JP3316344B2 - Audio signal playback device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an audio signal reproducing apparatus used for a video tape recorder (VTR) or the like.

[0002]

2. Description of the Related Art In recent years, VTRs capable of reproducing normal speed sound even at the time of double speed reproduction have been marketed.

[0003]

The above-mentioned VTR
However, there is no device in which normal-speed sound can be obtained at the time of high-speed reproduction at twice or higher speed, and there is no device that converts normal speed sound of 1-times speed into a slower sound speed.

Accordingly, the present invention improves on this point, so that a slow sound can be obtained regardless of whether the source of the normal 1 × speed sound is the EE sound or the reproduced sound of a video tape. The present invention is to propose a VTR which is suitably configured in the above manner.

[0005]

SUMMARY OF THE INVENTION According to the present invention, compression / expansion and / or deletion processing is performed on a reproduced audio signal depending on whether the reproduced audio signal is a voice section or a silent section. In a video tape recorder provided with a speech speed conversion processing unit that performs speech speed conversion processing by controlling a memory, a silent section of the sound is partially (or substantially entirely) deleted from the reproduced audio signal, and a word is deleted. The apparatus further includes processing means for converting the sound into a slow sound in real time by extending the time axis, and control means for resetting the memory for a predetermined period when the tape speed of the tape is changed.

[0006]

According to the above arrangement, even if the information content of the audio signal is changed, the changed voice is obtained by converting the voice speed immediately. Further, even if the tape speed changes, an audio signal of the changed tape speed can be obtained.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an audio reproducing system of a VTR according to the present invention. An audio signal reproduced from an audio track (horizontal track) of a video tape T by an audio head 1 is transmitted through an equalizer amplifier 2. EE / reproduction input selection switch circuit (first switch circuit) 3 is applied to one input.

The EE signal is a signal that directly outputs the input baseband signal, and is an unmodulated signal.

The audio signal EE from the fourth switch circuit 15 is supplied to the other input of the first switch circuit 3. The audio EE signal is an audio signal obtained from an external device such as another video tape recorder provided to the terminal 12 or an audio signal obtained from the tuner 15. That is, when the fourth switch circuit 15 selects the terminal a, an audio signal from an external device is output from the switch circuit 15, and when the terminal b is selected, an audio signal from the tuner / IF circuit 16 is output.

The signal selected by the first switch circuit 3 is input to a speech speed conversion circuit section 5 via a buffer amplifier 4, where the signal is subjected to a speech speed conversion process described later and supplied to a low-pass filter (LPF) 58. Switch circuit (second switch circuit) for normal reproduction voice / speech rate converted voice
7 is supplied to one input.

The output of the equalizer amplifier 2 is applied to the other input of the second switch circuit 7 via the buffer amplifier 6. Therefore, the second switch circuit 7 selects one of the reproduced audio signal obtained from the equalizer 2 and the audio signal subjected to the speech speed conversion processing, and selects one of the EE / reproduction output switching switch circuit (third switch circuit) 8. Is given to the input.

An EE audio signal obtained from a fourth switch circuit 15 is supplied to the other input of the third switch circuit 8, and the third switch circuit 8 is connected to the EE audio signal and the second switch circuit 7. And outputs it to the mute circuit 9. The signal output from the mute circuit 9 is output via a line amplifier 10 to an external device, for example, a television receiver.

13 is a microcomputer (microcomputer)
The microcomputer 13 allows the first, second,
The third and fourth switch circuits 3, 7, 8, 15 and the speech speed conversion circuit 5 are controlled. The microcomputer 13 includes a tuning unit 17.
, Whereby the tuner 16 selects a channel.

The speech speed conversion circuit 5 is composed of LC85400E manufactured by Sanyo Electric Co., Ltd., and basically comprises a bus line 50 and a microcomputer interface 5.
1, memory interface 52, clock generator 5
3. An ALC amplifier 54, an A / D converter 55, a DSP (digital signal processor) 56, and a D / A converter 57. The memory interface 52 exchanges data with an external memory (dynamic RAM) 11. I do. The speech speed conversion circuit unit 5 performs speech speed conversion by controlling the writing speed of the memory 11 as described later (the reading speed is constant), but the memory 11 is called a ring memory. The ring memory is a memory having a ring structure, and the ring structure is a memory in which the pointer of the last item of the chained list points to the first item.

The speech speed conversion circuit 5 causes the microcomputer 13 to change the voice reproduction speed. That is, the level of the audio signal input to the speech speed conversion circuit unit 5 is adjusted by an ALC (automatic level control) amplifier 54 to a level suitable for A / D conversion, and the A / D converter 55 converts the audio signal into a digital signal. After the conversion, the DSP 56 writes the data to the memory 11 via the interface 52 and reads the data from the memory 11. The digital signal read from the memory is converted into a digital signal by the D / A converter 57.
After the conversion, the signal is converted into an analog signal and output to the LPF 58. At this time, the DSP 56 adjusts the writing speed of the audio data to the memory 11 so that when the data is read with a constant clock at the time of reading, a voice whose speech speed has been converted can be obtained.

