JPH10136147A - Facsimile equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the detection accuracy by passing only a signal for a frequency band of an object tone signal and discriminating it to be detection of the signal when the energy level of the passing signal is a prescribed level or over and a detected frequency is within a prescribed range. SOLUTION: When an energy level detection section 24 outputs a tone detection signal ST, a frequency counter 25 starts the operation to input a detection frequency signal SK. Whether the detected frequency is higher than a lower bound of a specified frequency band or lower than an upper bound is checked, and when the detection of frequency is judged as a result, the operation of a voice reply device is stopped to start facsimile reception processing. Through the constitution above, when the detected frequency is within a prescribed range, the mis-detection is suppressed with high detection accuracy by deciding the detection of the object tone signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a facsimile apparatus connected to a public telephone network and having a function of detecting a tone signal of a predetermined signal level in a predetermined frequency band received from the public telephone network.

[0002]

2. Description of the Related Art Generally, a group 3 facsimile apparatus is connected to a public telephone network and has a function of detecting various tone signals received from the public telephone network. For example,
It has a function of detecting a dial tone received immediately after off-hook at the time of calling, a ringing tone detected at the time of incoming call, and various tone signals exchanged in the group 3 facsimile transmission procedure.

[0003] Such group 3 facsimile apparatuses often share the same telephone line with a telephone.
In such a case, immediately after the incoming call is detected and the incoming call is answered, it cannot be determined whether the calling terminal is a telephone or a facsimile machine. For example, "This is a facsimile machine. , Please press the start key. If you are talking, please wait for a while. " .

In this case, if the destination terminal (calling terminal) is a telephone or a facsimile apparatus operated by a human, an appropriate operation is performed after listening to the facsimile automatic switching voice message. When the other terminal is a facsimile apparatus having an automatic transmission function, when it detects that the incoming call has been answered, it starts an automatic transmission operation and sends out a predetermined tone signal CNG. When CNG is detected, the operation at the time of incoming call is started.

[0005]

However, such a conventional apparatus is, for example, a facsimile apparatus having an automatic transmission function as described above, and is prepared in a case where a tone signal CNG is transmitted. In this case, the function of the tone detecting means for detecting the tone signal CNG is enabled. However, since the transmission of the facsimile automatic switching voice message of the own terminal has not been completed in the short time, the received signal has the facsimile automatic switching voice message. If the voice signal of the message wraps around and the wraparound voice signal contains a signal in the frequency band of the tone signal CNG, the voice signal may be erroneously detected as the tone signal CNG. there were.

Further, since the frequency band and the signal level of tone signals such as dial tones are different in European countries, a facsimile apparatus to be shipped to European countries has a tone detecting circuit corresponding to each tone signal. And the cost of the apparatus increases.

The present invention has been made in view of the above circumstances, and has as its object to provide a facsimile apparatus which has good tone signal accuracy and can detect a plurality of tone signals.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a facsimile apparatus connected to a public telephone network and having a function of detecting a tone signal of a predetermined signal level in a predetermined frequency band received from the public telephone network. A first detection unit that outputs only a signal in a frequency band of a target tone signal among signals received from a network and outputs a first detection signal when an energy level of the passed signal is equal to or higher than a predetermined value; Means, a received signal from the public telephone network is binarized at a predetermined threshold level, the frequency of the binarized signal is detected, and the detected frequency is set in a frequency range corresponding to the frequency band of the target tone signal. A second detection signal for outputting a second detection signal, the first detection signal being output from the first detection means, and a second detection signal being output from the second detection means. When the detection signal is output is obtained so as to determine that it has detected the object tone signal.

Further, in a facsimile apparatus connected to a public telephone network and having a function of detecting a tone signal of a predetermined signal level in a predetermined frequency band received from the public telephone network, the facsimile apparatus includes: Only the signal in the frequency band of the target tone signal is passed, and when the energy level of the passed signal is equal to or higher than a predetermined value, the detection means for outputting a detection signal is provided. If a detection signal is output from the detection means during a period in which the terminal itself is not transmitting, it is determined that the target tone signal has been detected.

