JP3419599B2 - Facsimile machine - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a communication device,
In particular, the present invention relates to a facsimile apparatus that sets a coefficient in a filter of a modem and performs tone detection according to the output of the filter.

[0002]

2. Description of the Related Art Generally, when performing facsimile communication using a communication line such as a telephone line, it is necessary to first establish a line by a network control unit. That is, as shown in Japanese Unexamined Patent Publication No. 5-292286, etc., after the sending side facsimile dials and makes a call to the receiving side facsimile via a communication line, CNG (calling
Tone) signal, the receiving facsimile sends CN
The G signal is detected, and a CED (Called Terminal Identification) signal is transmitted to respond. When the receiving facsimile responds with the CED signal, the transmitting facsimile immediately sends out a signal notifying the start of the shortened protocol. In this way, a call is set between the facsimiles and a line is established, a mode for shortening the protocol is set, and communication is started in accordance with a well-known protocol transmission control procedure.

When detecting a single frequency signal such as CNG in the procedure for establishing a line, for example, "R96 FAX MODEM" is used.
TONE DETECTOR FILTER TUNING "(Rockwell, Applic
ation Note Order No.668 January 1985), in the tone detector in the modem, the filter is configured by setting the modem coefficient, and the output energy value of the filter is compared with a predetermined threshold value. It is necessary to set the tone detection function so that the tone detection is performed when it is higher than the threshold and the tone is not detected when the threshold is lower than the threshold.

In this way, when detecting a single frequency signal transmitted from the facsimile on the transmitting side via the telephone line,
If the receiving-side facsimile is not transmitting / receiving and is ready to receive, even if the signal sent from the transmitting-side facsimile is weak, if the tone detector with the AGC function is used, The detection signal is amplified, the energy value calculated from the filter becomes equal to or higher than a predetermined threshold level, and detection becomes possible. On the other hand, the receiving facsimile detects the CNG signal (1100 Hz) and then performs CE.
While transmitting the D signal (2100 Hz), the protocol shortening start signal (8
00 Hz) must be detected. In this way, when the receiving side facsimile sends a signal other than the signal (detection target signal) sent from the sending facsimile to the telephone line, Such problems arise. That is,
The problem is that the signal sent from the facsimile on the receiving side wraps around to the receiving end of the own machine and activates the AGC function of the tone detector, so that it does not operate on the signal from the facsimile on the transmitting side to be received. is there.

[0005]

In the prior art as described above, if the tone detection filter is set without considering the wraparound of the signal transmitted from itself (reception side facsimile), the transmission side facsimile will be set. When the signal level sent from the filter is small, the energy value calculated from the filter also becomes smaller than the threshold value, and tone detection becomes impossible. Also, the level of the sneaking signal changes depending on the transmission level from itself, the line load, etc., so whether or not the tone detection function operates normally is
It is always unstable.

In order to solve such a problem, even when the self-device (reception-side facsimile) is transmitting a signal, a filter is used with a value capable of tone detection of the signal transmitted from the transmission-side facsimile. If the amplifier value or energy threshold is set uniformly, noise may cause erroneous detection or the detection frequency width may become too wide if the sneak-in level from the device itself is low or if no signal is being sent. is there. Therefore, there is a problem in the detection function in making the filter settings uniform. Therefore, there may be a mechanism in which the operator manually switches the amplifier value or the energy threshold value set in the filter according to the state of whether or not the device itself is transmitting a signal. Is complicated and takes a long time to operate.

The present invention solves the above-mentioned problems, and sets a filter amplifier value and an energy threshold value according to a sneak signal from itself to accurately transmit a signal sent from a transmitting side facsimile. An object of the present invention is to provide a facsimile machine capable of tone detection. In particular, according to the first and second aspects of the invention, a filter is provided according to the input signal level so that the signal can be detected even when the input signal is sufficiently smaller than the non-detection signal such as noise. The purpose is to calculate and set the amplifier value.

