JP2002094380A - Digital to analog converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a digital to analog converter that applies detection processing to output signals from digital to analog conversion sections, detects a faulty channel, quickly avoids the faulty channel and selectively provides an output of normal channels. SOLUTION: The digital to analog converter is provided with digital to analog conversion sections for channels that convert a received digital signal into an analog signal, a fault detection means 11A that detects a faulty channel on the basis of output signals from the digital to analog conversions for channels (digital to analog converters 1 and output means 2) and a changeover means 10 that selects one output from among the digital to analog conversion sections for a normal channel among outputs of the digital to analog conversion sections for channels on the basis of an output of the fault detection means and provides an output, and also with a fault notice signal output means 7 that informs about the fault, a display means 8 and a loudspeaking means 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DA converter mounted on an audio signal processing device or the like and converting an audio signal transmitted as a digital signal into an analog signal.

[0002]

2. Description of the Related Art A conventional D / A converter is provided with an independent D / A converter and output means for each output stage, and is configured to convert a digitally transmitted audio signal into an analog signal and then output the analog signal through the output means. ing.

[0003]

However, in the conventional DA converter, if any part of the device fails, the failure can be known only by the fact that the input signal is not output from the final output stage. In addition, in the case of failure, unless the operator manually switches to another DA converter for both input and output, the failure state could not be solved.

The present invention has been made in order to solve such a conventional problem, and detects a faulty line to enable quick avoidance, and selects and outputs a normal line output from a plurality of lines. It is an object of the present invention to provide a DA converter capable of performing the above.

[0005]

In order to achieve the above object, a DA converter according to the present invention comprises a multi-line DA converter for converting an input digital signal into an analog signal, and a multi-line DA converter. Failure detection means for detecting a faulty line based on an output signal of the conversion unit; and an output of a DA conversion unit of any normal line among outputs of the DA conversion units of the plurality of lines based on an output of the failure detection unit. And a switching means for selecting and outputting the selected data. With this configuration, it is possible to quickly determine a failure in the DA converter, to quickly avoid a failed line, and to select and output a normal line output.

The failure detecting means includes first detecting means for detecting an output signal of a specific one of the plurality of D / A converters, and another one of the plurality of D / A converters. Second detection means for detecting the output signal of
Comparison means for comparing the signal components detected by these detection means, storage means for storing a reference value defining an allowable range, and a result output from the comparison means defined by the reference value stored in the storage means Processing means for determining whether or not within the allowable range to be performed, the switching means,
The output of the DA converter of the normal line is selected based on the output from the processing means. With this configuration, it is possible to quickly determine the failure of the DA converter and to quickly avoid the failed line.

Further, the failure detecting means includes first detecting means for detecting an output signal of a specific one of the plurality of DA converters, and at least two other DA converting means among the plurality of DA converters. A plurality of detecting means for respectively detecting output signals of the lines or more; a majority decision comparing means for comparing the signal components detected by these detecting means to determine a failed DA converter by majority decision; Storage means for storing data as a criterion,
Processing means for comparing the result output from the majority decision comparing means with a judgment criterion stored in the storage means to determine a faulty line, wherein the switching means operates normally based on an output from the processing means. It has a configuration for selecting the output of the DA converter of the line. With this configuration, there is an effect that a faulty line can be avoided by an accurate determination without bothering the operator and a normal line can be selected and switched.

[0008] Further, as the failure detecting means, two D
Two detecting means for detecting the output signal of the A-converter at fixed time intervals, two accumulating means for accumulating the detection results detected by these detecting means in time series, and a memory for pre-storing a reference value Means, comparison means for comparing the results stored in the two storage means with reference values stored in the storage means at predetermined time intervals, and storage means for storing data for determining failure in advance,
Processing means for comparing a result output from the comparing means with data stored in the storage means to determine which line of the output signals of the two DA converters is faulty, The switching means has a configuration for selecting the output of the D / A converter of the normal line based on the output from the processing means. This configuration has an effect of enabling a faulty line to be quickly avoided.

Further, the apparatus further includes an abnormality notification signal output means for outputting an abnormality notification signal based on the result output from the failure detection means, and a notification means for notifying the content notified from the abnormality notification signal output means. Configuration. With this configuration, it is possible to promptly notify by notification when an abnormality occurs.

