JP2001223588A - Transmission and reception system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transmission and reception system where on discontinuous sound is produced by a receiver side reproducing device even when discontinuous digital music data are outputted to a communication system in which transmission of a time code is not permitted. SOLUTION: A controller 11 adds an invalid/valid flag to demodulation data in the unit of frame in the case of outputting an error frame to a communication system 16. A reception section 21 of the receiver side reproducing device 20 receives the demodulation data in the unit of frame and the invalid/valid flag sent through the communication system 15 and temporarily stores them to a buffer memory 22. A controller 26 advance-reads the invalid/valid flag temporarily stored in this buffer memory 22. The controller 26 controls switches 23, 25 to select the demodulation data from the buffer memory 22 or a fade processing output from a fader 24 and provides an output of the selected data or output.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmitting / receiving apparatus for reproducing and transmitting predetermined digital data and for receiving and reproducing the transmitted digital data.

[0002]

2. Description of the Related Art In recent years, it has been considered to apply a 1-bit audio signal obtained by performing delta-sigma (ΔΣ) modulation to an analog audio signal to a high-quality recorder or data transmission. The 1-bit audio signal obtained by ΔΣ modulation has a sampling frequency 64 times (64 times as large as that of a so-called multi-bit digital signal having a sampling frequency of 44.1 KHz and a data word length of 16 bits, which has been used for conventional digital audio, for example). × 44.
At 1 KHz, the data word length is one bit, such as a very high sampling frequency and a short data word length.

[0003] In a music reproducing system for reproducing an optical disk on which music data or the like is recorded by a 1-bit audio signal, music data is often divided into fixed time intervals. For example, in the above-mentioned optical disk, a unit of a frame consisting of 1/75 second is used, and a time code is attached in a frame unit. Data compression is also performed on a frame basis.

Therefore, after reproducing the music data based on the 1-bit digital audio signal from the optical disk 111 using the optical pickup 112, the front-end processor 113 and the decoder 114 by the optical disk reproducing apparatus 110 shown in FIG. 11, it conforms to the IEEE1394 standard. Also in the case where data is transmitted to another reproducing apparatus 120 using the communication system 115 and is output as music from the other transmitting apparatus via the speaker 124, data is generally transmitted in frame units.

[0005] In the above-mentioned optical disk reproducing apparatus, music data is handled in units of frames.
When an operation such as REV or music selection is desired by the user, the frames are discontinuous, and the discontinuous points are actually reproduced as sound. Therefore, FIG.
The optical disk reproducing apparatus 100 having the configuration shown in FIG.
In this optical disc reproducing apparatus 100, an optical disc 101 on which music data or the like based on a 1-bit audio signal is recorded.
The front end processor 103 performs a waveform shaping process, an error correction process, and the like on the RF signal read by the optical pickup 102. Front-end processor 103
After the data subjected to the above processing is decoded by the decoder 104, the data is temporarily stored in the buffer memory 105, read out, subjected to the fader processing by the fader 106, and subjected to the analog audio signal by the 1-bit D / A converter 107. And amplified by the amplifier 108 before the speaker 1
09. The buffer memory 105 holds time codes in association with music data in frame units as shown in FIG. As described above, in the optical disc reproducing apparatus 100, since the time code is stored in the buffer memory 105 in association with the music data in units of frames, the discontinuity of frames due to operations such as CUE / REV and music selection is detected in advance. Thus, the frame data can be read from the buffer memory 105. Thereby, as shown in FIG. 14, frame N, frame N + 1,
After the frame N + 2, before the discontinuous point X occurring before the frame M is actually reproduced as a sound, the gain of the fader 106 is reduced from 1 to 0, and the abnormal sound caused by reproducing the discontinuous music data as it is. Can be prevented from occurring.

[0006]

However, FIG.
As shown in the figure, the optical disk reproducing apparatus 100 that has read data from the optical disk 101 outputs data before being input to the fader 106 in the same apparatus to the communication system 115, and the receiving side reproducing apparatus 120 stores the data in the buffer memory 121 and fader. 122, 1-bit D / A converter 123, amplifier 1
When the communication protocol does not include information such as a time code that allows the receiving side to determine that there has been data discontinuity, when the communication protocol does not include the discontinuous data, Is reproduced as it is, and an abnormal sound is generated.

[0007] The present invention has been made in view of the above-mentioned circumstances, and even if discontinuous digital music data is output to a communication system in which transmission of time code is not permitted, discontinuous digital music data is output by a receiving-side reproducing device. An object of the present invention is to provide a transmitting / receiving device that does not generate sound.