In a facsimile apparatus connected to a public telephone network and having a function of detecting a tone signal of a predetermined signal level in a predetermined frequency band received from the public telephone network, the facsimile apparatus includes: First detection means for passing only a signal in the frequency band of the target tone signal and outputting a first detection signal when the energy level of the passed signal is equal to or higher than a predetermined reference value, and a public telephone network From the received signal from a predetermined threshold level, and detects the frequency of the binarized signal.If the detected frequency is included in a frequency range corresponding to the frequency band of the target tone signal, A second detection signal that outputs a second detection signal, and sets a reference value of the first detection device according to the type of the target tone signal, First detection signal is outputted from the detection means, and, when the second detection signal from said second detecting means is output, is obtained so as to determine that it has detected the object tone signal.

In a facsimile apparatus connected to a public telephone network and having a function of detecting a tone signal of a predetermined signal level in a predetermined frequency band received from the public telephone network, the facsimile apparatus includes: First detection means for passing only a signal in the frequency band of the target tone signal and outputting a first detection signal when the energy level of the passed signal is equal to or higher than a predetermined reference value, and a public telephone network From the received signal from a predetermined threshold level, and detects the frequency of the binarized signal.If the detected frequency is included in a frequency range corresponding to the frequency band of the target tone signal, Second detection means for outputting a second detection signal, a value of a reference value of the first detection means, and a value of the first detection means according to the type of the target tone signal. When the pass frequency band is set and the first detection signal is output from the first detection means and the second detection signal is output from the second detection means, the target tone signal is detected. That is, it is determined that the operation has been performed.

Further, a plurality of types of target tone signals can be applied to the target tone signal. Further, the first detecting means can be configured by using a component of a demodulation unit of a group 3 facsimile modem device which realizes a modulation / demodulation function for data transmission.

[0013]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
An embodiment of the present invention will be described in detail.

FIG. 1 shows a group 3 facsimile apparatus according to an embodiment of the present invention.

In FIG. 1, a system control unit 1 performs various control processes such as a control process of each unit of the group 3 facsimile apparatus and a facsimile transmission control procedure process. The control processing program to be executed by the unit 1 and various data necessary for executing the control processing program are stored, and a work area of the system control unit 1 is configured. This is for storing various information unique to the group 3 facsimile apparatus. The clock circuit 4 outputs current time information.

The scanner 5 is for reading an original image at a predetermined resolution, the plotter 6 is for recording and outputting an image at a predetermined resolution, and the operation display unit 7 is a group 3 facsimile machine. It is used for operating the device, and includes various operation keys and various display devices.

The encoding / decoding unit 8 encodes and compresses the image signal and decodes the encoded and compressed image information into the original image signal.
This is for storing a large number of image information in a coded and compressed state.

The network control device 10 is for connecting the group 3 facsimile apparatus to a public telephone line network and has an automatic transmission / reception function.

The communication analog processing unit 11 is a network controller 1
It intervenes between the input / output of the terminal 0 and the input / output of the line of the group 3 facsimile modem 12 to execute various analog processing.

The group 3 facsimile modem 12 is for realizing a group 3 facsimile modem function. The group 3 facsimile modem 12 has a low-speed modem function (V.21 modem) for exchanging transmission procedure signals and mainly exchanges image information. High-speed modem function (V.17 modem,
V. 34 modem, V.34. 29 modem, V.29. 27ter modem etc.).

The tone detecting section 13 receives various tone signals received from the public telephone line network, for example, a tone signal CNG which is a calling signal in a group 3 facsimile transmission procedure.
And a dial tone.

The voice response device 14 includes various types of facsimile automatic switching voice messages such as "This is a facsimile device. Press the start key to send a facsimile. Please wait for a call." Is output as a response.

The control unit 1, the system memory 2,
Parameter memory 3, clock circuit 4, scanner 5, plotter 6, operation display unit 7, encoding / decoding unit 8, image storage device 9, network control device 10, group 3 facsimile modem 1
1, the tone detection unit 13 and the voice response device 14
It is connected to the internal bus 15, and data exchange between these elements is mainly performed through the internal bus 15.