[0010] In addition, a configuration is provided in which the notification means includes a display means for displaying the content notified from the abnormality notification signal output means. With this configuration, it is possible to promptly notify the user of an abnormality by a display.

[0011] Further, a configuration is provided in which the notification means includes a loudspeaker for loudspeaking the content notified from the abnormality notification signal output means. According to this configuration, when an abnormality occurs, it is possible to promptly notify the user even if the user is away from the apparatus by loudspeaking.

The detecting means has a structure for detecting an amplitude level of an output signal from the DA converter. With this configuration, it is possible to determine a failure accompanied by a fluctuation of the AC component in the device.

Further, the detecting means has a structure for detecting a DC offset component of an output signal from the DA converter. With this configuration, it is possible to determine a failure that involves a change in the signal DC component, such as damage to a component in the device.

Further, the DA converter is constituted by a DA converter for converting an input digital signal into an analog signal, and an output means for outputting the analog signal converted by the DA converter. Has a configuration for detecting the output of either the DA converter or the output means. This configuration has an effect of enabling failure detection including the DA converter or the output unit.

[0015]

(Embodiment 1) Embodiment 1 of the present invention will be described with reference to FIG. FIG. 1 is a block diagram showing a DA converter according to Embodiment 1 of the present invention. As shown in FIG. 1, the DA according to the first embodiment
The conversion device is applied to an audio output system, and includes a DA converter (DAC) 1 that converts an input digital signal into an analog signal, and an output unit 2 that outputs the converted analog signal. A fault detection circuit 11A for detecting a faulty line based on the output of the DA conversion unit, and an output of a normal line DA conversion unit based on the output of the fault detection circuit 11A. Switching means 10 for selecting and outputting. Further, abnormality notification signal output means 7 for outputting an abnormality notification signal based on the output from the failure detection circuit 11A, and display means 8 and loudspeaker means 9 as notification means for notifying the content notified from the abnormality notification signal output means 7 It has.

Here, as the failure detecting means 11A, a specific one-line DA converter 1 of a plurality of line DA converters is used.
First detection means 3A for detecting the output signal of the second circuit, second detection means 3B for detecting the output signal of another one of the plurality of D / A converters, and signal components detected by these detection means. , A storage unit 6 for storing a reference value defining an allowable range, and a result output from the comparison unit 4 within an allowable range defined by the reference value stored in the storage unit 6. Processing means 5 for determining whether or not
The switching unit 10 is configured to select the output of the D / A conversion unit of the normal line based on the output from the processing unit 5.

The first and second detection means 3A and 3B are:
The voltage level of the analog signal of each signal line is detected, and the comparing means 4 compares the detected voltage levels. The processing means 5 determines the result compared by the comparing means 4 by a predetermined calculation method, and when an abnormality is detected, a signal is sent from the abnormality notification signal output means 7 to the loudspeaker means 9 and the display means 8, Abnormality is notified by voice or sound. The switching unit 10 switches between a plurality of DA converters. The storage unit 6 stores a criterion value for the processing unit 5 to perform the failure detection processing.

The operation of the DA converter configured as described above will be described. First, the same signal is input simultaneously to the DA converters of a plurality of lines composed of the DA converter 1 and the output means 2. Next, an arbitrary DA converter (hereinafter, referred to as a line B) is selected for failure detection in addition to a DA converter (hereinafter, referred to as a line A) used as an output.
Each output of the DA converter (DAC) 1 of the line A and the line B is
The voltage data measured by the first and second detecting means 3A and 3B at all times or at a predetermined time interval is sent to the comparing means 4.

The comparing means 4 compares the absolute values of the voltages, for example, and sends the difference value to the processing means 5. The processing unit 5 extracts a reference value determined from an allowable range defined by a variation in circuit components stored in the storage unit 6 and performs a failure detection process using the reference value and data from the comparison unit 4. . Normally, when there is no failure in the circuit, the processing result is within the range defined by the above reference value,
If the processing unit 5 determines that the result of the processing is out of the allowable range based on the reference value, the processing unit 5 determines that the processing result is out of the allowable range based on the reference value.
To work. The abnormality notification signal output means 7 includes a display means 8
Alternatively, the loudspeaker 9 notifies the operator of the abnormality of the used line.

