JPH05266604A - Signal processor - Google Patents

Abstract

(57) [Abstract] [Purpose] A signal processing device in which a digital signal processing unit and an analog signal processing unit coexist, and easily diagnoses whether or not the entire operation is normal. An output analog signal sent from a digital-to-analog conversion means is folded back as an input analog signal of the analog-to-digital conversion means, and a predetermined test digital signal is input to a digital-signal processing means or a digital-analog conversion means and at the same time an analog-to-digital conversion. The operation of the analog digital conversion means, the digital signal processing means and the digital analog conversion means is diagnosed by the input digital signal sent from the means or the output digital signal sent from the digital signal processing means and the test digital signal. did.

Description

Detailed Description of the Invention

[0001]

[Table of Contents] The present invention will be described in the following order. Field of Industrial Application Conventional Technology Problems to be Solved by the Invention Means for Solving the Problems (FIG. 1) Action (FIG. 1) Example (FIGS. 1 and 2) Effect of the Invention

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal processing device, and is suitable for application to, for example, a digital audio tape recorder.

[0003]

2. Description of the Related Art Conventionally, a CUE signal recorded on a CUE track of a digital audio tape recorder is recorded using the same head as a recording and reproducing system of a digital audio signal in order to guarantee in-line with the digital audio signal. Then played.

Therefore, at the time of recording, the recording CUE signal is delayed by the encode delay time, and the pulse width modulation (PW
Modulation according to method M) and recording on the CUE track on the magnetic tape using the recording head. Further, at the time of reproduction, the reproduction signal obtained from the reproduction head is PWM-demodulated, delayed by the decode delay time, and transmitted as a reproduction CUE signal.

In this CUE signal recording / reproducing processing apparatus, a digital delay circuit is used as a delay circuit, the CUE signal consisting of an analog signal is once converted into a digital signal, delayed for a predetermined time, and then converted into an analog signal again. It is designed to be output.

Actually, by designating the encode delay time and the decode delay time as the setting data of the digital delay circuit, the recording and reproducing system can share the digital delay circuit in a time division manner.

[0007]

However, in the CUE signal recording / reproducing apparatus having such a structure, the circuit section for processing the digital signal and the circuit section for processing the analog signal coexist. When attempting to self-diagnose each circuit, there is a problem that the size of the diagnostic circuit itself becomes large, and in practice, the operation of the entire device cannot be easily self-diagnosed.

The present invention has been made in consideration of the above points, and even if the digital signal processing unit and the analog signal processing unit are mixed, it is possible to easily diagnose whether or not the overall operation of these units is normal. It is intended to propose a signal processing device.

[0009]

In order to solve such a problem, in the first aspect of the invention, an analog digital converting means 4 for converting the input analog signal S1 into an analog digital signal and transmitting the analog signal, and the analog digital converting means 4 transmits the analog signal. A digital signal processing means 6 for performing a predetermined digital signal processing on an input digital signal D1 to be transmitted, and a digital analog converting means 9 for converting the output digital signal transmitted from the digital signal processing means 6 into a digital analog signal and transmitting the digital signal. In the signal processing device 1 having the above, the output analog signal S2 sent from the digital analog converting means 9 is folded back as the input analog signal S5 of the analog digital converting means 4, and the predetermined test digital signal TDATA is sent to the digital signal processing means 6. input At the same time, the input digital signal D1 sent from the analog digital converting means 4 is detected, and the input digital signal MSB and the test digital signal TDATA, which are the detection results, are used to detect the analog digital converting means 4 and the digital signal processing means 6. Also, the operation of the digital-analog conversion means 9 is self-diagnosed.

In the second aspect of the present invention, the analog digital conversion means 4 for converting the input analog signal S1 into an analog digital signal and transmitting the analog digital signal and the input digital signal D1 transmitted from the analog digital conversion means 4 are predetermined digital signals. Digital signal processing means 6 for processing and transmitting, and digital signal processing means 6 thereof
In the signal processing device 1 having a digital-analog conversion means 9 for converting the output digital signal sent from the digital-analog converter and sending it, the output analog signal S2 sent from the digital-analog converter 9 is input to the analog-digital converter 4. It is folded back as an analog signal S5, a predetermined test digital signal TDATA is input to the digital-analog converting means 6, an output digital signal MSB sent from the digital signal processing means 6 is detected, and an output digital signal MSB which is the detection result. Also, the operation of the analog digital conversion means 4, the digital signal processing means 6, and the digital analog conversion means 9 is self-diagnosed by the test digital signal TDATA.