[0008]

According to the present invention, there is provided a transmitting / receiving apparatus for demodulating and transmitting digital data obtained by a predetermined modulating means.
A transmitting and receiving apparatus comprising: a receiving unit that receives and reproduces demodulated data from the transmitting unit; and a communication system for communicating the demodulated data between the transmitting unit and the receiving unit. Reproducing means for reproducing the digital data, demodulating means for demodulating the digital data reproduced by the reproducing means, first storage means for temporarily storing demodulated data from the demodulating means, First fade means for performing a fade process on the demodulated data read from the first storage means, transmitting means for transmitting the demodulated data from the demodulation means to the communication system, An invalid / valid flag indicating whether the demodulated data to be transmitted is invalid data or valid data is added to the demodulated data, and a fade process from the first fading means is performed. Data and first control means for selectively switching the demodulated data from the demodulation means, wherein the reception unit has been transmitted from the transmission means of the transmission unit via the communication system. Receiving means for receiving the demodulated data, second storage means for temporarily storing the demodulated data received by the receiving means, and demodulated data supplied via the second storage means A second fade processing means for performing a second fade processing on the basis of the invalid / valid flag added to the demodulated data temporarily stored in the second storage means by the transmission unit. Second control means for switching between the fade output data and the demodulated data from the second storage means.

Here, the first control means sets an invalid / valid flag for each unit in which the demodulated data is grouped by a predetermined time length depending on whether or not there is a discontinuous point in the demodulated data by the demodulating means. Add.

Further, there is provided an operation means for changing a reproduction speed of digital data in the transmission section, and the first control means fades from the first fade means of the transmission section in response to an operation of the operation means. The processing data and the demodulated data from the demodulating means are switched.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, in this embodiment, Δ
(1) a transmitting-side reproducing apparatus 1 that demodulates and reproduces and transmits 1-bit audio data obtained by modulation; a receiving-side reproducing apparatus 20 that receives and reproduces demodulated data from the transmitting-side reproducing apparatus 1; This is a transmission / reception system that includes a communication system 16 for connecting the reproduction device 1 on the side and the reproduction device 20 on the reception side and communicating the demodulated data.

The transmitting side reproducing apparatus 1 comprises an optical pickup 3 for reading out an RF signal, a focus error signal and a tracking error signal from the optical disk 2, and a front end processor 4 for performing a reproducing process on the RF signal read by the optical pickup 3. And the front-end processor 4
A decoder 5 for demodulating the 1-bit digital data for reproduction from the memory 5, a buffer memory 6 for temporarily storing the demodulated data from the decoder 5, and selectively performing a fade process on the demodulated data read from the buffer memory 6 A fader 8, a transmitting unit 10 for transmitting demodulated data from the decoder 5 to the communication system 16, and an invalid / valid flag indicating whether the demodulated data transmitted by the transmitting unit 10 is invalid data or valid data. In addition to the demodulated data, the fade processing data from the fader 8 and the decoder 5
A controller 11 for selectively controlling the switch 7 and the switch 9 to switch the demodulated data from the controller 9 and a 1-bit D / A converter 13 for converting a switching output from the switch 9 into an analog audio signal; And an amplifier 14 for amplifying a signal. The controller 11 has an operation unit 12 having a function of changing the playback speed on the transmission-side playback device 1 in accordance with a user operation.
Is also connected. The analog audio signal amplified by the amplifier 14 is output from the speaker 15. The front end processor 4 generates a focus servo, a tracking servo, and a thread servo signal for servo-controlling the optical pickup 3 based on the focus error signal and the tracking error signal from the optical pickup 3, and sends the signals to a servo circuit (not shown). Supply. FIG. 1 omits the servo circuit, a drive circuit for driving the optical pickup 3 based on each servo signal from the servo circuit, a spindle motor for rotating an optical disk, and the like.

As the communication system 16, a bus conforming to IEEE 1394, which is a high-speed serial interface standard, for example, i-LINK (trademark of Sony Corporation) can be used.

[0014] The receiving-side reproducing apparatus 20 includes:
A receiving unit 21 for receiving the demodulated data transmitted from the communication unit 16 via the communication system 16, a buffer memory 22 for temporarily storing the demodulated data received by the receiving unit 21,
A fader 24 for performing a fade process on demodulated data selectively supplied through the buffer memory 22;
The switch 23 selectively switches the fade processing data from the fader 24 and the demodulated data from the buffer memory 22 based on the invalid / valid flag added by the transmission side reproducing apparatus 1 to the demodulated data temporarily stored in the buffer memory 22.
And a controller 26 for controlling and switching the switch 25, and a 1-bit D / A converter 27 for converting a switching output from the switch 25 into an analog audio signal.
And an amplifier 28 for amplifying this analog audio signal
And The audio signal amplified by the amplifier 28 is output from a speaker 29.

