JP3175295B2 - Facsimile machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a facsimile apparatus, and more particularly to a facsimile apparatus having means for performing initialization for normal equalization using a training signal.

[0002]

2. Description of the Related Art A general facsimile communication procedure will be described with reference to a sequence diagram shown in FIG. In the figure, the called side sends out a non-standard function signal NSF in response to a calling signal CNG from the calling side. When the calling side detects this non-standard function signal NSF, it sends out a non-standard function setting signal NSS.

Further, the calling side issues a training signal having a predetermined pattern, and subsequently sends a training check TCF. When the called side detects the training signal and the training check TCF, it sends a reception preparation confirmation signal CFR. The above is the procedure of the phases A and B.

[0004] Subsequently, the calling side again sends out a training signal and then sends out image information PIX. When the reception of the image information is completed, the calling side sends a multi-page signal MPS, and the called side responds to this by sending a message confirmation signal MCF.
Is sent.

When all pages have been transmitted, the calling side transmits a procedure end signal EOP, and the called side transmits a message confirmation signal MCF. Finally, the calling side issues a line disconnection command DCN to terminate the communication.

In the above procedure, the line condition is confirmed by the training signal, and initialization for normal equalization of the modem is performed.

If the first training signal after sending the non-standard function setting signal NSS cannot be obtained due to line noise or the like, the called side can return to phase B and wait for the training signal again. However,
If line noise or the like occurs in the training signal arranged immediately before the image information, and the image information cannot be detected even after the scheduled time elapses after the transmission of the reception preparation confirmation signal CFR, the procedure shifts to a communication interruption procedure. Therefore, there is a problem that image information cannot be received.

For such a problem, each tap coefficient set in the modem when the initialization for normal equalization is performed by the first training signal is fixed, and the training signal before image information is fixed. There has been proposed a modem control method in which image information reception is started using the fixed tap coefficient without performing initialization for equalization (Japanese Patent Publication No. 3-76628).

Further, in this modem control system, when the image information reception starts, the tap coefficients are released and the automatic equalizer follows the line fluctuation so as to follow the gradual fluctuation of the line during the reception of the image information. I can do it.

[0010]

The above-mentioned conventional apparatus has the following problems. For example, when transmitting image information including a plurality of pages, the data transmission speed of the image information is 9600 bps, and the data transmission speed of the protocol signal between the image information is 300 bps. Then, since the tap coefficient of the modem is updated according to the difference in the data transmission speed, the training signal (data transmission speed of 9600 bps) arranged immediately before the next page of the image information makes it possible to normally receive the image information. Initialization for initialization is performed again. Therefore, if line noise or the like occurs in the training signal at this time, image information cannot be received.

In such a technical background, in the above-described modem control method, the fixed tap coefficient is released when the reception of the image information is started, so that the training signal is generated in the training signal immediately before the image information of the second and subsequent pages. There has been a problem that it is affected by noise. That is, in the above-described modem control method, once the fixed tap coefficient is released,
No measures have been taken to fix this again for receiving the next page. In other words, there is a problem that consideration is not given to the reception of a plurality of pages.

An object of the present invention is to solve the above problems,
An object of the present invention is to provide a facsimile apparatus which can receive image information composed of a plurality of pages without being affected by noise generated in a training signal arranged immediately before image information of each page.

[0013]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems and achieve the object, the present invention provides an image information head detecting means for detecting the head of received image information for each page, Image information end detection means for detecting the last part of the received image information, the tap coefficient of the automatic equalizer is fixed when initialization for normal equalization is performed by the training of phase B, and said The modem issues an instruction to release the fixing of the tap coefficient in response to the detection signal output from the image information head detection means, and further to fix the tap coefficient again in response to the detection signal output from the image information end detection means. And a means for supplying the tap update control means.

