JPS63160456A - Telewriting device - Google Patents

Abstract

PURPOSE:To send picture information at a fast speed by using the orthogonal amplitude modulation system so as to modulate a picture data converted from hand-written picture information and outputting the result to a transmission line and demodulating the modulated picture data. CONSTITUTION:The hand-written picture information is converted into an electric picture data by a picture data output means and the output of a picture data output means is modulated by the orthogonal amplitude modulation system by a full duplex MODEM 2 is modulated by the orthogonal amplitude modulation system and outputted to a line 10 to send the drawn picture information to the opposite telewriting device. As soon as the drawn picture information is sent via a line 10, the inputted modulated picture data via the line 10 from the opposite telewriting device by the MODEM 2 is demodulated. Further, the picture data being an output of a picture data output means and the demodulated picture data being an output of the MODEM 2 are displayed on a CRT display device 34. Thus, picture information with high density is sent.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a telewriting device.

[Prior Art] A telewriting device is a device that transmits and receives handwritten image information drawn using a predetermined pen or the like while communicating with a regular telephone over a telephone line.
The image information is transmitted from the telewriting device of one terminal to the telewriting device of the other terminal using a half-duplex FSK modem with a transmission speed of 300 bps. It goes in one direction to the lighting device.

[Problems to be Solved by the Invention] However, in the conventional telewriting device, since handwritten image information is transmitted using a half-duplex FSK modem, the telewriting of one terminal A is When the above image information is being transmitted from the device to the telewriting device of another terminal B via the telephone line, another handwritten image information is transmitted from the telewriting device of terminal B to the telewriting device of terminal A. The problem was that it could not be done.

Furthermore, in the telewriting device that transmits handwritten image information using a half-duplex FSK modem with a transmission speed of 300 bps as described above, the transmission speed is slow, so the information content drawn by the operator of terminal A is There is a limit to the ability to transmit all of the information, and there is a problem in that it is not possible to transmit image information with higher density, and therefore the transmission is limited to image information with lower density.

The purpose of the present invention is to solve the above-mentioned problems, and to simultaneously draw image information while the operator on the terminal A side is transmitting the image information of the nucleus writing from the terminal A to the telewriting device of the terminal B. The operator of terminal B on the receiving side of the image information can transmit another handwritten image information from terminal B to the telewriting device of terminal A, and the operator of terminal A can The drawn image information is transmitted at a faster transmission speed than the conventional device using an occupied bandwidth that is the same as or narrower than the occupied bandwidth of the transmission line when the image information was transmitted using the conventional device. The object of the present invention is to provide a telewriting device capable of transmitting information.

[Means for Solving the Problems] The present invention provides image data output means for converting handwritten image information into electrical signal image data, and a transmission line that modulates the output of the image data output means using a quadrature amplitude modulation method. full-duplex modulation/demodulation means for demodulating the modulated image data simultaneously inputted via the transmission line; and display means for displaying the output of the image data output means and the demodulated image data. It is characterized by having the following.

[Operation] With the above configuration, the image data output means converts handwritten image information into electrical signal image data, and then the modulation/demodulation means converts the output of the image data output means into an orthogonal amplitude modulation method. The drawing information is modulated and output to the transmission line, and the drawing information can be transmitted to the telewriting device on the other party's side. Further, simultaneously with the transmission of the drawing information, the modulation/demodulation means demodulates the modulated image data input from the telewriting device of the other party via the transmission line. Furthermore, the display means displays image data that is the output of the image data output means and demodulated image data that is the output of the modulation/demodulation means.

[Example 1] FIG. 1 is a block diagram of a drawing information bidirectional transmission type telewriting device 1 which is an embodiment of the present invention. 1, and can communicate with the operator at the other end using the telephone 7, as well as receive drawing information drawn by the telewriting section 3! It is characterized in that data is transmitted bidirectionally between the two telewriting devices 1 using a full-duplex modulator/demodulator 2 using a six-level orthogonal amplitude modulation method. Here, the orthogonal amplitude modulation method is a method that simultaneously performs amplitude modulation and phase modulation, and hereinafter, orthogonal amplitude modulation is referred to as QAM modulation.

