JPH04157985A - Signal absence processing device for vtr - Google Patents

Abstract

PURPOSE:To stably project character information by using a synchronizing signal generator incorporated in a camera part to generate a spurious synchronizing signal in the case of the absence of an external input video signal. CONSTITUTION:When the external input video signal is not inputted to an AGC circuit 2, the signal absence discrimination output goes to the high level, and a system controller 24 turns on the power source of a camera part 22 to start a synchronizing signal generator 23. Then, a composite synchronizing signal C2 is generated from the generator 23 and is supplied to a servo microcomputer 25 through an analog switch 21, and signals H' and V' are supplied to a spurious synchronizing signal inserting circuit 27 and a character generator 26. Consequently, a black signal to which signals H' and V' are inserted is applied to a fixed contact 11a, and character information has the phase locked to signals H' and V', and character information is stably projected on the black back screen of a view finder 9 and a monitor 14.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a camera-integrated VTR having a signal processing function in a no-signal input and no-signal playback state and a monitor on-screen function.

(b) Conventional technology Currently, when using a camera-integrated 7TR, character information displayed on the viewfinder (VF) (for example, REC/”P
Models that have a function (on-screen function) that allows the operator to output information such as B mode display, cassette insertion/removal display, and tape remaining amount display from the VTR line out to the monitor are being used.

An example of this on-screen function is shown in FIG. In Fig. 2, the luminance signal in the video signal input from the camera section or the line input end f to the AGC circuit (2) by the switch (1) is line-outed through the 75Ω driver (3), and the emphasis is The signal is recorded on a tape via a recording brightness processing circuit (4), and is also input to a synchronization separation circuit (5).

In the sync separation circuit (5), a composite sync signal (C
5YN (:) is separated and input to the servo microcomputer (6), and horizontal and vertical synchronization signals 1 and 2 synchronized with this are created. Iz is phase-locked to the synchronous signals H and V by the character generator (7). Text information is created. This character information is mixed with the luminance signal output from the AGC circuit (2) in a mixer (8) and sent to the viewfinder (9).
It is used as a switching control signal for the on-screen analog switch (11) via the selection switch (10), and each character constituting the character information is output based on the synchronization signals I-1 and V. The timing tenon located on the line emits an H level output.

The selection switch (10) is manually turned on when inserting character information on the monitor screen. In addition, the brightness signal from the AGC circuit (2) is applied to one fixed contact (lla) of the on-screen analog switch 01), and the other fixed contact (llb) is applied to the capacitor (lla).
2) is grounded via. Here, while the character information signal is at H level, that is, at the output timing in the video signal of each character constituting the character information, the on-screen analog switch (11) is on the fixed contact (llll) side, and the line The out signal line (13) is connected to a predetermined potential.
Conversely, while the character information signal is at L level, the on-screen analog switch (11) is a fixed contact (lla
) side, and the luminance signal is output to the monitor (1=1). Therefore, when the selection switch (10) is in the ON state, character information is inserted into the luminance signal and the monitor (10) is inserted into the brightness signal.
=1).

(c) Problems to be Solved by the Invention When the above-mentioned on-screen function is adopted in a camera-integrated VTR, the camera function is not used during external line input, so power consumption can be reduced by turning off the camera unit. It is possible to reduce the amount. Therefore, if no input signal is applied while the switch (1) is switched to the line input side, there is no signal input to the synchronous separation circuit (5), so
C-5ync is not supplied to the servo microcomputer. Therefore, the horizontal and vertical synchronization signal ■1, V is C-5sync
As a result, a phase lock cannot be achieved, and a synchronization signal having a regular period cannot be obtained. In this state, characters on the on-screen display or VF white display will be in a state where they are washed out, which poses a practical problem. This problem also occurs during no-signal reproduction.

(d) Means for Solving the Problems The present invention provides a synchronization separation means for separating a synchronization signal from an external input video signal inputted from the outside, and a non-signal for determining the presence or absence of an external input video signal based on the presence or absence of a synchronization signal. a camera section having a determination means, a synchronization signal generation means for creating a captured video signal, and a camera section that selects an output of the synchronization separation means when the no-signal determination means determines that the first state is that an external input video signal is input; , the second one to which no external input video signal is input.
a character generator for creating character information using the output of the selection means; The present invention is characterized by comprising a pseudo synchronous signal insertion means for creating a signal, and a superimposition means for superimposing character information on the externally input video signal in the first state and on the output of the insertion means which sends the pseudo synchronous signal in the second state.

(E) Function Since the present invention is configured as described above, even when there is no external input video signal, a pseudo video signal is created by the synchronization signal from the Domei signal generator of the camera unit, and character information is generated. is also created, so it is possible to always phase-lock the character information to the synchronization signal of the video signal displayed on the monitor.

(f) Example An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a circuit diagram of this embodiment, and the same parts as those in FIG. 2 are given the same reference numerals and their explanation will be omitted.

The composite sync (C1) taken out by the sync separation circuit (5) is supplied to the no-signal discrimination circuit (20) and the fixed contact (21a) of the analog switch (21).

The no-signal discrimination circuit (2 (1) is a composite sink (C1
) is monitored for a predetermined period of time, and when the composite sync is detected, it is determined that the first state is that a regular external input video signal is input to the AGC circuit (2), and the 1
It emits a 7-level discrimination output, and on the other hand, a composite sync (
CI) cannot be detected, the AGC circuit (2) determines that it is in a second state where no external input video signal is input, that is, a no-signal state, and issues an H-level discrimination output.

