like.

[0002]

2. Description of the Related Art A conventional VHS NTSC VCR for home use will be described as an example of a conventional video signal recording / reproducing apparatus with an OSD function.

FIG. 7 is a block diagram showing the configuration of the above-mentioned conventional VTR system. In FIG. 1, reference numeral 1 denotes a color signal processing IC, which is connected to a terminal 5 via a terminal 5 during recording.
A carrier color signal modulated with a carrier frequency of 58 MHz is input as an input color signal. The input color signal is subjected to signal processing such as low-frequency conversion by the recording color signal processing circuit 2, becomes a recording color signal having a carrier frequency of 629 kHz, and is output from the terminal 9.
The color signal processing IC 1 includes a 3.58 MHz oscillator 3 and a killer detection circuit 4 as constituent elements. The terminal 6 is an oscillation output terminal of the 3.58 MHz oscillator 3, and its output is often used as a reference clock of the servo IC.

The killer detection circuit 4 detects whether or not the signal input from the terminal 5 is a normal color signal. When the signal is a normal color signal, a low potential is output from the terminal 8 and an abnormal signal is output. At the time of a color signal, a high potential is output from the terminal 8. Here, the abnormal color signal refers to a black-and-white signal, a color signal having an extremely poor S / N, or a color signal having a different format. A color signal with a different format is a color signal processing IC
1 is in NTSC operation, the PAL signal or SE
The CAM signal and the like correspond to this, and the color signal processing IC
During AL operation, NTSC signal or SECAM
The signal corresponds to this. The output of the terminal 8 is input from the terminal 18 of the microcomputer 15 and serves as information for the microcomputer 15 to perform a color signal format determination operation. If the VTR is compatible with a plurality of signal formats, the microcomputer 15 determines whether the VTR is compatible with the signal format.
Switches the operation of each necessary part.

The terminal 16 of the microcomputer 15
It is connected to the terminal 13 of the OSD processing IC 10 and sends a control signal relating to OSD display. Usually, bus line control is often used. Specifically, it controls the type, position, and size of the character to be inserted, and switches between the superimpose mode, the background color mode, and the background colorless mode. The superimpose mode is suitable for displaying a VTR operation mode or the like because the background image can be viewed. In the background color mode, a synchronizing signal and a color signal corresponding to the background color are generated inside the OSD processing IC 10 irrespective of the signal input from the terminal 11, and the character is superimposed on the background color having a constant luminance level. In this mode, the characters are easy to see and are suitable for a VTR operation menu screen or the like. The background colorless mode is a mode corresponding to a state where the color of the background color mode is erased.

[0006] The terminal 12 of the OSD processing IC 10
The output of a 58 MHz fixed oscillator (hereinafter abbreviated as OSC) 28 is input. Usually this 3.58 MHz OSC28
Is multiplied by 4 in the OSD processing IC 10 to obtain 1
A 4.32 MHz reference signal is created. This 14.32
The MHz reference signal is a reference oscillation clock for setting the type, position, and size of a character, and is also used as a reference oscillation clock for generating a background color signal in the background color mode. In FIG. 7, the 3.58 MHz OSC 28 is
An OSD processing IC with a built-in oscillation circuit, which is provided outside the OSD processing IC 10 but has a built-in OSC circuit and needs only an external crystal oscillator, is generally used. As shown in FIG. 7, there are many ICs that can be used in two ways, that is, a mode for inputting external OSC oscillation.

[0007] A command from a remote controller 20 is input to a terminal 19 of the microcomputer 15 and receives a user's remote control operation to control the operation of the VTR.

Next, a processing flowchart of the microcomputer 15 related to the background color mode display will be described.

FIG. 8 is a flowchart showing a conventional process for turning the menu ON / OFF. When the user operates the remote controller 20 to input a menu ON command (step ST41), the background color mode menu image is immediately changed to O.
N state (step ST42), and then the menu O
When the FF command is input (step ST43), such control as to immediately turn off the background color mode menu image (step ST44) is performed.

FIG. 9 is a flowchart of a conventional process for no image. When it is determined that there is no image (step ST51), the background color image is immediately turned on (step ST52). When it is determined that there is an image (step ST53), the background color image is immediately turned off (step ST54). Perform control. This function aims to improve the quality of a VTR by producing a background color image instead of producing a noise image when there is no video, and has been widely used in recent VTRs. The detection of the presence or absence of an image is realized by, for example, a method in which the synchronization separation output pulse output from the luminance signal processing IC is taken into the microcomputer 15 and whether or not the cycle is correct is detected.