Further, according to the inventions of claims 3 and 4, even if the input signal is sufficiently smaller than the non-detection signal such as noise and the average energy value calculated from the filter is not a sufficient value, the signal The purpose is to calculate and set the energy threshold according to the input signal level so that the detection can be performed. Further, in the invention of claim 5, in the calculation method according to claims 2 and 4,
Focusing on the fact that the coefficient of the calculation formula is different for each detection frequency, the purpose is to have the coefficient of the calculation formula in the RAM and set the coefficient by the filter configuration.

Further, according to the invention of claim 6, the signal is transmitted from the device itself and the signal is transmitted so that the tone can be detected regardless of the level of the signal transmitted from the facsimile on the transmission side. The purpose is to configure a filter with an amplifier value corresponding to a desired frequency to be detected by setting a filter amplifier value in the case of no detection. Further, in the invention of claim 7, in the plural coefficient value setting means according to claim 6, the coefficient is selected by bit operation from the CPU, and the filter is configured by the amplifier value corresponding to the frequency to be detected. With the goal.

Further, according to the invention of claim 8, even when the energy value calculated by the filter is small, the signal is transmitted from the device itself and the signal is not transmitted so that the tone can be detected. The energy threshold of the case is set, and the filter is configured by the energy threshold according to the frequency for which detection is desired. further,
According to the invention of claim 9, in the plural energy threshold value setting means according to claim 8, the energy threshold value is selected by bit operation from the CPU, and the filter is constituted by the energy threshold value corresponding to the frequency to be detected. To aim.

[0011]

The invention according to claim 1 is
In a facsimile apparatus that sets a filter coefficient in a filter of a modem and performs tone detection by the energy value of the filter output, an amplifier that sets the amplifier value of the filter used for tone detection according to the AGC amplifier value output from the modem It has a value setting means.

The invention according to claim 2 has an amplifier value calculating means for calculating a filter amplifier value set according to the AGC amplifier value by calculation based on the AGC amplifier value. According to a third aspect of the present invention, in a facsimile apparatus in which a filter coefficient is set in a modem filter and tone detection is performed by the energy value of the filter output, detection / non-detection is determined according to an AGC amplifier value output from the modem. And an energy threshold setting means for setting the energy threshold of the tone detection filter output.

According to a fourth aspect of the present invention, there is provided energy threshold value calculating means for calculating an energy threshold value set according to the AGC amplifier value by calculation based on the AGC amplifier value. According to a fifth aspect of the present invention, the coefficient used in the formula for calculating the filter amplifier value and the energy threshold value calculated according to the AGC amplifier value is stored in the storage means, and the coefficient is set by the tone detection filter configuration of the modem. It has a setting means.

According to a sixth aspect of the present invention, a filter is configured by a coefficient set according to a frequency desired to be detected,
A tone detector for detecting the desired single frequency according to the magnitude of energy calculated from the filter,
It has a plurality of coefficient setting means capable of setting a plurality of the coefficients corresponding to the amplifier value of the filter. Claim 7
In the above described tone detector, the tone detector has an amplifier value selecting means for selecting a setting value to be used for energy calculation among the plurality of set coefficients by bit operation.

According to an eighth aspect of the present invention, a filter is constructed by a coefficient set according to a frequency desired to be detected,
A tone detector that detects a single frequency based on the magnitude of energy calculated from the filter is provided, and a plurality of energy threshold setting means that can set a plurality of energy thresholds for determining the tone detection are provided. According to a ninth aspect of the present invention, in the tone detector, there is provided energy threshold value selection means for selecting a setting value used for energy calculation from among the plurality of energy threshold values set by bit operation.

[0016]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a facsimile apparatus according to the present invention. In FIG. 1, 1 is a scanner for reading an original image and extracting image information, 2 is a plotter for recording the image on recording paper, 3 is a known code such as one-dimensional (MH), two-dimensional (MR, MMR) encoding system The encoding / decoding unit 4 that decodes the received image information and reproduces the original image information while performing the data compression by encoding the image information to be transmitted by the encoding method, modulates and transmits the image information, and A modem that transmits various procedure signals for transmission control,
Reference numeral 5 is a network control unit for connecting a telephone line and a telephone 9 to control a predetermined line for making and receiving calls, and 6 is an operation display unit for displaying an operation state of the device and for allowing an operator to perform various operations. Is a system control unit including a CPU, a ROM, a RAM and the like, and controls each of the above units, and 8 is a system bus for exchanging various control signals and data between the above units.

