JPH0449573A - Digital sound recording and reproducing device - Google Patents

Abstract

PURPOSE:To perform the same sure processing as recording start/end points at the time of reproducing by detecting discontinuity of data caused not only at the time of stop of running for recording of a recording medium but also in the middle of recording. CONSTITUTION:When a selected analog signal or a selected digital signal is selected and recorded, the switching operation of a changeover switch 9 of the analog input or the digital input recorded at present is detected to send a recording start/stop signal (d) to an ID code control part 11, and it is recorded in an ID code part of recording data by an ID code adding part 12. Thus, a discontinuous part due to switching from the analog input signal to the digital input or from the digital input signal to the analog input signal caused in the middle of recording is detected at the time of reproducing, and proper processing like fading processing is performed at the discontinuous point.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a digital audio recording and reproducing apparatus for recording and reproducing digital audio signals alone or together with video signals.

2. Description of the Related Art In recent years, so-called digital audio technology, in which audio signals are digitized and recorded and reproduced, has made remarkable progress. One of the representative examples is the compact disc (CD) and the digital audio tape recorder (DAT). Although these are audio-only examples, digitization of the audio portion of video tape recorders (VTRs) is rapidly progressing, and 8 mm video is a typical example.

One of the important technologies constituting these digital audio recording and reproducing devices is detection and processing of spliced portions during recording. In recording and reproducing devices, it is inevitable that discontinuities will occur in the data series at the boundary point between the old recorded part and the new recorded part, the so-called splicing point.
Especially in digital recording, modulation laws, data arrangement,
Since discontinuities occur in sequences of error correction codes, accurate detection and processing of splicing points has become an important issue.

A conventional digital audio recording/reproducing apparatus for this purpose is disclosed in, for example, Japanese Patent Publication No. 64-4265.

Hereinafter, the above-mentioned conventional digital audio recording/playback device will be explained with reference to the drawings.

FIG. 2 is a block diagram showing the configuration of a conventional digital audio recording and reproducing device.

In FIG. 2, 30 is an analog audio signal input terminal;
1 is an analog-to-digital converter (hereinafter abbreviated as AD converter); 32 is a digital signal processing unit (DSP) that includes data array conversion, error correction code generation and addition, etc.; 33
34 is a recording circuit including a recording amplifier, an electromagnetic conversion system, etc.; 35 is a recording medium such as a magnetic tape; 36
37 is a group of operation switches; 38 is a synchronization signal generation circuit; 39 is a reproduction circuit including an electromagnetic conversion system and reproduction amplifier; 40 is a synchronization signal extraction circuit;
1 is a digital signal processing unit including data array reconversion and error correction processing, 42 is a temporary level lowering means, 43 is a digital-to-analog converter (hereinafter abbreviated as DA converter), and 44 is an analog audio converter. This is the signal output end.

The operation of the conventional digital audio recording and reproducing apparatus configured as described above will be explained below.

During recording, the analog audio signal input from the input terminal 30 is converted into a digital audio signal by the AD converter 31, and the digital signal processing unit 32 performs data arrangement conversion, generation and addition of error correction codes, and synchronization. After a predetermined synchronization signal is added by the signal adding section 33, the signal is recorded onto the recording medium 35 by the recording circuit 34. At this time, the mechanical control unit 36 controls the running of the recording medium 35 according to the contents of the commands to the operation switch group 37, and at the same time generates a synchronizing signal including a recording start/end signal in conjunction with the running operation during recording. It is generated in the circuit 38 and added in the synchronization signal adding section 33. The recording start/end signal is recorded for a certain period of time immediately after starting recording and immediately before stopping recording.

During reproduction, the signal recorded on the recording medium 35 is transmitted to the reproduction section 39.
A synchronizing signal extraction circuit 40 detects a synchronizing signal that is a data delimiter, and a digital signal processing section 41 performs rearrangement and error detection and correction processing of the reproduced data based on this delimiter. At this time, at the same time as the synchronization signal is detected, the type of the synchronization signal is detected, and a detection signal indicating the splicing point at which recording is started/ended is sent to the temporary signal lowering means 42. At splicing points and signal portions exceeding the limit of error correction capability, the temporary signal lowering means 42 performs temporary level lowering processing of the reproduced signal, so-called muting processing, or fade processing such as cross-fade, fade-out, fade-in, etc. , the signal is converted back to an analog signal by the DA converter 43, and outputted from the output terminal 44 as an analog audio signal.