[0011]

In the prior art described above, a 3.58 MHz OSC or a 3.58 MHz crystal oscillator needs to be externally provided in order to generate the reference oscillation of the microcomputer 15, which causes an increase in cost. I was On the other hand, inside the color signal processing IC1,
A 3.58 MHz oscillator 3 is included as a component, and its oscillation output is usually output from a pin of the IC 1 to the outside. Therefore, this output is sent to the OSD processing IC 1
If it can be used by inputting it to the 0 terminal 12, cost reduction can be realized.

However, in the recording color signal processing,
The 3.58 MHz oscillator 3 is a voltage controlled oscillator (hereinafter referred to as VCO).
The relationship between the oscillation output and the color burst signal of the input color signal input from the terminal 5 needs to be phase-locked.
This phase lock state has been achieved using technology.
Further, in this PLL operation, a detection operation is performed only during a color burst period, and a detection potential is held in other periods.
Because of the intermittent PLL operation, the oscillation frequency of the 3.58 MHz oscillator 3 fluctuates due to a change in the detection potential during the detection period and other periods. Also, several H periods within the vertical retrace period of the video signal (1H represents one horizontal scanning period)
Since no signal color burst is inserted, a detection error occurs during this period, and the oscillation frequency also changes. When a TV signal received by a tuner is recorded, the frequency may be tuned to a frequency at which no broadcast signal exists. At this time, the input of the terminal 5 becomes a noise signal and the oscillation of the 3.58 MHz oscillator 3 Frequency fluctuates greatly.

These frequency fluctuations are turbulences of about 300 Hz, and correspond to about 0.01% in the ratio to 3.58 MHz. This disturbed 3.58M
The oscillation output of the 3 Hz oscillator 3 is simply converted to the OSD processing IC 1
When the signal is input to the terminal 12 of 0, the variation with respect to the setting of the type, position, and size of the character is a small fluctuation that does not cause any practical problem, but the color burst portion of the background color signal in the background color mode. This is a fluctuation amount that cannot be ignored as a fluctuation given to the phase between the non-burst portion and the non-burst portion, and the background color in the background color mode is greatly disturbed.

The present invention has been made in view of the above points,
The purpose is to use the color signal processing IC1 of 3.
The oscillation output of the 58 MHz oscillator 3 is supplied to the OSD processing IC 10
It is possible to reduce the cost of the reference oscillation section by using the reference oscillation section without any trouble.

[0015]

In order to achieve the above object, the present invention provides means for switching the operation of the 3.58 MHz oscillator 3 to an OSC operation in addition to the VCO operation required for the PLL operation. When an operation requiring output of the background color mode is performed at any time other than during the recording operation, the oscillator 3 is switched to the OSC operation in advance, and control is performed to output a background color image.

Further, since the killer detection information input to the terminal 18 of the microcomputer 15 detects the disturbance of the phase locked state of the PLL, if the oscillator 3 is set to the OSC operation, the killer detection operation becomes defective. Becomes
The signal format determination operation performed based on this information also causes erroneous determination. Therefore, this problem has been solved by storing a determination result immediately before switching the oscillator 3 to the OSC operation, and providing a control means for performing an operation of holding the previous value of the determination output during the OSC operation.

If an operation requiring output of the background color mode is performed during the recording operation, the 3.58 MHz oscillator 3 remains in the VCO operation, and the menu screen is not in the background color mode, but is superimposed. A means for controlling the display in the mode or the background colorless mode is provided to provide a solution having no practical problem.

[0018]

By providing the above means, 3.58M
Output of the oscillator 3 from the terminal 1 of the OSD processing IC 10
2 and use as OSD reference oscillation to construct a low cost system, the 3.58 MHz oscillator 3
Since there is no state where the screen is displayed in the background color mode during the CO operation, the problem that the background color is disturbed does not occur.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the illustrated embodiments. FIG. 1 is a block diagram showing a configuration of a VTR system according to an embodiment of the present invention.
S is an example of application to an NTSC home VTR. In FIG. 1, the same parts as those in the block diagram of the conventional system of FIG. 7 are denoted by the same reference numerals, and the description thereof will be omitted to avoid duplication. Only the differences will be described below.