Next, the transmitting side reproducing apparatus 1 and the receiving side reproducing apparatus 20 will be described in detail. First, a ΔΣ modulator that generates 1-bit audio data recorded on the optical disc 11 and reproduced by the transmission-side reproducing device 1 will be described with reference to FIG. 2, the ΔΣ modulator 30 includes an adder 32, an integrator 33, a 1-bit quantizer 34, and a 1-sample delay 36. The addition output of the adder 32 is supplied to the integrator 33, and the integrator 3
3 is supplied to a 1-bit quantizer 34. The quantized output of the 1-bit quantizer 34 is an output terminal 35
, And is fed back to the adder 32 through a one-sample delay unit 36, and is added to the analog audio signal supplied from the input terminal 31. The addition output from the adder 32 is integrated by the integrator 33. Since the integrated output from the integrator 33 is quantized by the 1-bit quantizer 34 for each sample period, it is possible to output 1-bit quantized data, that is, the 1-bit audio data from the output terminal 35. it can.

The 1-bit digital data modulated by the ΔΣ modulator 30 is read from the optical disk 2 by the optical pickup 3 as an RF signal. The RF signal read by the optical pickup 3 is supplied to a front-end processor 4. The front-end processor 4 performs reproduction processing such as waveform shaping processing and ECC processing on the RF signal, extracts 1-bit digital data for reproduction, and supplies the digital data to the decoder 5.

A decoder 5 extracts a frame from sector-by-sector data read by the optical pickup 3 from the optical disk 2 and reproduced by the front-end processor 4, obtains demodulated data in frame units, and temporarily records the demodulated data in the buffer memory 6. I do. FIG. 3 shows the relationship between sectors and frames. Frame N spans three sectors. Other frames also span multiple sectors. One sector has a fixed length of 2048 bytes. At this time, the time code added for each frame is also recorded in the buffer memory 6 as shown in FIG. 4 while corresponding to the frame data.

When the transmission-side reproducing apparatus 1 outputs data to the communication system 16, the demodulated data recorded in the buffer memory 6 is converted to a 1/75 second frame signal shown in FIG. Output in frame units according to.

Information that can be transmitted on a frame basis includes audio data, supplementary data, an invalid / valid flag, a track attribute, the number of channels,
There is a loudspeaker configuration,
The time code is not included in the transmission protocol of the communication system of the IEEE 1394 standard.

Among these pieces of information, the invalid / valid flag particularly indicates whether the corresponding frame is an error frame. The cause of the error frame is
This is because the front end processor 4 that processes the RF signal output from the optical pickup 3 and corrects the error outputs an error sector when the reading state of the optical disk is poor and the error cannot be corrected. The error sector can be detected by the controller 11 monitoring the sector error flag output from the front-end processor 4. A frame including even one byte of data included in the error sector is an error frame.

When an error frame occurs, the buffer memory 6 records "error" as frame error information. When outputting the error frame to the communication system 16, the controller 11 sets the invalid / valid flag to “invalid”, and the transmitting unit 10 adds the invalid / valid flag to the frame-based demodulated data. As described above, the invalid / valid flag indicates “invalid” or “valid” for an error frame including incorrect data.

That is, the flag is set in the controller 11
Is generated while monitoring the data for each frame demodulated by the decoder 5 and is sent to the transmission unit 10 to be added to the demodulated data for each frame. This flag is set to “invalid” when transmitting an error frame including abnormal data. When transmitting a normal frame other than an error frame, this flag is set to “valid”.

In the receiving-side reproducing apparatus 20, the receiving section 21 receives the demodulated data in frame units and the invalid / valid flag sent from the transmitting section 10 of the transmitting-side reproducing apparatus 1 via the communication system 15, and receives the buffer memory. 22 temporarily. The invalid / valid flag temporarily stored in the buffer memory 22 is pre-read by the controller 26. The controller 26 compares the demodulated data from the buffer memory 22 with the fader 2 based on the invalid / valid flag.
4 is switched and output by controlling the switches 23 and 25. Specifically, look ahead for the invalid / valid flag of the frame to be reproduced next,
Before reproducing the frame N whose flag indicates "invalid" as shown in FIG. 6, the gain of the fader 24 is reduced from 1 to 0 as shown in FIG. 7, and the reproduction of the invalid frame is completed. Thereafter, the fade of the fader 24 is gradually increased from 0 to 1 to release the fade.