(22) is a camera unit that is integrally attached to the VTR,
Composite sync (C
2) to create a captured video signal.

Further, the composite sink (C2) is supplied to the fixed contact (21b) of the analog switch (2]).

In addition, the camera unit (22) is controlled to turn off the power by the system controller (24), and in the first state where the no-signal discrimination output is 1-level, the system controller (24) Turn off the power to the camera unit (22)
In the second state where the discrimination output is at the H level, the power is turned on and the device is brought into the operating state.

The analog switch (21) connects the composite sync (C1) which is the output of the sync separation circuit (5) and the sync signal generator (2).
3) It selects the composite sync (C2) which is the output, and its switching control is performed according to the discrimination output of the no-signal discrimination circuit (20), and when the discrimination output is I, level, that is, the external input video signal In the first state where there is, composite sync (C]) is selected, and when the discrimination output is at H level,
That is, in the second state where no external input video signal exists, the composite sync (C1) cannot be taken out, so the composite sync (C2) is selected. .

The output selected by the analog switch (21) is input to the servo microcomputer (25).
) creates horizontal and vertical synchronization signals H1\' based on composite sync (C1), and generates pseudo horizontal and vertical synchronization signals based on this when composite sync (C2) is input. Create synchronizing signals H' and V'.

The character generator (26) is a servo microcomputer (2
Character information is created from the horizontal and vertical synchronizing signal H1■ or the pseudo horizontal and vertical synchronizing signals H', V' from 5). In addition, the pseudo horizontal and vertical synchronization signals H' and V' are
Although it is originally used for special playback, it is input to the character generator (26) and also to the pseudo synchronization insertion circuit (27).

In the first state, the pseudo synchronous insertion circuit (27) passes the luminance signal from the AGC circuit (2) as it is, and connects the fixed contact (lla) of the on-screen analog switch (11).
), and in the second state there is no signal with no output from the AGC circuit (2), so pseudo horizontal and vertical synchronization signals are inserted into this no signal, which is essentially equivalent to a black signal. The function is to create a video signal and apply it to the fixed contact (lla).

Next, the operation of each part constructed as described above will be explained in detail in each of the first and second states. First, switch (1
) is switched to the line input side and the external input 1 video signal is input from the line input section to the AGC circuit (2).
) is applied as is, and by selecting the composite sync (C1) at the analog switch (21), the horizontal and vertical synchronization (g, l) and ■ are input to the character generator (26). Character information is created, and the mixer (8) mixes this character information with the brightness signal from the AGC circuit (2) and displays it on the viewfinder (9), and the selection switch (10) is turned on.
If it is on, the on-screen analog switch (1
Due to the operation of 1), the luminance signal remains DC only during the character information period.
The signal is replaced with a level and output to the monitor (14). Therefore, in this first state, the luminance signal applied to the fixed contact (lla) includes the horizontal and vertical synchronizing signals H, which are the basis for creating character information in the character generator (26).
■ means that they are synchronized.

In this first state, the camera section (22) is in an inactive state with the power turned off.

On the other hand, even though the switch (1) is switched to the line input side, in the second state where no external input video signal is input to the AGC circuit (2), the no-signal discrimination output becomes H level. Due to this, the system controller (24) has a camera unit (
Turn on the power of 22) and turn on the synchronous signal generator (23).
Activate. As a result, composite sync (C2) is generated from the synchronization signal generator (23), which is supplied to the servo microcomputer (25) via the analog switch (21), and pseudo horizontal and vertical synchronization signals 11' and V' are generated in pseudo synchronization. Signal insertion circuit (27) and character generator (
26).

Therefore, the fixed contact (lla) has a pseudo synchronous signal H',
A black signal with ° inserted is applied, and the single character information is phase-locked to the pseudo synchronization signals H' and V', and the character information is stably displayed on the black back screen in the viewfinder (9) and monitor (14). It will be shown on screen.

In the above-described embodiment, only the recording system of the externally input video signal was described, but it goes without saying that the no-signal processing can be performed by similar operations in the reproducing system as well.

(G) Effects of the Invention According to the present invention as described above, when the external input video signal 3 does not exist, a pseudo synchronization signal is created using the IUI generator built in the camera unit and output to the monitor. The character information from the character generator is phase-locked to the video signal being displayed, allowing stable display of the character information.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of an embodiment of the present invention, and FIG. 2 is a circuit block diagram of a conventional example. (5) - Synchronization separation circuit, (20) No signal discrimination circuit, (22) Camera unit, (23) Synchronization signal generator, (21) Analog switch, (26 )・
... Character generator, (27) ... Pseudo synchronous insertion circuit.

Claims (1)

[Claims] (1) A synchronization separation means for separating a synchronization signal from an external input video signal inputted from the outside; a no-signal determination means for determining the presence or absence of an external input video signal based on the presence or absence of the synchronization signal; a camera unit having a synchronization signal generation means; and when the no-signal determination means determines that the first state is that an external input video signal is being input, the synchronization separation means output is selected and the external input video signal is input; Not the second
a selection means for selecting the output of the synchronization signal generation means when it is determined that the synchronization signal generation means is in the second state; a character generator for creating character information using the output of the selection means; A pseudo synchronization signal insertion means for creating a video signal as a signal; and an insertion means for inserting the character information into the external input video signal in the first state and into the output of the pseudo synchronization signal insertion means in the second state. VTR no-signal processing device.