JPS63169862A - Terminal equipment for drawn picture - Google Patents

Abstract

PURPOSE:To attain stable operation with less error at reproduction by superimposing audio information and recording the signal while digital information shifts the operating frequency band upward in case of recording the audio information and the digital information onto a magnetic tape. CONSTITUTION:A control section 5 fetching a picture drawn signal demodulated into digital information through a MODEM 4 analyzes the data and displays the result to a liquid crystal display device 6 as picture drawn information and outputs the signal to a MODEM 8 as a serial data in 300bps. A picture drawn signal and an audio signal inputted via a band elimination filter 2a and a switch S1 are added at an adder A2 and the overlapped signal is recorded on a cassette tape recorder 9. The signal passing through the low pass filter 10 is only the audio signal and outputted as the voice by a speaker 12 as a receiver. Moreover, the signal through the low pass filter 11 is inputted to the said MODEM 8 as the drawn picture data.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a terminal device for graphic communication (telewriting), and more specifically, it relates to a terminal device for graphical image communication (telewriting), and more specifically, a terminal device for transmitting an analog audio signal and a graphical digital signal on the same analog telephone line. The present invention relates to a terminal device for image communication that transmits and receives images.

[Conventional technology]

A conventional terminal device that sends and receives analog information and digital information together on the same telephone line was developed in Japanese Patent Laid-Open No. 59-3.
As stated in Publication No. 0350, information sent and received through telephone lines is classified into analog information and digital information, and when recording this information on a magnetic tape device, etc., it is necessary to distinguish between each information. The identification pattern is inserted between the image information and recorded. Furthermore, when reproducing this information, the identification pattern identifies whether the information recorded thereafter is analog information or digital information, and subsequent processing is performed according to the type of each identified information. Ta.

Apart from the first conventional technique mentioned above, there is a second conventional technique in which analog voice information and digital information are mixed and communicated on the same telephone line. A band division method (band division method) in which audio is multiplexed with audio and transmitted is known. To explain this further, using a telephone line, a part of the voice information transmission band is cut out with a band rejection filter, and digital information modulated by a modem is placed on top of it, thereby superimposing each information and transmitting and receiving it simultaneously. It is something.

In April 1985, the Ministry of Posts and Telecommunications standardized the standard communication method for telewriting. This clarifies the frequency band and level that should be cut out and cleared in order to superimpose digital information within the band used to carry digital information modulated by the modem, that is, the voice information transmission band. Ta.

[Problem that the invention seeks to solve]

As explained above, in conventional terminal devices that simultaneously transmit and receive analog information and digital information, the received information (analog voice information and graphic image digital information) is temporarily stored and can be played back later, increasing ease of use. In addition, although the first prior art describes the accumulation of received information, as already mentioned, it does not take into account the method of recording analog information and digital information separately. However, there was a problem in that it lacked the ability to simultaneously communicate analog information and digital information (simultaneous recording and playback).

In other words, in graphic communication, audio information and graphic image data are sent and received at the same time, and it is meaningful to view the graphic image on the display while listening to the audio information, but the graphic information is recorded separately. If so, during playback, the time when you hear the audio information and the time when you see the drawn image on the display will be different, making it meaningless.

Therefore, as a simple method, a method may be considered in which the digital information sent in a superimposed manner with the audio information is recorded as is on a magnetic tape and then played back. Therefore, the suitability of this method will be discussed below.

In the standard communication method of the Ministry of Posts and Telecommunications mentioned earlier, 300H from 1.6KH to 1.9KH is used for digital information.
, of which 1650Hz for digital logic '1' and 1850Hz for logic '0' are used.
is assigned.

When this digital information is transmitted over telephone lines,
The level is attenuated and noise is mixed in, causing distortion. If this is recorded as is on a recording tape or the like, factors that degrade the S/N will also be recorded at the same time. Furthermore, during reproduction, the frequency during reproduction fluctuates due to wow and flutter present in the magnetic tape device and expansion and contraction of the magnetic tape. Since the frequencies assigned to logic '1' and '0' are not 200H, L apart from each other, and the factors that degrade the S/N ratio mentioned above are added, there is a high probability that the data cannot be reproduced correctly and an error occurs. It will be expensive.