FIG. 2 shows a first embodiment of the filter structure of the tone detector in the facsimile apparatus according to any one of claims 1 to 5 of the present invention. The tone detector 20 provided in the modem 4 is a commonly used detector applied to the present invention, and includes two filters 11, 12 and an energy averaging filter 13 and a threshold comparator 14.
Composed of. A1 and A2 are amplifier values of a filter which constitutes the tone detector set according to the present invention, and B
1, B2, B3 and B4 are coefficients set according to the frequency to be detected. C1 and C2 are coefficients for calculating the average value of the energy calculated from this filter.
Further, D1 is an energy threshold value for determining whether or not detection is possible by referring to the calculated energy value, and is set by the present invention.

In the filters 11 and 12, the input signal I
Similar signal processing is performed on the NPUT. First, the input signal (INPUT) is the filter amplifier value A1 (A
2) is multiplied, a predetermined delay signal is added, and then doubled and output to the next stage. The output signal is delayed (Z) by a predetermined time, and the coefficient B set by the desired frequency is set.
1, B2 or B3, B4 are multiplied and added to the input signal. Filter 2 takes the absolute value of the output signal (A
BS) processing is performed. In the energy averaging filter 13, after being multiplied by the average value calculation coefficient C1, a predetermined delay signal is added and output to the next stage. The output signal is delayed by a predetermined time, multiplied by a predetermined coefficient C2, and added to the input signal. The threshold comparator 14 determines the output of the detection signal (FR1) by comparing the energy value of the input signal with a threshold value calculated in advance. (Claims 1 and 2) FIG. 3 is a flow chart for explaining the operations of the amplifier value setting means and the amplifier value calculating means of the tone detector described above.

When the CPU in the system control unit 7 detects a signal sent from the other side while the device itself is sending a signal, the CPU, for example, starts sending the signal (S101) and then, for example, the signal level Approximately 50ms until the temperature stabilizes
After ec has elapsed (S102), the AGC amplifier value is read from the modem 4 (S103). Next, a filter amplifier value is calculated from the read AGC amplifier value according to the following mathematical expression (1) (S104).

(A-AGC amplifier value) = filter amplifier value (1) Here, the value of a is set by the CPU according to the configuration of the filter. Next, the upper limit value or the lower limit value of the filter amplifier value is set, and the filter amplifier value not more than the upper limit value or not less than the lower limit value is set. That is, when the read AGC amplifier value is small (when the wrap-around level is large) and the calculated filter amplifier value exceeds a certain value, the calculation result may overflow due to the operational relation of the filter. Therefore, when the upper limit value is set to a value that does not cause overflow, and the filter amplifier value becomes a value equal to or higher than the upper limit value (S105), the amplifier values A1 and A1 of the filters 11 and 12 shown in FIG. The upper limit value AMP1 is set to A2 (S106).

Further, when the read AGC amplifier value is large (when the wraparound level is small) and the filter amplifier value becomes a certain value or less, the result of the energy average value calculated from the filter becomes small and the threshold value becomes small. Since it will not exceed the lower limit value, when the lower limit value is set and the calculated filter amplifier value is less than or equal to the lower limit value (S1
In 07), the lower limit value AMP2 is set to the amplifier values A1 and A2 of the filters 11 and 12 (S108).

When the calculated filter amplifier value is less than or equal to the upper limit value (S105) and greater than or equal to the lower limit value (S107), the filter amplifier value calculated by the above equation is set in the modem 4 together with other parameters ( S109). (Claims 3 and 4) FIG. 4 is a flow chart for explaining the operation of the energy threshold value setting means and the energy threshold value calculating means of the tone detector described above.

When the CPU in the system control unit 7 detects another signal sent from the other side while the device itself is sending the signal, the CPU starts sending the signal (S201), and then
For example, it takes about 50 minutes for the signal level to stabilize.
After the lapse of msec (S202), the AGC amplifier value is read from the modem 4 (S203). Next, read AGC
An energy threshold value is calculated from the amplifier value according to the following mathematical expression (2) (S204).