The recording start/end signal recording method is also shown in the above-mentioned Japanese Patent Publication No. 84-4285, but as shown in Fig. 3(A), two completely different types of synchronization signals (SY
NCI, 5YNC2) may be prepared, or a recording start/end signal may be added after the common synchronization signal (SYNC) as shown in FIG. 3(B).

Problems to be Solved by the Invention In the early stages of development of digital audio recording and playback devices, discontinuities in recorded data mainly occur at splice recording points.
That is, it is mainly used before and after the start and stop of the recording medium during recording, and it was sufficient to record the recording start/end signal in conjunction with the operation of the operation switch group as in the conventional example.

However, today, the specifications of digital audio recording and playback devices continue to expand from analog input/output to digital input/output, from a single sampling frequency to multiple sampling frequencies, from audio recording to data recording, etc. For example, “Japan Electronics Industry Association Standards,”
CP-340 digital audio interface,
(Refer to "September 1987"), due to changes in some of these specifications during recording, discontinuities are increasingly occurring in recorded data even when the recording medium does not stop during recording. .

Therefore, with only the above conventional configuration, the discontinuity occurring in recorded data cannot be detected during reproduction, and the discontinuity cannot be appropriately processed.

The present invention is intended to solve the above-mentioned conventional problems, and an object of the present invention is to provide a digital audio recording and reproducing device that can reliably detect the discontinuous portion of the data that occurs during recording and perform appropriate processing. shall be.

Means for Solving the Problems In order to achieve the above object, the digital audio recording and reproducing apparatus of the present invention has the configuration of the above conventional example in which a recording start/end signal is recorded at the rear of a synchronization signal in conjunction with the start and end of recording. In addition, the system detects changes in parameters that may cause discontinuity in data if they change during recording, and records recording start/stop signals in the same way as for normal recording start and end. have.

Effect: With the above-described configuration, the present invention makes it possible to detect discontinuities in data that occur during recording in addition to stopping the recording medium during recording, and to perform reliable processing similar to recording start/end points during playback. becomes.

Embodiments Hereinafter, embodiments of the digital audio recording and reproducing apparatus of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a digital audio recording and reproducing apparatus in an embodiment of the present invention.

In FIG. 1, 1 is an input terminal for analog audio signals, 2 is a changeover switch for analog audio signals from A H1...+An of input terminal 1, 3 is an AD converter, and 4 is a plurality of frequencies F sl+ . ... r Fsk, a sampling frequency oscillation source for driving the AD converter 3, 5 a changeover switch for selecting the sampling frequency, 6 a digital signal input end, 7 a DI+ of the input end 6. ...Digital signal changeover switch from Dn, 8 is a digital input interface section, 9 is an analog input and digital input changeover switch, 10 is a data arrangement conversion switch for recording signals in a predetermined format on a recording medium, and A digital signal processing unit (DS) that generates error correction codes, etc.
P), 11 is an ID code control unit for detecting switching signals from each of the above-mentioned changeover switches and recording a recording start/end signal as a part of the ID code in the same way as the splicing point; 12 is an ID code control unit for generating I for adding ID code to recorded data
D code addition section, 13 is a recording and playback switch, 1
4 is a rotating cylinder and a rotating head; 15 is a magnetic tape; 16 is a rotating reel for winding the magnetic tape 15;
7 is a mechanical control unit for driving and controlling the rotating head 14 and rotating reel 16; 18 is an operating unit such as an operation switch or a microcomputer that issues commands to the mechanical control unit 17; 19;
20 is an ID code detection unit, 20 is a digital signal processing unit that performs data array reconversion and error correction processing, etc., and 21 is a signal portion that exceeds the error correction capacity limit and a continuous data portion that performs cross-fade, fade-in/fade-out processing, or 22 is a DA converter, 23 is a digital output interface, 24 is an analog signal output end, and 25 is a digital signal output end.

The operation of the digital audio recording and reproducing apparatus of this embodiment configured as described above will be described below.