Further, according to the present invention, an instruction for fixing the tap coefficient of the automatic equalizer when the initialization for normal equalization is performed by the training of the phase B is supplied to the tap coefficient update control means of the modem. means for, the procedure changing means for shifting the end portion control procedure in response to the detection signal of image information end detection means for detecting the received image information for each page in the phase B, the phase B by the procedure changing means
When shifting, the tap coefficient is released and fixed.
After performing the initialization for proper equalization, the tap coefficient
There is a second feature in that means for re-fixing is provided.

[0015]

According to the first aspect of the present invention, the tap coefficients are fixed when initialization for normal equalization is performed by the first training, and the fixing of the tap coefficients is based on image information reception. Is released when is started. And
At the end of each page of image information, the tap coefficient is fixed again.

Further, according to the present invention having the second feature, when initialization for normal equalization is performed by the first training, the tap coefficients are fixed. It is retained even during reception. Then, the process returns to the phase B between the pages of the image information, and initialization for normal equalization is performed again by the training there,
The image information of the next page is received under the tap coefficient at that time.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a main block diagram showing a hardware configuration of the facsimile apparatus. In FIG. 1, a network control unit (NCU) 1 is connected to an end of a line, and a modem 2 is connected to the NCU 1. Further, the modem 2 is connected to a system controller 3 of the facsimile machine main body. The system control device 3 is connected to a bus 5 of a microcomputer including a CPU 5 and storage devices such as a ROM 6 and a RAM 7. A reading device 8 and a printer 9 are connected to the bus 4 to read a transmission original and print out a received original.

The receiving operation of the facsimile apparatus having the above configuration will be described below. First, the receiving operation of the first embodiment will be described with reference to the flowchart of FIG. In the figure, in step S1, a call signal CNG from the calling side is provided.
The presence / absence of an incoming call is determined based on whether or not an incoming call is detected. If an incoming call is detected, the process proceeds to step S2, in which the called station identification signal CED is transmitted, and subsequently, in step S3, the non-standard function signal NSF or the digital identification signal DIS is transmitted. In step S4, the reception of the non-standard function setting signal NSS or the digital command signal DCS is waited.

If the determination in step S4 is affirmative, the flow advances to step S5 to cancel each tap coefficient in the modem.
In step S6, it is determined whether or not the training signal has been received. If the training signal is obtained, the process proceeds to step S7, and it is determined whether the training check signal TCF has been received. If the training signal and the training check signal TCF have been received, each tap coefficient at that time is fixed in step S8. After fixing each tap coefficient, a reception preparation confirmation signal CFR is transmitted in step S9.

If no training signal or training check signal TCF has been received, the process proceeds from step S6 and step S7 to step S10, where a training failure signal FTT is sent out, and step S4 is executed.
Return to The calling side can fall back in response to the training failure signal FTT.

The operations of phases A and B described above are common to the second and third embodiments described later.

After transmitting the reception preparation confirmation signal CFR, in step S11 of FIG. 4, it is determined whether or not the head of the image information has been detected. This determination is made based on whether the first line has been detected. First 1 in ECM mode
The determination is made based on whether a frame is detected. If the head of the image information is detected, the process proceeds to step S12 to release the fixed tap coefficients.

In step S13, image information is received.
In step S14, it is determined whether the end of the image information has been detected. This determination is made based on whether or not the control return code RTC has been detected. In the case of the ECM mode, the determination is made based on whether or not the RCP frame is detected.

If the end of the image information has been detected, the flow advances to step S15 to fix each tap coefficient for receiving the next page. In step S16, a predetermined flag is set to "0", and the end of the image information is detected, and the fact that each tap coefficient is fixed is stored.

On the other hand, if the end of the image information cannot be detected, the process proceeds to step S17, and it is determined whether or not the dropout has occurred based on whether or not the carrier has become undetectable (silence). If it is not dropout, the process returns to step S13 to continue receiving image information. If it is determined that dropout has occurred, the process proceeds to step S18,
The flag is set to "1" to store that the end of the image information could not be detected. In this case, the fixation of each tap coefficient remains released.