Here, the 3.58 MHz oscillator 3 of the color signal processing IC 1 is controlled by the above-described PL by an oscillation control signal from the microcomputer 15 applied from the terminal 7.
Either a VCO operation required to realize the L operation or a fixed oscillation OSC operation can be selected. The oscillation output of the 3.58 MHz oscillator 3 output from the terminal 6 of the color signal processing IC 1 is output from the OSD processing I
The signal is input from the terminal 12 of C10 and is multiplied by 4 inside the OSD processing IC 10 to become a 14.32 MHz reference signal. Therefore, in the system configuration of FIG.
The 3.58 MHz OSC 28, which was required in the above, is unnecessary.

The internal operation of the color signal processing IC 1 will be additionally described below. FIG. 2 shows color signal processing I.
It is an internal block diagram of C1. In the figure, the block indicated by the dashed line is the recording color signal processing circuit 2,
The main components include a 3.58 MHz band pass filter (hereinafter abbreviated as BPF) 21, a frequency converter 22 and a 1.3 MHz low pass filter (hereinafter abbreviated as LPF) 23.

The 3.58 MHz oscillator 3 includes a switch 26
Is a VCO whose oscillation frequency changes according to the output voltage of the VCO. When the output of the LPF 25 is selected as the input of the switch 26, a loop composed of the phase comparator 24, the LPF 25 and the 3.58 MHz oscillator 3
This is a loop for performing the above-described PLL operation. 3.58 MHz
The color signal output from the BPF 21 is output to the phase comparator 24.
And becomes the reference input of the PLL. Although not shown in FIG. 2, the phase comparator 24 performs the phase comparison only during the color burst period, and performs the output holding operation during the other periods. As a result, the oscillation frequency of the 3.58 MHz oscillator 3 completely matches the color burst frequency of the input color signal and is in a phase locked state. When the fixed voltage source 27 is selected as an input of the switch 26, the oscillation frequency of the 3.58 MHz oscillator 3 becomes constant, that is, the 3.58 MHz oscillator 3 operates as an OSC.

3.58 MHz BPF 21 and 3.58
The output of the MHz oscillator 3 is input to the killer detection circuit 4. The killer detection circuit 4 is a circuit for detecting whether the two input signals are locked in a correct phase relationship, and outputs a low level from the terminal 8 when the phase lock state is normal, and outputs a high level when the phase lock state is abnormal. Output level. Therefore, when the color signal processing IC1 is an IC corresponding to a plurality of signal formats, if the input color signal does not match the signal format set by the color signal processing IC1, the output of the terminal 8 becomes high level. Becomes Therefore, the microcomputer 15 determines the output level of the terminal 8 to realize the signal format determination operation. However, the killer detection circuit 4 uses the P
Since the circuit detects the phase locked state realized by LL, when the 3.58 MHz oscillation circuit 3 performs the OSC operation, the signal format determination operation cannot be performed.

Next, a processing flow performed by the microcomputer 15 in this embodiment will be described.

FIG. 3 shows a menu ON / O according to this embodiment.
It is an example of the processing flow at the time of FF operation. As shown in the figure, in this processing flow, when a menu ON command is input (step ST1), the processing is changed depending on whether or not the VTR is recording (step ST2).

If recording is in progress (YES in step ST2)
In the case of (3), it is not possible to switch the 3.58 MHz oscillator 3 to the OSC operation, and the oscillation frequency fluctuates due to the VCO operation.
The background color is disturbed, which is not practical. Therefore, in this case, it is displayed as a menu image in the superimpose mode (step ST10). Thereafter, when a menu OFF command is input (step ST11), the menu image in the superimpose mode is deleted (step ST12).

If recording is not being performed (N in step ST2)
(In the case of O) If the 3.58 MHz oscillator 3 is switched to the OSC operation, the oscillation frequency does not fluctuate and display in the background color mode becomes possible. However, if the operation is switched to the OSC operation, the operation of discriminating the signal format becomes defective. Therefore, immediately before the operation is switched to the OSC operation, the discrimination information is stored in a previous value and the operation is stopped (step ST3). OSC of 3.58 MHz oscillator 3
The operation is switched (step ST4), and thereafter, a process of turning on the background color mode menu image is performed (step ST5). When an instruction to turn off the menu is input (step ST6), the process may be returned in the reverse procedure, and the background color mode menu image is turned off (step ST7), and the 3.58 MHz oscillator 3 is switched to the VCO operation (step ST8). ) And signal format determination start (step ST9).

