JPS6229944B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a facsimile control system, and an object of the present invention is to economically transmit control signals in facsimile communication without disturbing calligraphic signals or degrading received and recorded quality. do.

The transmission method for control signals in facsimile communication is (a) 1, which is different from the carrier wave frequency for calligraphic signals.
Alternatively, methods have been put into practical use, such as a method in which signals of a plurality of frequencies are switched with the drawing signal and transmitted, and (b) a method in which a code signal is inserted within the width of the phase synchronization signal.

However, these methods require (a) sending and detecting circuits that are separate from those for transmitting and recording the writing and drawing signals; Furthermore, (b) the method according to (a) above has the drawback that a part of the control signal appears in the calligraphic recording, degrading the recording quality.

For example, according to a method of transmitting a control signal to notify the receiving side of the end of transmission of the calligraphic signals of a transmitted document using a frequency other than the conventional carrier wave, the calligraphic images obtained on the receiving side at this time are: During the time from when the signal is detected to when recording is stopped, the signal is recorded as shown by line 25 in FIG. 4a. Furthermore, even in a system in which the end of a writing signal is signaled by stopping the carrier wave, black recording similarly appears as shown by line 25 in FIG. 4a in a positive modulation facsimile. This compares to Figure 4b where no control signal is recorded.
It can be said that the quality of the calligraphy and painting records is poor. Note that 24 and 24' in FIG. 4 indicate the receiving recording paper and the calligraphy recording portion, respectively.

The present invention has been made in view of the above-mentioned problems, and is directed to the transmission of control signals in facsimile communication.
It is an object of the present invention to provide a facsimile control system that can reliably and easily perform a detection operation without disturbing a writing signal or degrading recording quality.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of a transmitting side used in a facsimile control system according to the present invention, and FIG. 2 is a block diagram showing a schematic configuration of a receiving side.

In FIG. 1, reference numeral 1 denotes a transmission scanning circuit which performs reading scanning for each line at a predetermined timing and outputs a writing signal a to an amplifier 2. The transmission scanning circuit 1 then notifies the control circuit 8 of the start and end of reading, and also outputs the above-mentioned reading timing signal to the phase position signal generation circuit 3. Phase position signal generation circuit 3
Then, after counting a predetermined clock from the read timing signal, the phase position signal b is generated. 4
5 is a gate circuit, 5 is a carrier wave oscillation circuit, 6 is a modulation circuit for so-called white feed amplitude phase modulation of the amplified drawing signal a, 7 is a line connection circuit, and 8 is for opening/closing the gate circuit 4 and starting/stopping the modulation circuit 6. A control circuit 9 is a line terminal. Note that the white feed amplitude phase modulation here refers to a method in which amplitude phase modulation is performed so that the phase of the carrier wave in the white signal portions before and after the black signal in the drawing signal differs by 180 degrees.

In addition, in FIG. 2, 10 is a line terminal, 11
12 is a line connection circuit, 12 is an AGC circuit that adjusts the level of the signal d from the line connection circuit 11, and 13 is a synchronous detection circuit (not shown) and a filter (not shown) that extracts only the component synchronized with the carrier wave from the signal d. ), 14 is a ternary-to-binary conversion circuit, 15 is a recording circuit for recording with binary signal g, and 16 is a circuit for detecting a carrier wave from signal d. 17 is an automatic starting circuit that outputs the detection signal k; 17 is a detection circuit (not shown) that detects the zero-crossing point of the signal f; and a unit that is activated by the output of this detection circuit and outputs a pulse slightly longer than one main scanning period. The receiving side phase signal i obtained from the recording circuit 15 has a stabilizing circuit (not shown), etc.
18 is a control circuit which inputs signal j and outputs signal j and corrects the receiving side phase position. 18 is a control circuit, which includes a NAND circuit which takes the NAND of signal j and signal k, and the output of this NAND circuit and signal k. It detects the image signal end signal 21 from the transmitter, stops the recording circuit 15, and causes the end confirmation signal sending circuit 19 to send the signal m to the transmitter.

The transmission of control signals between the transmitter and the receiver configured as described above will be specifically explained using main part signal waveform diagrams on the transmitter side and the receiver side shown in FIGS. 3a and 3b, respectively.

After outputting a reading start signal to the control circuit 8, the transmission scanning circuit 1 reads the document at a predetermined timing and outputs a calligraphy signal a, and also outputs the timing signal to the phase position signal generation circuit 3. The control circuit 8 thereby activates the modulation circuit 6, opens the gate circuit 4, and inputs the phase position signal b generated by the phase position signal generation circuit 3 to the modulation circuit 6 as the signal c. The modulation circuit 6 applies amplitude phase modulation to each white signal portion of the drawing signal a amplified by the amplifier 2 so that the phase differs by 180 degrees between the white signal portions before and after the phase position signal c (white feed). performs amplitude phase modulation) and outputs a signal d,
This signal d is sent to the line from the line terminal 9 via the line connection circuit 7.