In step S19, a Q command, that is, a multi-page signal MPS, a message end signal EOM,
Wait for a procedure end signal EOP or the like. If one of these signals is detected, the process proceeds to step S20, and it is determined whether or not the flag is "0", that is, whether the end of the image information is detected and whether or not each tap coefficient is fixed.

If the flag is "0", step S20
Is affirmative, the process proceeds to step S21, and it is determined whether or not the quality of the received image information is good. If the quality is good, the process proceeds to step S22, where a message confirmation signal MCF is transmitted, and the process returns to step S11. If the quality of the received image information is poor, the process proceeds to step S23 to send out a retraining negative signal RTN. This retraining negative signal RTN indicates that image information can be received if the training signal is transmitted.

On the other hand, if the flag is "1", the flow advances to step S24 to determine whether or not the quality of the received image information is good. If the quality is good, the process goes to step S25 to send a retraining positive signal RTP. If the quality of the received image information is bad, the process goes to step S26 to send a retraining negative signal RTN. The retraining positive signal RTP indicates that communication cannot be continued unless the procedure is started from the beginning of the phase B.

After transmitting the retraining negative signal RTN and the retraining positive signal RTP, if the Q command is the message end signal EOM, the process returns to step S3, if the Q command is the multi-page signal MPS, the process returns to step S4, and if the procedure end signal EOP, If so, proceed to the communication end procedure.

Next, a second embodiment will be described with reference to the flowchart of FIG. In the second embodiment, the fixed tap coefficients are not released during image information reception, and the first training signal and training check signal TC are not released.
The image information is received while holding the tap coefficient determined in F. That is, every time one page of image information is received, the process returns to the phase B and the tap coefficient is updated.

FIG. 5 shows a process following step S9. In the figure, in step S30, image information is received. In step S31, it is determined whether the end of the image information has been detected based on whether the control return code RTC has been detected. In the case of the ECM mode, the determination is made based on whether or not the RCP frame is detected. If the end of the image information has been detected, the flow advances to step S32 to wait for a Q command.

On the other hand, if the end of the image information cannot be detected, the flow advances to step S33 to determine whether or not a dropout has occurred. If not dropout, step S
Returning to step 30, the reception of image information is continued, and if it is determined that dropout has occurred, the process proceeds to step S32.

In step S34, it is determined whether or not the quality of the received image information is good. If the quality is good, step S3
Proceeding to S5, the retraining affirmation signal RTP is transmitted. If the quality of the received image information is poor, the process proceeds to step S36 to transmit the retraining negative signal RTN. After transmitting the retraining negative signal RTN and the retraining positive signal RTP, if the Q command is the message end signal EOM, the process returns to step S3 in FIG. 3, if the multi-page signal MPS, the process returns to step S4, and if the procedure end signal EOP, If so, the procedure proceeds to a communication termination procedure.

Next, a third embodiment will be described with reference to the flowchart of FIG. In the second embodiment described above, 1
Since the process returns to the phase B every time the page ends, it may take too much time. Therefore, in the third embodiment, the process returns to the phase B every time the image information is completed only for the scheduled page.

FIG. 6 shows processing subsequent to step S9. In the figure, in step S40, the value of a counter for counting the number of pages of image information is cleared. In step S41, it is determined whether or not the head of the image information has been detected based on whether or not the first line has been detected. This determination is made based on whether the first frame is detected in the case of the ECM mode. If the head of the image information is detected, the process proceeds to step S42, where the value of the counter is incremented.

In step S43, image information is received.
In step S44, it is determined whether the end of the image information has been detected based on whether the control return code RTC has been detected.
In the case of the ECM mode, the determination is made based on whether or not the RCP frame is detected. If the end of image information can be detected,
Proceed to step S45 to wait for a Q command.

