JP3276863B2 - Answering machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a telephone answering machine, and more particularly, to a method of digitally encoding a message of a partner transmitted via a telephone line and storing it in a memory. The present invention relates to an improvement in a method of recording a message and a method of storing message data in an answering machine.

[0002]

2. Description of the Related Art Conventionally, in an answering machine for recording a message of the other party when the user is not present, a method of recording a message includes:
A method of recording the voice of the other party on a magnetic tape as an analog signal and a method of sampling and quantizing by an AD converter and storing the data in a digital memory are mainly used. The latter has the features that it has high reliability because there is no mechanism, and that random access and erasure of messages are easy.However, since the memory is more expensive than magnetic tape, the recording time is limited by the memory capacity. There is a disadvantage that it is large. Therefore, during recording, it is common to compress the data amount by performing encoding such as ADPCM instead of directly storing the quantized data. Naturally, the larger the degree of compression, the longer the length of a message that can be stored in a memory of a fixed capacity. However, compression-encoded audio generally degrades from the current audio, and the higher the degree of compression, the greater the degradation. The degraded voice is difficult to hear and gives the user inconvenience or discomfort.

[0003]

SUMMARY OF THE INVENTION The present invention minimizes the deterioration of sound quality due to such encoding, minimizes the inconvenience or discomfort given to the user, and uses a small memory capacity as efficiently as possible for a long time. The purpose is to enable message recording.

[0004]

According to a first aspect of the present invention, there is provided an answering machine having an automatic answering device for automatically answering a call signal and a voice signal of a partner. A plurality of bit rates, a memory for storing coded data obtained by the coding apparatus, and coded data stored in the memory are read out according to the coded bit rate. An encoding device for converting the encoding data into an audio signal, controlling the degree of compression of the encoding device and the encoding device, and storing the encoded data on the memory, the bit rate of each encoded data, A control unit that manages the remaining amount of available memory and a silence detection device that detects a silence state of a message of the other party, the control unit detects that the silence detection device detects a silence state When recording the other party's message, a high bit rate is used when the remaining memory is large, and a low bit rate is used when the remaining memory is low, according to a predetermined threshold provided for the remaining available memory. Instruct the encoding device to encode in, and, when instructed by a user, perform inverse encoding on the encoded data stored in the memory in a method according to a bit rate at the time of encoding. It is characterized by instructing the inverse encoding device.

According to a second aspect of the present invention, in the answering machine according to the first aspect, the control unit may be configured to control a bit rate when the silence detecting device detects a break in the message as a silent state. The feature is that the change of is allowed.

According to a third aspect of the present invention, in the answering machine according to the first or second aspect, the control unit determines that the silence detecting device is in a silence state between a call and a call. Is detected, the bit rate can be changed only between calls.

According to a fourth aspect of the present invention, there is provided the answering machine according to any one of the first to third aspects, wherein the control unit does not record or reproduce a message. As a result of appropriately examining the remaining amount of the memory, when the remaining amount of the memory is small compared with a predetermined threshold value provided for the remaining amount of the memory, the encoded data stored in the memory is subjected to the inverse encoding. A bit rate smaller than encoded data when the audio signal converted by the encoding device is stored in the memory while being read by the device and converted into an audio signal according to the encoded bit rate. And re-encodes the data in the memory.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an answering machine according to the present invention will be described below with reference to the drawings. FIG. 1 shows the first embodiment of the present invention.
FIG. 3 is a block diagram showing an embodiment. In the figure, reference numeral 1 denotes a telephone unit connected to a subscriber line, which has various operation buttons such as a handset and numeric keys. Reference numeral 2 denotes an automatic answering apparatus which, when the apparatus is set to the answering machine mode, receives an incoming call in response to an incoming signal under the control of the control section 3 and transmits a pre-recorded answer message to the subscriber. Send to line. Reference numeral 4 denotes an encoding device, which performs signal processing such as sampling, quantization, and compression of a recorded message of a communication partner transmitted via a subscriber line. The encoder 4 performs, for example, 8 bit logarithmic quantization at 8 ksample / s
64 kbps signal obtained by performing at a speed of, and a signal obtained by compressing this to 32 kbps by ADPCM voice coding, and 24 kbps by ADPCM voice coding
And has the ability to utter three types of signals, and one of the rates is selected by a rate selection signal from the control unit. In the following, the data encoded by these three methods are converted to 64 kbps data and 32 kbps data, respectively.
Data, 24 kbps data.