The switching means 10 switches the line to the output of another DA converter other than the lines A and B to which the same signal is input but is not used for failure detection, based on the output of the processing means 5. Thus, an acoustic trouble due to a line failure can be avoided instantaneously. Note that, based on the notification output of the display means 8 or the loudspeaker means 9, the operator may operate the switching means 10 to switch the line to an output by a DA converter other than the lines A and B.

As described above, according to the first embodiment, detection means 3 for detecting output voltages from a plurality of DA converters 1
A comparing means 4 for comparing the detected voltages, a processing means 5 for judging a result outputted from the comparing means 4 by a predetermined calculation method, a storing means 6 for storing data necessary for the processing,
By providing a switching means 10 for switching the line output, a display means 8 for notifying a line abnormality, and a loudspeaker means 9, the output of a normal line is selected from a plurality of lines based on the detection of an abnormal failure line. Can be output,
For example, even if an output line abnormality occurs during a performance in a theater or a concert hall, the output can be switched to a normal line promptly, and the performance can be continued without any trouble.
In addition, by storing the processing result itself when a failure is detected in the storage unit 6 additionally, when performing a failure detection process next, the comparison result of the comparing unit 4 is first compared with the above processing result. Faster failure determination is possible. Either the display means 8 or the loudspeaker means 9 may be used.

(Embodiment 2) FIG. 2 is a block diagram showing a DA converter according to Embodiment 2 of the present invention. The DA converter according to the second embodiment includes at least three DA converters as the DA converter, and the failure detection circuit 11B includes a first detection unit 3A that detects an output signal of a specific one-line DA converter. And second and third detection means 3B and 3C for detecting the output signals of the other two DA converters, respectively, and the signal components detected by these detection means 3 (collectively 3A, 3B and 3C). Majority decision comparing means 12 for comparing and judging a failed DA converter by majority decision
Storage means 6 for storing data of the result of comparison by majority decision comparing means 12 as a criterion;
And a processing unit 13 for comparing the result output from the storage unit 6 with the determination criterion stored in the storage unit 6 to determine a faulty line. The switching unit 10 controls the normal line based on the output from the processing unit 13. Is configured to select the output of the DA converter. The same parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

The operation of the DA converter configured as described above will be described. For convenience of explanation of the operation, it is assumed that the number of the required DA converters composed of the DA converter 1 and the output means 2 is at least three. First, the same signal is input to three DA converters at the same time. Next, in addition to a DA converter used as a normal output (hereinafter, referred to as a line A), any two DA converters (hereinafter, referred to as lines B and C) are selected for failure detection. DA changer (DAC) 1 for line A, line B, line C
Are continuously or at predetermined time intervals detected by the detecting means 3A, 3B, 3C, and the majority comparing means 12
The measured voltage data is sent to

The majority comparing means 12 determines a faulty line based on the obtained voltage data, for example, as follows. Now, let the voltages detected from the three lines be a, b, and c, respectively, and let XX be the 2-bit data composed of the results of (ab) · (ac). If the result of each subtraction is zero including an error due to component variation, the bit is set to 0, and if the result is not zero, the bit is set to 1. The relationship between the failed line and XX obtained from the comparison result is as shown in the table below.

[0025]

[Table 1]

The above data is stored in the storage means 6 as a criterion, and is compared with XX by the processing means 13 to determine a faulty line. After determining the line, the processing unit 13 automatically switches the switching unit 10 to disconnect the failed line, select and output one of the other normal lines, and output the line to the abnormality notification signal output unit 7. Notify abnormalities.
The abnormality notification signal output means 7 is provided by the display means 8 or the loudspeaker means 9.
To inform the operator that the line has been switched to a normal line.

As described above, according to the second embodiment, the outputs of at least three or more DA converters are detected, the detection results are compared, and a faulty line is determined based on the comparison result.
By switching the line, the troubled line can be avoided by an accurate judgment without bothering the operator, and the loudspeaking can be continued without causing any serious trouble during a performance in a theater, for example.

In the above description, three lines are used for the determination. However, even when the number of the lines is four or more, the same can be implemented by increasing the number of bits of the determination data. Further, only one of the display means 8 and the loudspeaker means 9 for notifying the abnormality may be used.