On the other hand, if the end of the image information cannot be detected, the flow advances to step S46 to determine whether or not a dropout has occurred. If not dropout, step S
The process returns to step S43 to continue receiving image information. If it is determined that dropout has occurred, the process proceeds to step S45.

In step S47, it is determined whether or not it is time to return to the phase B and update the tap coefficient based on whether or not the value of the counter is equal to the predetermined comparison value. If the counter value is equal to the expected comparison value, step S4
The process advances to step S9, and if they are not equal, the process advances to step S48. The processing in steps S48 to S53 is the same as the processing in steps S21 to S26, and a description thereof will be omitted.

In the third embodiment, whether or not it is time to update the tap coefficient is determined by whether or not the image information of the expected number of pages has been received, and the protocol procedure is changed according to the result of this determination. Instead of returning to the phase B, the determination may be made based on whether or not the scheduled time has elapsed. For example, a timer is started after the reception preparation confirmation signal CFR is transmitted, and each time image information of one page is received, the timer is checked to detect whether or not a predetermined time has elapsed. What is necessary is just to change and return to phase B.

Next, a function for causing the operations of the above-described first to third embodiments to be performed will be described. FIG. 1 is a block diagram showing main functions for causing the operations of the first to third embodiments to be performed. This block diagram collectively shows functions for performing the operations of the first to third embodiments, and only necessary parts are extracted therefrom to extract each of the first to third embodiments. Operation can be performed.

In the figure, a modem 2 has an automatic equalizer 1
0 is provided, and the tap coefficient of the automatic equalizer 10 is updated according to the state of the line according to the instruction from the tap update control unit 11. In this embodiment, whether to fix the tap signal by fixing the instruction signal from the tap update control unit 11 or release the fixation and make the update of the tap coefficient follow the state of the line is determined by the image information head unit. The determination is made based on the detection result of the image information or the detection result of the image information end unit, and the selection is made.

The line condition judging section 12 judges the line condition based on the state of the signal taken from the input line I. The protocol control unit 13 performs protocol control according to a predetermined procedure. The image information head detector 14 detects the image information head based on the signal taken from the input line I. The image information end detecting section 15 detects the image information end section based on a signal taken from the input line. The detection result storage unit 16 stores that the image information end unit has been detected. The procedure change determination unit 17 determines whether to perform an operation of forcibly returning the protocol control procedure to the phase B or to execute a normal protocol procedure. The counter 18 or the timer 19 is provided to provide a criterion for determining whether or not to change the procedure. Each time the image information head is detected, the value of the counter 18 is incremented, and the timer 19 measures the elapsed time from the start of the phase C processing.

With this configuration, first, the line status determination unit 12
Receives the training signal and, when determining that the training check signal TCF has been normally received, sends a signal s1 to the tap update control unit 11 to fix each tap coefficient. This signal s1 is transmitted to the protocol control unit 13
And the protocol control unit 13 outputs the output line O
To output a reception preparation confirmation signal CFR. On the other hand, when initialization for normal equalization is not performed, the line status determination unit 12 outputs a signal s2 to the protocol control unit 13. The protocol controller 13 outputs a training failure signal FTT to an output line in response to the signal s2.

When the image information head detector 14 detects one line or one frame of the image information and detects the image information head, it sends a signal s3 to the tap update controller 11 to release the fixed tap coefficients. Let it. Then, when the image information end detection unit 15 detects the control return code RTC and detects the last part of the image information, the tap coefficient is fixed again to the value at that time by the detection signal s4. The detection result storage unit 16 stores whether the last part of the image information has been detected, or whether the control return code RTC has not been detected due to noise or the like and the last part of the image information has not been recognized.

If the last part of the image information has not been detected based on the data in the detection result storage unit 16, the procedure change determination unit 17 changes the normal protocol control procedure to force the phase B Instruction signal s for returning to processing
5 is output to the protocol control unit 13.

