JP3418527B2 - Audio transmission apparatus and method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voice transmission method provided for communicating and transmitting an analog signal such as voice or musical sound, and converting it into a digital data code for a digital communication line for direct use in its implementation. The present invention relates to an audio transmission device having a built-in audio codec.

[0002]

2. Description of the Related Art Various encoding methods have been developed as a method of converting an analog signal such as voice or musical sound into a signal for a digital communication line, and a conventional voice transmission apparatus has various codes according to its use. The adoption method is adopted.

[0003]

Therefore, it is necessary for both the sender and the receiver to know in advance which coding method is used in the voice transmission device of the other party, and it is used for communication. In this case, there is a problem that it is very troublesome, and in order to improve the interoperability, it is necessary to install a transmission device (encoding / decoding device etc.) that matches the encoding method adopted by the other device. Since a large number of transmission devices must be prepared, there is a problem that the installation cost becomes high.

Further, there is a problem that when the clock signal suddenly changes during communication (for example, frequency change, interruption, etc.), an unpleasant noise or an acoustic impact sound is emitted to the other party or himself.

The main objects to be solved by the present invention are as follows. That is, the first object of the present invention is to
It is an object of the present invention to provide a voice transmission device and method for a digital communication line, which can cope with various encoding / decoding methods by one unit and have a low installation cost.

A second object of the present invention is that a voice codec has a plurality of encoding / decoding algorithms, and the encoding / decoding algorithms can be arbitrarily selected from the outside. Is intended to be provided.

A third object of the present invention is that the speech codec has a plurality of encoding / decoding algorithms, and an appropriate encoding / decoding algorithm is automatically selected based on a predetermined external signal obtained from a digital communication line. A voice transmission device and method for a digital communication line capable of performing encoding / decoding by the above method.

A fourth object of the present invention is to provide a voice transmission device for a digital communication line, which does not generate unpleasant noise or acoustic shock noise to the other party or himself when the data clock signal changes during communication. And to provide a method.

Other objects of the present invention include the specification, drawings,
In particular, it will be apparent from the description of each claim in the claims.

[0010]

In order to solve the above problems, the present invention provides a voice codec with a plurality of encoding / decoding algorithms, and the voice codec has a plurality of encoding / decoding algorithms among the plurality of encoding / decoding algorithms. Arbitrary algorithms for executing the processing are configured to be selectable.

Further, according to the present invention, a voice codec having a plurality of encoding / decoding algorithms, a clock frequency detecting means for detecting a clock frequency supplied from a digital communication line, and the plurality of encoding / decoding algorithms. , The algorithm corresponding to the clock frequency detected by the clock frequency detecting means is automatically switched.
A control means for selecting is provided.

Further, according to the present invention, in addition to the clock frequency detecting means, a clock signal presence / absence detecting means and a mute operation switching means are provided, and each of the clock frequency detecting means and the clock signal presence / absence detecting means is supplied from a digital communication line. A control means is provided for activating the mute operation switching means to detect the change of the clock frequency and the change of the state of the presence or absence of the clock signal to put the audio codec in the mute state for a certain time.

More specifically, in order to solve the problem, the present invention adopts the novel characteristic construction means and methods listed below from the superordinate concept to the subordinate concept. To achieve.

That is, the first feature of the device of the present invention is that the voice codec having a plurality of encoding / decoding algorithms and the clock supplied from the digital communication line among the plurality of encoding / decoding algorithms. It has a control means for automatically selecting a predetermined algorithm corresponding to the frequency of the signal and executing an encoding / decoding process for the voice codec by the selected algorithm, and outputs an analog signal such as voice or musical sound. A voice transmission device that performs pulse code modulation and transmits / receives an analog signal via the digital communication line, wherein the control means detects a frequency of a clock signal supplied from the digital communication line, Algorithm switching means for switching and selecting the algorithm of the voice codec,
Clock signal presence / absence detection means for detecting whether or not a clock signal is supplied from the digital communication line,
Mute operation switching means for putting the audio codec in a muted state for a certain period of time when the clock signal from the digital communication line changes from the no-state to the present state, and the mute operation switching means in synchronization with the clock signal supplied from the digital communication line. A configuration of a voice transmission device having a timing generation / transmission means for generating a timing signal for activating a voice codec is adopted.