Next, the operation when the speech speed conversion circuit unit 5 enters the slow mode will be described with reference to FIG. 2. When the EE sound or the reproduced sound at the normal speed is output as shown in FIG. At time T, a voice "speech rate conversion applied to VTR" is reproduced, and when the speech rate conversion in the slow mode is performed on this voice, as shown in FIG. 2), the silent sections Tx, Ty and Tz in FIG.
As shown in (b), each of "speech rate conversion", "applied to VTR", and "technique" is expanded, and as a result, "speech rate conversion is a technique applied to VTR" is slow as a whole. That is, the user can hear the sound at the set speed.

Next, E supplied from the fourth switch 15
An operation in the case of viewing the E audio signal in the slow mode will be described. In the delay mode, the microcomputer 13 switches so that the first switch circuit 3 selects the EE audio signal. Therefore, the first switch circuit 3 outputs an EE audio signal, which is supplied to the speech speed conversion circuit unit 5 via the buffer amplifier 4. At this time, the speech speed conversion circuit 5 is set by the microcomputer 13 so as to be in the slow mode. E
The -E audio signal is supplied to the second switch circuit 7 via the LPF 58 after the above-mentioned speech speed conversion processing is performed in the speech speed conversion circuit unit 5.

Since the second switch circuit 7 is set by the microcomputer 5 so as to select the output of the LPF 58, the voice signal whose speech speed has been converted is input to the third switch circuit 8. At this time, the third switch circuit 8 is used. Since the circuit 8 selects the output of the second switch circuit 7, the third
The switch circuit 8 outputs an audio signal whose speech speed has been converted to the slow mode, which is supplied to the line amplifier 10 via the mute circuit 9 and amplified and output.

When the EE voice is to be viewed as it is without performing the speech speed conversion, the microcomputer 13 switches the third switch circuit 8 so as to select the output of the fourth switch circuit 15, and also outputs the signal from the tape. When the reproduced voice is viewed without converting the voice speed, the second switch circuit 7 is switched to select the output of the buffer amplifier 6 and the third switch circuit 8 selects the output of the second switch circuit 7. Is controlled by the microcomputer 13 so as to be switched.

When the 1x speed reproduced audio signal from the tape is viewed in the slow mode, the microcomputer 13 switches so that the first switch circuit 3 selects the output of the equalizer amplifier 2. Therefore, the first switch circuit 3 outputs a reproduced audio signal of the tape, and this is supplied to the speech speed conversion circuit unit 5 via the buffer amplifier 4. At this time, the speech speed conversion circuit 5 is set by the microcomputer 13 so as to be in the slow mode. The audio signal reproduced from the tape is supplied to the second switch circuit 7 through the LPF 58 after the above-mentioned audio speed conversion processing is performed by the audio speed conversion circuit unit 5. Since the second switch circuit 7 is set by the microcomputer 13 so as to select the output of the LPF 58, the audio signal of the tape whose speech speed has been converted is input to the third switch circuit 8.
At this time, since the third switch circuit 8 selects the output of the second switch circuit 7, the third switch circuit 8 outputs an audio signal whose speech speed has been converted to the slow mode, and this is a mute circuit. The signal is supplied to a line amplifier 10 via an amplifier 9 and output after amplification.

By the way, in the state where the fourth switch 15 selects the terminal b and the EE voice signal from the tuner 16 is converted to the speech speed in the slow mode for viewing, the user changes the channel selection state. That is, consider a case where the channel is changed from the sixth channel to the eighth channel by the tuning unit 17 according to a command from the microcomputer 13. At this time, the first switch circuit 3 selects the output of the fourth switch 15, the second switch 7 selects the output of the LPF 58,
The third switch 8 selects the output of the second switch 7.

The state of the memory 11 immediately before the user switches to the eighth channel is as shown in FIG.
The EE audio signal of the sixth channel is written to all addresses of the memory 11. When the channel is changed in this state, the audio data of the program is written (the writing start point is indicated by W). (T
In m), the previous audio data, that is, the EE audio signal of the sixth channel remains, so that the read address advances and the data of Tm is read. This means that, even if the channel is switched to, the EE audio signal of the channel before switching is heard for a while, and a difference between the video and the audio occurs.

Therefore, in the present invention, the following measures are taken.

That is, according to the flowchart of FIG. 4, if there is no change in the channel selection state in step 1 (S1),
The microcomputer 13 loads the information into the memory 11 (S
3) and take-out (S4), and the speech speed conversion process is performed as it is. If the channel selection state is changed in step 1 (S1), the microcomputer 3 resets the memory 11 so that the memory 11 is reset. 5 is controlled (S2). When the memory 11 is reset, the memory 11 becomes as shown in FIG.
Reading starts after writing for a while (Tmin) as in (C). An appropriate time is set as the period for resetting the memory depending on the time until the sound after the channel switching is output.