(Embodiment 3) FIG. 3 is a block diagram showing a DA converter according to Embodiment 3 of the present invention. The DA converter according to the third embodiment includes two lines as DA converters, and two D converters as the failure detection circuit 11C.
First and second detection means 3A and 3B for detecting the output signal of the A conversion unit at fixed time intervals, and two accumulation means 14A for accumulating the detection results detected by these detection means in time series, respectively. 14B, a storage means 16 for storing the reference value in advance, and two storage means 14A
A comparing means 15 for comparing the result stored in the storage means with the reference value stored in the storing means at predetermined time intervals; and a storing means 6 for storing data for determining a failure in advance.
And a processing unit 17 for comparing the result output from the comparison unit 15 with the data stored in the storage unit 6 to determine which of the output signals of the two DA converters has a fault. The switching unit 18 is configured to select the output of the D / A converter of the normal line based on the output from the processing unit 17.

The operation of the fault detection circuit 11C of the DA converter configured as described above will be described. The same signal is simultaneously input to two D / A converters configured by a D / A converter (DAC) 1 and an output unit 2. The first and second detectors 3A and 3B measure the voltage data at regular time intervals and send them to the storages 14A and 14B in a time series. The storage means 14A and 14B convert the sent detection voltage into 1-bit data depending on the magnitude of the reference voltage, and store, for example, 8 bits as serial data in the order of measurement. When a predetermined time has elapsed, the storage units 14A and 14A
B sends the serial data stored in the comparing means 15,
The comparing means 15 obtains a result by performing a predetermined calculation method, for example, a difference.

When some states assumed as the failure mode are actually generated in advance, the storage means 16 stores a number of data which may occur as operation results, and stores these data and the actual operation results. The comparison unit 15 further performs comparison, and when there is a corresponding one, an error signal corresponding to the failure mode is notified to the processing unit 17. When a calculation result of a pattern not stored in the storage unit 16 is received, a general-purpose error signal is notified, and the calculation result is newly stored.
The processing means 17 receives the error signal, determines which line is faulty by comparing it with the data in the storage means 6, switches the switching means 18 to output a signal from the normal line, The notification signal output means 7 is notified of the line abnormality. The abnormality notification signal output means 7 uses the display means 8 and / or the loudspeaker means 9 to notify the operator of the notified contents, and notifies the operator of the line abnormality, its contents, and automatic switching of the line.

As described above, according to the third embodiment, 2
The operator obtains the detection result from the two detection means a plurality of times within a certain period of time, compares the detection result with the data in the storage means stored as a continuous data pattern, determines a faulty line based on the result of the comparison, and switches the line, thereby enabling the operator If there is at least one spare line, it is possible to automatically receive a failure avoidance process even in the event of a line failure, so that the performance can proceed smoothly without hindering operation. Further, since the failure information reported by the display means 8 and the loudspeaker means 9 differs depending on the content of the failure, a quick response at the time of repair can be expected by obtaining detailed information on the content of the failure. Further, when a failure of a type not present in the storage means 16 occurs, the storage means 16 accumulates the calculation results as a new database. Means 17 to abnormality notification signal output means 7
By modifying the output signal to the system, it is possible to grow the system into a system which can flexibly cope with various failures.

In the above description, the comparison is made using the serial data. However, a method of converting the serial data into parallel data and comparing the data may be used. Further, in the above description, the detection means 3 is installed immediately after the DA converter 1, but by installing the detection means 3 between the output means 2 and the switching means 18, it is possible to detect a failure including the output means 2. Becomes In this case, by using the DC offset component of the output signal as a result of the detection means, it is possible to perform a DC failure of the circuit, for example, a small failure such as an operational amplifier in an output stage being destroyed by static electricity suddenly applied to an output connector. Can be estimated. In addition, by using a time-series change pattern of the amplitude level of the circuit signal within a certain time after power-on, for example, as a result of the detecting means, and comparing and accumulating the data as data over a long period of time, It is also possible to determine a change, for example, a loss of capacitance of the coupling capacitor. Further, by providing a plurality of detecting means in the output means, it is possible to narrow down the faulty portion more accurately.