Further, in the third invention, in the signal processing device 1 in which the analog digital converting means 4, the digital signal processing means 6 and the digital analog converting means 9 are combined in at least two systems, the first digital analog converting means 9 is used. The first output analog signal transmitted from the second analog digital conversion means 4 is folded back as a second input analog signal, and a predetermined test digital signal TDATA is output to the first digital signal processing means 6.
The second input digital signal MSB sent from the second analog digital conversion means 4 or the second output digital signal MSB sent from the second digital signal processing means 6, and the detection thereof. Resulting second input digital signal MSB or second output digital signal MSB and test digital signal TDAT
According to A, the operation of the second analog digital conversion means 4, the first or second digital signal processing means 6 and the first digital analog conversion means 9 is self-diagnosed.

Furthermore, in the fourth invention, the first and second analog digital converting means 4, the first and second analog digital converting means 4,
The digital signal processing means 6 and the first and second digital analog converting means 9 are shared in a time-divisional manner as required.

[0013]

The output analog signal S2 sent from the digital / analog conversion means 9 is converted into the analog / digital conversion means 4
As an input analog signal S5 of the input signal, a predetermined test digital signal TDATA is input to the digital signal processing means 6 or the digital analog converting means 9, and the input digital signal D2 or digital signal processing means sent from the analog digital converting means 4 is input. The operation of the analog digital converting means 4, the digital signal processing means 6 and the digital analog converting means 9 is diagnosed by the output digital signal MSB and the test digital signal TDATA sent from Even when the means 6 and the analog signal processing means 4 and 9 are mixed, it is possible to easily diagnose whether or not the operation of all of them is normal.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a digital audio tape recorder to which a CUE signal recording / reproducing system according to the present invention is applied as a whole, and a recording CUE signal S1 which is an analog signal input from a line is amplified by an input amplifier circuit 2. The signal is input to the analog digital conversion circuit (AD) 4 through the first input terminal a and the output terminal c of the first selector 3 for selecting recording / reproducing. The analog signal S1 is converted into a digital signal D1 here, and is input to the delay circuit 6 through the first input terminal a and the output terminal c of the second selector 5 which selects the delay input for self-diagnosis.

The delay circuit 6 is an interface 7
The delay time is set by the control signal from the system control circuit 8 input through the digital control circuit 8 and the input digital signal D1 is delayed by the actual recording encode time and the reproduction decode time. Input into (DA) 9. The digital signal D1 is returned to the analog signal S2 delayed by the encoding time here, and this is pulse-width modulated by the PWM modulation circuit 10. The resulting recording signal S4 is amplified by the recording amplifier circuit 11 and magnetically recorded by the recording head 12A. It is recorded on the tape as a CUE signal.

On the other hand, during reproduction, the CUE signal recorded on the magnetic tape 13 is reproduced by the reproduction head 12B, and the reproduction signal S4 obtained as a result is amplified by the reproduction amplifier circuit 14 including an equalizer and reproduced for self-diagnosis. The signal is input to the PWM demodulation circuit 16 through the first input terminal a and the output terminal c of the second selector 15 that selects the input. Here, the reproduction signal S4 is PWM demodulated, and the analog signal S5 obtained as a result is the second input end b and the output end c of the first selector 3.
And is input to the analog digital conversion circuit (AD) 4.

The analog signal S5 is now converted into a digital signal D2 to select a second delay input for self-diagnosis.
Through the first input terminal a and the output terminal c of the selector 5 of
It is input to the delay circuit 6. At this time, the delay circuit 6
Delays the input digital signal D2 by the decoding time and inputs it to the digital-analog conversion circuit 9. The digital signal D2 is returned here to the analog signal S6 delayed by the decoding time, and this is the output amplifier circuit 1.
Amplified by 7 and transmitted as a reproduced CUE signal S7.

Here, in the case of this embodiment, in addition to the circuit section for performing the above-mentioned normal recording / reproducing processing, the test signal generating circuit 19 and the test signal detecting circuit 20 are provided in the substrate of the CUE signal recording / reproducing system. The second selector 5 for selecting the delayed input for self-diagnosis is arranged, and the operation of the circuit section can be self-diagnosed when the power is turned on, for example.