A second feature of the device of the present invention is that a voice codec having a plurality of encoding / decoding algorithms and a clock signal supplied from a digital communication line from among the plurality of encoding / decoding algorithms. It has a control means for automatically selecting a predetermined algorithm corresponding to the frequency and executing an encoding / decoding process for the voice codec by the selected algorithm, and pulse-codes an analog signal such as voice or musical sound. A voice transmission device for modulating and transmitting / receiving an analog signal through the digital communication line, wherein the control means detects a frequency of a clock signal supplied from the digital communication line, and the voice signal. Algorithm switching means for switching and selecting a codec algorithm, and the digital communication line A clock signal presence / absence detecting means for detecting whether or not a clock signal is supplied from the digital communication line, and a mute operation switching means for putting the audio codec in a mute state for a certain period of time when the frequency of the clock signal from the digital communication line changes. , A timing generating and transmitting means for generating a timing signal for activating the voice codec in synchronization with a clock signal supplied from the digital communication line.

A third feature of the device of the present invention is that the clock signal whose frequency is detected in the first or second feature of the device of the present invention is a data clock signal only, a frame clock signal only, or a data clock signal. And the configuration of an audio transmission device which is both a frame clock signal and a frame clock signal.

The first feature of the method of the present invention is that the analog signal such as voice or musical sound is pulse-code modulated and the analog signal is transmitted / received through the digital communication line. Based on the frequency of the clock signal to be supplied, a predetermined corresponding algorithm is automatically selected from among a plurality of encoding / decoding algorithms, and the automatic switching control is performed to the automatically selected algorithm, and the algorithm is supplied from the digital communication line. Encoding / decoding processing is performed by a timing signal generated in synchronism with a clock signal, and when the supply of the clock signal from the digital communication line changes from a non-existing state to an existing state, the encoding / decoding processing is performed. This is in the adoption of the structure of the audio transmission method in which the mute state is maintained for a fixed time.

A second feature of the method of the present invention is that the analog signal such as voice or musical sound is subjected to pulse code modulation and the analog signal is transmitted and received through the digital communication line, and is supplied from the digital communication line. Based on the frequency of the clock signal to be supplied, a predetermined corresponding algorithm is automatically selected from among a plurality of encoding / decoding algorithms, and the automatic switching control is performed to the automatically selected algorithm, and the algorithm is supplied from the digital communication line. Encoded by timing signal generated in synchronization with clock signal /
When the frequency of the clock signal supplied from the digital communication line is changed by performing the decoding process, the encoding / coding
This is the adoption of a configuration of a voice transmission method in which the decoding process is muted for a certain period of time.

A third feature of the method of the present invention is that the clock signal supplied from the digital communication line according to the first or second feature of the method of the present invention is a data clock signal only, a frame clock signal only, or a data clock signal. This is in adopting a configuration of a voice transmission method that is both a clock signal and a frame clock signal.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Before describing the embodiments of the present invention, the terms used in this specification will be described.

The term "voice" used in the present specification means, in a narrow sense, a conversation sound of a person who intends to transmit through a telephone line. In a broad sense, in addition to the voice in the narrow sense, a musical sound, a modem sound, a FAX sound, and any other acoustic signal to be transmitted through a communication line. Therefore, when referring to the voice transmission device and the voice transmission method in the title of the invention and others,
Used in a broad sense.