Data exchange between the network controller 10 and the group 3 facsimile modem 12 is performed via the communication analog processor 11.
Signal exchange between 0, the tone detection unit 13 and the voice response device 14 is also performed via the communication analog processing unit 11.

FIG. 2 shows an example of the tone detector 13.

In FIG. 1, a received signal SR input from the communication analog processing section 11 is
And a signal binarization processing unit 22. The band-pass filter 21 outputs a target tone signal to be detected,
For example, it is for passing a signal in the frequency band of the tone signal CNG. In this case, since the frequency of the tone signal CNG which is the target tone signal is 1100 Hz, the pass frequency band of the band-pass filter 21 is 11 Hz.
It is good to set to 00 ± 100Hz.

Output signal SF of band pass filter 21
Are added to the energy averaging filter unit 23. The energy averaging filter unit 23 averages the signal energy of the input signal SF, and the output signal SFm is applied to the energy level comparison unit 24.

The energy level comparing section 24 compares the input signal SFm with a predetermined reference value, and outputs a tone detection signal ST when the signal SFm is larger than the reference value. Here, for example, assuming that the desired detection level of the target tone signal is -43 dBm, the reference value is:
A margin is preferably set to -45 dBm.

The signal binarization processing section 22 binarizes the input received signal SR at a predetermined threshold level TS (see FIGS. 3 (a) and 3 (b)). SS is added to the frequency counter unit 25.

The frequency counter 25 receives the binary signal SS
Of the rising edge (Ta in FIG. 3 (b)) or the falling edge interval (Tb in FIG. 3 (b)) to detect the repetition frequency of the corresponding binarized signal SS. The detection frequency signal SK is output to the next-stage device (for example, the system control unit 1).

With the above configuration, when the system control unit 1 detects an incoming call and responds to the incoming call, it causes the voice response unit 14 to transmit a facsimile automatic switching voice message.
An operation for detecting the tone signal CNG is performed in preparation for a case where the partner terminal is a facsimile machine.

FIG. 4 shows an example of the process of detecting the tone signal CNG.

First, it is monitored that the tone detection signal ST is output from the energy level detecting section 24 (decision 10).
1) When the result of the determination 101 is YES, the operation of the frequency counter 25 is started (process 102), and the detected frequency signal SK is input (process 103).

Then, it is checked whether or not the detected value is larger than the lower limit F1 of the prescribed frequency band and smaller than the upper limit F2 (decisions 104 and 105), and the result of the decision 105 is YES. If it is, it is determined that the target tone signal (in this case, the tone signal CNG) has been detected (step 106). If the result of determination 104 or 105 is NO, it is determined that the target tone signal could not be detected. (Process 107).

If it is determined that the tone signal CNG has been detected, the operation of the voice response device 14 is stopped, and
When the group 3 facsimile reception process is started and it is determined that the tone signal CNG has not been detected, a predetermined incoming call process is executed after the message transmission of the voice response device 14 ends.

As described above, in the present embodiment, the condition for detecting and judging the target tone signal is such that the reception level of the signal in the frequency band of the target tone signal is larger than a predetermined value and the received signal at that time. When the detection frequency is included in the predetermined range ", the detection accuracy of the target tone signal is high, and the erroneous detection can be greatly suppressed.

In the above-described embodiment, when an incoming call is answered, the voice response device 14 transmits a facsimile automatic switching voice message. However, when such a voice message is not transmitted, the target tone signal is not transmitted. Since there is almost no disturbance signal other than white noise in the frequency band, it can be determined that the tone signal CNG has been detected on condition that the tone detection signal ST is output.

FIG. 5 shows an example of the configuration of the tone detector 13 for detecting a dial tone. 2, the same reference numerals are given to the same parts as those in FIG. 2 and the corresponding parts.

In FIG. 3, a reception signal SR input from the communication analog processing section 11 is
And a signal binarization processing unit 22. The band-pass filter 21 is for passing a signal in a frequency band of a dial tone, which is a target tone signal to be detected in this case. In this case, for example, in Italy, the detection frequency is 41
At 0-440 Hz, the non-detection frequency is less than 350 Hz, and greater than 550 Hz. In Portugal, the detection frequency is 300 to 450 Hz and the non-detection frequency is 160
Hz. Therefore, in this case, the pass frequency band of the band-pass filter 21 of the band-pass filter 21 is preferably set to about 250 to 600 Hz.

