JPH0722373B2 - Playback device - Google Patents

Description

TECHNICAL FIELD The present invention relates to recording / reproducing an audio signal using a still image recording / reproducing device such as a so-called electronic still camera device.

[Outline of Invention]

INDUSTRIAL APPLICABILITY The present invention relates to a device for expanding a signal on the time axis and reproducing
By configuring the memory address in a ring,
The continuity of the reproduced signal between tracks is maintained.

[Conventional technology]

It has an image pickup device such as CCD, and it has an arbitrary field or 1
An electronic still camera device has been proposed in which a frame signal is recorded on a magnetic disk (Shokai 57-197,
No. 021).

That is, in such an apparatus, the video signal from the image pickup apparatus is gated and taken out for one field or one frame at an arbitrary shutter operation time, and this signal becomes one annular track for one field. Is recorded on the magnetic disk. The signal of one frame is recorded by using two tracks. Therefore, in this device, a video signal of a still image can be formed by repeating one track or alternately reproducing two tracks.

It has been proposed to further enable the recording of audio signals in such devices. For that purpose, for example, a method of compressing the audio signal on the time axis using a digital signal processing technique, increasing the frequency band of the audio signal to the band of the video signal, and recording using the same recording system as the video signal is considered. To be In this case, for example, the audio signal up to 5kHz is 600
By doubling the time base compression, it is possible to obtain a signal with a video band of 3 MHz. In this case, it is possible to record an audio signal for about 10 seconds, which is 600 times that during one field period (1/60 seconds).

That is, FIG. 4 shows a block diagram of an example of a recording apparatus therefor. In this figure, the video signal is input terminal (1)
To a predetermined recording signal in the recording circuit (2),
It is supplied to the FM modulation circuit (5) through the non-linear pre-emphasis circuit (3) and the switching switch (4).
It is recorded as a signal on the disk D by the magnetic head (6).

Further, the audio signal is supplied to the input terminal (11) and is supplied to the AD conversion circuit (13) through the noise reduction encoder circuit (12). This digitally converted signal is supplied to the memory device (14). A sampling signal of an audio signal in the band of 5 MHz is generated by the oscillator (21), and this signal is supplied to the address counter (22) that drives the AD conversion circuit (13) and the memory device (14). Further, an oscillator (23) having an oscillation frequency 600 times that of the above-mentioned oscillator (21) is provided, and a signal from this oscillator (23) is supplied to the address counter (22).

Further, a magnetic piece provided on a predetermined portion of the disk D is detected by the pick-up head (24), and a detection signal related to the rotation phase of the disk D is supplied to the memory controller (25). Then, for example, the signal written in the memory device (14) immediately after this detection signal is read out at a speed of 600 times.

The read signal is supplied to the DA conversion circuit (15).
A signal from the oscillator (23) is also supplied to the conversion circuit (15). Then, the analog-converted signal is supplied to the FM modulation circuit (5) through the pre-emphasis circuit (16) having a linear characteristic and the switching switch (4) and recorded as an FM signal on the disk D by the magnetic head (6). It

In this way, the audio signal can be time-axis compressed and recorded on the disk D by using the recording system of the video signal.

By the way, in such a device, the above-mentioned 10 seconds may not be enough for the length of the audio signal to be recorded. Therefore, in that case, it is recognized as a standard that a plurality of tracks on the disk D are used and signals are sequentially recorded on them.

However, in the case of reproducing an audio signal from the disk D recorded in such a manner, in the conventional apparatus for expanding the time axis, a device having only one device having a capacity corresponding to one track is used as one track. After the time-axis expansion reading of (1) is completed, there is a gap between the writing of the next track and the start of reading, and during this period, the reproduced audio signal cannot be obtained.
For this reason, the reproduced sound temporarily becomes silent, and it is extremely inconvenient for the reproducing apparatus to generate the silent sound during the reproduction.

Further, in such reproduction, when a track of a video signal is provided and the audio signal is reproduced while displaying a still image from this video track, the video track is read after the time-axis expansion reading of one audio track. The time during which the head that has been playing is accessing the next voice track is added to the above-mentioned open time, resulting in more silent time. There is no problem if the display of the still image is interrupted to some extent.

On the other hand, it is conceivable that two or more memories are provided and the time axis expansion is performed by alternately using these, but providing two or more memories complicates the circuit configuration and causes memory switching. It will not be easy to control.

[Problems to be solved by the invention]

The conventional device is configured as described above. For this reason, there is a problem that a silent period is generated when reproducing an audio signal over a plurality of tracks.

