MXPA99007223A - Provision to overload two images without fluctuac - Google Patents

Abstract

In order to avoid, during the manipulation mode, the fluctuation of a second image superimposed on a first image, an arrangement comprises: means (1,2,7) for providing a signal representative of a first image to a screen, said signal which includes a vertical synchronization signal, means (11) for providing a pseudo-vertical synchronization signal, characterized in that they also include: generating means (12) for generating a second image, said generating means having at least one input (19). ) to receive a signal to synchronize the second image with the first image, control means (12) having an output (20) indicating the mode in which the arrangement is working, selecting means (13) to selectively provide said vertical pseudo synchronization to said input (19) depending on the output (20) of the control means. Figure

Description

VIDEO MACHINES DESCRIPTION OF THE INVENTION The invention is in the field of arrangements that provide a representative signal of at least two images that are to be displayed superimposed on a screen. For example, in a VCR a composite video signal is 1 emitted / recorded from / on a tape, by means of magnetic read and write heads, amplified and then sent to an integrated video circuit that processes the amplified signal received from the heads . Superimposed, in a known way, on the first image, there could be a second image, for 'example what is known as a Picture on Screen (OSD). Such an OSD is most of the time a set of conventional signs or characters that are generated in a dedicated circuit (OSD generator) in accordance with the control issued by a user, for example with a remote control. The OSD is generated most of the time in a dedicated circuit such as a mi crocont r or 1 ad that receives the user's commands and displays an image of agreement with said control and a computer program ident ident e. The OSD is generated independently from a video signal and must appear in the same place, from one image to the next. That means that said OSD must be synchronized with the main image. In order to synchronize the OSD signal with the displayed image, the dedicated OSD circuit receives the horizontal and vertical synchronization pulses (Hsync and Vsync) from a synchronous separator circuit that receives the composite video signal and extracts from said horizontal sync pulses. and vertical. Then by counting the pulses of a timer that starts from one of the horizontal synchronization pulses that appears after a certain number of other horizontal synchronization pulses, starting from each vertical synchronization pulse, it is possible to find the moment in the one who starts the OSD. The signal of s i croni z ation extracted by the synchronous separating circuit is known as the composite synchronization signal (Csync). Csync includes Hsync (horizontal synchronization) and Vsync (Vertical Sync) .