Output signal SF of band pass filter 21
Are added to the energy averaging filter unit 23. The energy averaging filter unit 23 averages the signal energy of the input signal SF, and the output signal SFm is applied to the energy level comparison unit 27.

The threshold setting section 28 stores a threshold value TT which defines a detection level of a target tone signal (in this case, a dial tone). The stored threshold value TT is used as an energy level comparing section 27.
Is added to Here, for example, in Belgium, the detection level is set to -3 to 20 dBm and the non-detection level is set to less than -28 dBm, and in Spain, the detection level is set to 0 to -35 dBm and the non-detection level is set to -45 dBm. Therefore, appropriate values may be set according to the detection level range and the non-detection level range.

The energy level comparing section 27 compares the input signal SFm with a threshold value TT added from the threshold setting section 28, and determines whether the signal SFm has a threshold value T.
If it is larger than T, a tone detection signal ST is output.

The signal binarization processing section 22 binarizes the input received signal SR at a predetermined threshold level TS, and the output binary signal SS is applied to the frequency counter section 25. . Here, the threshold level TS in this case is preferably set to a value smaller than the minimum value set in the threshold setting unit 28.

The frequency counter 25 receives the binarized signal SS
, The repetition frequency of the corresponding binarized signal SS is detected by measuring the time of the interval between the rising edge and the interval between the falling edges, and the detected frequency signal SK is used as the next-stage device (for example, system control). Section 1).

With the above configuration, when detecting the dial tone, the system control unit 1 executes the processing shown in FIG.

First, the threshold value TT of the value corresponding to the detection level range and the non-detection level range of the dial tone as the target tone signal is stored in the threshold setting unit 28 of the tone detection unit 13 (processing 201), and the energy level is determined. It is monitored that the tone detection signal ST is output from the detection unit 24 (decision 202), and if the result of the decision 202 is YES, the operation of the frequency counter 25 is started (processing 2).
03), and input the detection frequency signal SK (Process 20)
4).

Then, it is checked whether or not the detected value is larger than the lower limit value F1 of the prescribed frequency band and smaller than the upper limit value F2 (decisions 205 and 206), and the result of the decision 206 is YES. When it is determined that the target tone signal (the dial tone in this case) has been detected (process 207), and when the result of the determination 205 or 206 is NO, it is determined that the target tone signal could not be detected ( Process 208).

When it is determined that a dial tone has been detected, the processing shifts to a processing operation corresponding to the event. When it is determined that a dial tone cannot be detected, a processing operation corresponding to the event occurs. Move to

FIG. 7 shows a tone detector 13 according to still another embodiment of the present invention. Note that the same reference numerals as in FIGS. 2 and 5 denote the same or corresponding parts in FIG.

In the figure, a received signal SR input from a communication analog processing section 11 is applied to a programmable bandpass filter 30 and a signal binarization processing section 22. The programmable bandpass filter 30 is for passing a signal in the frequency band of the target tone signal to be detected, and the passband can be appropriately set by a frequency setting signal FF externally applied. it can. For example, when the target tone signal is a dial tone, the pass frequency band is 250-600.
Hz, and when the target tone signal is the tone signal CNG, the pass frequency band is set to 1000 to 12
Set to 00 Hz.

The output signal SF of the programmable bandpass filter 30 is applied to the energy averaging filter unit 23. The energy averaging filter unit 23 averages the signal energy of the input signal SF, and outputs the output signal SFm to the energy level comparison unit 2.
7 has been added.

The threshold setting section 28 stores a threshold value TT defining the detection level of the target tone signal. The stored threshold value TT is applied to the energy level comparing section 27. Where, for example,
When the target tone signal is a dial tone, an appropriate value may be set according to the detection level range and the non-detection level range of the dial tone as in the above-described embodiment. Further, when the target tone signal is the tone signal CNG, the threshold value TT may be set to -45 dBm.