The standard communication method for telewriting does not include a function to correct errors, so it is necessary to prevent errors as much as possible. In other words, it can be seen that simply recording the digital information sent in a superimposed manner with the audio information as is is not appropriate because the probability of errors occurring during playback increases.

An object of the present invention is to realize stable recording and reproduction of image information with fewer errors while maintaining simultaneous communication of audio and digital information in a terminal device for image communication. The purpose is to increase ease of use.

[Means for solving problems]

The above purpose focused on the fact that the upper limit of the frequency band for voice communication used on telephone lines is 3.5 KHz, and that the frequency characteristics of recording and playback of magnetic tape devices are flat up to about 10 KHz. , 4KH, which is not used when communicating via telephone lines, is digital information sent and received over telephone lines.

By shifting to the above frequency range, the interval between the frequency corresponding to logic 1 and the frequency corresponding to logic O is widened, and then recording is performed on the magnetic tape and reproduction is performed.

Alternatively, the frequency band for digital information may be transferred to a usable band based on the recording/playback frequency characteristics of the magnetic tape device, and the audio information excluding the digital information from the information on the telephone line may be transferred to the magnetic tape. This is achieved by recording and reproducing the digital information, which has undergone frequency conversion, into one channel of the device and into another channel.

[Effect]

Separating information sent and received via an analog telephone line into analog voice information and digital image information, and superimposing image information is a function of conventional telewriting. After using and receiving,
When recording the separated image information on a magnetic tape, the digital information is frequency-converted to shift the frequency band used upward, and then the digital information is superimposed with the audio information and recorded. Due to the wow and flutter that exists in magnetic tape devices,
Since it becomes possible to absorb frequency fluctuations that occur in reproduced information, there are fewer errors during reproduction and stable operation is achieved.

〔Example〕

The present invention will now be described in detail with reference to the drawings.

FIG. 1 is a professional diagram showing a first embodiment of the present invention. The embodiment shown in the figure has a circuit section M surrounded by a broken line in a conventional terminal device for image communication (basic terminal device).
It can be said that it is an addition of . In other words, the first
In the figure, what remains after removing the circuit portion M is a conventional terminal device for image communication.

In Fig. 1, a 2vA 4-wire converter 1, band elimination filters (band rejection filters) 2a, 2bs
Band-pass filters 3a, 3b, a modem 4 for modulating and demodulating the drawn image data, a control section 5 which is composed of a microcomputer and executes the function of telewriting (drawn image communication), a liquid crystal display device 6, and the drawn image data as coordinate information. The input tablet 7, speaker 12, microphone 13, and adder A1 constitute a basic terminal device for communication of drawn images.

A changeover switch S1 for connecting the circuit portion M is added to this. The circuit section M includes a modulation/demodulation device 8, an audio cassette tape recorder 9 for recording and reproducing audio and graphic image data, a low-pass filter 10 for extracting audio information from the information reproduced by the audio cassette tape recorder 9, and a low-pass filter 10 for extracting graphic image data. It is composed of a bypass filter 11 and an adder A2.

FIG. 2 is a graph showing the allocation of frequency bands in mixed communication of audio information and drawn image data, which is defined in the telewriting standard communication system. Normally, the band (voice band) used in general subscriber telephone networks is 3.5K.
The band is from H, to below. Of this audio band,
As seen in Figure 2, from 1.6KH1l to 1.9KH
, 300H2 band is to be cut out by a band elimination filter and used for communication of drawn image data.

Therefore, if approximately 1.6 KHz is assigned to logic '0', approximately 1.9 KH is assigned to logic '1'.

Or vice versa.

Returning to FIG. 1, the basic operation as a terminal device for communicating drawn images will be explained first.

At the time of transmission, the speaker's voice is converted into an electrical signal by a microphone 13 serving as a transmitter, and a frequency band of 4KH or higher is removed from the frequency band by a Buri filter (not shown) to form a voice band. This audio signal, which takes the audio band, is then cut out by a band elimination filter 2b to remove the band (1.6 to 1.9 KH, band described with reference to FIG. 2) for carrying the drawn image data. .