[Means for solving problems]

According to the present invention, when the audio signal is time-axis expanded and reproduced from the medium in which the audio signal is time-axis-compressed and recorded in a plurality of tracks, the memory (43) for expanding the audio signal in the time-axis is used. The capacity is one track's worth of data (EF
(FFFF), the address of the memory (counters (52) (54)) is configured in a ring shape, and a single head (31) traces any of the above tracks. The first signal taken out by the trace is written in the memory, the written signal is expanded by the time axis and read out, and this reading is from the end (EFFF) of the writing range of the first signal. It is detected that a predetermined amount before (EOOO) is reached, and by this detection, the next head track is traced at the first head, and the second signal extracted by this trace is transferred to the second head of the memory. This is a reproducing apparatus in which after the end of signal 1 (FOOO), writing is performed according to the ring-shaped address.

[Work]

According to this, since the addresses of the memory are configured in a ring shape, the continuity of the reproduced signal can be maintained even when reproducing over a plurality of tracks.

〔Example〕

In FIG. 1, the signal reproduced from the disk D by the magnetic head (31) is supplied to the FM demodulation circuit (32). When the demodulated signal is a video signal, this signal has a non-linear characteristic de-emphasis circuit (33) and a reproduction circuit (3
4), output terminal (3
6) is taken out.

When the demodulated signal is a voice signal, this signal is supplied to the AD conversion circuit (42) through the de-emphasis circuit (41) having a linear characteristic. The digitally converted signal is supplied to the memory device (43). The oscillator (2
An oscillator (51) having the same frequency as that of 3) is provided, and a signal from this oscillator (51) is supplied to an AD conversion circuit (42) and an address counter (52) that controls writing in the memory device (43). . Further, an oscillator (53) having a frequency equal to that of the oscillator (21) is provided, and a signal from the oscillator (53) is supplied to an address counter (54) which controls reading of the memory device (43).

The read signal is supplied to the DA conversion circuit (44).
A signal from the oscillator (53) is supplied to the conversion circuit (44). The analog-converted signal is taken out to the output terminal (46) through the noise reduction decoder circuit (45).

Further, the reproduction signal from the magnetic head (31) is supplied to the system control circuit (55). In this control circuit (55), for example, tracking control of the magnetic head (31) is performed. Also this control circuit (55)
A signal indicating that the video track has been tracked from is supplied to the muting circuit (35), and the muting is canceled during this time.

Further, a signal from the pickup head (56) equivalent to the head (24) is supplied to the memory controller (57). Further, a signal from the control circuit (55) indicating that the audio track has been tracked is supplied to the controller (57). Then, the signal period from the first detection signal to the next detection signal after being tracked by the voice track is detected, and this signal is detected by the address counter (5
It is supplied to the memory 2) and the memory (43) is written during this period.

Further, the end of the signal period is detected by the controller (57), this signal is supplied to the latch circuit (58), and the address of the counter (52) at that time is latched. The latched value is supplied to the arithmetic circuit (59) to subtract the predetermined value, and the subtracted value is supplied to the comparison circuit (60). Then, the comparison circuit (60) compares the read address from the counter (54) with each other, and supplies a signal when they match each other to the system control circuit (55).

In addition, the value latched by the latch circuit (58) is displayed by the counter (5
It is supplied to the preset part of 2). Further counter (5
2) (54) is composed of a ring counter that returns to the value corresponding to the first address after the value corresponding to the final address of the memory (43) and reads the count.

In this device, the capacity of the memory (43) is made slightly larger than the data amount of the audio signal for one track.

That is, for example, data for one track is stored in the memory [OOOO].
_As shown in FIG. 2, the capacity of the memory (43) is set to, for example, [OOOO] _H to [FFFF] _H when the amount corresponds to the address of H1 to [EFFF] _H. Note that [] _H represents a hexadecimal value. Further next constructed the first address [OOOO] ring as _H is followed in this end of the address [FFFF] _H.

Therefore, in this device, during the signal period detected by the controller (57), for example, the signal from the first voice track is written to the addresses [OOOO] _H to [EFFF] _H of the memory (43), and this termination is performed. The address [FOOO] _H next to is latched in the latch circuit (58). This allows the calculation circuit (59)
Outputs, for example, [EOOO] _H.

On the other hand, the time-axis expanded signals are sequentially read from the address [OOOO] _H. And this read address is [EOOO] _H
Then, this is detected by the comparison circuit (60), this signal is supplied to the system control circuit (55), and the head (31) is moved so that the next second voice track is reproduced. The time required to read the addresses [EOOO] _H to [EFFF] _{H is} the time required to move the head (31).