In the above example, the information content of the audio signal is changed from one channel to the EE audio signal of another channel.
That is, 1 is reset. Therefore, as soon as the screen is switched from one channel to another channel, the voice of the screen of the changed channel can be converted into a speech speed.

With the above-described configuration, even if the information content of the audio signal input to the speech speed conversion circuit unit is changed by, for example, tuning in the slow mode,
You can watch without delay between the image and the voice whose speech speed has been converted.

Also, during playback, the tape speed may be switched from standard (SP) to triple (EP), for example, during playback of the sound reproduced from the tape T. That is, a curling sound is generated, and this curling sound is also taken into the speech speed conversion device and output after the speech speed conversion. Needless to say, such a sound in which the curling sound is converted into a speech speed is extremely hard to hear.

That is, the tape speed is set at the time of recording by the tape speed setting switch 22 at the time of recording. At the time of reproduction, the microcomputer 13 detects a change in the control signal picked up by the control head 20, and the microcomputer controls the tape speed. Then, the capstan 21 is controlled to change the tape speed.

Now, a state in which the first switch 3 selects the output of the equalizer amplifier 2, the second switch 7 selects the output of the LPF 58, and the third switch 8 selects the output of the second switch 7, ie, In the state where the playback sound of the tape T is output after converting the speech speed, the tape speed becomes S
Consider the case where the state changes from P to EP.

Memory 11 before tape speed changes
3A is as shown in FIG. 3A, and the audio signal before the tape speed switching, that is, the audio signal of SP is written to all addresses of the memory 11.
When the tape speed is changed in this state, the changed tape speed, that is, the audio data of the EP is written (the writing start point is indicated by W), but the writing is simply started from the previous state from the W point. Even WR
During the period (Tm), the previous audio data, that is, the audio signal of the SP remains, so that the read address advances and the data of the Tm is read. This means that, even if the tape speed is switched, an audio signal of the tape speed before the switching is heard for a while, and a difference between video and audio occurs. In addition, since the curling sound at the time of switching is also written, this curling sound is also reproduced.

In view of the above, the present invention has the following measures.

That is, according to the flowchart of FIG. 5, if the tape speed is not changed in step 1 (S1), the microcomputer 13 fetches (S3) and fetches (S4) information from and to the memory 11 and talks as it is. The speed conversion process is performed. If the tape speed is changed in step 1 (S1), the microcomputer 3 controls the speech speed conversion circuit unit 5 to reset the memory 11 (S2). When the memory 11 is reset, it becomes as shown in FIG. 3 (B), and reading starts after audio information is written for a while (Tmin) as shown in FIG. 3 (C). At this time, by appropriately setting the period in which the memory is kept in the reset state, it is possible to avoid writing the curling sound at the time of switching the tape speed to the memory.

With the above configuration, even if the tape speed changes, the sound or curling sound before the change is not output.

[0035]

As described above, according to the present invention, even if the information content of the audio signal input to the speech speed conversion circuit portion is changed, there is no time lag between the image and the speech speed converted sound. An audio signal reproducing device that can be viewed can be provided.

[Brief description of the drawings]

FIG. 1 is a main block diagram of a video tape recorder embodying the present invention.

FIG. 2 is a diagram showing an example of an operation description of a video tape recorder embodying the present invention.

FIG. 3 is an explanatory diagram of an operation of a memory for speech speed conversion according to the present invention.

FIG. 4 is a diagram showing a flowchart for explaining control according to the present invention.

FIG. 5 is a flowchart illustrating another control according to the present invention.

[Explanation of symbols]

 T video tape 1 magnetic head 3 first switch circuit 5 speech speed conversion circuit section 7 second switch circuit 8 third switch circuit 10 line amplifier 11 memory 12 EE audio signal input terminal 13 microcomputer 15 fourth switch

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁷ identification symbol FI H04N 5/928 H04N 5/92 J 5/93 5/93 G (58) Field surveyed (Int.Cl. ⁷ , DB name) G10L 11 / 02,13 / 08 G10L 19 / 00,21 / 04 G11B 20/02 H04N 5/928-5/93

Claims (1)

(57) [Claims] 1. A speech speed conversion process for compressing / expanding and / or deleting a reproduced audio signal from a memory according to whether the reproduced audio signal reproduced from a tape is an audio section or a silent section. In a video tape recorder provided with a speech speed conversion processing unit performed by control, a part (or substantially all) of a silence section of the sound is deleted from the reproduced sound signal, and a word is expanded by extending a time axis. A video tape recorder, further comprising: processing means for converting into a sound that is slow in time; and control means for resetting the memory for a predetermined period when the tape speed of the tape is changed.