(Device Example 1) FIG. 1 is a first device example according to an embodiment of the present invention, in which 1 is an analog input / output terminal for inputting / outputting analog signals such as voices and musical tones. Reference numeral 2 is a communication circuit for amplifying analog signals such as voice and musical sound to an appropriate level for communication, 3 is an A / D & D / A converter (A / D converter 31, D / A converter 32), 4 is a voice codec ( Encoding means 41 / decoding means 42). here,
The audio codec 4 has a memory (not shown) having a plurality of algorithms necessary for performing the encoding and decoding processes.

The transmission signal amplified by the communication circuit 2 is A /
After being sampled and quantized by the D converter 31, pulse code modulation (PC
M). The received signal is demodulated by the decoding means 42 of the audio codec 4 and then converted into an analog signal by the D / A converter 32.

Reference numeral 5 is a control circuit which is a control means, and controls an algorithm switching unit 7 which switches an algorithm required for the operation of the timing generation / transmission unit 6 and the voice codec 4 which will be described later. Furthermore, the encoding means 41 of the audio codec 4
It receives the signal sent from the digital communication line 9 as the transmission data Dt, and receives the received data Dr sent from the digital communication line 9 in the decoding means 42 of the audio codec 4.

Reference numeral 6 denotes a timing generation / transmission unit, which is in communication.
The A / D converter 31, the D / A converter 32, the encoding means 41, and the decoding means 42 are synchronized with a clock signal (data clock signal or frame clock signal) supplied from the control circuit 5 via a digital communication line. Generates timing signals required for operation. The timing generation / transmission unit 6 is composed of, for example, a crystal oscillator.

An algorithm switching unit 7 is controlled by the control circuit 5 and switches the algorithm required for the operation of the encoding unit 41 and the decoding unit 42.

Reference numeral 8 is a digital communication line 9 and a control circuit 5.
It is a communication line control circuit that controls the interface with
As illustrated, the transmission data Dt and the reception data Dr are exchanged between the control circuit 5 and the digital communication line 9. Further, the data clock signal Cd and the frame clock signal C sent from the digital communication line 9
f is sent to the control circuit 5 via the communication line control circuit 8. In the case of this embodiment, the frame clock signal Cf
Need not be sent to the control circuit 5.

The audio codec 4 follows the encoding / decoding algorithm set by the control circuit 5 among a plurality of algorithms required for the operations of the encoding means 41 and the decoding means 42 of the audio codec 4, respectively. , And performs encoding / decoding processing. In addition, the encoding unit 41 appropriately outputs the pulse code modulated (encoded) signal as needed.
Performs data compression processing. Further, the decoding means 42 demodulates (decodes) the received signal and, if the received signal is subjected to data compression processing, performs appropriate data decompression (expansion) processing.

The switching control of the algorithm switching unit 7 by the control circuit 5 is performed by a predetermined operation (for example, manual operation).

(Method Example 1) FIG. 2 is a flowchart showing a first method example which is an embodiment of the present invention, and is an operation example executed based on the configuration of the apparatus example 1. Hereinafter, this method example 1 will be described with reference to FIG.

The control circuit 5, based on the predetermined operation,
Encoding means 41 or decoding means 42 of the audio codec 4
Constantly monitors which algorithm is selected and instructed to execute the processing (ST1
1). When switching the algorithm setting is instructed (S
T12), the algorithm to be adopted by the audio codec 4 is switched according to the setting instruction, and the coding / decoding process is executed by the switched algorithm (ST1).
3). If the algorithm setting is not instructed to switch,
The audio codec 4 continues to operate as it is (ST1
3).

(Device Example 2) FIG. 3 shows a second device example according to an embodiment of the present invention, which is different from the device example 1 in that a clock supplied from the digital communication line 9 via the communication line control circuit 8 is used. A clock frequency detection unit 10 for detecting the frequency of a signal (data clock signal Cd or frame clock signal Cf, or both) is further provided (in the case of the present device example 2, the clock signal is supplied to the clock frequency detection unit 10). Is not entered directly (see Figure 3).