On the other hand, the drawn image information written on the tablet 7 is taken into the control section 5 and simultaneously displayed on the liquid crystal display device 6. The control unit 5 creates a communication data packet specified in the "Telelighting Standard Communication Method" from the captured image information, and transmits it at 300 bps (bi
t per 5 seconds) as serial data to the modem 4. Modem 4 is based on CCITT recommendation ■, 21
satisfies the specifications.

The "Telelighting Standard Communication System" uses CCITT Recommendation ■, 21 high frequencies for communication of drawn image data, and uses the logic '1' of digital information as drawn image data.
゛ is 1650H, logic ゛0' is 18508. It is specified to be expressed as This situation is shown in FIG.

In Figure 3, 1650Hz corresponding to logic '1'
(1,65KHz) also corresponds to logic 'O゛1 85
0Hz (1.85KHz) is also the band (1°6 to 1.9KH) for image data transmission that was previously cut out from the audio band by the band elimination filter 2b.
z) will be found to be within the range.

In this way, the modem 4 converts the digital signal as drawn image data into a frequency signal, and passes it through the bandpass filter 3b.
After limiting the band by , superimposing it on the audio signal in an adder A1, limiting the frequency band to 3.5 KHz or less by a post filter (not shown),
Output from the 2-wire/4-wire converter 1 to the telephone line.

When receiving, the received signal from the telephone line is sent to the 2-wire 4-wire converter 1.
and band elimination filter 2
a and input to the bandpass filter 3a. The remaining audio band signals from which the band for drawing image data has been blocked by the band elimination filter 2a are transmitted to the speaker 1 as a receiver via the switch S1 connected to the contact (A) side.
2 is output as audio.

On the other hand, the bandpass filter 3a extracts only the band of the drawn image data and sends it to the modem 4. The modem 4 demodulates the frequency signals corresponding to logic '0' and logic '1 into digital signals, and inputs the result to the control unit 5 as serial data of 300 bps.

The control unit 5 analyzes this data and displays it on the liquid crystal display device 6 as drawn image data.

This completes the explanation of the basic operation of the terminal device for drawing image communication, which simultaneously transmits and receives voice information and handwritten drawing image information.

Next, the operation related to the present invention, that is, the operation related to the circuit portion M will be explained. As previously explained, the present invention aims to improve the usability of this type of terminal device by recording the received information (audio information and graphic image information) on a tape recorder or the like so that it can be played back later. . Therefore, when recording the received information, the control unit 5 that has taken in the image signal demodulated into digital information by the modem 4 analyzes this data and displays the image image on the liquid crystal display device 6 as described above. It is displayed as information and is output to the modulation/demodulation device 8 as 300 bps serial data. At this time, the modulation/demodulation device 8 acts as a modulation device, and according to the information input as serial data, if it is logic '1', 48
00Hz, and in the case of logic "0", it is output as a 9600Hz signal.

This drawn image signal and the band elimination filter 2a
The adder A2 superimposes the audio signal input via the S switch S1, and the superimposed signal is recorded on the cassette tape recorder 9. In this case, the band used for the audio signal and the band used for the drawn image data are as shown in FIG.

In other words, in FIG. 5, it can be seen that the band up to 3.5 kHz is used for audio, and the band above 3.5 kHz is used for image data.

Next, the operation when reproducing the information recorded as described above will be explained.

Since the frequency band of the signal reproduced by the cassette tape recorder 9 is as shown in FIG. 5, it is input to the low-pass filter 10 and the bypass filter 11 in FIG. The corner frequency of the low-pass filter 10 is 3.5 KHz.

The corner frequency of the bypass filter 11 is 4KH.

This is a filter. Further, at this time, the control unit 5 outputs an operation command to the switch S1 so that the switch S1 is switched to the terminal (b) side and connected to the low-pass filter 10.

Therefore, the signal that passes through the low-pass filter 10 becomes only an audio signal, which is output as audio by a speaker 12 serving as a receiver. On the other hand, the signal that has passed through the bypass filter 11 is input to the modulation/demodulation device 8 as drawn image data.