B * (AGC amplifier value) ² = energy threshold value (2) Here, the value of b is set by the CPU according to the configuration of the filter. Next, the upper limit value or the lower limit value of the energy threshold value is set, and the energy threshold value not more than the upper limit value or not less than the lower limit value is set. That is, when the AGC amplifier value is large (when the wrap-around level is small) and the calculated threshold value is equal to or higher than a certain value, the energy average value of the filter calculation result does not exceed the threshold value and cannot be detected. Therefore, when the upper limit value is set and the calculated energy threshold value is equal to or more than the upper limit value (S205), the threshold value comparator 1 shown in FIG.
The upper limit TH1 is set to the energy threshold D1 of 4 (S
206).

Further, when the AGC amplifier value is small (when the wraparound level is large) and the calculated threshold value is below a certain value, the energy average value of the filter calculation result exceeds the threshold value due to noise input. In order to make a false detection, a lower limit value is set, and when the calculated energy threshold value is equal to or lower than the lower limit value (S207), the lower limit value TH2 is set to the energy threshold value D1 of the threshold value comparator 14 (S208). ).

Further, the calculated threshold value is less than or equal to the upper limit value (S20
5) If the value is equal to or more than the lower limit value (S207), the energy threshold value calculated by the above equation, together with other parameters,
The modem 4 is set (S209). (Claim 5) In such an amplifier value calculating means and an energy threshold calculating means, coefficients used for each calculation are stored in advance in a storage means such as a RAM in the system control unit 7, and a coefficient setting means (CPU) is used. ), The coefficient corresponding to the tone detection filter configuration of the modem 4 is read and set. With such a configuration, it is possible to set the optimum filter amplifier value and energy threshold value for tone detection of the signal sent from the transmitting facsimile.

Next, FIG. 5 shows a second embodiment of the filter structure of the tone detector in the facsimile apparatus according to any one of claims 6 to 9 of the present invention. The processing procedure of tone detection is the same as that of the first embodiment, and therefore its explanation is omitted.
In FIG. 5, A11, A12 and B11, B12
Is the amplifier value of the filter that constitutes the tone detector set according to the present invention. C11, C12, C13, C
14 is a coefficient set according to the frequency to be detected.
Further, D11 and D12 are for calculating the average value of energy calculated from this filter. Furthermore, E1
Reference numerals 1 and E12 are energy threshold values for determining whether detection is possible by referring to the energy value calculated by the filter, and are set by the present invention. here,
The filter amplifier value set in the filters 21 and 22 and the energy threshold value set in the threshold value comparator 24 each have two values, and are switched according to the signal transmission state of the own device.

The details will be described below. (Claims 6 and 7) FIG. 6 is a flow chart for explaining the operation of the plural amplifier value setting means and the amplifier value selecting means used in the tone detector of the second embodiment. All of these operations are processed by the CPU in the system control unit 7.

The CPU sets various coefficients necessary for tone detection. At that time, the filter amplifier value for the frequency to be detected is set in the tone detector (S301). Subsequently, in step S302, it is determined whether or not the device itself is transmitting a signal (tone), and if the signal is not transmitting, the flag of the predetermined bit F of the tone detector is set to "0" (S304). ), The amplifier value of the filter is set to A11 and A12. When a signal is being sent, the flag of the predetermined bit F of the tone detector is set to "1" (S303), and the amplifier values of the filter are set to B11 and B12.

The tone detector sets a predetermined bit G (detection bit) to "1" by detecting the signal.
The CPU determines whether or not a signal is detected by monitoring the predetermined bit G of this tone detector. Here, the bit F is a bit that controls which of a plurality (two types) of filter amplifier values is selected, and
Controlled by. (Claims 8 and 9) FIG. 7 is a flow chart for explaining the operations of the plural energy threshold value setting means and the energy threshold value selecting means of the tone detector used in the tone detector of the second embodiment. Is. All of these operations are processed by the CPU in the system control unit 7.