The basic operation is the same as that of the conventional example, and the mechanical control section 17 controls the traveling of the recording medium 5 based on the command from the operation section 18, and also receives the recording start/end signal a in conjunction with the recording start and stop operations. is sent to the ID code control section 11, and the ID code addition section 12 records it in the ID code section within the recording data.

The conventional method for recording start/end signals is the third conventional method.
As shown in Figures (A) and CB), two independent synchronization signals are
Types (SYNCI, 5YNC2) may be provided and identified by switching between the two, or a common synchronization signal (SYNC)
A dedicated recording start/end signal recording section may be provided at the rear of the recording section. In addition, by expanding the latter idea and expanding the types of data that can be recorded and improving the reliability of recording signals, we
), the block address (BA) and ID code (ID code) are written at the end of the synchronization signal (SYNC).
tlon Code: Identity code, hereinafter abbreviated as ID. ) and parity (PT) generated from both may be added, and a recording start/end signal may be recorded as part of the ID code.

In addition to the basic operation of the conventional example described above, in this example, the first
, the analog signal A + + from the m input terminals 1
...When recording with lAl1 selected, the switching operation of the analog input changeover switch 2 during recording is detected, a recording start/stop signal is sent to the ID code control unit 11, and the I
The D code addition unit 12 records the ID code in the recorded data. As a method for detecting the switching operation of switch 2, for example, if it is a mechanical switch, it may be possible to use a multiple switch to decode the set position and use a change in the decoded value, or if it is an electronic switch, it may be detected directly. A change in the set address value may also be used. This makes it possible to detect discontinuities caused by switching of analog input signals that occur during recording during playback, and to perform appropriate processing such as fade processing at the discontinuity points.

Second, the digital signal D + from the n input terminals θ
t ... When recording is performed by selecting IDn, the switching operation of the digital input changeover switch 7 during recording is detected, and the recording start/stop signal C is sent to the ID code control section 11, and the ID code addition section 12 ID in recorded data by
It is recorded in the code section. As a method for detecting the switching operation of the switch 7, for example, if the switch is an electronic switch such as a data selector, a change in the set address value may be used. This makes it possible to detect discontinuities caused by switching digital inputs during recording during playback, and to perform appropriate processing such as fade processing at discontinuity points.

Thirdly, if either the selected analog signal or the selected digital signal is selected and recorded,
Detects the switching operation of the analog input and digital input switch 9 during recording, and outputs the recording start/stop signal d.
is sent to the ID code control section 11, and the ID code addition section 12
This is recorded in the ID code section of the recorded data. As a result, discontinuities caused by switching from an analog input signal to a digital input signal or from a digital input signal to an analog input signal that occur during recording can be detected during playback, and appropriate fade processing etc. can be performed at the discontinuous point. Processing can now be performed.

Fourth, k types of sampling frequencies F s++ ...I
When one type of Fsk is selected and the AD converter 3 is driven to record, the switching operation of the sampling frequency selection switch 6 during recording is detected, and the recording start/stop signal e is sent to the ID code control unit. 11, and the ID code adding section 12 records it in the ID code section within the recording data. This makes it possible to detect discontinuities caused by switching of sampling frequencies that occur during recording during reproduction, and to perform appropriate processing such as fade processing at discontinuous points.

Fifth, when the digital signal from the input terminal 6 is decoded and recorded by the input interface section 8, the switching of the sampling frequency of the digital input signal during recording is considered as additional information of the transmitted data or data transmission. It is detected from the change in rate, and a recording start/stop signal f is sent to the ID code control section 11, and the ID code adding section 12 records it in the ID code section in the recording data. This makes it possible to detect discontinuities caused by switching of the sampling frequency of the digital input signal during recording during reproduction, and to perform appropriate processing such as fade processing at the discontinuity points.

one! 6-Sixthly, the recording medium 15 receives the command from the mechanical control unit 17.
When the recording medium 15 is traveling at a constant speed and recording, the recording medium 15 detects that the traveling speed of the recording medium 15 changes from standard speed to below standard speed or from below standard speed to standard speed during recording, and records. The start/stop signal g is sent to the ID code control section 11, and the ID code addition section 12 records it in the ID code section within the recording data. This makes it possible to detect discontinuities caused by switching of the running speed of the recording medium 15 during recording during reproduction, and to perform appropriate processing such as fade processing at the discontinuity points.