The energy level comparing section 27 compares the input signal SFm with a threshold value TT added from the threshold setting section 28, and determines whether the signal SFm has a threshold value T.
If it is larger than T, a tone detection signal ST is output.

The signal binarization processing section 22 binarizes the input received signal SR at a predetermined threshold level TS, and the output binarized signal SS is applied to the frequency counter section 25. . Here, the threshold level TS in this case is preferably set to a value smaller than the minimum value set in the threshold setting unit 28.

The frequency counter 25 receives the binarized signal SS
, The repetition frequency of the corresponding binarized signal SS is detected by measuring the time of the interval between the rising edge and the interval between the falling edges, and the detected frequency signal SK is used as the next-stage device (for example, system control). Section 1).

With the above configuration, when detecting the tone signal, the system control unit 1 executes the processing shown in FIG.

First, a threshold value TT of a value corresponding to the target tone signal is set in the threshold setting unit 2 of the tone detection unit 13.
8 (process 301), and a frequency signal FF corresponding to the target tone signal is added to the programmable bandpass filter 30 (process 302), so that the circuit state is adapted to the detection of the target tone signal.

In this state, the energy level detector 24
Is monitored (step 303). If the result of the determination 303 is YES, the operation of the frequency counter 25 is started (step 304), and the detected frequency signal SK is input (step 304). 305).

Then, it is checked whether or not the detected value is larger than the lower limit value F1 of the prescribed frequency band and smaller than the upper limit value F2 (decisions 306 and 307), and the result of the decision 307 is YES. When it is determined that the target tone signal has been detected (step 308),
Alternatively, if the result of determination 307 is NO, it is determined that the target tone signal could not be detected (process 30).
9).

When it is determined that the target tone signal has been detected, the processing shifts to a processing operation corresponding to the event. When it is determined that the target tone signal cannot be detected, the processing corresponding to the event occurs. Move to processing operation.

Now, the group 3 facsimile modem 12
Means for determining the level of a signal in the frequency band of the transmission signal to be detected at that time on the input side of the reception signal so that the transmission signal exchanged in the group 3 facsimile transmission procedure can be appropriately detected; Usually equipped,
Therefore, such means can be shared as a part of the tone detection unit 13.

FIG. 9 shows an example of the configuration of the tone detector 13 in that case. In FIG. 2, FIG. 2, FIG.
The same parts as those in FIG. 7 and corresponding parts are denoted by the same reference numerals.

In the figure, a programmable bandpass filter 30, an energy averaging filter unit 23, an energy level comparing unit 27, and a threshold setting unit 2
Reference numeral 8 uses the circuit elements built in the group 3 facsimile modem 12 as they are.

Therefore, in this case, the independent tone detecting section 13 can be constituted by the signal binarizing processing section 22 and the frequency counter section 25, so that the tone detecting section 13 can be configured to be very small, Good tone detection can be achieved at a small additional cost.

In each of the embodiments described above, the case where the present invention is applied to a group 3 facsimile apparatus has been described. However, the present invention is similarly applied to other data transmission apparatuses having an equivalent group 3 facsimile communication function. Can be applied to

[0066]

As described above, according to the present invention,
The target tone signal detection determination condition is set to “when the reception level of the signal in the frequency band of the target tone signal is higher than a predetermined value, and the detection frequency of the reception signal at that time is included in a predetermined range”. Since the setting is made, there is an effect that the detection accuracy of the target tone signal is high and the erroneous detection can be largely suppressed.

If there is no disturbance signal for detecting the target tone signal, it is determined that the target tone signal has been detected if the reception level of the signal in the frequency band of the target tone signal is higher than a predetermined value. There is also obtained an effect that the target tone signal can be detected at low cost.

Further, since the comparison reference value of the reception level at the time of detecting the target tone signal can be made variable, there is also obtained an effect that a plurality of tone signals having different detection level prescribed values can be appropriately detected.

Further, since the pass frequency band of the received signal when detecting the target tone signal and the comparison reference value of the received level can be made variable, a plurality of tones having different specified values of the frequency band and the detected level can be obtained. An effect is also obtained that a signal can be accurately and appropriately detected.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating the configuration of a group 3 facsimile apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating an example of a tone detection unit.

FIG. 3 is a waveform chart for explaining operations of a binarization processing unit and a frequency counter.

FIG. 4 is a flowchart showing an example of a tone signal CNG detection process.

FIG. 5 is a block diagram showing another example of the tone detector.

FIG. 6 is a flowchart illustrating an example of dial tone detection processing.

FIG. 7 is a block diagram showing still another example of the tone detector.

FIG. 8 is a flowchart showing still another example of the tone signal detection processing.

FIG. 9 is a block diagram showing an example of a case where a tone detection unit is configured using circuit elements of a group 3 facsimile modem.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 System control part 2 System memory 10 Network controller 11 Communication analog processing part 12 Group 3 facsimile modem 13 Tone detection part 21 Band pass filter 22 Signal binarization processing part 23 Energy averaging filter part 24, 27 Energy level comparison part 28 Threshold setting unit 30 Programmable bandpass filter

Claims (6)

[Claims] 1. A facsimile apparatus connected to a public telephone network and having a function of detecting a tone signal of a predetermined signal level in a predetermined frequency band received from the public telephone network. First detection means for outputting only a signal in the frequency band of the target tone signal and outputting a first detection signal when the energy level of the passed signal is equal to or higher than a predetermined value; The received signal is binarized at a predetermined threshold level, the frequency of the binarized signal is detected, and if the detected frequency is included in a frequency range corresponding to the frequency band of the target tone signal, the second A second detection unit that outputs a detection signal; a first detection signal is output from the first detection unit; and a second detection signal is output from the second detection unit. A facsimile apparatus that determines that the target tone signal has been detected. 2. A facsimile apparatus connected to a public telephone network and having a function of detecting a tone signal of a predetermined signal level in a predetermined frequency band received from the public telephone network. A detection unit that outputs only a signal in the frequency band of the target tone signal and outputs a detection signal when the energy level of the passed signal is equal to or higher than a predetermined value. A facsimile apparatus characterized in that when a detection signal is output from the detection means during a period in which the terminal itself is not transmitting, it is determined that the target tone signal has been detected. 3. A facsimile apparatus connected to a public telephone network and having a function of detecting a tone signal of a predetermined signal level in a predetermined frequency band received from the public telephone network. First detection means for passing only a signal in the frequency band of the target tone signal and outputting a first detection signal when the energy level of the passed signal is equal to or higher than a predetermined reference value; From the received signal from a predetermined threshold level, and detects the frequency of the binarized signal.If the detected frequency is included in a frequency range corresponding to the frequency band of the target tone signal, A second detection means for outputting a second detection signal, wherein a reference value of the first detection means is set according to the type of the target tone signal, and the first detection means is provided. A facsimile apparatus characterized in that when the first detection signal is output from the output means and the second detection signal is output from the second detection means, it is determined that the target tone signal has been detected. 4. A facsimile apparatus connected to a public telephone network and having a function of detecting a tone signal of a predetermined signal level in a predetermined frequency band received from the public telephone network. First detection means for passing only a signal in the frequency band of the target tone signal and outputting a first detection signal when the energy level of the passed signal is equal to or higher than a predetermined reference value; From the received signal from a predetermined threshold level, and detects the frequency of the binarized signal.If the detected frequency is included in a frequency range corresponding to the frequency band of the target tone signal, A second detection means for outputting a second detection signal, wherein a value of a reference value of the first detection means and a communication value of the first detection means are provided in accordance with a type of the target tone signal. When the over frequency band is set and the first detection signal is output from the first detection means and the second detection signal is output from the second detection means, the target tone signal is detected. A facsimile machine characterized by determining that the facsimile has been performed. 5. The facsimile apparatus according to claim 3, wherein there are a plurality of types of said target tone signals. 6. The apparatus according to claim 1, wherein said first detecting means is constituted by using a component of a demodulation section of a group 3 facsimile modem apparatus which realizes a modulation / demodulation function for data transmission. The facsimile apparatus according to claim 2 or 4.