JP2006186591A - D/a conversion device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent deterioration of an analog signal to be obtained by conversion by supplying power of a voltage corresponding to a format, which is inherent in an input digital signal, to a re-quantization part in a D/A conversion device provided with a pre-stage processor and the re-quantization part and having a configuration of supplying power for operation individually to both parts. <P>SOLUTION: A control means 8 controls a voltage of power which is supplied to the re-quantization part 4 by a power supply means 7, so as to correspond to the format of a current input digital signal on the basis of a control value of data showing the format included in the input digital signal. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a D / A converter that inputs a digital signal, for example, a signal related to sound, converts the signal into an analog signal, and outputs the analog signal.

  In particular, the present invention provides a pre-processing unit that performs pre-stage processing for D / A conversion on an input digital signal, and a re-quantization unit that substantially performs D / A conversion on the signal from the pre-processing unit. The present invention relates to a D / A converter having a configuration in which power for operation is supplied, but power is supplied to a pre-processing unit and a re-quantization unit independently.

The D / A converter operates upon receiving power supply. As a D / A conversion device, there is an invention disclosed in the following publication.
Japanese Patent Application Laid-Open No. 07-079164

  For example, the above publication discloses a D / A converter, and there is no description that power is supplied for the function of converting an input digital signal and outputting an analog signal. The need for power supply is well known to those skilled in the art.

  The D / A conversion device has, as main functional requirements, a pre-processing unit that performs pre-stage processing for D / A conversion on an input digital signal, and a signal from the pre-processing unit substantially D It can be understood as a requantization unit that performs / A conversion.

Here, the pre-processing unit has a problem that if the voltage of the supplied power is high, the amount of generated heat increases, and if the amount of generated heat is excessive, the input digital signal cannot be detected. In addition, there is a problem that the pre-processing unit cannot detect the input digital signal even when the voltage of the supplied power is too low.
Therefore, the voltage of the power supplied to the pre-processing unit is required to be a steady voltage within a certain range.

On the other hand, in order to ensure a dynamic range with respect to a constant noise value (semiconductor residual noise limit value), the requantization unit relatively decreases the semiconductor residual noise limit value as the supplied voltage increases. Thus, a better noise state can be obtained.
Therefore, it is required to further increase the voltage of power supplied to the requantization unit.

  Therefore, in order to obtain a D / A conversion device that converts an input digital signal into an analog signal that is more reliably detected and noise is further suppressed, first, power supply to the pre-processing unit and reconnection are performed. It is necessary to adopt a configuration in which the power supply to the quantization unit is performed individually and independently.

Next, as described above, the voltage of the power to be supplied to the pre-processing unit is kept lower than the pre-processing unit generates heat and cannot process the input digital signal, and the digital signal cannot be detected. It is preferable to set a constant range that is not too low and a steady value.
The specific value to be set is already widely known experimentally.

On the other hand, the power supplied to the requantization unit performs an ON-OFF function corresponding to the digital data when the requantization unit receives the digital data from the pre-processing unit and performs the requantization function. It is for supplying to an element.
Therefore, although some impedance is generated here, Kirchhoff's first law works strongly. Therefore, if the voltage of the supplied power is large based on Kirchhoff's first law, the current is increased by that amount. When the voltage of the supplied power exceeds a certain level or more, the noise becomes excessive and cannot be put to practical use.

  On the other hand, as described above, when the voltage of power supplied to the re-quantization unit is lower or lower, the dynamic range with respect to a constant noise value (semiconductor residual noise limit value) becomes relatively low and noise is reduced. Will be relatively large, resulting in a worse noise condition.

  However, the requantization unit actually needs to be supplied with power of a voltage corresponding to the format in which the input digital signal is uniquely added.

  In other words, if the power of the voltage not corresponding to the format added to the digital signal is supplied to the requantization unit and requantization is performed, the voltage value of the analog signal obtained by conversion is the original value. As a result, there arises a problem that the magnitude of the output signal from the output terminal is different from what is originally obtained.

The present invention has been made in view of the above circumstances, and power supply to a pre-processing unit that performs pre-processing for D / A conversion and a re-quantization unit that substantially performs D / A conversion is performed. Each is performed independently, and even if the format changes due to a change in the input digital signal, the power of the corresponding voltage is supplied to the re-quantization unit following the change in the format, and as a result Another object of the present invention is to provide a D / A converter capable of securing an analog signal obtained by conversion.
It is another object of the present invention to provide a D / A converter that does not deteriorate the analog signal and does not require processing such as amplification and attenuation at a later stage by obtaining an analog signal having such contents.

  The invention of the present application corresponds to the format of the digital signal that is input at that time based on the control value of the data included in the digital signal and indicating the format of the digital signal. It is a D / A converter of the composition controlled to do.