The CPU sets various coefficients necessary for tone detection. At that time, the filter amplifier value for the frequency to be detected is set in the tone detector (S401). Subsequently, in step S402, it is determined whether or not the device itself is transmitting a signal (tone). If the signal is not transmitting, the flag of the predetermined bit H of the tone detector is set to "0" (S404). ), The energy threshold for detection determination is set to E11. When a signal is being sent, the flag of the predetermined bit H of the tone detector is set to "1" (S403), and the energy threshold for detection determination is set to E12.

The tone detector sets a predetermined bit G (detection bit) to "1" by detecting the signal.
The CPU determines whether or not a signal is detected by monitoring the predetermined bit G of this tone detector. In this way, the filter amplifier value or the energy threshold value is switched depending on whether the device itself is transmitting a signal or not. This setting value switching operation is controlled by bit operation of the CPU in the system control unit 7.

[0033]

According to the first aspect of the present invention, the amplifier value setting means sets the amplifier value of the filter of the modem used for tone detection in accordance with the AGC amplifier value output from the modem. Even if the level of the wraparound signal sent from is high, the tone can be detected (regardless of the signal level) even if the signal sent from the sending facsimile is at a low level.

According to the invention of claim 2, the AGC amplifier value set by the amplifier value setting means of claim 1 is calculated from the predetermined coefficient and the AGC amplifier value by using the amplifier value calculating means. Therefore, it is possible to set the optimum amplifier value for tone detection of the signal transmitted from the facsimile on the transmission side according to the level of the wraparound signal transmitted from the own device.

According to the third aspect of the invention, the AG output from the modem by the energy threshold setting means.
Since the energy threshold of the tone detection filter output that determines detection or non-detection is set according to the C amplifier value, even if the level of the wraparound signal transmitted from the own device is large,
It is possible to detect the tone even if the signal sent from the transmitting facsimile has a low level (regardless of the signal level).

According to the invention described in claim 4, the energy threshold value set by the energy threshold value setting means in claim 3 is calculated from the predetermined coefficient and the AGC amplifier value by using the energy threshold value calculating means. So
It is possible to set the optimum energy threshold for tone detection of the signal transmitted from the facsimile on the transmission side according to the level of the wraparound signal transmitted from the own device.

According to the invention described in claim 5, the coefficient used in the calculation by the amplifier value calculation means and the energy threshold value calculation means according to claims 2 and 4 is stored in the storage means (RAM), and the coefficient setting means. By using, the coefficient corresponding to the tone detection filter configuration of the modem is read out and set, so that the optimum filter amplifier value and energy threshold value for tone detection of the signal sent from the transmitting facsimile can be set.

Further, according to the invention of claim 6, instead of the amplifier value setting means of claim 1, a plurality of coefficient value setting means capable of setting a plurality of coefficients corresponding to the filter amplifier value is used. Thus, it is possible to configure a filter by setting a plurality of filter amplifier values according to the frequency desired to be detected. That is, it is possible to set the amplifier value when the signal is sent from the device itself and when the signal is not sent, and it is calculated from the filter by switching the filter amplifier value according to the sending situation of the signal from the device itself. Since the energy value can be set to a predetermined value, even if the level of the sneak-in signal sent from the device itself is high, even if the signal sent from the sending facsimile is at a low level ( Tone detection can be performed (regardless of).

According to the invention described in claim 7, the filter amplifier value set by the plural coefficient value setting means according to claim 6 is used to select the amplifier value used for energy calculation by using the amplifier value selecting means. Since the detection can be selected by the bit operation from the CPU according to the desired frequency, it becomes easy to switch a plurality of filter amplifier values, and the load on the switching process is reduced.

According to the invention described in claim 8, detection is desired by using a plurality of energy threshold value setting means capable of setting a plurality of energy threshold values instead of the energy threshold value setting means according to claim 3. A filter can be configured by setting a plurality of energy thresholds according to the frequency to be set. That is, it is possible to set the energy threshold when the signal is sent from the device itself and when the signal is not sent, and it is possible to switch the energy threshold according to the sending situation of the signal from the device, so that the filter Even if the calculated energy value is small, the tone can be detected.