Reference numeral 5 denotes a memory for accumulating message data encoded by the encoding device 4 with information on the speed thereof. At this time, the control unit grasps the use state of the memory by managing the start and end addresses of the data recording. Reference numeral 6 denotes an inverse encoding device which decodes the message data stored in the memory 5 and converts it into an analog audio signal. When the user makes a message reproduction request to the control unit 3, the control unit 3 reads out the stored data from the memory 5 to the decoding device 6, and reads the data from the memory 5 as 64 kbps data, 32 kbps data, In accordance with whether the data is 24 kbps data, an instruction is given to convert the data into an analog signal by an appropriate method and output the analog signal to the speaker 8. Reference numeral 7 denotes a microphone for recording a response message.

The present invention makes use of the fact that the recording time length of a message actually used has a certain distribution, and the probability that a message is recorded to near the capacity of the memory is not necessarily large. That is, when the remaining memory is large,
When the encoding rate is increased (decreasing the degree of compression), sound quality is emphasized. When the remaining capacity of the memory is reduced, the encoding rate is decreased (decreasing the degree of compression) to emphasize recording time.
For this purpose, the control unit 3 monitors the remaining amount of the memory 5 and controls the coding rate.

FIG. 2 shows the control unit 3 in the embodiment of FIG.
1 shows an example of a method of managing the memory 5 according to the first embodiment.
In this example, the capacity of the memory for the encoded data is 2 Mbytes, and when the remaining amount of the memory falls below 1 Mbyte,
The coding rate is changed from 64 kbps data to 32 kbps data, and when the coding rate falls below 0.5 Mbytes, the coding rate is changed from 32 kbps data to 24 kbps data.

The coded data is managed in segments of, for example, 4 kbytes in size, and for each segment, a flag indicating whether it is in use, and if it is in use, the next Segment address and segment data are 64kbps data, 32kbps data, 24kb
It has information to distinguish whether it is PS data. However, if a segment is in use and there is no segment following it, a special value that cannot be an address is set as the address information of the next segment, so that it is the last segment. Shall be shown. Each message is associated with its start segment, and one message is formed by sequentially following the segments from this start segment and reading out the last segment sequentially. It is assumed that a memory for storing the segment information and the message information is appropriately prepared separately from the encoded data memory.

At the time of message recording, the control unit 3 searches for an unused segment having the youngest address,
This is the start address of the message. At the same time that the encoded data is written to this segment, its busy flag is set, and when this segment has been used up, the address of the next unused segment is set as the address of the next segment, and the process proceeds. Similarly, when the message ends, the segment at that time is marked as the last segment. The next message is recorded in the same manner. In order to delete a specific message, the busy flag is reset in order from the start segment of the message to the last segment.

The control unit 3 can manage the use amount of the memory 5 in units of the size of the segment (4 k bytes in this case) at the same time as operating the use flag of the segment. According to the size of the unused area of the memory 5 which is known from this, if it is 1 Mbyte or more, 64 kbps data is selected as the encoding method. Also, if it is less than 1 MB and 0.5 MB or more, 32 kbps
Select data, and if it is less than 0.5 Mbytes, select 24 kbps data. Thus, the message length that can be recorded in 2 MB memory is 1024/8/64 + 512/8/32 + 512/8/24 = 426.7
(Seconds). If this were all recorded at 64kbps,
It is 256 seconds, and the recordable time is greatly increased. Also, when the number of messages is small, they are recorded at a high sound quality of 64 kbps, so that it is difficult to cause problems such as difficulty in listening to the messages.

In this example, the data rate is switched by
Although performed in segment units, in some cases, switching in the middle of a message may result in unnatural discontinuity in sound quality. In order to avoid this, switching of the data rate may be performed only between messages. Alternatively, in addition to this, a mechanism for detecting a non-voice portion may be provided, and switching may be performed at a break in voice.