In FIG. 1, audio signals and image signals input from the telewriting device 1 of the other party via the telephone line IO are passed through a hybrid circuit 4 to a band-elimination filter (hereinafter referred to as BEF) 5 and a band-pass filter ( Below, B
It's called PF. )6, the image signal is removed in BEF5 and only the audio signal is extracted, and then the telephone 7
On the other hand, after only the image signal is extracted in the BPF 6, the hybrid circuit 1 of the full-duplex modem 2
1 is output. Further, the audio signal output from the telephone 7 is output to the telewriting device l of the other party via the BEF 5, the hybrid circuit 4, and the telephone line 10.

The hybrid circuit 11 of the full-duplex modem 2 is an image signal synthesis/separation circuit that outputs the image signal input from the BPF 6 only to the analog filter 12, and performs digital-to-analog conversion (hereinafter referred to as D/A conversion). ) The image signal input from the device 23 is output only to the BPF'6. However, in reality, reflected waves are generated that go around from the D/A converter 23 to the analog filter 12 via the hybrid circuit 11 and are reflected back at the 2-wire to 4-wire conversion point in the middle of the line, so these are eliminated. To do this, a pseudo echo generator 15, which will be described in detail later, is used. The image signal input to the analog filter 12 is converted into an analog/digital converter (hereinafter referred to as A/D converter) 13 after unnecessary band components such as noise are removed.
The signal is D-converted into a 1200 bps digital image signal, and is input to the first input terminal of the differential amplifier 14.

On the other hand, a pseudo echo signal output from a pseudo echo generator 15, which will be described later, is input to the second input terminal of the differential amplifier 14. The differential amplifier 14 takes the difference between the two input signals, and outputs an image signal included in the image signal input to the first input terminal from the D/A converter 23 to the analog filter 12 via the hybrid circuit 11. 1, which is equipped with a PLL circuit for suppressing the phase jitter after canceling the component and the reflected wave turned back at the 2-wire to 4-wire conversion point in the middle of the line with the pseudo echo signal and amplifying the difference voltage.
It is output to the 6-level QAM demodulator 16. . The digital image signal input to the 16-value QAM demodulator 16 has a carrier frequency of 1.
After being QAM demodulated at 800 Hz, the signal is input to the descrambler 18 via the line automatic equal-sided type I7 that compensates for the band characteristics in the telephone line IO, and a descramble operation is performed based on a predetermined generating polynomial. Descrambler 18
The digital image signal output from
After being stored in , it is output to the pattern synthesizer 32 .

The pattern synthesizer 32 synthesizes a digital image signal inputted from the received image memory 3I and a digital image signal inputted from a light pen image memory 37 and a drawing memory 41, which will be described later, on one predetermined screen. The combined digital image signal is output to the scanner 33. Based on the input digital image signal, the scanner 33
A dummy rask signal is applied to a portion of a predetermined screen that becomes a white screen to generate the above-mentioned human-generated digital image signal.
Generates a digital image signal for one field and displays it on a CRT.
It outputs to the display 34 and the X-Y plotter 39.

When the operator positions the light pen 35 at a predetermined position on the screen of the CRT display 34 and presses a switch (not shown) on the light pen 35 to turn it on, the light pen 35 moves onto the screen of the CRT display 34. The CRT display 34 detects the bright line beam emitted from the CRT display 34.
The above position information is detected and outputted to the light pen image memory 37 via the auxiliary position memory 36 that temporarily stores the position information of the light pen 35 moving at high speed. The image memory 37 generates a digital image signal based on the input position information and outputs it to the pattern synthesizer 32 and the transmission image memory 38. Here, the CRTT display 34 has a higher resolution than the CRT display of the conventional device, and the auxiliary physical memory 36 is a memory having a large number of identification positions compared to the memory of the conventional device. This improves the sampling accuracy of handwritten image information.

The pattern synthesizer 32 receives a digital image signal transmitted from the telewriting device I on the other side and manually inputted from the received image memory 31, and a digital image signal of drawing information to be drawn using a light pen 35 on a CRT display 34. After combining the digital image signal of the drawing information drawn using the tablet 40 on one predetermined screen, the digital image signal that is the combined image information is sent to the scanner 33.
CRT display 34 and X-Y plotter 3 via
9, so it is sent from the other party's telewriting device l to the own terminal's telewriting device! A composite image of the image received by the terminal and the image drawn using the light pen 35 of the telewriting section 3 of the own terminal and the tablet 40 can be viewed on the screen of the CRT display 34, and if necessary, An X-Y block 39 can be used to create a hard copy of the composite image.