Further, according to the invention described in claim 9, by using the energy threshold value selecting means for the energy threshold value set by the plural energy threshold value setting means according to claim 8, the energy threshold value used for energy calculation is Since the detection can be selected by the bit operation from the CPU according to the desired frequency, switching of a plurality of energy threshold values becomes easy, and the load on the switching process is reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a facsimile apparatus of the present invention.

FIG. 2 is a filter configuration diagram showing a first embodiment of the tone detector applied to the facsimile apparatus of the present invention.

FIG. 3 is a flowchart showing a filter amplifier value setting procedure of the tone detector of the first embodiment applied to the facsimile apparatus of the present invention.

FIG. 4 is a flowchart showing an energy threshold setting procedure of the tone detector of the first embodiment applied to the facsimile apparatus of the present invention.

FIG. 5 is a filter configuration diagram showing a second embodiment of the tone detector applied to the facsimile apparatus of the present invention.

FIG. 6 is a flowchart showing a filter amplifier value setting procedure of the tone detector of the second embodiment applied to the facsimile apparatus of the present invention.

FIG. 7 is a flowchart showing an energy threshold setting procedure of the tone detector of the second embodiment applied to the facsimile apparatus of the present invention.

[Explanation of symbols]

1 scanner 2 plotters 3 Encoding and decoding unit 4 modem 5 Network control device 6 Operation display section 7 System control unit 8 system bus 9 telephones 10 Facsimile machine 11, 21 Filter 1 12, 22 Filter 2 13, 23 Energy averaging filter 14, 24 threshold comparator 20, 30 tone detector

Continuation of front page (56) Reference JP-A-3-253150 (JP, A) JP-A-63-15551 (JP, A) JP-A-3-3525 (JP, A) JP-A-62-82880 (JP , A) JP 3-32150 (JP, A) JP 3-237808 (JP, A) JP 57-109412 (JP, A) JP 60-114008 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H04N 1/32-1/36 H04N 1/42-1/44 H03H 17/00 611

Claims (9)

(57) [Claims] 1. In a facsimile machine in which a filter coefficient is set in a filter of a modem and a tone is detected by an energy value of the filter output, the facsimile machine is used for tone detection according to an AGC (automatic gain control) amplifier value output from the modem. A facsimile apparatus comprising an amplifier value setting means for setting an amplifier value of the filter. 2. A facsimile apparatus according to claim 1, further comprising an amplifier value calculating means for calculating a filter amplifier value set according to the AGC amplifier value by calculation based on the AGC amplifier value. . 3. In a facsimile apparatus which sets a filter coefficient in a filter of a modem and performs tone detection based on an energy value of the filter output, tone detection for determining detection / non-detection according to an AGC amplifier value output from the modem. A facsimile apparatus having an energy threshold setting means for setting an energy threshold of a filter output. 4. A facsimile apparatus according to claim 3, further comprising an energy threshold value calculating means for calculating an energy threshold value set according to the AGC amplifier value by calculation based on the AGC amplifier value. 5. A coefficient setting means for storing a coefficient used in a calculation formula of a filter amplifier value and an energy threshold value calculated according to the AGC amplifier value in a storage means and setting the coefficient by a tone detection filter configuration of a modem. 5. The facsimile machine according to claim 2, which has the facsimile machine. 6. A tone detector comprising a filter having a coefficient set according to a desired frequency to be detected, and a tone detector for detecting the desired single frequency according to the magnitude of energy calculated from the filter, A facsimile machine comprising a plurality of coefficient setting means capable of setting a plurality of the coefficients corresponding to the amplifier value of the filter. 7. The tone detector according to claim 6, further comprising an amplifier value selecting means for selecting a setting value used for energy calculation among the plurality of set coefficients by bit operation. Facsimile machine. 8. A tone detector comprising a filter configured by a coefficient set according to a desired frequency to be detected, and a tone detector for detecting a single frequency according to the magnitude of energy calculated from the filter. A facsimile apparatus having a plurality of energy threshold value setting means capable of setting a plurality of energy threshold values for determining the 9. The tone detector according to claim 8, further comprising energy threshold value selecting means for selecting a setting value used for energy calculation among the plurality of energy threshold values set by bit operation. Fax machine.