Seventhly, when the digital signal from the input terminal 6 is decoded and recorded by the input interface section 8, if a signal prohibiting copying is sent along with the digital audio signal, the audio signal is not recorded. If the copy prohibition condition is canceled, recording will start, and the switching between stopping and starting audio signal recording will be detected, and recording will start/start.
A stop signal is sent to the ID code control section 11, and the ID code addition section 12 records it in the ID code section of the recording data. This makes it possible to detect discontinuous portions of audio signal recording due to copy prohibition and copy prohibition release that occur during recording, and to perform appropriate processing such as fade processing at discontinuous points.

Eighth, when the digital signal from the input terminal 6 is decoded and recorded by the input interface unit 8, if a signal with copy prohibition conditions is sent along with the digital audio signal, the digital audio signal is The DA converter 22 converts the signal back to an analog signal, inputs it to the analog input terminal 1, and records it. When the copy prohibition condition is lifted, direct digital recording starts, and the data is converted from digital to analog or from analog to digital. The switching of audio signal recording is detected, a recording start/stop signal i is sent to the ID code control section 11, and the ID code adding section 12 records it in the ID code section in the recorded data. This makes it possible to detect discontinuous portions of audio signal recording due to copy prohibition and copy prohibition release that occur during recording, and to perform appropriate processing such as fade processing at discontinuous points.

Ninth, when a digital signal input from the input terminal 6 is decoded and recorded by the input interface section 8, the input signal may become an audio signal due to a change in the value of the auxiliary signal sent along with the digital signal. It detects that the signal is switched to data other than audio, or from data other than audio to audio signal, and sends a recording start/stop signal j to the ID code control unit 11, and the ID code addition unit 12 converts the data in the recorded data. It is recorded in the ID code section. Due to this,
Discontinuities caused by switching from an audio signal to a non-audio signal or from a non-audio signal to an audio signal that occurred during recording can be detected during playback, and appropriate processing such as fade processing can be performed at the discontinuous point. It can be done.

Tenthly, a plurality of recording formats with different numbers of quantization bits of audio signals are input to the digital signal processing unit 10 according to the recording performance determined by the characteristics of the recording medium 15, the running speed of the mechanical control unit 17, etc. When recording is performed by selecting with an added predetermined switch, a change in the selection of the recording format during recording is detected, and a recording start/stop signal k is sent to the ID code control unit 1.
1, and the ID code addition section 12 records it in the ID code section within the recording data. This makes it possible to detect discontinuous portions due to switching of recording formats that occur during recording during reproduction, and to perform appropriate processing such as fade processing at discontinuous points.

Eleventh, when a video signal is recorded together with digital audio by an audio/video dual-purpose head provided on the rotary cylinder 14 or an independently provided video-only head,
Video signal recording format changes from NTSC to PAL SE
When switching to CAM system etc. or vice versa, the field frequency of the video signal will change from 80Hz to 50Hz.
z or from 50 Hz to 80 Hz, the recording format of the digital audio signal is also switched accordingly. Therefore, the switching of the video signal recording format is detected as, for example, the switching of the rotation control frequency of the rotary cylinder or the like by the mechanical control unit 17, and recording is started/
A stop signal 1 is sent to the ID code control section 11, and the ID code adding section 12 records it in the ID code section in the recording data. This makes it possible to detect discontinuous parts of the digital audio signal due to switching of the video signal recording format that occurred during recording during playback, and to perform appropriate processing such as fade processing at the discontinuous points.

In this embodiment, the recording method on the recording medium is as follows:
4 on the magnetic tape 15, of course other methods such as a fixed head or a magnetic disk may be used.

Further, each item listed in this embodiment is independent, and all may be implemented at the same time or may be used in any combination.

As described above, according to this embodiment, in addition to the conventional configuration in which recording start/end signals are recorded after the synchronization signal in conjunction with the start and end of recording, analog input switching and digital By detecting input switching, switching between analog manual input/digital input, or sampling frequency switching, etc., and recording recording start/stop signals in the same way as normal recording start and end, It is possible to reliably detect data discontinuities that occur outside of the recording run start/stop portions, and to perform reliable correction processing during playback.

