HU208892B - System of videotelephone - Google Patents

Abstract

A videophone system is arranged to record time and date data with the associated video data on a tape so that the video data can easily be discriminated. The video phone system comprises A/D converter 1, central processing unit 7, gate array 2, D/A converter 3 video amplifying and synthesizing circuit 4, interface 6, memory 5, and universal timer integrated circuit 8. Date and time data are simultaneously recorded upon recording the video data to a tape so that the video data can be displayed on the monitor simultaneously with date and time data upon reproducing the tape, and thereby the picture can be discriminated more easily and simply. <IMAGE>

Description

BACKGROUND OF THE INVENTION The present invention relates to a video telephony system that displays an image of the other party during a telephone conversation. The system includes an A / D converter for converting a video camera's output analog video signal to a digital signal; a gate network connected to the output of the A / D converter which generates the output signals of the A / D converter and / or transmits the signals in a controlled manner; a memory storing video information connected to the gate network; a CPU connected to the gate network for transmitting and receiving video information via an interface and for executing various controls; a D / A converter for converting the gate network output signals to an analog signal; a video amplifier and synthesizer that mixes the output signals of the D / A converter with picture and line sync signals and then converts it to the original video signal and transmits it to a display device.

The state of the art is shown in FIG. 1 in the configuration of a conventional videophone system depicted in block diagram depth. Referring to Figure 1, the system component is a (1) A / D converter for converting (VI) an analog video signal from a video camera or other source into a digital signal; a CPU (7), i.e. a central processing unit for transmitting and receiving video signals via the interface (6) and performing various other control functions, a gate network (2) for generating the output signals of the A / D converter (1), or (1) for recording the output signals of the A / D converter and the video signals received by the CPU (7) into the memory (5) under the control of the CPU (7) and reading out the data recorded in the memory (5) and then ) To output output according to CPU control; a D / A converter (3) for converting the output signals of the gate network (2) to an analog signal; and (4) a video amplifier and synthesizer for mixing the output signal of the D / A converter (3) with the picture and line sync signals and then restoring the original video signal and transmitting it to the monitor.

The analog video signal (VI) obtained from the video camera or the like is converted to a digital signal by the A / D converter (1) and then output through the gate network (2) to the output video signals (3). Converted to an analog signal by the D / A converter and then mixed with picture and serial sync signals, this restores the original video signal in the video amplifier and synthesizer (4) and feeds the resulting video signal (VO) to the monitor and displaying it during a telephone conversation. make it visible.

In this user-created stop mode, a control signal corresponding to the stop mode is transmitted from the CPU (7) to the gate network (2). According to this, the gate network (2) writes the amount of video information digitized by the A / D converter (1) and corresponding to a still image into the transmission area of the memory (5). It then immediately blocks the A / D converter (1) and outputting one still image video information from the memory transmission area (5), this output video information is transmitted through the D / A converter (3) and the video amplifier and synthesizer (4) monitor as described above. This will display a still image.

In the user-initiated transmission mode, the corresponding control signal is transmitted from the CPU (7) to the gate network (2). Accordingly, the gate network (2) reads and formats the video information (VO) stored in the transmission area of the memory (5), which the CPU (7) makes available for transmission by AM or AMPM modulation and then through the interface (6) via the L1NE output phone line. The reason for modulation is that the upper limit of the telephone line transmission frequency is 3.4 kHz.

Further, when the video data (VD) is transmitted from the CPU (7), a two-tone audio signal (A), a stop period (B), a portion containing control signals (C), and video information (D) are successively transmitted. As shown in Fig. 2, the two-level audio signal (A) consists of 1.6 and 2 kHz signals and has an approx. After a 0.4 second stop period (B), various control signals (C) are output, and then the video information (D) is read and transmitted via the gate network (2), which requires various data to accurately decode the video information (D), such as e.g. format, mode, correct decoding length, etc. are transmitted via various control signals (C).

In FIG. A second (E) stop period of 0.4 seconds can also be seen.

On the other hand, if video information is received through the interface (6) and the telephone line and a two-level audio signal (A) is detected in the received signal, then different control signals and video information will be received and then the A / D converter (1) converts them into a digital signal and, after demodulation, captures the demodulated video signals through the gate network (2) and writes it to the reception area of the memory (5).

After this recording, the video information recorded in the reception area of the memory (5) is read and transmitted by the gate network (2) under the supervision of the CPU (7) providing control. These output signals are displayed through the D / A converter (3) and the video amplifier and synthesizer (4) so that the received still image is displayed in stop mode.