Furthermore, when the operator traces the surface of the tablet 40 with a predetermined pen or the like, the tablet 40 converts the drawing information into a digital image signal and outputs it to the drawing memory 41, and the digital image signal is temporarily stored in the drawing memory 41. After that, it is output to the pattern synthesizer 32 and the transmission image memory 38. Here, the tablet 40 is configured with a tablet having a larger number of identification positions than the tablet of the conventional device, thereby improving the sampling accuracy of handwritten image information.

The digital image signal manually input and temporarily stored in the transmission image memory 38 is input to the synchronization input section 19 of the full-duplex modem 2, and in the synchronization input section 19, the input digital image signal is synchronized from the modem side. The signal is input to the full-duplex modem 2 in accordance with the signal. After the synchronized digital image signal is scrambled using a predetermined generating polynomial in the scrambler 20, it is converted into an I66 value QA.
In the modulator 21, I66 at a carrier frequency of 1800Hz
Value QA modulated. The digital image signal subjected to 16-level QAM modulation is filtered by a digital filter 22 that extracts only the components of about 150 Hz centered around the carrier frequency of 1800 Hz, after which unnecessary harmonic components are removed.
/A converter 23 and pseudo echo generator 15. The pseudo echo generator 15 sets the impulse response characteristic of the transfer function as the tap coefficient of the generator 15 so that it is equivalent to the transfer function of the path through which the echo passes, performs convolution with the human signal, and generates a pseudo echo. It is output to the differential amplifier 14 as a signal. As a result, the differential amplifier 1
At the output of No. 4, the tap coefficient is controlled so that the echo signal is minimized. On the other hand, the D/A converter 23 performs D/A conversion on the input digital image signal, and transmits the digital image signal to the telewriting device of the other party via the hybrid circuit 11, BPF 6, hybrid circuit 4, and telephone IQ. to be transmitted.

This is a case where the two telewriting devices (1) of terminals A and B configured as described above are connected via the telephone line 10, and drawing information is transmitted to the terminals using the tablet 40 of the telewriting device (1) of terminal A. On the other hand, the operator of terminal B uses the light ben 35 to modify the image information, and the image information for the correction is transferred from the telewriting device 1 of terminal A to the telewriting device of terminal A! The operation transmitted to is explained below.

The operator of terminal A uses tablet 4 of telewriting department 3.
0 is drawn with a Ben etc., the tablet 40 outputs the digital image signal of the drawing information to the pattern synthesizer 32 and the transmission image memory 38 via the drawing memory 41, and outputs the digital image signal input to the pattern synthesizer 32. is outputted to the CRT display 34 via the scanner 33 and displayed on the screen of the CRT display 34. On the other hand, the transmission image memory 38 outputs the input digital image signal to the full-duplex modem 2. Furthermore, the full-duplex modem 2 converts the input digital image signal into a band-limited 16-level QAM image signal with a carrier frequency of 1800 Hz, and transmits the signal to the terminal B via the BPF 6, the hybrid circuit 4, and the telephone line 10. output to the telewriting device 1.

In the telewriting device 1 of the terminal, the 16-value QAM image signal received by the modem 2 is demodulated into a digital image signal, and then the received image memory 31, pattern synthesizer 32 and scanner of the telewriting unit 3 33 to the CRT display 34,
It is displayed on the screen of the CRT display 34 of the telewriting section 3. When the operator of terminal B modifies the drawing information drawn by the operator of terminal A displayed on the screen of the CRT display 34, the operator of terminal B uses the light ben 35 to correct the drawing information displayed on the screen of the CRT display 34.
By drawing on the screen of the T-display 34, the corrected drawing information is converted into a digital image signal and sent to the auxiliary body image memory 36 and the light-ben image memory 3.
7. CR via pattern synthesizer 32 and scanner 33
Output to T display 34 and CRT display 3
4, the digital image signal is output to the transmission image memory 38, and is 16-value QAM modulated by the modem 2 as described above, and the 16-value QA
M image signal is sent to the telewriting device of terminal A via BPF 6, hybrid circuit 4 and telephone line 10! is output to. As a result, the above-mentioned corrected drawing information drawn using the light ben 35 of the telewriting device 1 of terminal B, as described above, is transferred to the telewriting device of terminal A!
be displayed on the screen of the CRT display 34.