At this time, the modulation/demodulation device 8 functions as a demodulation device and outputs the demodulated data to the control section 5. Upon receiving this, the control unit 5 restores the data before recording and displays it on the display device 6.

According to this embodiment, using an inexpensive monaural audio cassette tape recorder or the like, it is possible to record and reproduce graphical image information at the same time as audio information with high quality, making it possible to use a graphical image communication terminal device like an answering machine. Even if the content of the communication is important and needs to be confirmed again at a later date, it is possible to accumulate information in case the communication is important and needs to be confirmed again at a later date, which has the effect of increasing usability. .

FIG. 4 is a block diagram showing a specific example of the modulation/demodulation device 8 in FIG. 1. In the same figure, a 4.8 KHz oscillator 41, a 9.6 KHz oscillator 42, a multiplexer 4
3. A modulation operation is performed by a low-pass filter 44 and an inverter 45. That is, the digital input is logic '0'.
or '1', the multiplexer 43 outputs the oscillator 41.
or 42, and outputs a 4.8 KHz or 9.6 KHz signal via the low-pass filter 44.

In FIG. 4, a phase detector 47, an integrator 48, a VCO
<Voltage controlled oscillator) 49 performs demodulation operation. These circuits are the well-known PLL (phase-locked loop)
The output frequency of a voltage controlled oscillator (VCO) 49 is tuned to the input frequency. The digitized signal is output from integrator 48.

FIG. 6 is a block diagram showing a second embodiment of the present invention. In this figure, the same parts as in FIG. 1 are given the same reference numerals. In addition, 14 is a stereo cassette tape recorder.

The basic operation of this embodiment is the same as that in FIG. In this embodiment, during reception and recording, the received audio signal is input to the recording right channel of the stereo cassette tape recorder 14 via the band elimination filter 2a1 switch SL (solid line position). A drawn image signal as modulated data from the modulator/demodulator 8 is input to the left channel for recording. That is, the data restored by the modem 4 through the bandpass filter 3a is input from the control unit 5 to the modulation/demodulation device 8 as serial data of 3QQbps, and here the logic '1' of the serial data is set to 2400H.
z, logic '0' is 4800H.

The signal is modulated as follows and input to the recording left channel of the stereo cassette tape recorder 14.

This is achieved by using the oscillator 41 with the configuration of the modem 8 shown in FIG.
．． This can be achieved by simply changing the 42 frequencies.

The information recorded in this manner is output as audio from the speaker 12 via the switch S1 (position indicated by the broken line) since only audio is reproduced from the right reproduction channel of the stereo cassette tape recorder 14. On the other hand, the drawn image signal reproduced and outputted from the reproduction left channel is input to the modulation/demodulation device 8 and demodulated into digital serial data in the same manner as described in the first embodiment. The control unit 5 receives and restores this data to data, and displays it on the liquid crystal display device 6.

According to this embodiment, it is possible to simultaneously record and reproduce audio and graphic image data without providing a special filter for recording and reproduction.

FIG. 7 is a block diagram showing a third embodiment of the present invention. The basic operation as a terminal device for image communication is as follows. Second
Since this is the same as in both embodiments, only the operations related to the present invention will be described below.

When recording information sent via a telephone line, each switch 31. S2. S3 is in the solid line position, and the first
As in the case of the embodiment, the audio signal received through the band elimination filter 2a and the data received through the band pass filter 3a and digitized by the modem 4 are guided to the modulation/demodulation device 8 via the control section 5. The modulated image signal is superimposed by an adder A2 and recorded in an audio cassette tape recorder 9.

Also, when reproducing recorded information, similarly to the first embodiment, switch S1 is switched to the low-pass filter 10 side (position indicated by the broken line), and the audio signal that is reproduced by the tape recorder 9 and passed through the low-pass filter 10 is the speaker 12
The drawn image data outputted from the CPU 1 and passed through the bypass filter 11 is demodulated by the modulation/demodulation device 8, processed by the control section 5, and then displayed on the liquid crystal display device 6.

Next, an operation (this operation is a feature of this embodiment) of recording requirements for information to be transmitted in advance on the tape recorder 9 and transmitting this information when necessary will be described.