In the present device example 2, when the clock frequency detection unit 10 receives the clock signals Cd and Cf from the digital communication line 9 via the communication line control circuit 8, the clock frequency detection unit 10 detects the frequency of the received signal, and also detects the frequency. Information is sent to the control circuit 5. Based on the received frequency information, the control circuit 5 discriminates and determines a predetermined algorithm corresponding to the frequency one-to-one, and the algorithm switching unit 7 discriminates and determines among a plurality of algorithms in the audio codec 4. The selected algorithm automatically. The audio codec 4 executes encoding / decoding processing according to the selected algorithm.

The other structure is the same as that of the device example 1.

(Method Example 2) FIG. 4 is a flowchart showing a second method example according to the embodiment of the present invention, which is an operation example executed based on the configuration of the apparatus example 2. Hereinafter, this method example 2 will be described with reference to FIG.

The control circuit 5 monitors whether or not the clock signal is supplied from the digital communication line 9 via the communication line control circuit 8 by using the clock frequency detection unit 10 (ST21), and the clock frequency detection unit 10 controls the clock frequency detection unit 10. It is constantly determined whether or not the frequency of the detected clock signal has changed (ST22). When no frequency change is detected, the control circuit 5 causes the audio codec 4 to execute the current operation as it is (ST23).

When it is detected that the clock frequency supplied from the digital communication line 9 has changed, the control circuit 5
Determines whether or not there is a predetermined algorithm corresponding to the changed frequency one-to-one (ST2
4) The algorithm switching section 7 selects the algorithm determined and determined among the plurality of algorithms in the voice codec 4 (ST25). And audio codec 4
Performs the encoding / decoding process according to the new algorithm selected by switching (ST26).

If there is no algorithm corresponding to the clock frequency detected by the clock signal detecting section 10, the control circuit 5 judges that the audio codec 4 does not have a predetermined algorithm to be processed, and the operation of the audio codec 4 is performed. Is stopped (ST27).

As described above, according to the method example 2, the algorithm of the voice codec 4 is automatically selected according to the frequencies of the clock signals Cd and Cf supplied from the digital communication line 9 via the communication line control circuit 8. Or, since it is selected by switching, it can be encoded / selected according to the transmission device on the other side.
There is an advantage that the operability is remarkably improved because it is not necessary to set the decoding algorithm.

(Device Example 3) FIG. 5 shows a third device example according to an embodiment of the present invention, which is different from the device example 2 in that a mute operation switching section 11 for putting the audio codec 4 into a mute state and a digital signal. Communication line 9
The clock signal presence / absence detection unit 12 for detecting the presence / absence of the clock signal (data clock signal, frame clock signal, or both) from FIG.

The feature of the present device example 3 is that the clock signal presence / absence detection unit 12 detects a change in the presence / absence of the clock signal supplied from the digital communication line 9, or the clock frequency detection unit 10 detects the clock frequency. When the change of the above is detected, the control circuit 5 activates the mute operation switching unit 11 and puts the audio codec 4 into the mute state for a certain period of time. This mute state can be created by the mute operation switching unit 11 configured by a computer program incorporated in the control circuit 5.

The other structure is the same as that of the device example 2.

(Method Example 3) FIG. 6 is a flowchart showing a third method example which is an embodiment of the present invention, and is an operation example executed based on the apparatus example 3. Hereinafter, this method example 3 will be described with reference to FIG.

The control circuit 5 monitors whether or not the clock signals Cd and Cf are supplied from the digital communication line 9 via the communication line control circuit 8 by the clock signal presence / absence detection unit 12 and the clock frequency detection unit 10 (ST3
1), it is continuously determined whether the clock signals Cd and Cf are detected (ST32).