In addition, the CRT of the telewriting device l of terminals A and B
A hard copy of the drawing information on the screen of the display 34 can be obtained using the X-Y block 39 if necessary.

Furthermore, of course, at the same time as the bidirectional transmission of the drawing information, the operators of the terminals A and B can talk over the phone using the telephone 7.

In the above embodiment, the 16-value QAM image signal containing drawing information generated and output by the telewriting section 3 is in the frequency band of the telephone line IO (0 to 3.4 KHz).
18001 (z±150Hz), and on the other hand, the audio signal output from the telephone 7 includes components in the entire frequency band of the telephone line Since the signal components are removed, the audio signal and the image signal are frequency division multiplexed in the telephone line IO, and one telephone line, 1llO
It is possible to transmit audio signals and image signals at the same time. Here, some components of the audio signal corresponding to the occupied band of the image signal are removed, but since the removal band is extremely narrow, the clarity of the audio signal does not deteriorate in practical terms. .

Also,! Set the carrier frequency of the 66-value QA image signal to 1800H.
z, the center frequency of the second harmonic of the 16-value QAM image signal is 3600 Hz, and since the second harmonic of the 16-value QAM image signal exists outside the band of the telephone line lO, the 16-value QAM image The second harmonic of the signal does not affect the audio signal.

As explained above, in the above full-duplex modem 2, the I66-value QA modulator 21 and the 16-value QAM demodulator 16
Therefore, the above-mentioned image information can be transmitted at about four times the transmission speed in the same occupied band compared to, for example, a two-phase PSK full-duplex modem. Here, if necessary, handwritten image information may be transmitted compared to the conventional device, and in this case, the transmission speed of image information compared to the conventional device will be four times or less.

[Effects of the Invention] As detailed above, according to the present invention, image data converted from handwritten image information is modulated by the orthogonal amplitude modulation method and output to a transmission line, and at the same time, it is inputted via the transmission line. Since it is equipped with a full-duplex modulation/demodulation means that demodulates the modulated image data, handwritten image information can be transmitted bidirectionally between the telewriting devices of two terminals, and the telewriting device of the conventional example described above can be transmitted bidirectionally between the telewriting devices of two terminals. There is an advantage that there is no need to provide a communication control function for the right to transmit image information, which is provided in the half-duplex modem of the device.

In addition, since it is equipped with a full-duplex modulation/demodulation means using the orthogonal amplitude modulation method, it is possible to use an occupied band that is the same or narrower than the occupied band of the transmission line when transmitting the image information using the conventional device The above image information can be transmitted at a higher transmission speed than the above device.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a drawing information bidirectional transmission type telewriting device which is an embodiment of the present invention. 2... Full-duplex modem, 3... Telewriting section, 4.11... Hybrid circuit, 5... Band-elimination filter (BEF), 6... Band-pass filter (BPF), 7 ...Telephone, IO...Telephone line, 12...Analog filter, 13...Analog-digital converter (A/D converter), 14...Differential amplifier, 15...Pseudo echo Generator, 16...16-value QAM demodulator, 17...Line automatic equal side type, 18...Descrambler, 19...Synchronization input section, 20...Scrambler, 2! ... 16-level QAM modulator, 22 ... Digital filter, 23 ... Digital-to-analog converter (D/A converter), 31 ... Received image memory, 32 ... Pattern synthesizer, 33 ...Scanner, 34...CRT display, 35...Light pen, 36...Auxiliary position memory, 37...Light pen image memory, 38...Transmission image memory, 39...X- Y block, 40...Tablet, 41...Drawing memory.

Claims (1)

[Claims] (1) An image data output means for converting handwritten image information into image data of an electrical signal; and modulating the output of the image data output means using an orthogonal amplitude modulation method and outputting the modulated signal to a transmission line; 1. A telewriting device comprising: full-duplex modulation/demodulation means for demodulating modulated image data inputted by the user; and display means for displaying the output of the image data output means and the demodulated image data. .