[0034]

As described above, according to the present invention, a plurality of D / A converters for converting an input digital signal into an analog signal, and a faulty line based on the output signals of the plurality of D / A converters are provided. And a switching means for selecting and outputting the output of the D / A converter of any normal line from the outputs of the D / A converters of the plurality of lines based on the output of the failure detection circuit. Because it is equipped, it is possible to select and output the output of a normal line among a plurality of lines based on the detection of an abnormal failure line, to quickly detect a failure during operation and put a heavy burden on the operator It is possible to provide a DA converter capable of avoiding a failed line without any trouble and capable of quick recovery at the time of repair.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a DA converter according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a DA converter according to a second embodiment of the present invention;

FIG. 3 is a block diagram showing a DA converter according to a third embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 DA converter (DAC) 2 Output means 3A 1st detection means 3B 2nd detection means 3C 3rd detection means 4, 15 Comparison means 5, 13, 17 Processing means 6 Storage means 7 Abnormal notification signal output means 8 Display means 9 Loudspeaking means 10, 18 Switching means 11A, 11B, 11C Failure detection circuit (fault detection means) 12 Majority comparison means 14A, 14B Storage means 16 Storage means

Claims (10)

[Claims] A plurality of D / A converters for converting input digital signals into analog signals; a failure detection unit for detecting a failed line based on output signals of the plurality of D / A converters; Means of said plurality of lines based on the output of
A switching unit for selecting and outputting the output of the D / A conversion unit of any normal line from the output of the conversion unit. 2. The method according to claim 1, wherein the failure detecting means includes a plurality of D lines.
The first which detects the output signal of one specific line in the A conversion unit
And the other one of the DA converters of the plurality of lines.
Second detection means for detecting an output signal of the line, comparison means for comparing signal components detected by these detection means, storage means for storing a reference value defining an allowable range,
Processing means for determining whether the result output from the comparing means is within an allowable range defined by a reference value stored in the storage means, and the switching means comprises: 2. The DA converter according to claim 1, wherein the output of the DA converter of the normal line is selected based on the output. 3. The system according to claim 2, wherein the failure detecting means comprises a plurality of D lines.
The first which detects the output signal of one specific line in the A conversion unit
Detecting means for detecting output signals of at least two or more other lines among the DA converters of the plurality of lines, and comparing the signal components detected by these detecting means, and determining a faulty DA by majority decision. Majority decision means for judging a converter, storage means for storing data of the comparison result by the majority decision means as a judgment criterion, and comparing the result outputted from the majority decision comparison means with the judgment criterion stored in the storage means 2. A processing unit for determining a failed line, wherein the switching unit selects an output of a DA converter of a normal line based on an output from the processing unit. DA converter. 4. The failure detecting means includes two detecting means for detecting output signals of the two DA converters at fixed time intervals, respectively, and accumulating detection results detected by these detecting means in time series. Two storage means, a storage means for storing a reference value in advance, a comparison means for comparing the results stored in the two storage means with a reference value stored in the storage means at predetermined time intervals, Storage means for storing in advance the data for performing the comparison, and comparing the result output from the comparison means with the data stored in the storage means, to determine which line out of the two output signals of the two DA converters has a fault. The switching means selects the output of the D / A converter of the normal line based on the output from the processing means. DA conversion device. 5. An abnormality notification signal output means for outputting an abnormality notification signal based on a result output from the failure detection means, and a notification means for notifying the content notified from the abnormality notification signal output means. 2. The method according to claim 1, wherein
A DA converter according to any one of claims 1 to 4. 6. The DA converter according to claim 5, further comprising a display unit for displaying the content notified from the abnormality notification signal output unit as the notification unit. 7. The DA converter according to claim 5, further comprising a loudspeaker for loudspeaking the content notified from the abnormality notification signal output unit, as the notification unit. 8. The DA converter according to claim 2, wherein said detecting means detects an amplitude level of an output signal from said DA converter. 9. The DA converter according to claim 2, wherein said detecting means detects a DC offset component of an output signal from said DA converter. 10. The D / A converter includes: a D / A converter that converts an input digital signal into an analog signal;
10. An output unit for outputting an analog signal converted by the A converter, wherein the detection unit detects an output of one of the DA converter and the output unit. The DA converter according to any one of the above.