First, when recording requirements as information to be transmitted, switch S3 is set to the microphone 13 side (broken line position).

Based on the coordinate values as drawn image data written on the tablet 7, the control unit 5 creates data for transmission according to the data format of the telewriting standard communication system. This data is input to the modulation/demodulation device 8, and the signal modulated in the same manner as described in the first embodiment and the audio signal input from the microphone 13 are filtered by a burry filter (not shown) at a frequency of 3.5 KHz or less. The band-limited signals are superimposed in an adder A2 and recorded in an audio cassette tape recorder 9.

When the information recorded in this manner is to be output through a telephone line, the switch S2 is set to the band elimination filter 2b side (dotted line position), and the switch S1 is also set to the low pass filter 10 side (dotted line position). Among the signals reproduced by the audio cassette tape recorder 9,
The audio signal is extracted by a low-pass filter 10,
The signal is output through the speaker 12 via the switch S1, and is also output via the switch S2 and the band elimination filter 2b. The drawn image data passes through a bypass filter 11 and is demodulated into serial data by a modulation/demodulation device 8, and then is sent to a modem 4 as 300 bps data via a control unit 5 using a method defined in the telewriting standard communication method. The signal is outputted according to the above, and reaches the adder A1 via the bandpass filter 3b, where it is superimposed with the audio signal and outputted to the telephone line in the format shown in FIG.

According to this embodiment, it is possible not only to record and reproduce information received via a telephone line (but also to record the requirements for the information to be transmitted in advance and then transmit it, further improving the convenience of the user. It has the effect of gaining.

FIG. 8 is a block diagram showing a fourth embodiment of the present invention. In this figure, the same parts as in FIGS. 1, 6, and 7 are given the same reference numerals. In addition, 15 is a ringing tone detector, and 16 is a tone detector.

In the initial state, the switch 51 is set to the band elimination filter 2a side (solid line position), the switch S2 is set to the microphone 13 side (solid line position), and the switch S3 is set to the speaker 12 side (solid line position). corresponds to the hook switch of a telephone receiver, and is in the oven state when on-hook and in the closed state when off-hook, but the switch S5 can also be turned on and off by a control signal from the control section 5. ing.

The method of transmitting, receiving, recording and reproducing information when the user of the terminal device is not away but is nearby is the same as described in the explanation of the third embodiment with reference to FIG. 7. A case where the user is absent and the service is used like an answering machine will be explained below.

The user uses a switch (not shown) to set the phone to be used like an answering machine.

At this time, the switch S5 is in the open state since the camera is in the on-footer state. When a telephone call is received from outside, the ringtone detector 15 detects the ringtone and controls the control unit 5.
Let me know. Since the ringing tone is a signal obtained by modulating a 400H2 signal with a cycle of 15 Hz or more and 20H2 or less, the ringing tone detector 15 detects this.

When the control unit 5 receives the ringing detection signal, after the ringing tone rings five times, it closes the switch S5 and connects the telephone line. After this, a message to the effect that the user is absent is output to the telephone line. This message is recorded and registered in advance by the user in a memory (not shown) before being output.

The control unit 5 controls the tone detector 1 while outputting the message.
Monitor the output of 6. Tone detector 16 identifies the transmitted dial tone. When there is no output from the tone detector 16, the control section 5 puts the audio cassette tape recorder 9 into the recording state, and records audio and graphic data in the same manner as in the third embodiment described above. do.

While outputting the message, tone detector 1
6 is output, and if it is a dial tone having the same pattern as the pattern registered in advance, the operation mode of the terminal device is set to remote mode, and the terminal device can be controlled from the outside. After this, a dial tone sent from outside via the telephone line
The information previously recorded on the audio cassette tape recorder 9 is played back, or the information to be transmitted from the terminal device is newly recorded on the tape recorder 9.

This practice is accomplished in a manner similar to that used in traditional answering machines.

According to this embodiment, it is possible not only to record voice messages and drawing image data, but also to play back previously recorded voice and data from the outside, and to record new information to be sent, improving usability. It can be increased significantly.