Then, the signal d passes from the line terminal 10 of the receiver to the line connection circuit 11 and the AGC circuit 12, and then enters the demodulation circuit 13 and the automatic startup circuit 16. Demodulation circuit 1
3, first, a synchronous detection circuit (not shown) extracts only the component synchronized with the carrier wave from the signal d to obtain a signal e, and then this is filtered (not shown) to obtain a ternary level signal f. The signal is output to the ternary-to-binary conversion circuit 14 and the phase detection circuit 17 as follows. Then, the recording circuit 15 is driven according to the binary signal g from the ternary-to-binary conversion circuit 14 to perform reception and recording. The phase verification circuit 17 includes a detection circuit (not shown), a monostable circuit (not shown), etc., and the demodulation circuit 13
A ternary signal f from the recording circuit 15 and a timing signal i indicating the recording start position for each line are input from the recording circuit 15. Here, in the detection circuit (not shown), the signal f
A correction signal is sent to the recording circuit 15 on the control line 2 to make the signal i follow the signal h indicating the phase position on the transmitting side.
2. For example, this may be done by increasing or decreasing the main scanning frequency of the recording circuit 15 depending on the difference in phase position between the signal h and the signal i. In addition, in the phase verification circuit 17, the signal h is input to an internal monostable circuit (not shown), and the
A pulse slightly exceeding the main scanning period is generated and a signal j is output to the control circuit 18. Automatic start circuit 16
Then, the carrier wave is detected from the signal d, and a signal k that becomes high level when the carrier wave is detected is output. Control circuit 18
is equipped with a NAND circuit that NANDs signals j and k, and an AND circuit that ANDs the output of the NAND circuit and signal k, and detects a state in which a carrier wave is present but a phase position signal is not present. The end confirmation signal sending circuit 19 sends the signal m to the transmitting side, thereby completing the transmission and reception.

Now, some further explanation will be given regarding the control of the receiving side performed from the transmitting side during the above-mentioned series of transmitting and receiving operations. As already mentioned, the control circuit 8 on the transmitting side causes the gate circuit 4 and the modulation circuit 6 to make the phase different by 180 degrees for each white signal portion in the drawing signal of the signal d and for the white signal portions before and after the phase signal c. When the image signal ends, the control circuit 8 receives the image signal end signal from the transmission scanning circuit 1 and closes the gate circuit 4. In other words, the signal a input to the modulation circuit 6 is at a low level, and the signal c indicating the phase position is also not input, so that phase reversal does not occur and carrier waves of the same phase of 0 phase or π phase are continuously transmitted. become. This state is indicated by the end signal 20 of the signal d.
The end signal 20 based on this white signal has no phase inversion, and has a waveform 20 on the receiving side.
Therefore, since the zero crossing point is not detected by the detection circuit (not shown) in the phase verification circuit 17 to which the signal f is input, there is no input to the monostable circuit (not shown), so the signal j is at a low level. Become. This causes the control circuit 18 to output signal 1. Signal 1 is sent to the end confirmation signal sending circuit 19, while control line 2
1 to the recording circuit 15 to stop it.

Therefore, there is no need to separately provide a detection circuit 23 (broken line in Figure 2), which is required in conventional devices that transmit control signals with a frequency different from that of the carrier wave, and it is possible to control the end of the image signal by simply adding the gate circuit 4 on the transmission side. becomes.
The received image is also shown in Figure 4b, as shown in Figure 4a.
It becomes easier to see without the line 25 present in the image.

In this embodiment, the phase at the phase position is inverted once as shown in FIG. 5a, but it may be inverted multiple times as shown in FIG. 5b.

Furthermore, although the detection of phase inversion on the receiving side is performed at the transmission phase position, it is of course not limited to this, and the detection timing may be any time as long as it is detected periodically.

As is clear from the above description, the present invention inverts the phase of the carrier wave for each white signal in the calligraphy signal while the calligraphy signal is being transmitted on the transmitting side, and continues to transmit white signals of the same phase for a certain period of time after the end of the calligraphy signal. The facsimile control system is characterized in that the calligraphy signal is received on the receiving side while detecting the phase inversion, and if the phase inversion is not detected for a certain period of time, it is regarded as an instruction to end the calligraphy signal. This has the effect that control signal transmission and detection operations in facsimile communication can be carried out reliably and easily without disturbing calligraphic signals or degrading received recording quality.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a schematic configuration of a transmitting side used in a facsimile control system according to an embodiment of the present invention, FIG. 2 is a block diagram showing a schematic configuration of a receiving side, and FIG. FIG. 3b is a diagram of the main signal waveforms on the receiving side of FIG. 2, FIG. 4a is a diagram showing received image recording by the conventional device, and FIG. FIG. 5 is a waveform diagram for explaining another embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Transmission scanning circuit, 2... Amplifier, 3... Phase position signal generation circuit, 5... Carrier wave oscillation circuit, 6
... Modulation circuit, 7 ... Line connection circuit, 8 ... Control circuit, 9, 10 ... Line terminal, 11 ... Line connection circuit, 12 ... AGC circuit, 13 ... Demodulation circuit,
14...Three value-to-binary conversion circuit, 15...Recording circuit, 16...Automatic start circuit, 17...Phase verification circuit, 18...Control circuit, 19...Completion confirmation signal sending circuit.

Claims (1)

[Claims] 1 On the transmitting side, during the transmission of the calligraphy signal, the phase of the carrier wave is inverted for each white signal in the calligraphy signal, and a phase position signal is inserted between the calligraphy signals, and after the end of the calligraphy signal, the white signal of the same phase is continuously transmitted for a certain period of time. and transmitting the calligraphy signal on the receiving side while detecting the phase inversion and the phase position signal,
A facsimile control system characterized in that if the phase reversal is not detected for at least one line, it is regarded as an instruction to end the drawing signal.