Effects of the Invention As described above, the present invention, in addition to the conventional configuration of recording a recording start/end signal at the rear of a synchronization signal in conjunction with the start and end of recording, also provides a method for recording discontinuity in data if a change occurs during recording. By detecting changes during recording in each functional element that may cause problems during playback, and recording start/end signals in the same way as for normal recording start and end, the recording run of the recording medium can be controlled. It becomes possible to reliably detect data discontinuities that occur in a recording medium other than at start/stop points, and during reproduction, processing similar to that at recording start/end points can be performed, which has great practical effects.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a digital audio recording/playback device according to an embodiment of the present invention, FIG. 2 is a block diagram showing the configuration of a conventional digital audio recording/playback device, and FIG. 3 is a block diagram showing a synchronization signal and recording start/playback device. FIG. 3 is a format diagram showing the structure of a data block for recording an end signal. 1... Analog signal input terminal, 2... Analog signal changeover switch, 3... AD converter, 4...
- Sampling frequency oscillation source, 5... Sampling frequency selection switch, 6... Digital signal input terminal, 7
...Digital signal selection switch, 8...Digital input interface section, 9...Analog/digital input selection switch, 10.20...
・Digital signal processing section, 11... ID code control section, 12... ID code adding section, 13... Record/playback switch, 14... Rotating cylinder and rotating head, 15... Magnetic tape , 18
... Rotating reel, 17... Mechanical control section, 1
8... Operation unit, 19... ID code detection unit, 2
1... Fade processing/processing section, 22... DA converter, 23... Digital output interface,
24...Analog signal output end, 25...Digital signal output end.

Claims (9)

[Claims] (1) In a digital audio recording/playback device that has a function of recording a recording start/end signal in conjunction with the start and stop of running of a recording medium during recording, in addition to the start/stop of running of a recording medium, recording during recording A digital audio recording/playback device that detects changes in setting conditions and records recording start/end signals. (2) When switching the selection of input signals from multiple analog audio input terminals, or when switching the selection of input signals from multiple digital audio input terminals, or from the analog audio input terminal to the digital audio input terminal, 2. The digital audio recording and reproducing apparatus according to claim 1, wherein the recording start/end signal is recorded when the input selection is switched from the digital audio input terminal to the analog audio input terminal. (3) The recording start/end signal is recorded when the selection of the sampling frequency of the analog-to-digital converter is switched or when the sampling frequency of the input signal from the digital audio input terminal is switched. digital audio recording and playback device. (4) The digital audio recording according to claim 1, wherein a recording start/end signal is recorded when the running speed of the recording medium is switched from a standard speed to a non-standard speed or from a non-standard speed to a standard speed. playback device. (5) When the content of the input signal from the digital audio input terminal switches from an audio signal to a data signal other than audio,
2. The digital audio recording and reproducing apparatus according to claim 1, wherein a recording start/end signal is recorded when switching from a data signal other than audio to an audio signal. (6) The digital audio recording/reproducing apparatus according to claim 1, wherein the recording start/end signal is recorded when a plurality of data recording formats having different numbers of quantization bits are selected for recording the digital audio signal. (7) In a digital audio recording/playback device that has a function of recording a recording start/end signal in conjunction with the start and stop of running of a recording medium during recording, in addition to the start/stop of running of a recording medium, digital When a signal prohibiting copying is sent along with the input signal from the audio input terminal, recording of the audio signal is stopped after recording the recording start/end signal, and the condition prohibiting copying is canceled.
A digital audio recording/playback device that starts recording an audio signal and also records a recording start/end signal. (8) In a digital audio recording/playback device that has a function of recording a recording start/end signal in conjunction with the start and stop of a recording medium during recording, digital audio When a signal prohibiting copying is sent along with the input signal from the input terminal, the recording start/end signal is recorded, the digital audio signal is converted to an analog signal by a digital-to-analog converter, and the signal is converted from analog to digital again. A digital audio recording/playback device that converts the signal into a digital signal using a converter and records the signal, and when copy protection is released, records a recording start/end signal and starts digital direct recording. (9) In a digital audio recording/playback device that has a function of recording a recording start/end signal in conjunction with the start and stop of the recording medium during recording, and is capable of simultaneously recording a video signal, A digital audio recording and reproducing device that detects not only the start/stop of running but also the switching of the television format of the video signal being recorded, and records the recording start/end signal.