The detailed configuration includes an input end for inputting an external digital signal, a pre-stage processing unit connected to a subsequent stage of the input end, and performing pre-stage processing to convert an input digital signal into an analog signal; Connected to the subsequent stage of the pre-processing unit, a re-quantization unit that converts a digital signal from the pre-processing unit into an analog signal, an output terminal that outputs an analog signal from the re-quantization unit, and the pre-processing unit A first power supply means for supplying power; a second power supply means for supplying power to the requantization section; and a second power supply section for receiving a digital signal input from the input terminal. Is provided with a control means for controlling the voltage of the power supplied to the requantization unit,
The control means is included in the digital signal from the input terminal, and based on the control value of the data indicating the format of the digital signal, the voltage of the power supplied by the second power supply means is input at that time. This is a D / A converter configured to be controlled to correspond to the signal format.

  The present invention is configured to individually supply power for operation to a pre-processing unit that performs pre-processing of D / A conversion and a re-quantization unit that substantially converts a digital signal into an analog signal, and Based on the control value of the data indicating the format of the input digital signal, the power supply voltage to the requantization unit is controlled to correspond to the format of the digital signal input at that time. In the pre-processing unit, the digital signal is processed with the supply power of a constant voltage, and in the re-quantization unit, the digital signal is supplied with the power of the voltage corresponding to the format with respect to the specific format added to the digital signal. Due to the configuration, the requantization unit outputs the requantized output as a value adapted to the format at that time, resulting in noise. Analog signal gill the output is secured a D / A converter to be obtained.

The present invention will be described in detail based on the embodiment shown in FIGS. However, the present invention is not limited to the embodiments.
The D / A converter 1 includes an input terminal 2, a pre-processing unit 3, a requantization unit 4, an output terminal 5, power supply units 6 and 7, a control unit 8, and an operation / display panel 9. It is provided.

  The input terminal 2 is for inputting an external digital signal. Specifically, the input terminal 2 is connected to a digital signal receiving device, a digital recording medium reproducing device, or the like, which is located in the subsequent stage.

The pre-stage processing unit 3 is connected to the post-stage of the input terminal 2 and performs pre-stage processing to convert an input digital signal into an analog signal.
The pre-processing unit 3 specifically includes an oversampling action for moving noise within the audible band to the outside of the audible band, a mute action for suppressing noise generated when stopping and switching the signal output, and the number of bits of the input digital signal. Δ-Σ conversion action or the like is converted into the number of bits that can be processed by the requantization unit 4.
Here, the Δ-Σ conversion is performed using a noise shaping technique.

Here, the pre-processing unit 3 receives power supply for operation from the power supply means 6, but if the supply power voltage is high, the pre-processing unit 3 generates a large amount of heat, and the heat generation amount is excessively large. In such a case, there arises a problem that an input digital signal cannot be detected.
On the other hand, there is a problem that the pre-processing unit 3 cannot detect the input digital signal even when the voltage of the supplied power is too low.

  Therefore, in the D / A converter 1, the voltage of the power supplied from the power supply means 6 to the pre-processing unit is a steady value within a certain range in which the amount of generated heat is suppressed and the digital signal detection function is not impaired. Is set.

The re-quantization unit 4 is connected to the subsequent stage of the pre-processing unit 3, operates by supplying power from the power supply means 7, and substantially converts the digital signal from the pre-processing unit 3 into an analog signal. .
That is, when the requantization unit 4 receives the digital data from the pre-processing unit 3 and performs the requantization operation, the power supply unit 7 performs the ON-OFF function corresponding to the digital data. Electric power is supplied to (not shown).

Here, the digital signals input from the input terminal 2 each have a uniquely added format, and the format of all the input digital signals is not necessarily the same.
In this regard, no problem arises when the requantizer 4 functions in accordance with the format of the input digital signal.

However, if the requantization unit 4 performs requantization without corresponding to the format of the input digital signal, there arises a problem that an analog signal that should originally be obtained cannot be obtained if the format is compatible.
In other words, if the input digital signal is not processed in a format corresponding to the digital signal in the conventional technique, the requantization unit 4 cannot obtain the original output level as a result from the digital signal. In the latter stage, signal degradation occurred.
Conventionally, with respect to the signal degradation that occurs in the subsequent stage, an approach has been made to prevent the degradation by performing processing such as amplification and attenuation on the analog signal obtained by requantization.

  In the D / A converter 1, the control means 8 is configured so that requantization is performed corresponding to the format of the digital signal when the format of the input digital signal is different for each digital signal. It is configured to function.

