JP2930364B2 - Digital audio effector - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a digital audio interface based on a digital audio interface format.

2. Description of the Related Art A digital audio interface demodulation circuit and a digital signal processor are used to demodulate data modulated by a digital audio interface format, change the demodulated data to target audio data, and then re-modulate the data to a digital audio interface format. (DSP) and a digital audio interface modulation circuit are used.

Hereinafter, a conventional digital audio eflector will be described. FIG. 3 is an electrical connection diagram of a conventional digital audio effector. In FIG. 3, 1 is a demodulation block, 2 is a DSP, and 7 is a modulation block.

To demodulate the data (digital I / O data) modulated by the digital audio interface format, change it to the target audio data, and modulate it back to digital I / O data, demodulate the digital I / O data. At 1, demodulation is performed to digital audio data, the demodulated digital audio data is changed to target audio data at DSP2, and modulated to digital I / O data at modulation block 7. At this time, it is added to the modulation block 7.
MCK is the sampling frequency used as a master clock arrives (F _S) of 128 times the clock (256F _S in 4ch mode)
It is.

However, in the above-described conventional configuration, the Ub included in the VUCP in the digital I / O data input to the demodulation block 1
There is a problem that data of it and Cbit are missing.

The present invention solves the above-mentioned conventional problems, and Ubit, Cb
It is an object of the present invention to provide a digital audio efcter that can change audio data to target audio data while keeping the data of it as it is.

Means for Solving the Problems In order to solve the above problems, the digital audio efector of the present invention is provided with a demodulation block for demodulating digital I / O data, and the digital audio data demodulated by the demodulation block is used for the purpose. A DSP for changing to audio data is provided, while NRZ data (digital I / O data demodulated to NRZ) generated in the demodulation block is extracted during the demodulation of audio data, and this NRZ data is output from the DSP. A first synchronizing circuit for synchronizing with the audio data, and a data selector for selecting either audio data passed through the DSP or NRZ data passed through the first synchronizing circuit. A noise removal circuit is provided to remove noise at the time of switching, and the Cbi of NRZ data generated in the demodulation block
A second synchronization circuit for synchronizing the block with the data output from the noise elimination circuit is provided by taking out a block clock indicating the beginning of the block of t.
A modulation block for modulating data passed through the noise removal circuit into digital I / O data is provided.

Operation With the above configuration, the pre-angle data and VUCP data (Ubi-Phase data) are added to the NRZ generated during the demodulation in the demodulation block.
t, Cbit, P (parity) bit data)
These sub data can be selected and taken out by the data selector and taken into the audio data through the demodulation block. As a result, the digital I / O data Ubi
Digital I / O that changes audio data to the target audio data while keeping t and Cbit data as they are
Data can be output.

Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows the electrical connection of a digital audio efcter according to an embodiment of the present invention. In FIG. 1, 1
Is a demodulation block for demodulating digital I / O data, 2 is a DSP for changing digital audio data demodulated by demodulation block 1 to target audio data, 3 is a demodulation block generated during demodulation in demodulation block 1 and 1 The shift register 4, which is a first synchronization circuit for synchronizing the NRZ data output from the DSP 2 with the audio data output from the DSP 2, is used for synchronizing the audio data output from the DSP 2 with the NRZ data passed through the shift register 3. A data selector 5 for selecting either one is a D flip-flop (DF) which is a noise removal circuit for removing noise at the time of data switching.
F) and 6 are Cb of the NRZ data output from the demodulation block 1.
A shift register that synchronizes the block indicating the beginning of the block of it with the beginning of the Cbit block of the NRZ data included in the data output from DFF5, and 7 converts the data output from DFF5 into digital I / O data. Modulation block to modulate.

The operation of the thus-configured digital audio FF will be described below. The demodulation block 1 demodulates digital I / O data. The audio data output from the demodulation block 1 is input to the DSP 2 and changed to the target audio data. On the other hand, the NRZ data generated in the demodulation block 1 during the demodulation of the audio data is synchronized with the audio data passed through the DSP 2 by the shift register 3, and the data selector 4
As shown in the timing diagram, audio data a through DSP 2 or shift register 3
The NRZ data b is selected by the switching pulse d. The data output from the data selector 4 passes through DFF5 in order to remove noise at the time of data switching. The block clock generated in demodulation block 1 is replaced with the NR included in the data passed through DFF5.
Passed through the shift register 6 to synchronize with the beginning of the C bit block of Z data, and passed through the DFF 5 to the modulation block 7
The NRZ data and the clock C passed through the shift register 6 are input and modulated to digital I / O data e. M applied to shift registers 3, 6DFF5 and modulation block 7
CK (in the 4ch mode 256F _S) 128 times the clock of the sampling frequency used as a master clock arrives (F _S) is.

Therefore, it is possible to output digital I / O data in which the audio data is changed to the target audio data without changing the Ubit and Cbit of the digital I / O data.

As described above, according to the present invention, the audio data is changed to the target audio data without changing the Ubit and Cbit of the digital I / O data stably and accurately.
It can output I / O data easily and is very useful in practice.

[Brief description of the drawings]

FIG. 1 is an electrical connection diagram showing a digital audio filter according to an embodiment of the present invention, FIG. 2 is a timing diagram of each block output in the embodiment, and FIG. 3 is an electrical diagram showing a conventional digital audio converter. FIG. 1 ... demodulation block, 2 ... DSP, 3 ... shift register (first synchronization circuit), 4 ... data selector, 5 ...
DFF (noise removal circuit), 6 shift register (second
7) Modulation block.

Claims (1)

(57) [Claims] A demodulation block for demodulating data (digital I / O data) modulated by a digital audio interface format; a digital signal processor for converting demodulated digital audio data into target audio data; During demodulation in demodulation block
A first synchronizing circuit for synchronizing the data demodulated to the NRZ with audio data passed through the digital signal processor, and a first synchronizing circuit for synchronizing the audio data passed through the digital signal processor with the NRZ data passing through the first synchronizing circuit A data selector that selects one of the two, a noise removal circuit that removes noise at the time of data switching, and a block clock that indicates the beginning of the Cbit block of the data that has been demodulated to NRZ, and synchronizes the data with the data that passed through the noise removal circuit. Second to take
And a modulation block that modulates the data that has passed through the noise elimination circuit into digital I / O data.The Ubit and Cbit data contained in the data demodulated to NRZ are used as they are in the audio Digital audio efcta configured to convert data to the desired audio data.