The fader 24 of the receiving side reproducing device 20 receives the demodulated data from the switch 23 via the input terminal 41 and supplies the data to the multiplier 42 as shown in FIG.
The gain from the gain adjuster 45 is also supplied to the multiplier 42. The gain adjuster 45 is supplied with a gain control signal from the controller 26 via the control terminal 44. Therefore, the multiplier 42 outputs a fade-out or fade-in signal obtained by multiplying the demodulated data by the gain adjusted as determined by the controller 26 pre-reading the invalid / valid flag. The fade-out or fade-in signal is converted into a multi-bit signal by being multiplied by the gain. Therefore, a post-multiplier 42 is provided with a ΔΣ modulator 43 for converting the multi-bit signal into 1-bit digital data again. Is arranged. The 1-bit digital data from the ΔΣ modulator 43 is supplied to the switch 25 via the output terminal 46. The fader 8 provided inside the transmission-side reproducing device 1 has the same configuration as that of FIG. 8 and operates in the same manner.

In the transmission-side reproducing apparatus 1, when the user selects and operates CUE / REV, music selection, etc., via the operation unit 12, the front-end processor 4
Outputs a plurality of sectors having consecutive sector addresses, and then outputs consecutive sectors starting from another sector address.

The decoder 5 extracts a frame from a group of sectors having consecutive sector addresses as shown in FIG. 3, and writes only the completely extracted frame into the buffer memory 6.

Therefore, the frames written in the buffer memory 6 are not error frames, although the time code becomes discontinuous when there is a discontinuity in the sector, as shown in FIG.

However, if a discontinuous frame, which is not an error frame, is output as 1-bit audio data as it is, an abnormal sound is generated. Therefore, when outputting these frames to the communication system 16, FIG.
(A), the invalid / valid flag of one frame (FIG. 10 (b)) immediately before the discontinuous point of the frame or one frame immediately thereafter (FIG. 10 (d)) is set to "invalid". As a result, the reproducing device on the receiving side can perform the operations shown in FIGS.
As shown in the above, the gain of the fader can be set to 0 in a sufficient range including the discontinuous point to prevent generation of abnormal noise.

On the other hand, if no error frame occurs during data demodulation in the decoder 5 of the transmission side reproducing apparatus 1, the controller 11 sets the invalid / valid flag to "valid" when outputting a normal frame to the communication system 16, The transmitting unit 10 adds the data to the demodulated data in frame units.

The receiving side reproducing apparatus 20 pre-reads the invalid / valid flag of the frame to be reproduced next, judges that the flag indicates "valid", and switches both the switch 23 and the switch 25 to the terminal b. The normal audio output to which no fade processing is applied is amplified by the amplifier 28 and output from the speaker 29.

It should be noted that what has been described above is that 1-bit audio data reproduced from the optical disc 2 is transmitted from the transmission-side reproducing apparatus 1 to the receiving-side reproducing apparatus 20 using the communication system 16, and the receiving-side reproducing apparatus 20 transmits the 1-bit audio data. In this operation, the invalid / valid flag added to the 1-bit audio data is pre-read, and the fader processing output of the fader 24 or the normal 1-bit audio is switched and output.

In addition to the above operation, in the transmission-side reproducing apparatus 1 alone, the controller 11 switches the switches 7 and 9 in accordance with the user's operation using the operation unit 12, and the fader 8 A fade processing output obtained by performing a fade processing on the output,
It selectively switches between demodulated data from decoder 5 and 1
The signal is converted into an analog audio signal by the bit D / A converter 13 and then amplified by the amplifier 14. The audio signal amplified by the amplifier 14 is output from a speaker 15.

As described above, according to the transmission / reception system shown in FIG. 1, discontinuous digital music data is output to the communication system 16 from which the transmission of the time code is not permitted from the transmission side reproducing apparatus 1. Also, the receiving-side reproducing device 20 does not generate abnormal noise at discontinuous portions.

Even if CUE / REV or music selection is performed on the transmission side, there is no need to perform special processing on the reception side, and an audio signal can be output in the same manner as when an invalid frame due to an error frame is present.

In the transmitting and receiving systems 1 and 20 of the transmitting and receiving system according to the above-described embodiment, the demodulated data (1-bit digital data) or the fader processed data (1-bit digital data) is converted into 1-bit D / D data. The signals are converted into analog audio signals by the A converters 13 and 27, then amplified by the amplifiers 14 and 28, and sent to the speakers 15 and 29. The speakers 15 and 29 can directly convert 1-bit digital data into sound output. , The 1-bit D / A converters 13 and 27 can be omitted.

