JPH04343553A - Voice recording/reproducing lsi - Google Patents

Abstract

PURPOSE:To improve using efficiency based upon the application of variable length recording in a telephone set based upon the application of a voice recording/reproducing LSI. CONSTITUTION:A voice signal outputted from a microphone amplifier 1 is converted into PCM data by an A/D converter 2 and encoded as PCM data by an ADPCM encoder 5 and the encoded PCM data are stored in an external sound memory through a control circuit 10 and a memory interface 12. On the other hand, data stored in the external memory are decoded to PCM data by an ADPCM decoder 6 via a memory interface circuit 12 and control circuit 10 and the decoded data are converted into an analog voice signal by a D/A converter 3 and outputted. At the time of variable length recording, an offset address obtained by subtracting a fixed address value from the address value of a stop address register 8 is set up in an offset address register 9 so that an alarm tone can be outputted before a fixed time before the end of one recording area and the alarm tone is generated before the end of the recording area.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voice recording/playback LSI, and more particularly to a voice recording/playback LSI used in an answering machine.

0002

2. Description of the Related Art Conventionally, microcassette tapes have generally been used as recording media for recording messages in answering machines. However, in recent years, as the capacity of IC memories has increased and the cost per bit has decreased, solid-state recording systems for recording messages on IC memories have emerged and are attracting attention.

At first, the recording time of an answering machine was short, so the main use was to voice a response message when receiving a call, but with the increase in the capacity of IC memory, in the future There is also a trend toward solid-state recording of message messages. The biggest advantage of this solid-state recording method is that it enables random access of messages, and compared to mechanical microcassette tapes,
Reliability is greatly improved.

[0004] Particularly in the case of an answering machine, an important function is to control the answering machine from outside using the telephone's push-button signals and listen to messages recorded on the answering machine. In some cases, solid-state recording that allows random access to messages has the advantage of greatly improved operability.

FIG. 2 shows a conventional recording/playback LS.
FIG. 3 is a block diagram showing an audio memory map managed by a conventional recording/playback LSI.

[0006] The recording/playback operation by the conventional recording/playback LSI will be explained below.

[0007] First, recording is performed according to the following procedure. The audio signal amplified by the microphone amplifier 13 is A
/D converter 14 converts it into PCM data and converts it into ADP
It is input to the CM encoder 17. In the ADPCM encoder 17, the audio signal converted into PCM data is compressed and encoded, and stored in an external audio memory (not shown) connected to a memory interface terminal 72 via a control circuit 21 and a memory interface circuit 23. be done.

On the other hand, reproduction is performed by the following procedure. The data stored in the external memory is input to the ADPCM decoder 18 via the memory interface terminal 72, the memory interface circuit 23, and the control circuit 23, and is decoded in the ADPCM decoder 18 to become PCM data, which is then sent to the D/A converter. 15, is converted into an analog audio signal, and is output from an output terminal 67.

These control operations regarding recording and playback are sent via the host CPU interface circuit 22 from a data bus connected to the terminal 70 and an external CPU (not shown) connected to the host CPU interface terminal 71. The following command is input to the control circuit 21 and interpreted, and the control signal is output from the control circuit 21 through this interpretation.

The external audio memory that stores the data compressed and encoded by the ADPCM encoder 17 is composed of an address table 101 and a data area 102, as shown in FIG. When initializing the memory area, the data area 102 is divided into recording areas 1, 2, . . . , N, as shown in FIG. Further, the address table 101 is composed of a start address table including start addresses 1, 2, ..., N, and a stop address table including stop addresses 1, 2, ..., N. is address data indicating the start address of each recording area during recording and playback, and the stop address table is address data indicating the end address of each recording area during recording and playback.

Furthermore, the conventional recording/playback LS shown in FIG.
I is provided with an address counter 19 and a stop address register 20 in order to perform the above-mentioned address control by the control circuit 21, and the address counter 19 indicates an execution address during recording and playback. At the start of recording, address table 1
From 01, the stop address of the recording area before the designated recording area is loaded into the address counter 19 and set as the recording start address. Also, at the start of playback,
The start address of the designated recording area from the address table 101 is loaded into the address counter 19 and set as the playback start address. During recording and playback, after accessing the external audio memory at the address indicated in the address counter 19, the address counter 19 is incremented sequentially.

The stop address register 20 is a register indicating the end address of the recording/playback process. When recording starts, the start address of the recording area next to the designated recording area is loaded from the address table 101, and the recording ends. Set as address. At the start of playback, the stop address of the designated recording area is loaded from the address table 101 and set as the playback end address. During recording and playback, the contents of the address counter 19 and the contents of the stop address register 20 are compared and verified at any time. Then, when the contents of the address counter 19 and the contents of the stop address register 20 match, the recording/playback process ends. Further, the recording/reproducing process can also be terminated by a command given from an external CPU via the data bus connected to the terminal 70.

[0013] When the message is recorded on a solid state, the operability is greatly improved, but the recording time is limited by the cost of the IC memory, so it has to be shorter than when using tape. In recording/playback LSIs, the A/D converter compresses PCM digital data to improve memory usage efficiency. Currently, the mainstream compression method is the ADPCM method, and in this case, audio data can be compressed to about 18 Kbps. Therefore, if an 8-bit DRAM is provided for recording a message, it will take about 444 seconds (7 minutes and 4 hours).
0 seconds) continuous recording is possible. For example, if the setting is made to allow fixed length recording in 16 recording areas, the recording time per recording area will be approximately 28 seconds. Therefore, since solid-state recording requires less recording time than tape recording, it is necessary to record as efficiently as possible.