Also, whether or not the end of the image information has been detected is not used as a criterion in the procedure change determination unit 17, but
It may be determined whether the expected number of pieces of image information has been received or whether the scheduled time has elapsed. That is, whether the procedure is changed is determined based on whether the value of the counter 18 or the timer 19 matches the comparison value. In this case, whether or not the end of the image information has been detected is determined only by the value of the counter 18 or the timer 19.

If the comparison value to be compared with the value of the counter 18 is set to “1”, the procedure is changed for each page, and the process can return to the phase B. That is, the tap coefficient is fixed as determined by the training signal in the phase B during the reception of the image information, and is released between each page to follow the fluctuation of the line.

The determination by the procedure change determination unit 17 is performed immediately after detecting the Q command after the end of the image information, that is, the post message command.

As described above, in the present embodiment, the tap coefficients are released from being fixed at the same time as the reception of the image information, so that it can follow the fluctuation of the line, and the tap coefficients are fixed again when the reception of the image information is completed. To prepare for receiving the next page.

Also, in consideration of the case where the control return code RTC indicating the end of the reception of the image information cannot be obtained due to the influence of noise, the example in which the tap coefficient is not updated during the reception of the image information is shown. . That is, reception of image information is performed in phase B
, The tap coefficients determined by the training using the training signal and the training check signal TCF in the phase B are fixed as they are, and the process proceeds to the phase C.

[0051]

As is apparent from the above description, according to the present invention, the tap coefficient is fixed in the phase B, and after the image information reception is started, this fixed state is released. The image information can be normally received even when the noise or the like occurs, and the line fluctuation can be followed even during the image information reception. This normal reception of image information can also be realized when image information of a plurality of pages is received.

Since the fixed tap coefficient is updated between each page or between a plurality of pages while receiving the image information, the control return code RTC indicating the end of the image information is not detected. Can also normally receive the image information of the next page.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a main part function of a facsimile apparatus showing one embodiment of the present invention.

FIG. 2 is a block diagram showing a hardware configuration of a facsimile apparatus showing one embodiment of the present invention.

FIG. 3 is a flowchart (part 1) illustrating an operation of the first embodiment;

FIG. 4 is a flowchart (part 2) illustrating the operation of the first embodiment.

FIG. 5 is a flowchart showing the operation of the second embodiment.

FIG. 6 is a flowchart showing the operation of the third embodiment.

FIG. 7 is a sequence diagram illustrating a protocol example of facsimile communication.

[Description of Signs] 1 ... NCU, 2 ... Modem, 3 ... System control unit,
10: automatic equalizer, 11: tap update control unit, 12
... Line status judging unit, 14 ... Image information head detecting unit, 15 ...
Image information end detection unit 17: Procedure change determination unit

Claims (2)

(57) [Claims] 1. A facsimile apparatus that receives image information via a modem having an automatic equalizer and a tap coefficient update control unit that updates a tap coefficient of the automatic equalizer by following a change in a line condition. Image information head detection means for detecting the head of the received image information for each page, image information end detection means for detecting the last part of the received image information for each page, and normal equalization by phase B training When the initialization is performed, the tap coefficient is fixed, and the fixing of the tap coefficient is released in response to a detection signal output from the image information head detecting means. And a means for supplying an instruction to fix the tap coefficient again to the tap coefficient update control means in response to a detection signal output from the facsimile apparatus. Millimeter device. 2. A facsimile apparatus for receiving image information via a modem having an automatic equalizer and a tap coefficient update control means for updating a tap coefficient of the automatic equalizer by following a change in a line condition. An image information end detecting means for detecting the last part of the received image information for each page; and an instruction for fixing the tap coefficient when initialization for normal equalization is performed by training in phase B. Means for supplying to the coefficient update control means; procedure changing means for shifting the control procedure to phase B in response to the detection signal of the image information end detecting means; and when the procedure changing means shifts to phase B.
In order to release the fixed tap coefficients,
After the above initialization, the tap coefficients are fixed again.
Facsimile apparatus characterized by comprising a that means.