JPH0484552A - Voice storage device - Google Patents

Abstract

PURPOSE:To prevent occurrence of pulse noise and deterioration in speech quality by discriminating mis-detection of a DTMF detection section at reproduction of a voice message with reproduction control while reproduced output sound quantity is continuously decreased. CONSTITUTION:When a subscriber enters a box number, it is converted into a numeral string by a DTMF detection section 5, a central control section 9 reproduces a designated voice message. In this case, when a frequency component of a voice signal during reproduction is similar to that of a DTMF signal, the detection section 5 sends an erroneous detection output to a line control section 6. When the detection output is entered to the line control section 6 at a preset time, a reproduced sound volume control section 10 decreases an output sound volume from a voice reproduction section 3 continuously to decrease the sound volume inputted to the detection section 5 through bypassing thereby avoiding mis-detection. In this case, the message reproduction sound volume is continuously decreased. Thus, the transmission of pulse noise to the line is prevented and the deterioration in the speech quality is avoided.

Description

[Detailed description of the invention] (Industrial application field) The present invention transmits voice messages over telephone lines.

(Prior Art) Conventionally, as a voice storage device using an analog telephone line, there is, for example, an answering machine. With the increase in the amount of information in recent years, the demand for such devices as information storage means is rapidly increasing. Furthermore, a voice mail device has been developed that improves the efficiency of communication and reduces the troublesome work associated with telephone calls by accumulating and comprehensively managing messages sent via telephones in the office, and has already entered the practical stage. ing.

A voice mail device connected to such a conventional analog line will be described below.

FIG. 3 is a block diagram of a conventional voice mail device.
is a line interface unit that is connected to an analog line and performs line control and input/output separation.The analog signal outputted from it is converted into digital data by the audio recording unit 2, and then converted into digital data with information compression as necessary. Output a signal. 3 is an audio playback unit that converts the digital signal back into an analog signal and outputs it to the line interface unit 1; 4 is a playback output disconnection unit that connects and disconnects the output of the audio playback unit 3 to the line interface unit 1; 5 is a telephone DTM detects DTMF signals sent via line
6 is a line control unit that controls the input/output of audio signals and the telephone line by controlling the line interface unit 1 and the reproduction output disconnection unit 4; 7 is a line control unit that controls the input/output of audio signals and the telephone line; A DTMF output section outputs a DTMF signal to the interface section I; 8 is an audio storage section that stores output audio data from the audio recording section 2 and audio data input to the audio playback section 3; This is a central control unit that manages the recording and playback of audio data.

The conventional voice mail device configured as described above operates as follows. That is, FIG. 4 shows the reproduction output cutting section 4.
First, when reproducing a message, the line interface section 1 detects a ring tone from the telephone line, takes the line off-hook, and notifies the line control section 6. The line control unit 6 notifies the central control unit 9 that there is an incoming call, and the central control unit 9 accordingly sends voice guidance to the voice storage unit 8 informing that the call is a voice mail device.
The signal is output from the system, converted to an analog signal by the audio playback section 3, inputted to the line interface section I, and sent to the telephone line as voice guidance (for example, "This is the message center. Please enter your box number.") Output. When the subscriber who hears the above guidance enters the other party's box number (for example, N312J) using the pushbutton key on the phone, that box number will become DTM.
DTM as F signal via line interface section l
The signal is input to the F detection section 5, converted into a code of a number string representing the box number, and sent to the central control section 9. center side if
When the fa9 receives the code of the number string representing the box number from the line control unit 6, it outputs the message corresponding to the box number from the voice storage unit 8, converts it back to an analog signal by the voice playback unit 3, and sends it to the line interface. section l and output the message on the telephone line. On this occasion,
Since the separation of the human outputs of the line interface section 1 is not perfect (=4), the message goes around to the DTMF detection section 5 via the line interface section 1 as shown by the broken line. At this time, D T M F to message 1.
If it contains frequency components similar to the signal, DTMF
The detection unit 5 may malfunction. In order to prevent this malfunction, when the audio playback section 3 is outputting audio, the DTMF
When the detection output of the detection section 5 is input to the line control # section 6 for a preset time, the line control section 6 causes the reproduction output disconnection section 4 to disconnect the output from the audio reproduction section 3 (see Fig. 4). , time t4]), the influence of the message going around to the DTMF detection unit 5 is eliminated. If the detection output from the DTMF detection unit 5 continues after the disconnection, the line control unit 6 determines that it is a DTMF signal transmitted by the subscriber, converts it into a number, and outputs it to the central control unit 9. After the DTM F detection output disappears, the playback output disconnection unit 4 connects the output of the audio playback unit 3 to the input of the line interface unit 1, and resumes sending out the playback sound to the line (time t42 in the figure).

On the other hand, after the disconnection, if the detection output from the TMF detection unit 5 disappears, the line control unit 6 determines that the detection is an erroneous detection due to the looping of the reproduced audio, and causes the reproduction output disconnection unit 4 to detect the detection output from the audio reproduction unit 3. The output of the line interface unit 1 is reconnected to the input of the line interface unit 1 (time frame 42 in the figure). When the subscriber finishes listening to the message, he presses the pushbutton key that notifies him of the end, and then presses the D button.
The TMF detection unit 5 detects this and notifies the line control unit 6, and the line control unit 6 notifies the central control unit 9 that the end key has been pressed.