  That is, the control means 8 stores the format of the input digital signal (not shown), compares the format of the input digital signal with the format stored in the storage unit, A recognition signal (not shown) for recognizing the format of the digital signal and a drive signal so that the power supply means 7 supplies the power of the voltage corresponding to the format recognized by the recognition unit to the requantization unit 4. An output unit (not shown) is provided.

  When receiving the operation signal from the operation / display panel 9, the control unit 8 outputs a drive signal to the power supply unit 6 so as to supply the above-described constant voltage power to the pre-processing unit 3. .

  The operation / display panel 9 is provided with a main switch to display ON / OFF of the operation of the entire apparatus and the mode of the current D / A conversion process.

The D / A converter 1 is configured as described above. Hereinafter, functions of the D / A conversion device 1 will be described.
First, the operator connects a CD playback device (not shown), which is a digital signal generator, to the front stage of the input terminal 2, and connects a filter device and an amplifier (both not shown) to the rear stage of the output terminal 5.

Next, the D / A converter 1 is operated by operating the operation / display panel 9 to turn the main power supply from OFF to ON.
Here, the digital signal input from the input terminal 2 is sent to the pre-processing unit 3 and the control means 8.

  The pre-processing unit 3 performs pre-processing to convert the digital signal from the input terminal 2 into an analog signal. In other words, the pre-processing unit 3 performs an oversampling action for moving noise within the audible band to the outside of the audible band, a mute action for suppressing noise generated when stopping or switching the signal output, and the number of bits of the input digital signal. A ΔΣ conversion operation for converting the number of bits that can be processed by the requantization unit 4 is performed.

In this pre-processing of the pre-processing unit 3, the power supply means 6 supplies power of a steady voltage within a certain range in which the amount of heat generated in the pre-processing unit 3 is suppressed and the digital signal detection function is not impaired. Is done by doing.
That is, the control unit 8 sends a drive signal for supplying the power of the constant voltage to the pre-processing unit 3 to the power supply unit 6 along with the operation of the D / A converter 1.

  On the other hand, when receiving the digital signal from the input terminal 2, the control means 8 calls the format stored in the storage unit for the format of the input digital signal, and compares the format by the recognition unit to input the digital signal. The output unit sends a drive signal to the power supply means 7 so as to supply the re-quantization unit 4 with power of a voltage corresponding to the recognized format.

Here, when the requantization unit 4 receives the preprocessed digital signal from the preprocessing unit 3, the switching element performs an ON-OFF function on the digital data based on the power supply from the power supply unit 7. Convert to analog signal.
At this time, the switching element of the requantization unit 4 functions with a data voltage (control value) corresponding to the format of the current input digital signal, so that the converted signal has a magnitude of the voltage originally obtained. It is an analog signal.

Further, since the analog signal obtained here is not deteriorated, it is not necessary to perform processing such as amplification and attenuation in the subsequent stage.
The output terminal 5 receives the analog signal from the requantization unit 4 and sends it to the means, device, etc. connected to the subsequent stage.

  In the D / A converter 1, the analog signal obtained by the conversion in the requantization unit 4 is indicated by a voltage value, but may be indicated by a current value.

  In the D / A converter 1, the current input digital signal format is specified by the cooperation of the storage unit and the recognition unit of the control means 8, but the format of the input digital signal is set. A method may be used in which the identification is performed by comparison with the value.

It is a block diagram explaining the structure of the D / A converter of the embodiment of this invention. It is a flowchart figure explaining the principal part of the action | operation of the example shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 D / A converter 2 Input terminal 3 Pre-processing part 5 Requantization part 6, 7 Power supply means 8 Control means 9 Operation / display panel

Claims (2)

An input terminal for inputting a digital signal from the outside, a pre-stage processing unit that is connected to a subsequent stage of the input terminal and performs pre-stage processing to convert the input digital signal into an analog signal, and a subsequent stage of the pre-stage processing section A re-quantization unit that converts a digital signal from the pre-processing unit into an analog signal, an output terminal that outputs an analog signal from the re-quantization unit, and a first that supplies power to the pre-processing unit Power supply means, a second power supply means for supplying power to the re-quantization section, and a digital signal input from the input terminal, and the second power supply section to the re-quantization section Control means for controlling the voltage of the supplied power is provided;
The control means is included in the digital signal from the input terminal, and based on the control value of the data indicating the format of the digital signal, the voltage of the power supplied by the second power supply means is input at that time. A D / A converter configured to be controlled to correspond to a signal format.
  The control unit compares the format of the input digital signal with the storage unit storing the format of the current input digital signal and the format stored in the storage unit, and the format of the input digital signal And an output unit for outputting a drive signal so that the second power supply means supplies the power of the voltage corresponding to the format recognized by the recognition unit to the re-quantization unit. The D / A conversion device according to claim 1.

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