Further, when the second voice track is tracked and the signal of the signal period is output from the controller (57),
This signal is written in the memory (43), but since [FOOO] _H has been preset in the address counter (52) at this time, the signal is written in the addresses [FOOO] _H to [DFFF] _H. . And the next address [EOOO] _{H at} this end
Is latched by the latch circuit (58), and the arithmetic circuit (5
[DOOO] _H is output from 9).

By repeating this operation, the signals from the plurality of voice tracks are reproduced in order. The counter (54) continuously generates addresses [OOOO] _H to [FFFF] _{H in} a ring shape, so that the written signal is continuously read from the memory (43).

In this way, the signal recorded on the disk D can be expanded on the time axis and reproduced, and in this case, the reproduced sound does not become silent due to the open time such as the movement of the head, and a continuous reproduced audio signal is obtained. be able to.

Moreover the apparatus described above, the audio tracks A _1, A ₂ provided in association with the video track V as shown in FIG. 3, the audio while reproducing the still picture repeat video tracks V tracks A _1, A
_It can also be used when playing the ₂ signal.

That is, in the above description of the operation, the end detection signal in the signal period of the voice track is the system control circuit (55).
And the head (31) is moved to the video track V by this. Then, it is moved to the next voice track by the signal from the comparison circuit (60) and is returned to the video track V again by the end detection signal of the signal period of this voice track.

In this way, while the video track V signal is being reproduced as a still image, the audio track A ₁ and A ₂ signals can be expanded on the time axis and reproduced. In this case, according to the above-mentioned device, even when the head is moving. Playback sound is not interrupted. Since the video is a still image display, there is little problem even if some discontinuity occurs.

〔The invention's effect〕

According to this, since the addresses of the memory are formed in a ring shape, it is possible to maintain the continuity of the reproduced signal even when reproducing over a plurality of tracks.

[Brief description of drawings]

FIG. 1 is a block diagram of an example of the present invention, and FIGS. 2 to 4 are diagrams for explaining the present invention. (31) is a magnetic head, (42) is an AD conversion circuit, (43) is a memory device, (44) is a DA conversion circuit, (46) is an output terminal,
(51) (53) is an oscillator, (52) (54) is an address counter, (55) is a system control circuit, (57) is a memory controller, (58) is a latch circuit, (59) is an arithmetic circuit, (60) ) Is a comparison circuit.

Claims (2)

[Claims] 1. A reproducing apparatus adapted to expand the audio signal on the time axis from a medium recorded on a plurality of tracks by compressing the audio signal on the time axis and reproduce the address, wherein the address is ring-shaped. A memory for expanding the time axis having a capacity slightly larger than the amount of data for one track of an audio signal, a single head, and a system control for controlling reproduction from the medium by the single head. And a memory control means for writing a first signal extracted by tracing any of the tracks with the single head into the memory, and extending the time-axis of the written signal and reading the signal. A detection means is provided for detecting that the reading is performed by a predetermined amount before the end of the writing range of the first signal, and the system control means is operated by the signal from the detection means. Of the second signal extracted by tracing the next track by the single head, and terminating the writing range of the first signal of the memory by the memory control means. After that, the reproducing device is configured to write according to the address configured in the ring shape. 2. A video signal for a predetermined period is recorded on a predetermined track, and the audio signal is time-axis-compressed so that the video signal is repeatedly reproduced from a medium recorded on a plurality of tracks and the audio signal is timed. In a reproducing device adapted to axially expand and reproduce, a memory having addresses arranged in a ring and having a capacity slightly larger than the data amount of one track of the audio signal, for time axis expansion, A single head; system control means for controlling reproduction from the medium by the single head; and a first signal extracted by tracing any of the tracks by the single head to the memory. Memory control means for writing and writing the written signal on the time axis and reading it, and that this reading is a predetermined amount before the end of the writing range of the first signal. Detecting means for outputting the first signal, which is obtained by tracing a track of the audio signal by the single head and writing the extracted first signal in the memory, and then by the system control means. A single head is controlled so as to repeatedly trace the track of the video signal, and the system control means controls the single head according to the signal from the detection means. Then, the second signal extracted by tracing the next track of the audio signal is formed in the ring shape after the end of the writing range of the first signal in the memory by the memory control means. And the second signal is written in the memory, and then the system controller controls the single head to track the video signal repeatedly. Playback device designed to run.