When the clock signals Cd and Cf are not detected, it is judged whether or not the clock signals Cd and Cf are not detected on the way (ST33). If YES, that is, the clock signals Cd and Cf are received. If it is determined that the audio codec 4 has been interrupted, the audio codec 4 is muted for a certain period of time (ST34), and then the device is put into the power-down state (ST35). This power down state can be created by lowering the level of the driving voltage supplied to each part of the device. In the case of NO, that is, the clock signal Cd,
If it is determined that Cf has not been detected for a certain period of time, the device is put into the power-down state without performing the mute process (ST35).

When the reception of the clock signals Cd and Cf is continuously detected, the clock signals Cd and Cf are further added.
Is suddenly detected (ST
36), if it is NO, it is further judged whether or not there is a change in the clock frequency (ST37), and it is N
In the case of O, that is, when the frequency change is not observed, the operation of the audio codec 4 at that time is continued as it is (S
T38). If a frequency change is observed, the audio codec 4 is muted for a certain period of time (ST39),
It is determined and determined whether there is an algorithm corresponding to (matching with) the clock frequency (ST40), and if not, the operation of the voice codec 4 is stopped (ST41). If there is a corresponding (matching) algorithm, that algorithm is automatically selected (ST42), and the operation of the voice codec 4 is executed by the selected new algorithm (ST43).

On the other hand, when it is determined that the clock signals Cd and Cf are suddenly received, after the audio codec 4 is muted for a certain period of time (ST39), an algorithm corresponding to (matching with) the clock frequency is set. It is determined / determined whether it is present (ST40), and if not, the operation of the audio codec 4 is stopped (ST41). If it is determined that there is a corresponding (matching) algorithm, that algorithm is automatically selected (ST42) as described above, and the operation of the voice codec 4 is executed by the selected new algorithm (ST43).

As described above, according to the method example 3, even if the clock signals Cd and Cf change during communication, the transmission / reception of the audio codec 4 is automatically muted, so that the communication partner There is an advantage that there is no problem that an unpleasant noise or an acoustic impact sound is emitted to oneself.

In each device example and method example in the above embodiment, the clock signal C fetched from the digital communication line 9 for selecting the encoding / decoding algorithm.
As d and Cf, only the data clock signal Cd, only the frame clock signal Cf, or the data clock signal C
Any combination of d and the frame clock signal Cf may be used. Furthermore, since decoding (demodulation) is the reverse operation of encoding (modulation), the encoding / decoding algorithm is a pair.

[0050]

As described above, according to the present invention,
Since the voice codec has multiple encoding / decoding algorithms and the algorithm that allows the voice codec to perform its processing by a predetermined operation is selected as a voice transmission method, voice transmission is aimed at the realization of that method. It is not necessary to provide a plurality of devices, and it is possible to provide a voice transmission device with low installation cost.

Further, since the selection switching of the algorithm can be automatically performed by the frequency of the clock signal supplied from the digital communication line, it is possible to provide a voice transmitting apparatus and method having very good operability.

Furthermore, during communication, when the presence or absence of the clock signal or the state change of the frequency changes, the transmission / reception of the audio codec is automatically muted. There is an advantage that there is no problem that a strong impact sound is emitted.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a device example 1 according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a method example 1 in the embodiment of the present invention.

FIG. 3 is a diagram showing a device example 2 according to an embodiment of the present invention.

FIG. 4 is a flowchart showing a second method example according to the embodiment of the present invention.

FIG. 5 is a diagram illustrating a device example 3 according to an embodiment of the present invention.

FIG. 6 is a flowchart showing a third method example according to the embodiment of the present invention.