Upon receiving the end command, the central control section 9 finishes reading out the audio storage section 8, and the playback ends.

(Problem to be Solved by the Invention) However, in the above-mentioned voice mail device, due to the erroneous detection judgment of the DTMF detection unit due to the playback sound going around to the receiver side when playing a message, the playback audio output may sometimes be completely The problem is that the reproduced audio output becomes discontinuous at the time of disconnection, pulse noise occurs, and the quality of the call deteriorates.

An object of the present invention is to provide an audio storage device that solves the above-mentioned problems.

(Means for Solving the Problems) The present invention has achieved the above object by providing a line control unit that closes and opens a telephone line, a DTMF detection unit that detects a DTMF signal from the line control unit, and a DTMF detection unit that detects a DTMF signal from the line control unit. a voice message storage section that stores voice messages; a playback control section that plays back the voice messages recorded therein and transmits them to the telephone line via the line control section; a playback volume control section that controls the output volume; and the DTMF. This is achieved by a configuration that includes a central control section that controls the playback control section and the line control section so as to perform overall control of the voice message playback based on the control signal from the detection section.

(Function) According to the present invention having the above configuration, the volume is continuously and appropriately reduced instead of completely cutting off the playback sound to prevent the DTMF detection unit from making a false positive judgment due to the playback sound going around to the receiving side when playing a message. This prevents the pulse noise that occurs when the volume is changed discontinuously from being transmitted to the line, thereby preventing deterioration in speech quality.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a voice mail device according to an embodiment of the present invention.

In FIG. 1, reference numeral 10 denotes a playback volume control section, and the other symbols refer to the same parts as in FIG. 2, and the detailed explanation refers to the explanation in FIG. 2. The present invention is configured as described above and operates as follows.

FIG. 2 shows an example of the output waveform of the playback volume control unit IO. When a subscriber plays back a message via the line, the line interface unit 1 off-hook the line in the same way as in the conventional example, and the audio A voice guidance will be output informing you that it is a mail device. When the subscriber inputs the box number, it is converted into a number string by the DTMF detection unit 5, and the voice message specified by the central control unit 9 is played back and sent to the subscriber via the line interface unit 1. , because the input/output separation of the line interface section 1 is not complete, the signal goes around to the DTMF detection section 5. At that time, the frequency component of the audio being played is DTMF.
If it is similar to the signal, the DTMF detection section 5 sends an erroneous detection output to the line control section 6. When the detection output is input for a preset time, the line control unit 6 causes the playback volume control unit 10 to continuously lower the output volume from the audio playback unit 3 (FIG. 2, time t31). , the volume input to the DTMF detection unit 5 due to wraparound is reduced to avoid false detection. At this time, since the message reproduction volume is continuously decreasing, there is little pulse noise generated at discontinuous points in the waveform. Furthermore, since the auditory sense operates logarithmically and the time it takes to reduce the volume is approximately several tens of milliseconds, there is little auditory sense of volume reduction.

After the line control unit 6 continuously lowers the playback volume, the DTMF
If the detection output from the detection unit 5 continues, it is determined to be a DTMF signal transmitted by the subscriber, converted into a number and output to the central control unit 9, and after the DTMF detection output disappears, the playback volume control unit 10 continuously returns the playback volume (time t32 in the figure). At this time as well, since the playback volume is returned continuously, there is little pulse noise generated at discontinuous points in the waveform. On the other hand, if the detection output from the DTMF detection unit 5 disappears after the playback volume is continuously lowered, the line control unit 6 determines that it is a false detection and causes the playback volume control unit 10 to continuously (time t32 in the figure).

When the subscriber finishes listening, he presses the pushbutton key that notifies him of the end, which is detected by the DTMF detection unit 5 and sent to the line control unit 6.
The line control unit 6 notifies the central control unit 9 that the end pushbutton key has been pressed, and the reproduction of the audio storage unit 8 ends.

(Effects of the Invention) As described above, the voice mail device of the present invention is provided with a playback volume control section to detect a DTMF false detection during message playback by continuously lowering the playback volume to prevent the generation of pulse noise. Since it is performed while preventing communication, it has the effect of allowing reproduction without deteriorating call quality, and the configuration is simple and easy, so there are many benefits to using it.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a voice mail device according to an embodiment of the present invention, and FIG. 2 is an output waveform diagram of its playback volume control section.
FIG. 3 is a block diagram of a conventional voice mail device, and FIG. 4 is an output waveform diagram of its main parts. 1...Line interface section, 2...Audio recording section, 3...Audio playback section, 4...Playback output disconnection section, 5...DTMF detection section, 6...Line control section, 7 ...DTMF output section, 8...audio storage section, 9...central control section, 10...playback volume control section. Patent applicant Matsushita Electric Industrial Co., Ltd. = 11-

Claims (1)

[Claims] A line control section that closes and opens a telephone line, a DTMF detection section that detects DTMF signals from the telephone line, a voice message storage section that stores voice messages, and a voice message recorded thereon that is played back to control the line. a playback control section that transmits data to the telephone line via a playback control section; a playback volume control section that controls the output volume of the playback control section; and a playback control section and line that perform overall control of voice message playback based on control signals from the DTMF detection section; The audio storage comprises a central control unit that controls the control unit, and determines whether the DTMF detection unit has erroneously detected the DTMF detection unit during voice message playback by continuously lowering the playback output volume using the playback volume control. Device.