If, after recording in the memory (5), the video information is to be recorded by a user operating the device, the video information recorded in the memory (5) is read and transmitted by the CPU controlled gate network (2) and this video information is modulated ) In the CPU, as in the previous transmission case, and thereafter the two-level audio signal, the stop period, the control signals and the video information are successively transmitted via the interface (6) to the tape where they are recorded.

Thus, the video information recorded on the tape is transmitted to the CPU (7) via the interface (6) similarly to the receive case and subsequently recorded on the receiving area (5) of the memory via the CPU (2) controlled by the CPU (7), and the data recorded in the reception area of the memory (5) is transmitted to the display device, the monitor via the gate network (2), the D / A converter (3) and the video amplifier and synthesizer (4).

But such a standard videophone system is backwards2

Note that sequentially recorded images cannot be identified during tape playback, and accurate image identification is impossible afterwards.

It is an object of the present invention to provide a videophone system that displays the date and time of each still image during tape playback and display on the monitor, thereby allowing easier and simpler image identification.

The invention is based on the discovery that timing ICs commonly used in the art can be appropriately adapted to achieve this aim, taking into account the capabilities of the structure described above. The control and storage interface can be implemented, for example, for tape recording - via an interface that also provides telephone line interface.

The present invention accomplishes the above object in its most general form by adding a universal timing IC to a circuit arrangement which is connected to and controlled by the output of the universal timer IC and the CPU, and the output of this universal timer IC is provided with date and time data. connected to an input of a transmitting interface to a magnetic tape device.

When recording video signals to the tape via the interface (6), the date and time information of this universal timer IC is preferably transmitted and recorded before the two-level audio signal is recorded. Thus, when playing back the tape, the date and time information is displayed together with the video signals.

For the sake of clarity, the invention will now be described in more detail with reference to the accompanying drawings.

The block diagram in Figure 1 illustrates the configuration of a known videophone system.

Figure 2 illustrates a standard format structure for attachment to tape.

Figure 3 is a block diagram illustrating the configuration of a preferred embodiment of the present invention.

Figure 4 illustrates a form of fastening to a tape according to the present invention.

FIG. 5 is a flowchart of the video telephony system of FIG. 3.

FIG. 6 is a flowchart of the reception condition of the videophone system of FIG. 3.

Figures 7A-7E illustrate transmitting waveforms and Figures 8A and 8B show transmitting waveforms.

In the following, a preferred embodiment of the present invention will be described in detail with reference to the drawings. Figure 3 is a preferred embodiment of a videophone system according to the present invention having the following static structure.

First, there is an (1) A / D converter which has an analog video signal (VI) from a video camera or similar source. The arrangement includes a central processing unit, that is, according to its abbreviation in Hungarian, a CPU (7) connected to the output of the A / D converter (1) via a gate network (2). This is a bidirectional signal flow connection and is therefore indicated by two lines in the drawing. The same is true of a memory (5) also connected to the gate network (2). This memory (5) comprises a reception area and a transmission area. Via a interface (6) for transmitting and receiving video information, the CPU (7) is connected to the telephone line, or optionally to a direct signal recording element, such as a magnetic head amplifier. This is what the LINE I / O is for. A D / A converter (3) is connected to the output signals of the gate network (2), followed by a video amplifier and synthesizer (4) having a picture and serial sync input to be signaled and an output (VO) of the reset video signal to the monitor. . The monitor is not shown. Finally, we see a universal timing IC (8) connected to the interface (6) which generates the date and time data (8). These date and time data are displayed on the TAPE output of interface (6). The universal timer IC is provided with an external timing member which may be a quartz crystal or other capacitive element.

The layout works as follows. The A / D converter (1) converts the analog video signal (VI) from a video camera or other source to a digital signal. This goes to the gate network (2) for signal distribution, coupling and matching. The video information is transmitted and received via the interface (6) via its LINE I / O. Typically, this symbolizes a standard subscriber line. The circuitry transmits the video signals received by the CPU (7) to the memory (5), reads the data recorded in the memory (5) and then outputs it according to the control of the CPU (7). The D / A converter (3) converts the output signals of the gate network (2) into analog signals. The video amplifier and synthesizer (4) mixes the output signals of the D / A converter (3) with picture and line sync, then restores the original video signal and then transmits it to the monitor. Universal timer IC (8) transmits current date and time data to interface (6) via its TAPE output and records video signals via interface (6) under the control of CPU (7).