[Explanation of symbols]

1 ... Analog input / output terminal 2 ... Call circuit 3 ... A / D & D / A converter 4 ... Voice codec 5 ... Control circuit 6 ... Timing generation transmission unit 7 ... Algorithm switching unit 8 ... Communication line control circuit 9 ... Digital communication line 10 ... Clock frequency detector 11 ... Mute operation switching section 12 ... Clock signal presence / absence detection unit 31 ... A / D converter 32 ... D / A converter 41 ... Encoding means 42 ... Decoding means

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Claims (6)

(57) [Claims] 1. A voice codec having a plurality of encoding / decoding algorithms, and a predetermined algorithm corresponding to the frequency of a clock signal supplied from a digital communication line from among the plurality of encoding / decoding algorithms. And a control means for automatically selecting and executing an encoding / decoding process for the voice codec by the selected algorithm, performing pulse code modulation on an analog signal such as voice or musical sound, and connecting the digital communication line. A voice transmission device that transmits and receives an analog signal via the control means, wherein the control means detects a clock frequency detecting means for detecting a frequency of a clock signal supplied from the digital communication line, and an algorithm for switching and selecting an algorithm of the voice codec. A clock signal is supplied from the switching means and the digital communication line. A clock signal presence / absence detecting unit for detecting whether the audio signal is present or not, a mute operation switching unit for muting the audio codec for a certain period of time when the clock signal from the digital communication line changes from a no-state to an existing state, And a timing generation / transmission means for generating a timing signal for activating the voice codec in synchronization with a clock signal supplied from a digital communication line. 2. A voice codec having a plurality of encoding / decoding algorithms, and a predetermined algorithm corresponding to the frequency of a clock signal supplied from a digital communication line from among the plurality of encoding / decoding algorithms. And a control means for automatically selecting and executing an encoding / decoding process for the voice codec by the selected algorithm, performing pulse code modulation on an analog signal such as voice or musical sound, and connecting the digital communication line. A voice transmission device that transmits and receives an analog signal via the control means, wherein the control means detects a clock frequency detecting means for detecting a frequency of a clock signal supplied from the digital communication line, and an algorithm for switching and selecting an algorithm of the voice codec. A clock signal is supplied from the switching means and the digital communication line. A clock signal presence / absence detecting unit for detecting whether or not the digital signal is present, a mute operation switching unit for muting the audio codec for a certain time when the frequency of the clock signal from the digital communication line changes, and the digital communication line. And a timing generation / transmission means for generating a timing signal for activating the audio codec in synchronization with a clock signal supplied from the audio transmission device. 3. The clock signal of which the frequency is detected is a data clock signal only, a frame clock signal only,
Or, it is both a data clock signal and a frame clock signal, The audio transmission device according to claim 1 or 2, characterized in that. 4. An analog signal such as voice or musical sound is subjected to pulse code modulation to transmit / receive the analog signal through a digital communication line, which is based on a frequency of a clock signal supplied from the digital communication line in voice transmission. The corresponding predetermined algorithm is automatically selected from among a plurality of encoding / decoding algorithms, and the automatic switching control is performed according to the automatically selected algorithm, which is generated in synchronization with the clock signal supplied from the digital communication line. Encoding / decoding processing is performed by a timing signal, and when the supply of the clock signal from the digital communication line changes from a non-existing state to an existing state, the encoding / decoding processing is muted for a certain period of time. A voice transmission method characterized by. 5. An analog signal such as voice or musical sound is subjected to pulse code modulation to transmit / receive the analog signal via a digital communication line, and the analog signal is transmitted / received based on a frequency of a clock signal supplied from the digital communication line. The corresponding predetermined algorithm is automatically selected from among a plurality of encoding / decoding algorithms, and the automatic switching control is performed according to the automatically selected algorithm, which is generated in synchronization with the clock signal supplied from the digital communication line. Audio transmission characterized by performing encoding / decoding processing with a timing signal, and when the frequency of a clock signal supplied from the digital communication line changes, the encoding / decoding processing is muted for a certain period of time. Method. 6. A clock signal supplied from the digital communication line is a data clock signal only, a frame clock signal only,
Alternatively, it is both a data clock signal and a frame clock signal, The voice transmission method according to claim 4 or 5, wherein: