JPH0951557A - Tone detecting device and tone detecting method - Google Patents

Abstract

(57) [Abstract] (Correction) [PROBLEMS] To provide an apparatus and a method for tone detection that does not cause false detection as a tone signal regardless of the quality of voice input. SOLUTION: A voice pitch extracting means 3 for extracting a voice pitch component from a tone band signal and a third amplitude averaging means 4 for obtaining an average amplitude level of the extracted voice pitch signal.
Then, the pitch judgment means 5 for judging whether or not the averaged voice pitch level is higher than the threshold value, and the output of this output and the tone / out-of-band level comparison and judgment means 8 for judging whether or not it is a tone signal. The voice pitch component is extracted from the separated tone signal, the average amplitude level is obtained, the obtained voice pitch level is compared with a threshold value, and the tone signal level is determined. When the difference between the out-of-band signal levels exceeds the specified value, it is determined that the signal is a tone signal when the comparison result is less than or equal to the threshold value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the field of telecommunications, and more particularly to a technique for detecting a dial tone in telephone communication.

[0002]

2. Description of the Related Art As a conventional tone detecting device, for example, one having a structure shown in FIG. 6 is known. FIG. 6 is a block diagram showing the basic configuration of a conventional tone detecting device. 11 is tone band-pass filtering means, 12 is out-of-band filtering means, 16 and 17.
Is an amplitude averaging means, a tone / out-of-band level comparison / determination means, and 19 is a determination means.

Next, the operation of the apparatus having such a configuration will be described with reference to FIG. FIG. 7 is a flowchart showing the operation of the conventional device. First, when a data signal is input (S21), this data signal is input to the tone bandpass filtering means 11 and the out-of-band filtering means 12, respectively.
Separated into tone band signal and out-of-band signal (S2
2).

An average amplitude level of each of the separated tone band signal and out-of-band signal is obtained by the first and second amplitude averaging means 16 and 17 (S23).
The tone signal level and the out-of-band signal level obtained by the first and second amplitude averaging means 16 and 17 are compared by the tone / out-band level comparison / determination means 18 (S2).
4, S25), if the difference between the two is smaller than the specified value, it is judged as voice input (S26), and if it is larger than the specified value, it is judged as a tone signal, and the subsequent processing is performed. (S27).

[0005]

However, the human voice quality (mainly frequency band) varies, and depending on the voice quality, the difference between the tone signal level and the out-of-band signal level may exceed a specified value. In some cases, voice input may result in erroneous determination as tone detection.

The present invention has been made in view of the above circumstances, and an object of the invention is to provide a tone detecting device and a tone detecting method which will not erroneously detect a tone signal regardless of the quality of voice input. To provide.

[0007]

In order to solve the above problems, the present invention provides a tone band filtering means 1 for filtering a tone band signal and an average amplitude level of the tone band signal filtered by the tone band filtering means 1. A first amplitude averaging means 6 for obtaining, an out-of-band filtering means 2 for filtering signals other than the tone band signal, and a second for obtaining an average amplitude level of the out-of-band signal filtered by the out-of-band filtering means 2. The tone signal level obtained by the amplitude averaging means 7 and the first amplitude averaging means 6 is compared with the out-of-band signal level obtained by the second amplitude averaging means 7, and it is determined whether it is larger than a specified value. In a tone detection device having a tone / out-of-band level comparison / determination means 8 for determining whether or not, a voice pitch extraction means 3 for extracting a voice pitch component from the tone band signal and the voice Third amplitude averaging means 4 for obtaining the average amplitude level of the voice pitch signal extracted by the switch extracting means 3, and the voice pitch level averaged by the third amplitude averaging means 4 is greater than the threshold value. Pitch judgment means 5 for judging whether it is large, output of the pitch judgment means 5 and output 8 of the tone / out-of-band level comparison judgment means
From the above, an apparatus having a judging means 5 for judging whether or not it is a tone signal is used.

Alternatively, the tone band signal and the out-of-band signal are separated (S1), the respective average amplitude levels of both signals are obtained (S4), and the obtained tone signal level and the out-of-band signal level are compared ( S5) In the tone detection method of judging that the signal is a tone signal when it is equal to or more than the specified value (S6, S7), a voice pitch component is extracted from the separated tone signal (S3), and the obtained voice pitch signal is extracted. An average amplitude level is obtained (S4), the voice pitch level thus obtained is compared with a threshold value (S8), and the tone signal level is compared with the out-of-band signal level, and when the value exceeds a specified value, In addition, when it is less than this threshold value, it is determined as a tone signal (S9, S10, S11).

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram showing a basic configuration of a tone detecting device according to the present invention.
In the figure, 1 is tone band filtering means for filtering the frequency band of the tone signal, 2 is out-of-band filtering means for filtering the frequency band other than the tone signal band, and 6 is the tone signal filtered by the tone band filtering means 1. A first amplitude averaging means for averaging the amplitudes to obtain the value of the average level thereof, and 7 for averaging the signals other than the tone band filtered by the out-of-band filtering means 2 to obtain the value of the average level thereof. 2 amplitude averaging means, 8 compares the tone signal level and the out-of-band level which are the average values of the tone signal and tone out-of-band signal levels averaged by the first and second amplitude averaging means, It is a tone / out-of-band level comparison / determination means for determining whether or not it is larger than a prescribed value.

Reference numeral 3 is a voice pitch extracting means for extracting a voice pitch component from the tone signal filtered by the tone bandpass filtering means 1, and 4 is the voice pitch extracting means 3
The third amplitude averaging means 5 for obtaining the average level of the pitch signal obtained from the above, compares the averaged voice pitch level with a predetermined threshold value, and determines whether the voice pitch level is higher than the threshold value. Pitch judging means for judging whether or not, 9 is judged whether it is a voice input or a tone signal from the output of the judgment result of the tone / out-of-band level comparing and judging means and the pitch judging means and the output of the first amplitude averaging means 6. However, it is a judging means for judging the tone signal level and the subsequent processing.

Next, the main operation of the device having such a configuration will be described. In addition to the conventional device or method, the present invention is characterized in that a voice pitch component is extracted, the average level of the voice pitch signal is compared with a predetermined threshold value, and this is used as a judgment element for tone detection. Have. In this way, focusing on the existence of pitch in human voiced sound,
By detecting the pitch degree included in the input signal, the voice signal and the tone signal are distinguished.

FIG. 2 conceptually shows the operation of the tone signal extracting means 3, the third amplitude averaging means 4 and the pitch determining means 5 which are characteristic parts of the present invention. Omitted. Further, the tone signal extracting means 3 is shown in FIG.
Half wave rectifying means 31 and envelope detecting means 3 as shown in FIG.
2. Pitch band filtering means 33. The detailed configuration for extracting the voice pitch is not limited to this, and any other technical means may be used as long as the same function can be obtained.

The tone band signal filtered by the tone band filtering means 1 is half-wave rectified by the half-wave rectifying means 31 of the tone signal extracting means 3, and the plus side waveform is extracted. Next, envelope detection is performed by the envelope detection means 32, and the pitch component signal is extracted. From the extracted pitch signal, only the pitch component of the voice frequency band is extracted by the pitch band filtering means 33 (for example, a bandpass filter of fc = 80-500HZ) that filters only the voice band. The extracted voice pitch signals are averaged by the third amplitude averaging means 4 to obtain an average level. The obtained voice pitch level and a predetermined threshold value are compared by the pitch determination means 5 to determine whether or not it is higher than the threshold value.

If it is larger than the threshold value, it is recognized that there is a voice pitch component, and it is judged that the voice is input.
The threshold value is obtained by an empirical rule or the like. As described above, by extracting the pitch component peculiar to the voice, the voice input and the tone signal input can be reliably discriminated, and the malfunction can be prevented. Further, here, for convenience of explanation, the operation is described by the analog expression means, but in reality, the digital PCM signal is handled, and the above-mentioned respective elements are constituted by the well-known digital signal processing means.

Next, the operation of such tone detection will be described. FIG. 3 is a flowchart showing the tone detection operation. First, a data signal such as a tone signal or a voice signal is input (S1). The tone band signal and the out-of-band signal are separated from the input data signal by the tone band filtering means 1 and the out-band filtering means 2 (S2). Then, the voice pitch signal is extracted by the voice pitch extracting means 3 from the separated tone band signal (S3).

The average levels of the three signals of the tone band signal, the out-of-band signal and the voice pitch signal are respectively calculated as a first amplitude averaging means 6, a second amplitude averaging means 7 and a third amplitude averaging means 7.
It is calculated by the amplitude averaging means 4 (S4). The tone signal level and the out-of-band level respectively obtained from the first amplitude averaging means and the second amplitude averaging means are compared (S5). If the difference between the two is not greater than the specified value (S
6) It is determined that the input is voice (S7). If the difference between the two is greater than or equal to the specified value (S6), the voice pitch level obtained by the third amplitude averaging means is compared with a predetermined threshold value (S8). If the voice pitch level is equal to or higher than the threshold value (S9), it is determined that the voice is input (S1).
0), if it is less than or equal to the threshold value (S9), it is determined that a tone signal is detected, and the subsequent processing is advanced (S11).

As described above, by judging the voice pitch in addition to the conventional method, the tone signal can be surely detected even for voices of any voice quality, and various audible sounds on the communication line, DTMF signals, An answer tone or the like in data communication can be reliably detected. Further, although two different frequency signals are used in the DTMF signal, even in this case, the voice and the tone signal can be reliably detected without being confused with each other.