FIG. 4 shows a menu ON / O according to this embodiment.
It is another example of the processing flow at the time of FF operation. 4 is different from the processing flow of FIG. 3 in that the processing during recording is performed by displaying the menu image in the superimpose mode in FIG. 3, but in FIG. (Step ST10 in FIG. 3 is replaced by step ST13, and step S10 in FIG.
The only difference is that T12 is replaced with step ST14). In such a colorless background mode, no disturbance of the background color appears on the screen, so that there is no practical problem in the processing of FIG.

FIG. 5 is an example of a processing flow for no image according to the present embodiment. As shown in the figure, in this processing flow, when it is determined that there is no video (step ST21)
The processing is changed depending on whether the VTR is recording or not (step ST2).

If recording is in progress (YES in step ST2)
In the case of (1), as described above, if the background color mode display is performed, the background color is disturbed, and there is a practical problem. Therefore, in this case, the mode is not switched to the background color mode.
The noise screen is output as it is. For the purpose of improving the quality of the VTR, although the operation is slightly unwilling, the state where recording is being performed without any video is a very rare state, and may be considered as an operation having no practical problem. .

If recording is not being performed (N in step ST2)
When the 3.58 MHz oscillator is switched to the OSC operation, the screen can be displayed in the background color mode as described above. The processing procedure at this time is substantially the same as the processing at the time of the above-described menu ON / OFF operation described in FIG. 3 (steps ST5, ST6, ST7 in FIG. 3 and steps ST22, ST23, ST24 in FIG. 5). Since the processing flow is substantially the same simply by substituting the processes of the background color image ON, the determination of the presence of the image, and the background color image OFF, the description is omitted.

FIG. 6 shows another example of the processing flow for the absence of an image according to the present embodiment. 6 is different from the processing flow of FIG. 5 in that processing during recording is not performed in FIG. 5 and processing for outputting a noise screen as it is without switching to the background color mode is performed. However, in FIG. 6, only the screen display in the background colorless mode (the processing in steps ST25, ST26, and ST27) is performed. In the case of the background colorless mode, the disturbance of the background color does not appear on the screen, so that this processing has no practical problem.

In the embodiment described above, the NTSC
Although the method has been described by way of example, the present invention
It is needless to say that the present invention is not limited to the system and can be applied to the PAL system and other systems. NT
In the SC system, the carrier frequency of the carrier color signal is 3.58.
MHz, but for example in the PAL system 4.43 MH
In this case, the oscillation frequency of the oscillator 3 or the OSC 28 is not 43.58 MHz but 4.43 MHz.
Becomes Oscillation frequencies in other systems may be considered to match the carrier frequency of the carrier chrominance signal in each system.

[0034]

As described above, according to the present invention, the oscillation output of the oscillator of the color signal processing IC can be used without any trouble as the reference oscillation of the OSD processing IC. Reduction can be achieved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a main configuration of a home VTR system according to one embodiment of the present invention.

FIG. 2 is a block diagram showing an internal configuration of a recording color processing IC 1 in FIG.

FIG. 3 shows a menu ON / OFF according to an embodiment of the present invention.
It is a flowchart figure which shows an example of the processing flow at the time of operation.

FIG. 4 shows a menu ON / OFF according to an embodiment of the present invention.
It is a flowchart figure which shows another example of the processing flow at the time of operation.

FIG. 5 is a flowchart illustrating an example of a processing flow for no video according to an embodiment of the present invention.

FIG. 6 is a flowchart illustrating another example of the processing flow for no image according to an embodiment of the present invention.

FIG. 7 is a block diagram showing a configuration of a main part of a conventional home VTR system.

FIG. 8 is a flowchart illustrating a processing flow at the time of a menu ON / OFF operation according to the related art.

FIG. 9 is a flowchart showing a processing flow for no video according to the related art.