In the above embodiments, a liquid crystal display device was used as the display device, but a CRT (cathode-r
It operates in exactly the same way even if a display device such as ay tube) or a plasma display device is used. In addition, although the data transfer rate between the control unit 5 and the modulation/demodulation device 8 was set to 300bp3,
Exactly the same effect can be achieved at other speeds.

〔Effect of the invention〕

If recording and playback are performed under the condition that the audio and graphic data mixed method specified in the telewriting standard communication method is carried out as is, problems may occur due to expansion and contraction of the tape during playback, wow and flutter that exists in the tape recorder, etc. Frequency fluctuations often make it impossible to reproduce correct data, but according to the present invention, it is possible to widen the interval between the frequencies assigned to data logic 'O' and 1', and the audio signal Because the recording and playback of graphic image data is performed in a band or channel that is not listed, it has the effect of ensuring simultaneous recording and playback of audio signals and graphic image data using inexpensive audio cassette tapes. .

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a first embodiment of the present invention;
The figure is a characteristic diagram of the filter for separating audio signals and drawn image data, Figure 3 is a characteristic diagram of the band for drawn image data, and Figure 4 is a characteristic diagram of the filter for separating audio signals and drawn image data.
FIG. 5 is a block diagram showing the modulation/demodulation device in the figure, FIG. 5 is a mixed recording format diagram of audio signals and graphic image data, FIG. 6 is a block diagram showing the second embodiment of the present invention, and FIG. 7 is a block diagram showing the second embodiment of the present invention. FIG. 8 is a block diagram showing the fourth embodiment of the present invention. Explanation of symbols 1...2-wire 4-wire converter, 2a, 2b...Band elimination filter, 3a+3b...Band pass filter, 4...Modem, 5...Control unit, 8... Modulation/demodulation device, 9... Audio cassette tape recorder, 10... Low pass filter, 11... Bypass filter, 14... Stereo cassette tape recorder agent Patent attorney Akira Namiki

Claims (1)

[Claims] 1. When frequency multiplexing and transmitting analog voice signals and graphic image digital data in one line of an analog telephone network,
A part of the transmission band of the audio signal is cut out by a band rejection filter, and the digital image data obtained by modulating the image information with a modem is placed thereon and transmitted, and the audio signal and the image data are transmitted and received simultaneously. A communication terminal device is provided with a magnetic recording/reproducing device and a modulation/demodulation device, and when recording received information (analog audio signal and digital image data), the digital image data received and demodulated by the modem in the terminal device is transferred to the digital image data received and demodulated by the modem in the terminal device. By modulating the data through a modulation/demodulation device, the frequencies assigned to logic 1 and logic 0 of the data in the communication over the telephone line are changed to a high frequency that is not used in the communication within the recording/reproduction band of the magnetic recording/reproduction device. area (frequency conversion) to widen the interval between the frequencies respectively assigned to logic 1 and logic 0, and then record it on a magnetic recording medium in the magnetic recording and reproducing device together with the received analog audio signal, and when reproducing. A terminal device for graphic communication, characterized in that an analog audio signal and digital graphic data are separated from a signal reproduced from a magnetic recording medium, and the digital digital data is demodulated by the modulation/demodulation device and visually displayed. 2. In the graphical image communication terminal device according to claim 1, the magnetic recording and reproducing device comprises a stereo type magnetic recording and reproducing device, and on one channel thereof,
A terminal device for image communication, characterized in that the image digital data is recorded with a wider interval between the frequencies respectively assigned to logic 1 and logic 0, and the received analog audio signal is recorded on the other channel. 3. In the terminal device for graphical image communication according to claim 1, there is provided a ring tone detector for detecting a ring tone from the outside via a telephone line, and a dial input from the telephone line during a call. The device is equipped with a tone detector for detecting tones, and even when the user is absent, the ring tone detector detects an incoming call and connects the phone to record the analog audio signal and the digital image data in the magnetic recording and reproducing device. Also, during a call, the tone detector detects a dial tone input from the outside via the telephone line, and detects the information (audio signal and image data) previously recorded in the magnetic recording/reproducing device. ) is capable of being taken out to the outside.