[0018]

The preferred embodiments of the present invention will be described below. FIG. 4 shows a first embodiment of the present invention. The boot ROM 22 stores an algorithm (program) for realizing each means or method shown in FIG. 1 or 3, and the DSP ( Digital
The DSP 21 is read into the internal memory of the Signal Processor), and this DSP 21 operates as a device having each unit of FIG. 1 or a device for realizing the method shown in FIG. Then, the input data is judged by the DSP 21, and 1 is output from the tone detection result output port of the DSP 21.
The determination result is output as bit data.

FIG. 5 shows a second embodiment of the present invention. In this example, a CPU 23 which is another processor is provided in place of the boot ROM 22 shown in FIG.
To read the same program as above into the internal memory of the DSP 21. In addition, the judgment result is CP through the internal bus.
It is sent to U23. In this way, DSP that operates at high speed
21 is used, and since tone detection is performed by digital signal processing by software, it is a small and simple configuration.
Moreover, tone detection can be performed at high speed and reliably. It is possible to obtain the same function by analog signal processing by using a well-known signal processing means. However, as described above, the digital signal processing requires a small size and a simple configuration, Since the number can be easily changed, it can be said that the configuration of the above embodiment is excellent in this respect.

[0020]

As described above, according to the apparatus of the present invention, in addition to the result from the tone / out-of-band level comparison / determination means,
Since the voice pitch extraction means, the third amplitude averaging means, and the voice pitch determination by the pitch determination means are also input to the determination means, it is possible to reliably detect tone signals for voices of any voice quality, and to communicate. Various audible tones on the line, DTMF signals, answer tones in data communication, etc. can be reliably detected, and two different frequency signals are used in the DTMF signal. Even in this case, the voice and tone signals are also used. It is possible to provide a device that can be reliably detected without being confused with.

Further, according to the method of the present invention, in addition to the conventional method, the voice pitch level is extracted and compared with a predetermined threshold value. Tone signal can be detected and various audible sounds on the communication line,
DTMF signals, answer tones in data communication, etc. can be detected with certainty, and two different frequency signals are used in DTMF signals. Even in this case, voice and tone signals are not confused and reliable. Can provide a detectable method.

[Brief description of drawings]

FIG. 1 is a block diagram showing a basic configuration of an apparatus according to the present invention.

FIG. 2 is a voice pitch extracting means, a third amplitude averaging means,
It is a figure which showed notionally the main effect | action of a pitch determination means.

FIG. 3 is a flowchart showing the operation or method of the device according to the present invention.

FIG. 4 is a diagram showing a first embodiment of the present invention.

FIG. 5 is a diagram showing a second embodiment of the present invention.

FIG. 6 is a block diagram showing a schematic configuration of a conventional tone detection device.

FIG. 7 is a flowchart showing an operation of a conventional tone detecting device or a tone detecting method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 tone band-pass filtering means 2 out-of-band filtering means 3 voice pitch extracting means 4 third amplitude averaging means 5 pitch determining means 6 first amplitude averaging means 7 second amplitude averaging means 8 tone / out-band level comparison Judgment means 9 Judgment means 31 Half-wave rectification means 32 Envelope detection means 33 Pitch band filtering means

Claims (2)

[Claims] 1. Tone band filtering means for filtering a tone band signal, first amplitude averaging means for obtaining an average amplitude level of the tone band signal filtered by the tone band filtering means, and other than the tone band signal. Out-of-band filtering means for filtering the signal, second amplitude averaging means for determining the average amplitude level of the out-of-band signal filtered by the out-of-band filtering means, and tone determined by the first amplitude averaging means. A tone detecting apparatus comprising: a tone / out-of-band level comparing / determining means for comparing a signal level with an out-of-band signal level obtained by the second amplitude averaging means to determine whether or not it is greater than a prescribed value. A voice pitch extracting means for extracting a voice pitch component from the band signal and an average amplitude level of the voice pitch signal extracted by the voice pitch extracting means are obtained. A third amplitude averaging means, a pitch determining means for determining whether the voice pitch level averaged by the third amplitude averaging means is higher than a threshold value, and an output of the pitch determining means. A tone detecting device, comprising: a determining unit that determines whether or not the signal is a tone signal based on the output of the tone / out-of-band level comparing and determining unit. 2. Separating tone band signals and out-of-band signals,
In the tone detection method for obtaining the average amplitude level of both signals, comparing the obtained tone signal level and the out-of-band signal level, and determining that the tone signal is a tone signal when the value is equal to or greater than a specified value, the separated tone signal Extract the voice pitch component from the, obtain the average amplitude level of the obtained voice pitch signal,
The voice pitch level thus obtained is compared with a threshold value, the tone signal level is compared with the out-of-band signal level, and when the tone signal level is equal to or higher than a specified value, the tone signal is lower than the threshold value. A tone detection method characterized by determining that