During the electronic mode, the electronic mode (a mode often said EE mode, in which the recording is not executed, although a signal from a source, for example a video camera, goes through the circuits VTR 'and can be displayed on a TV monitor) or playback modes, the Csync signal is free of noise. Problems occur during manipulation modes such as pa s or advance or rewind. The synchronous separating circuit exhibits "parasitic" vertical synchronization pulses, __e_specially when the modulated reproduction frequency signal (PB-FM) is weak. -Said parasitic signal appears in the period between two segments. Since the dedicated OSD circuit is using the signal as a reference for the OSD generation, the OSD would fluctuate vertically. This is highly undesirable, especially during assembly recording when the pause mode is used to see for example the beginning and end of each recording sequence, and at the same time, the OSD must be clearly legible. The purpose of the invention is to solve this vertical jitter problem that appears each time a handling mode is used. A way Manipulation is a mode in which the speed of the tape is different from the normal playback speed, for example pause or rewind or fast forward. To avoid this problem, according to the invention, a switching circuit is implemented to supply the dedicated OSD circuit, which is often a microcontroller, with the normal vertical synchronization signal coming from the incriminated circuit s eparator during the EE and playback phases, although the switch for the PV signal (pseudo vertical) during manipulation modes such as the pause mode, the slow or search movement. This PV signal is generated during manipulation modes only. A pre-existing circuit can be used for a VCR. It is very stable because it is derived from the DFF (drum jogger), which is constructed using the information from the drum collection. It does not depend on the resistance of the FM playback or on the performance of the ep-rio r-in p arial circuit. To summarize the invention, an arrangement comprising: means for providing a signal representative of a first image to a screen, the signal including a vertical synchronization signal, - means for providing a pseudo-vertical synchronization signal, generating means for generating a second image, the generating means having minus one input for receiving a signal for synchronizing the second image with the first image, control means having an output indicating the mode in which the arrangement is operating, - selecting means for selectively providing the vertical synchronization signal or the pseudo vertical synchronization signal to said input depending on the output in the control means. In accordance with the preferred embodiments: - the generating means comprise a screen image generator, the means for providing the signal - Representative of the first image include a rotating drum set with at least one pair of magnetic heads for reading a magnetic tape, - the means for providing a synchronization signal - pseudo vertical comprise a control circuit that elaborates the pseudo vertical synchronization signal on the basis - to the control pulses generated by the rotating drum, the The arrangement further includes separating means for extracting the pseudo-vertical synchronization signal from the signal representative of the first image, the selecting means being in the form of a switch with a first input connected to the separating means, with a second input connected to the circuit. of control with a third input connected to the control means and with an output connected to the input of the generating means. The invention will now be described in accordance with Figure 1 which represents a schematic diagram of a part of a VCR equipped with the invention. A VCR according to the invention comprises a mechanical unit 1 equipped with a drum 2 around which a cassette or a tape is rolled in a known manner about half a turn. The drum is equipped in a known manner with at least a pair of magnetic heads for reading and writing on the belt. Each head of the cloth is active in turn when it reaches the side of the drum that is in contact with the belt. The change of the head is done in a known manner according to a tilting signal. The DFF supplied by a control circuit 11. The swing signal DFF is made based on CP control pulses of the pickup signal. In the reading mode of the heads, the amplified reproduction, the modulated frequency signal coming from the heads known as PB-FM, is emitted at an output 4 of the "mechanical unit 1 and sent through a link 5 to an input 6 of a signal processor circuit The processor circuit 7 is often in the form of a circuit known as a video IC The circuit processes the PB-FM signal to extract it from the composite video pattern and the synchronous signal known as a CVBS signal, said CVBS signal contains the video signal and composite synchronization signals known as Csync. As is well known, the signal of synchronization is to synchronize the frame scan and the lines of the picture of a cathode ray tube with the video signal. The Csync signal contains the vertical synchronization pulses that form the vertical synchronization signal known as Vsync and the horizontal synchronization pulses that produce the horizontal synchronization signal known as Hsync. The CVBS signal is one of the input signal of the VCR. Said signal is available at an output 8 of the video IC 7. Said output is coupled in a known manner to an input 9 of a synchronization separator circuit 10. Said circuit 10 frequently in the form of a dedicated IC extracts the signal Csync from the CVBS signal. The Csync signal is sent to the control circuit. In one embodiment of the invention, this circuit is a key element, for example TMP90. Said circuit 11, among other functions elaborates from said signal a vertical pseudo synchronization signal, the signal PV. The VCR can also broadcast a Picture on Screen signal. Said OSD signal is produced by a screen image generator, for example a mi cr o c on t r o r 1. In one embodiment of the invention, it is the microcontroller with ST92R195. Said generator of On-Screen Image is in a known way synchronized by means of the composite synchronization signal, Csync. As explained earlier in the manipulation mode it is caught by vertical parasitic pulses. According to the invention, in order to avoid fluctuation of said Screen Image, when the VCR is in one of the manipulation modes, the vertical synchronization signal that is fed to the Screen Image generator is no longer the signal of vertical synchronization that is trapped, but the pseudo vertical synchronization signal that comes from the control circuit 11. In an embodiment of the invention, this change is made by means of a controllable switch 13. Said switch 13 has three ends, a first 14, a second 15 and a third 16 and two positions, a first and a second. The first end 14 is coupled to an output 17 of the control circuit 11 of the drum 2 which receives the pseudo-vertical synchronization signal. The second end 15 is coupled to an output 18 of the opaque display circuit s that receives the conventional vertical synchronization signal. The third end is connected to an input 19 of the Display Image Generator (OSD) 12. The On-Screen Image Generator (OSD) ~~ 12 is as already said a dedicated circuit that has an input forecast to receive the vertical synchronization signal. When the switch 13 is in the first position, said third end 16 is connected to the second end 15 so as to receive the vertical synchronization signal coming from the sync-separator circuit 10. When the switch 13 is in the second position, said third end 16 is connected to the first end 14 so as to receive the pseudo-vertical synchronization signal. The change from one position to another is made by a logic control signal produced by the Display Image generator 12, and supplied in an output 20 of said circuit 12. It could be sent from another coupled circuit to receive a piece of information representing that the VCR is controlled to be in the manipulation mode.

Claims (6)

1. An arrangement comprising: means for providing a signal representative of a first image for a screen, said signal including a vertical synchronization signal, means for providing a pseudo-vertical synchronization signal, characterized in that they also include generating means for generating a second image, said generating means having at least one input for receiving a signal for synchronizing the second image with the first image, - control means having an output indicating the mode in which the arrangement is operating, selecting means for selectively providing said vertical synchronization signal or said pseudo-vertical synchronization signal for said input depending on the output of the control means.

2. The arrangement according to claim 1, wherein the generating means comprises a screen image generator.

3. The arrangement according to claim 1, wherein the means for providing the signal representative of the first image includes a rotary drum equipped with at least a pair of magnetic heads for reading a magnetic tape.

4. The arrangement according to claim 3, wherein the means for proportioning a pseudo-vertical synchronization signal comprises a control circuit that produces the pseudo-vertical synchronization signal based on the control pulses generated by the rotating drum.

5. The arrangement according to claim 4, further including separating means for extracting the vertical synchronization signal from the signal representative of the first image.

6. The arrangement according to claim 5, wherein the selecting means is in the form of a switch with a first input connected to the separator means, with a second input connected to the control circuit with a third input connected to the "media". control and with an output connected to the input of the generating means. SUMMARY In order to avoid, during the manipulation mode, the fluctuation of a second image superimposed on a first image, an arrangement comprises: means (1,2,7) for providing a signal representative of a first image to a screen, said signal including a synchronization signal see ti ca'l, - means (11) to provide a pseudo-vertical synchronization signal, characterized in that they also include generating means (12) to generate a second image, said generating means that have at least one input (19) for receiving a signal for synchronizing the second image with the first image, control means (12) having an output (20) indicating the mode in which the arrangement is operating, selecting means ( 13) to selectively provide said vertical synchronization signal or said pseudo synchronization signal vertical to said entrance (19) depending on the exit (20) of the control means. Figure 1