[Explanation of symbols]

Reference Signs List 1 color signal processing IC 2 recording color signal processing circuit 3 3.58 MHz oscillator 4 killer detection circuit 5, 6, 7, 8, 9, 11, 12, 13, 14, 16,
17, 18, 19 terminals 10 OSD processing IC 15 microcomputer 20 remote control 21 3.58 MHz BPF 22 frequency converter 23 1.3 MHz LPF 24 phase comparator 25 LPF 26 switch 27 fixed voltage source 28 3.58 MHz OSC

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04N 5/91-5/956 H04N 9/79-9/898

Claims (5)

(57) [Claims] 1. A video signal recording apparatus including a color signal recording circuit, a microcomputer, and an on-screen display circuit, wherein the color signal recording circuit includes an oscillator and a phase comparator as constituent elements, and the oscillator and the phase comparator Constitutes a phase-locked loop (hereinafter abbreviated as PLL) using a color burst of an input video signal as a reference input, and operates the first output of the oscillator so that the oscillation output of the oscillator and the color burst operate in phase lock. And a second oscillation state of the oscillator that oscillates at a fixed frequency without causing the oscillator to perform the PLL operation. The oscillation output of the oscillator is used as a reference clock for on-screen display, When a menu ON operation is performed during the recording operation, the first oscillation state of the oscillator is selected, and characters are superimposed on the video of the input video signal of the on-screen display circuit. The menu screen is displayed in the output mode (hereinafter referred to as superimpose mode). If the menu is turned on during non-recording operation,
Selecting the second oscillation state of the oscillator,
With the on-screen display function, the microcomputer controls the on-screen display circuit to display a menu screen in a mode for generating a background color and a character (hereinafter referred to as a background color mode). Video signal recording device. 2. A video signal recording apparatus including a color signal recording circuit, a microcomputer, and an on-screen display circuit, wherein the color signal recording circuit includes an oscillator and a phase comparator as constituent elements, wherein the oscillator and the phase comparator Constitutes a PLL using a color burst of an input video signal as a reference input, and operates a first oscillation state of the oscillator such that an oscillation output of the oscillator and the color burst are phase-locked. Switching means for selectively switching to a second oscillation state of the oscillator which oscillates at a fixed frequency without performing the PLL operation, so as to take any one of the oscillation states; It is input to the above-mentioned on-screen display circuit as a reference clock for on-screen display. When the operation is performed, the first oscillation state of the oscillator is selected, and the on-screen display circuit generates a colorless background and character having a constant luminance level (hereinafter referred to as a background colorless mode). ) To display the menu screen. If the menu is turned on during non-recording operation,
Selecting the second oscillation state of the oscillator,
A video signal recording device with an on-screen display function, wherein the microcomputer controls the on-screen display circuit to display a menu screen in a background color mode. 3. A video signal recording device including a color signal recording circuit, a microcomputer, and an on-screen display circuit, wherein the color signal recording circuit includes an oscillator and a phase comparator as components, and the oscillator and the phase comparator Constitutes a PLL using a color burst of an input video signal as a reference input, and operates a first oscillation state of the oscillator such that an oscillation output of the oscillator and the color burst are phase-locked. Switching means for selectively switching to one of the second oscillation state and the second oscillation state which oscillates at a fixed frequency without performing the PLL operation. The oscillation output of the oscillator is an on-screen display. Input to the above-mentioned on-screen display circuit as a reference clock of the input video signal during non-recording operation. When a state is detected, the second oscillation state of the oscillator is selected, and a background color screen is displayed by the background color mode of the on-screen display circuit. A video signal recording apparatus with an on-screen display function, wherein the microcomputer controls the display so that the background color screen is not displayed when the absence state is detected. 4. The color signal recording circuit according to claim 1, wherein the color signal recording circuit detects whether the input video signal is a color signal of a signal format that matches an operation state of the color signal recording circuit. Wherein the microcomputer has a signal format determining function of determining a signal format of an input video signal based on output information of the killer detecting circuit, wherein the oscillator is in the first oscillation state. Wherein the control is performed such that the signal format determination function is operated during the period, and the signal format determination function is stopped during the period when the oscillator is in the second oscillation state. , Video signal recording device with on-screen display function. 5. The discrimination result obtained in the first oscillation state before the change when the oscillator changes from the first oscillation state to the second oscillation state. During the period of the second oscillation state after the change, control is performed such that the signal format determination function is stopped and the determination output is held in accordance with the stored content. A video signal recording device with an on-screen display function.