Figure 4 illustrates a form of tape recording structure according to the present invention. The CPU (7) drives the universal timer IC (8) and transmits the date and time (T) data to the tape via the interface (6), and subsequent signal recording as described in Figure 2. It happens. The two-level audio signal (A), the stop period (B), the various control signals (C) and the video information (D) are recorded in this order, and then a stop period (E) is left.

The logical operation of the present invention is illustrated in the flowchart of FIGS. 5 and 6, and the signal generation is shown in FIGS

Figure 8 follows the waveforms.

The analog video signal (VI) obtained from the camcorder or the like is converted into a digital signal in the A / D converter (1) and then recorded via the gate network (2) in the transmission area of the memory (5). The video information recorded here will be displayed on the monitor in the form of still images on the (2) gate network,

EN 208 892 Β through the D / A converter (3) and the video amplifier and synthesizer (4) as previously seen in Figure 1.

As stated above, the video information recorded in the transmission area of the memory (5) is read by the CPU (2) controlled by the CPU (7) after switching to the broadcast mode, the video information is modulated in the CPU (7) and then transmitted to the (6) via an interface to the telephone line, the LINE I / O, as shown in the flowchart of Figure 5. That is, as shown in FIG. 7E, the two-level audio signal (A) is first transmitted through the interface (6), then leaving a typically 0.4 second stop period (B) followed by various control signals (C) and D) transmitting video information sequentially through the interface (6) to the telephone line.

Further, when the video information is received by the interface (6) over the telephone line, it is executed in the same manner as described in Figure 1 and is displayed on a monitor. 8B, when the video information is received by the interface (6), the first two-level audio signal (A) is received by the interface (6) and transmitted by the CPU (7) as a reception status signal. Consequently, the CPU (7) then receives control signals (C) and video information (D) via the interface (6), which it converts and demodulates into a digital signal. The demodulated video information is stored through the gate network (2) in the receiving area of the memory (5) as shown in the flowchart of FIG. 6. The stored video information is displayed as a still image on the monitor via the gate network (2), the D / A converter (3) and the video amplifier and synthesizer (4).

On the other hand, when reading the video information stored in the memory (5) for recording to tape, the CPU (7) first outputs a low-level (OE) output enable signal - the drawing shows that it is a negative signal and a high-level READ read control signal. 7A and 7B, and then driving the universal timer IC (B) accordingly, the date and time data (TD) is generated in the format of FIG. 7C. The above signal is then transmitted to the tape via the interface (6), exactly as shown in Figures 7D and 7E, with the aforementioned two-level audio signal (A), the various control signals (C), and the video information (D). and / or recording - TAPE signal - via interface (6). Resetting the resulting TI recorded tape containing date and time data as shown in Figure 8A and receiving the date and time data via interface (6) as shown in the flowchart of Figure 6. transmitting it to the CPU (7) and then recording it in the receiving area of the memory (5) by controlling the CPU (7) through the gateway (2), and then the CPU (7) recognizes the receiving state in the interface (6). en detects based on the (A) two-level audio signal and receives the control signals (C) and the video information (D). The video information (D) is again converted and demodulated into digital signals and then written to the receiving area of the memory (5) via the gate network (2). In this way, after recording the video information in the memory (5), the TI recorded date and time data and (D) video information are read at the gate network (2) and simultaneously on the D / A converter (3) and the video amplifier and are displayed on the monitor via a synthesizer.

As described in more detail above, according to the present invention, the date and time data and video information are simultaneously recorded on tape. When you restore the tape, the video information and its associated date and time information are displayed simultaneously, which means that the user can easily and easily identify the image later.

Claims (2)

A video telephone system comprising an A / D converter (1) for converting a video camera's analog video signal (VI) into a digital signal; connected to the output of the A / D converter (1), a gate network (2) which generates and / or transmits signals in a controlled manner to the output signals of the A / D converter (1); a memory (5) for storing video information connected to the gate network (2); a CPU (7) connected to the gate network (2) for transmitting and receiving video information via an interface (6) and for executing various controls; a D / A converter (3) for converting the output signals of the gate network (2) to an analog signal; a video amplifier and synthesizer (4) for mixing the output signals of the D / A converter (3) with picture and line synchronization signals and then converting it to the original video signal and transmitting it to a display device; further comprising a universal timing IC (8) coupled to and controlled by the output of the CPU (7) and an output of the universal timing IC (8) with a date and time data (T, TD) is connected to an input of a transfer interface (6) to the recording means. Video telephony system according to claim 1, characterized in that the writing of the date and time data (T, TD) of the universal timer IC (8) on the tape can be performed before the recording of the video information on the tape, controlled by the CPU (7). (6) is built into the system.