[0036]

According to the present invention, even when discontinuous digital music data is output to a communication system in which transmission of a time code is not permitted, discontinuous sound is not generated in the receiving-side reproducing device. .

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a transmission / reception system according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration of a ΔΣ modulator that generates 1-bit audio data.

FIG. 3 is a diagram showing a relationship between a sector and a frame used in the embodiment.

FIG. 4 is a diagram showing a data configuration inside a buffer memory used in the transmission-side reproducing device of the embodiment.

FIG. 5 is a diagram showing a frame configuration output from the transmission-side reproduction device to a communication system.

FIG. 6 is a diagram showing a data configuration inside a buffer memory used in the receiving side reproducing device of the embodiment.

FIG. 7 is a diagram for explaining an operation when an invalid frame is reproduced by the receiving reproduction device.

FIG. 8 is a block diagram illustrating a detailed configuration of a fader used in the reception-side reproduction device.

FIG. 9 is a diagram showing discontinuous frames in a buffer memory of the transmission side reproducing apparatus.

FIG. 10 is a diagram illustrating a valid flag before and after a discontinuous frame and a gain of a fader of the receiving side reproducing apparatus.

FIG. 11 is a diagram for explaining the principle of a conventional transmission / reception system.

FIG. 12 is a block diagram showing a configuration of a conventional optical disc reproducing apparatus having a fader.

FIG. 13 is a diagram showing a data structure in a buffer memory of frame data to which a time code is added.

FIG. 14 is a diagram for explaining the operation of the optical disc reproducing device shown in FIG. 12;

FIG. 15 is a diagram showing a configuration of a conventional transmission / reception system.

[Explanation of symbols]

Reference Signs List 1 playback side playback device, 2 optical disk, 3 optical pickup, 4 front end processor, 5 decoder, 6 buffer memory, 7, 9 switch, 8 fader, 10 transmission section, 11 controller, 12 operation section, 15 communication system, 20 reception Side playback device, 21 transmission unit, 22 buffer memory, 23, 25 switch, 24
Fader, 26 controllers

Claims (7)

[Claims] A transmitting section for demodulating and transmitting digital data obtained by a predetermined modulating means; a receiving section for receiving and reproducing demodulated data from the transmitting section; A transmission / reception device comprising: a communication system that communicates the demodulated data. The transmission unit includes: a reproducing unit that reproduces the digital data; and a demodulation that demodulates the digital data reproduced by the reproducing unit. Means for temporarily storing demodulated data from the demodulation means.
Storage means; and first fade means for performing a fade process on the demodulated data read from the first storage means; and transmission means for sending out the demodulated data from the demodulation means to the communication system; An invalid / valid flag indicating whether the demodulated data transmitted by the transmitting means is invalid data or valid data is added to the demodulated data, and the fade processing data from the first fading means and the First control means for selectively switching between the demodulation data from the demodulation means and the demodulation data, wherein the reception section transmits the demodulation data transmitted from the transmission section of the transmission section via the communication system to the reception section. Receiving means for receiving; second storage means for temporarily storing the demodulated data received by the receiving means; and decoding means supplied via the second storage means. Fade means for performing a second fade process on tone data; and second fade based on an invalid / valid flag added by the transmission unit to the demodulated data temporarily stored in the second storage means. A transmission / reception apparatus comprising: a second control unit that switches between fade output data from a processing unit and the demodulated data from the second storage unit. 2. The method according to claim 1, wherein the first control unit adds an invalid / valid flag for each unit obtained by combining the demodulated data with a predetermined time length according to whether or not there is a discontinuous point in the demodulated data by the demodulating unit. The transmission / reception device according to claim 1, wherein 3. An operation unit for changing a reproduction speed of digital data in the transmission unit, wherein the first control unit fades from a first fade unit of the transmission unit in response to an operation of the operation unit. 2. The transmitting / receiving apparatus according to claim 1, wherein the processing data and the demodulated data from the demodulating means are switched. 4. The transmission / reception apparatus according to claim 1, wherein said first storage means of said transmission section stores said demodulated data and information relating to an elapsed time added to said demodulated data. 5. The demodulated data and the invalid / added data added to the demodulated data are stored in the second storage means of the receiving unit.
The transmission / reception device according to claim 1, wherein a valid flag is stored. 6. The method according to claim 1, wherein the predetermined modulating means performs 1 modulation by ΔΣ modulation.
The transmission / reception apparatus according to claim 1, wherein the transmission / reception apparatus is a ΔΣ modulator that generates bit digital data. 7. The transmission / reception apparatus according to claim 1, wherein the transmission section reproduces the digital data read from the recording medium by the reproduction means and demodulates the digital data by the demodulation means.