FIG. 3 is a block diagram showing another embodiment of the present invention. In this example, in addition to FIG. 1, the input of the encoding device can be obtained from the output of the inverse encoding device.

Here, the type of encoding is, for example, 64 kbps.
Data and 32 kbps data, 64 kbps data if the unused area of the memory is 1 Mbyte or more, 32 kbps if it is less than that
It is assumed that ps data is selected. Furthermore, the unused area is 0.
When the data size is less than 5 Mbytes and neither recording nor reproduction of a message is performed, the 64 kbps data already stored is sequentially read from the memory 5 and de-encoded by the de-encoding device 6, and the transmission line 9 is read. The data is re-encoded by the encoding device 4 as 32 kbps data and stored in the memory 5. At this time, the read 64 kbps data is deleted. In this way, when the volume of messages increases,
Eventually, by using the entire capacity of the memory 5 with 32 kbps data, the recording time will be 2048/8/32 = 512 (seconds), and the maximum recording time will be longer than in the embodiment of FIG. Can be. In addition, when there are few messages, recording is performed at a high sound quality of 64 kbps.

[0018]

As described above, the answering machine according to the present invention comprises: an encoding device for digitally encoding a voice signal of a communication partner transmitted through a line at a plurality of bit rates; A memory that stores the encoded data obtained by the encoding device, an inverse encoding device that reads the encoded data accumulated in the memory, and converts the encoded data into an audio signal according to a bit rate at the time of encoding; A control unit that controls the degree of compression of the encoding device and the inverse encoding device, and manages the storage position of encoded data on the memory, the bit rate of each encoded data, and the remaining amount of available memory. This minimizes the inconvenience or discomfort experienced by the user due to the deterioration of the sound quality due to the encoding, and makes it possible to effectively use the limited memory to record for a long time.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a memory management method according to the first embodiment.

FIG. 3 is a block diagram showing a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Telephone part 2 Automatic answering device 3 Control part 4 Encoding device 5 Memory 6 Decoding device

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04M 1/64-1/658

Claims (4)

(57) [Claims] And 1. A answering machine that automatically responds to the call signal, a coding apparatus for coding an audio signal of the other party at multiple bit rates, the coded data obtained by the encoding device a memory for storing, reading out the stored encoded data in the memory, code
An inverse encoding device that converts the audio signal into an audio signal in accordance with the encoded bit rate , and controls the degree of compression of the encoding device and the inverse encoding device, and stores the encoded data on the memory ,
A control unit that manages the bit rate of each encoded data and the remaining amount of available memory, and a silence detection device that detects a silence state of a message of the other party
Comprising the door, the control unit, the silence detector detects a silence
When recording the message of the other party, a high bit rate is used when the remaining memory capacity is high, and a low bit rate is used when the remaining memory capacity is low, according to a predetermined threshold provided for the remaining memory capacity. in instructing the encoder to encode, and the encoded data sometimes stored in the memory under the direction of the user to reverse coding in a way corresponding to the bit rate at the time of encoding Instructing the inverse encoding device; 2. An answering machine according to claim 1.
Then, the control unit sends a message indicating that the silence detection device is in a silence state.
An answering machine which permits a change in bit rate when a break in a message is detected . 3. An answering machine according to claim 1 or claim 2.
In the talking device, the control unit determines that the silence detection device is in a silence state and talks.
An answering machine, wherein when an interval between a call and a call is detected, a change in bit rate is allowed only between the calls. 4. The method according to claim 1, wherein
In telephone answering device, wherein, if the recording messages neither be done playing, appropriate result of examining the remaining amount of memory, as compared to a predetermined threshold value provided regarding the remaining amount of the memory, the memory When the remaining amount is small , the encoded data stored in the memory is read out by the inverse encoding device, and the encoded video data is read.
To an audio signal according to the
The audio signal converted by the encoding device is stored in the memory.
Bits smaller than encoded data when stored
An answering machine for re-encoding at a rate and re-accumulating in the memory .