JPH01204555A - Tone signal detector - Google Patents

Abstract

PURPOSE:To detect a busy tone by using a software counter so as to count the state of overflow of a hardware counter and confirming number of ON-time and OFF-time for a prescribed number of times while confirming the count of a repetitive tone within a prescribed time. CONSTITUTION:A signal supplied from an exchange via line terminals L1, L2 is picked up by a tone pickup circuit 2, fed to a waveform shaping circuit 4 via an amplifier circuit 3, where the shaped signal is counted by a pulse counter 5 and fed to an input port or a CPU. A cycle (software) counter counted up by the initial overflow output at the ON-time of a pulse counter 5 within the specification of a reference timer is provided in addition to the pulse counter 5 and the count of the software counter is monitored. When the frequency of signal is correct, the ON-time and the OFF-time are counted respectively and when the count reaches a prescribed value, the signal is detected. Thus, even an intermittent signal such as a busy tone can be detected.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a tone signal detection device for detecting intermittent signals of a constant frequency, such as detecting signals sent from an exchange on a telephone side. It is.

[Conventional technology]

In recent years, a device has been proposed that automatically dials and sends necessary information by setting a certain degree. The device first checks the dial tone and, after all calls have been made, transmits information if the other party is not busy.

[Problem to be solved by the invention]

However, although it is necessary for such a device to check various tones, there is no suitable means for detecting intermittent signals such as visit tones.

[Means to solve the problem]

In order to solve such problems, the present invention uses a pulse counter that counts waveform-shaped pulses of a tone signal up to a certain value, and a count-up method that uses the first overflow output when the pulse counter is on within the standard value of the reference timer. A cycle counter is provided to monitor the count of the cycle counter.

[Effect]

When the frequency of the signal is correct, the on-time and off-time are each counted, and when the count reaches a predetermined value, the signal is detected.

〔Example〕

FIG. 2 is a block diagram of the invention applied to a main device such as a button telephone. In the figure, a transmitter (microphone) provided in a telephone call circuit 1 is configured to be short-circuited and open-circuited by a control signal supplied from an output port of a CPU (not shown), and when it is open, a telephone call is possible. .

A signal supplied from an exchange (not shown) via a line terminal LIrL2 is picked up by a tone pickup circuit 2, and is supplied to a waveform shaping circuit 4 via an amplifier circuit 3, where the shaped signal is sent to a pulse counting circuit 5.
is counted and supplied to the CPU's input port. This pulse count circuit 5 is reset in response to a reset signal supplied from the output port of the CPU, and tone detection is performed as shown in FIG. 1 using the count value until the pulse count circuit 5 is reset.

After the start in FIG. 4, as shown in step 100, all counters such as the time counter, on-time counter, off-time counter, and (on, off) cycle counter are reset and set to the initial state.
Set the transmitter (T) in the communication circuit to the open state. Thereafter, the pulse counter 5 is reset as shown in step 101. Since the telephone is normally in a standby state, the operation in the standby state will be explained first.

Since no tone signal is supplied in the standby state, the pulse count circuit 5 does not count, and sends out a signal at the CPU input port "L" level.

Therefore, the pulse countover in step 102 is
"NO", the time count is incremented by 1 in step 103, and step 1
At 04, it is determined whether the time count has exceeded. Since this is the first processing, the determination is NOJ and the process returns to step 102. And the flow starts from step 102
104 is cycled, so step 104 eventually becomes "YE".
It is determined to be SJ. Then, in step 105,
The time count that expired earlier is added to the off time and set as a new off time, but the off time at this point has not been detected, so let's start first.

The overtime time count is registered as off time in the Wr regulation. After registration, it is determined in step 106 whether the off-time has exceeded, but at this point it is determined that step 8 is rNOJ, and in step 107 it is determined whether or not it is the first time-over when the on-time changes to the off-time. , it is determined that the current condition is rNOJ, and the flow returns to step 101.

Since no tone signal is received during the waiting period, the flow continues to cycle through steps 101 to 107, and eventually the off time of step 105 exceeds the specified off time.
It is determined that the off time has exceeded in step 106, and the flow returns to step 100.The above operation is then repeated during the waiting period.

When a tone signal is eventually received, the pulse count circuit 5 starts counting. FIG. 3 is a diagram showing signal waveforms. FIG. 3(a) is the picked-up tone signal, FIG. 3(b) is the waveform-shaped signal, and FIG. 3(c) is the output of the pulse count circuit 5. , FIG. 3(d) shows a reset signal supplied to the pulse count circuit 5. Since the above-mentioned time count over is set to the period T1 in (c), when the tone signal is being picked up, a time count over state occurs at the period TI as shown in (e). In addition, since the count-over of the pulse count circuit 5 is set to be shorter than this period T1, the pulse counter over-time at step 102 is determined to be YES J before the time count-over at step 104 is determined to be YES J. Then, it is determined in step 109 that the time count is within the standard.

Here, we count the time from resetting the pulse counter until it reaches count over.
You can check the frequency of the tone. Judgment is made by determining whether or not the time count to be checked is within the standard value range, and if it is too long or too short, it will be determined as rNOJ, and if it is only within the standard value range, it will be determined as YES J. It has become.

If it is determined in step 109 that the time count is within the standard (YESJ), as shown in step 110, the on-time plus the time count is set as the new on-time. At this point, since the process of step 110 is performed first after being reset, the added on-time is zero, so the time count value becomes the it-on time. Then, in step 111, it is determined that the on-time has expired.

Next, in step 112, it is determined whether or not it is the time of the first pulse countover when the off-time changes to the on-time.
It is checked whether the off-time is within the standard, that is, whether the off-state time is within the standard, but since the off-time was previously determined to be over in step 106, the determination in step 113 is "NO". and the flow returns to step 100. During the on-time, the tone signal is continuously supplied and the above-described operation is repeated, but each time it is determined as rNOJ in step 113.

When the on-time ends and the off-time arrives, the time count is not over in step 104 as described above, and the time count is added in step 105, and a new off-time is registered. and step 1
In step 06, it is determined that the off time has exceeded, and in step 107, it is determined whether or not this is the first time over when the on time changes to the off time. r
It is determined as YES J, and the on-time standard in step 108 is determined to be 1'-YF3 J, and the flow returns to step 102. However, in the previous on-time, when the tone signal was sent out midway, the on-time is not within the regular standard, so the determination in step 108 is NO. Further, the determination in step 108 becomes l'-No J only after the signal is normally supplied. Then, perform the above operations in steps 102 to 107, or
This time, step 107 satisfies the condition, so rNOJ
It is determined that Therefore, the flow cycles through steps 101-107 during the off-time, each time at step 105.
Off time is updated.

When off time ends, it changes to on time, step 1
The pulse count of 02 is over and the time count of step 109 is within the standard! When it is determined that DrYEsJ, the on-time is added in step 110, the on-time over in step 111 is determined to be "NO", and the first over 70- from off to on in step 112 is determined to be "YES J," Step 113 Even within the off-time standard, it is judged as “YESJ” and step 1
At step 14, the cycle counter increments by one count, at step 115 it is determined as "YES J," and at step 116 the transmitter is shorted (
(to prevent malfunction), the flow returns to step 101.

When the flow reaches step 112 again, this time it is not the first overflow, so the conditions for this step are not met, and the flow returns to step 101. Therefore, during on-time, the flow is at step 1 of this route.
01, 102, 109, 110, 111, and 112, and the on-time is updated each time.

When the on-time ends, the above-described off-time operation and on-time operation are repeated, and the cycle counter counts up the combination of the on-time and off-time as one cycle.

When the on-time and off-time are repeated a predetermined number of times, the cycle counter eventually overflows, so that JYESJ is determined in step 117, and the detection of the visit tone ends as shown in step 118.

Here, the off time and on time are added until the cycle counter counts over, but in step 1
The time for determining off-time over in step 06 and the time for determining on-time over in step 111 are set longer than the cumulative on-time and cumulative off-time until the cycle counter exceeds, so during normal operation, If the off-time in step 106 is over or the on-time is over in step 111, it will not be determined as [YESJ].

When a visit tone is detected as described above, there is no point in continuing the line connection process any further, so all you have to do is stop the call and release the line, and if necessary, emit data again after a predetermined period of time. Good.

In addition, although the above embodiment described the visit tone,
The invention is not limited to this, and may be used for any detection of intermittent tones, such as ringback tones.

〔Effect of the invention〕

As explained above, in this invention, the hardware counter is only a counter that counts tone signals up to a certain value,
The state of over 70- on the counter is counted by a counter, and the number of on-time and off-time is checked a predetermined number of times while checking the count number within a predetermined time of the repeated tone. Since it is possible to detect various frequencies simply by switching the time-related settings of the soft timer, it has the effect of being able to economically support the detection of many types of tones.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing an embodiment of the present invention, FIG. 2 is a block diagram showing an example of a device to which the invention is applied, and FIG. 3 is a waveform diagram of each part. 1... Call circuit, 2... Tone pickup circuit, 3... Amplification circuit, 4... Waveform shaping circuit, 5
...Pulse count circuit. To patent issue Tamura Electric Manufacturing Co., Ltd.

Claims (5)

[Claims] (1) In a tone signal detection device that detects a tone signal with a constant frequency and a constant intermittent cycle consisting of on time and off time, there is a reference timer that operates repeatedly, and a waveform shaping pulse of the tone signal that is linked to this reference timer. A pulse counter that counts up to a certain value, a cycle counter that counts up by the first overflow output of the pulse counter within the on-time within the standard value of the reference timer, and a cycle counter that counts up when the overflow output is the second or more time during the on-time. A tone signal detection device comprising: a reset means for resetting a pulse counter when the cycle counter reaches a certain value; and a determination means for transmitting a tone signal detection output when the cycle counter reaches a certain value. (2) In the tone signal detection device according to claim 1, means for determining the total value at the on-time point based on the overflow output of the pulse counter, and comparison means for comparing the total value with a predetermined on-time value. A tone signal detection device comprising: (3) In the tone signal detection device according to claim 1, means for determining the total value at the off time based on the overflow output of the reference timer, and means for comparing the total value with a value at a predetermined off time. A tone signal detection device comprising: (4) The tone signal detection device according to claim 1, further comprising determining means for determining whether or not the immediately preceding off time is within the standard when the pulse counter outputs the first overflow during the on time. Tone signal detection device. (5) The tone signal detection device according to claim 3, further comprising determining means for determining whether or not the immediately preceding on-time is within the standard when the first overflow output occurs during the off-time of the reference timer. Tone signal detection device.