[0014] Effective methods for increasing recording efficiency include (1) a method of variable length recording, and (2) a method of generating a warning sound before one recording area ends (for example, 10 seconds before). .

[0015] Variable length recording means, for example, in the case of the above-mentioned fixed length recording, the recording time per recording area is 28
If the message ends before seconds (e.g. 10 seconds),
The remaining portion (18 seconds) remains unused and is transferred to the next recording area, resulting in very poor memory usage efficiency. Therefore, if a message ends before the time allotted in advance to one recording area,
Automatically change the start address of the next recording area,
This method uses all memory. Also, the method of generating a warning sound before one recording area ends is because in the case of solid-state recording, it is difficult to convey a message without worrying about the recording time, as with tape recording. , from the answering machine, before the recording area ends (for example,
This method outputs a warning sound every 10 seconds) to draw the speaker's attention so that the message can be conveyed efficiently. The speaker is informed in advance that when a warning sound is emitted by the response message, the remaining time is, for example, 10 seconds.

[0016]

[Problems to be Solved by the Invention] In the conventional audio recording/playback LSI described above, in order to improve the usage efficiency of audio memory, it is necessary to use the above-mentioned (1) variable length recording method or (2) one recording area method. It is desirable to use one of the methods of generating a warning sound before the end of the process. In the case of fixed-length recording mentioned above, since the length of one recording area is fixed, the host C that controls the recording and playback LSI
It is sufficient if the time is measured in the PU and control is performed so that a warning sound is emitted a certain amount of time before the end of one recording area.However, in the variable length recording area mentioned above, the length of one recording area Since the time is undefined depending on the recording time, there is a drawback that it is difficult to perform time management in the host CPU and generate a warning sound before one recording area is completed.

[0017]

[Means for solving the problem] Audio recording and playback L of the present invention
The SI converts an audio signal into PCM, compresses the data, stores the encoded audio signal in an IC memory, reads out the encoded audio signal from the IC memory, decodes it, and reproduces and outputs the audio signal. In the recording and playback LSI, when recording and playing back the audio signal, an address counter indicating an execution address of the IC memory, a stop address register indicating an end address of recording and playback processing, and an address value of the stop address register. and an offset address register for setting an offset address by subtracting a certain address from the address value, and a function to generate a warning sound at the offset address when recording an audio signal to notify that the end of recording is near. It is characterized by having the following.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention. As shown in FIG. 1, this embodiment includes a microphone amplifier 1, an A/D converter 2, and a D/A converter 3.
, push button signal detection receiver 4, and ADPCM
Comprising an encoder 5, an ADPCM decoder 6, an address counter 7, a stop address register 8, an offset address register 9, a control circuit 10, a host CPU interface circuit 11, and a memory interface circuit 12. configured.

The audio memory map managed in the audio recording/playback LSI of the present invention has start addresses 1, 2, . . . , as shown in FIG. 3, as in the conventional example.
An address table 101 formed by a start address table including N and a stop address table including stop addresses 1, 2, . . . , N, and a data area 102 formed by recording areas 1, 2, .
It is composed of

At the time of initialization, the data area 102 is divided into recording areas. Start address 1, 2,...
The start address table containing N is address data that indicates the start of each recording area during recording and playback, and the stop address table containing stop addresses 1, 2, ..., N indicates the end address during recording and playback. This is the address data shown.

Furthermore, in this embodiment shown in FIG.
The difference between the present invention and the conventional example is that in this embodiment, an offset address register 9 is newly added in connection with the control action by the control circuit 10. The function of this offset address register 9 is to set a fixed address from the address of the stop address register 8 so that a predetermined warning sound can be output at a fixed time before one recording area ends during variable length recording. The purpose is to generate the warning sound in response to the subtracted address, that is, the offset address. The operations of the components other than the offset address register 9 are the same as in the conventional example described above, and their explanation will be omitted. The function of the offset address register 9 solves the problem that a warning sound is generated before one recording area ends during variable length recording.

[0023]

As explained above, the present invention notifies that the end of recording is near at a time corresponding to an offset address obtained by subtracting a certain address from this address, based on the value of the stop address register. By generating a warning sound, even when a variable length recording area is adopted, it is possible to generate a warning sound at an appropriate time before the end of recording, making it possible to use an audio recording and playback LSI with high usage efficiency due to variable length recording. The effect is that it can be supplied.

[Brief explanation of drawings]

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

FIG. 2 is a block diagram showing a conventional example.

FIG. 3 is a diagram showing a memory map of an audio data memory.

[Explanation of symbols]

1, 13 Microphone amplifier 2, 14 A/D converter 3, 15 D/A converter 4, 15 Push button signal detection receiver 5,
17 ADPCM encoder 6, 18 A
DPCM decoder 7, 19 Address counter 8, 20 Stop address register 9
Offset address register 10, 21
control circuit

Claims (1)

[Claims] Claim 1: Converting an audio signal into PCM, storing the encoded audio signal in an IC memory, reading out the encoded audio signal from the IC memory, decoding it, and outputting the reproduced audio signal. In an audio recording/playback LSI that performs recording/playback of the audio signal, an address counter indicating an execution address of the IC memory, a stop address register indicating an end address of recording/playback processing, and a stop address register of the stop address register are provided. an offset address register for setting an offset address by subtracting a certain address from the address value with the address value as a reference, and when recording an audio signal, a warning sound is generated at the offset address to notify that the end of recording is near. A voice recording/playback LSI characterized by having a function of generating voice.