In practice, the test signal generation circuit 19 outputs the repetitive pattern of the maximum value and the minimum value of the digital-analog conversion circuit 9 as the test pattern data TDATA, as shown in FIGS. 2 (A) and 2 (B). When the digital analog conversion circuit 9 performs 8-bit digital analog conversion of 2's complement method, the maximum value is 7F (H).
((H) represents a hexadecimal number) and the minimum value is 80 (H).
2A shows the highest bit (MSB) of the 8 bits of the test pattern data TDATA.
(B) represents 1 to 7 bits.

The test pattern data TDATA generated by the test signal generating circuit 19 is input to the delay circuit 6 through the second input terminal b and the output terminal c of the second selector 5. The test pattern data TDATA is delayed by the delay circuit 6 by the digital data encoding time, and then converted into an analog signal by the digital analog conversion circuit 9.

This analog signal is pulse-width modulated by the PWM modulation circuit 10 and does not pass through the normal recording / reproducing system of the recording / amplifying circuit 11, the recording head 12A, the magnetic tape 13, the reproducing head 12B and the reproducing / amplifying circuit 14, Directly through the second input terminal b and the output terminal c of the third selector 15 to the PW
It is input to the M demodulation circuit 16.

The reproduced signal returned to the analog signal by the PWM demodulation circuit 16 is input to the analog digital conversion circuit 4 through the second input terminal b and the output terminal c of the first selector 3. The input analog signal is converted into a digital signal here, and is input to the delay circuit 6 through the first input terminal a and the output terminal c of the second selector 5.

This digital signal is delayed by the delay circuit 6 by the decoding time of the digital data and then sent to the digital analog conversion circuit 9 and at the same time, the highest bit (M) of the delayed digital signal is output.
SB) is input to the test signal detection circuit 20.

The test signal generation circuit 19 uses the test pattern data TDA in addition to the test pattern data TDATA.
A window signal WD having a window at a time point t1 at which the encode delay and the decode delay are separated from the timing t0 at the beginning of TA (FIG. 2 (C)).
Is generated and sent to the test signal detection circuit 20.

As a result, in the test signal detection circuit 20, the CUE signal recording / reproducing system depends on whether or not the delayed most significant bit (MSB (FIG. 2D)) edge exists in the window of the window signal WD. Then, the test signal detection circuit 20 evaluates whether or not the whole is operating normally, so that the test signal detection circuit 20 determines whether the condition COND (FIG. 2) is reached at a timing t2 when an edge exists in the window.
(E)) is inverted, and this is sent out to the system control circuit 8 through the interface 7. In this way, for example, when the power is turned on, self-diagnosis of the circuit section can be executed.

In practice, the test signal generating circuit 19 is controlled by the system control circuit 8 to switch the first, second and third selectors 3, 5 and 15 during the self-diagnosis operation. First, when the test pattern data TDATA is transmitted, the first, second and third selectors 3, 5 and 15 are switched to the second input terminal b. Then, for example, after the encode delay time has passed, the second
The selector 5 is switched to the first input terminal a, and the above-mentioned self-diagnosis is executed in this manner.

According to the above configuration, when the power is turned on, the test pattern data TDATA, which is a repetition of the maximum value and the minimum value of the digital analog conversion, is input to the delay circuit 6, and the digital analog conversion circuit 9 and the PWM modulation circuit are sequentially input. 10, the PWM demodulation circuit 16, the analog digital conversion circuit 4, and the delay circuit 6 again are passed to detect whether or not the inversion of the highest bit of the test pattern data is present in the window corresponding to the total delay time. By doing so, it is possible to realize the digital audio tape recorder 1 capable of surely performing self-diagnosis of the CUE signal recording / reproducing system in which the digital signal circuit and the analog signal processing circuit coexist.

In the above embodiment, the case where the change in the sign of the MSB of the digital signal transmitted from the delay circuit is detected in a predetermined window as the self-diagnosis timing has been described. If it is long, the window corresponding to the day delay time,
You may make it detect the change of the sign of MSB of the digital signal input into a delay circuit.

Further, in the above-mentioned embodiment, the case where the analog digital conversion circuit, the delay circuit and the digital analog conversion circuit are shared in a time division manner has been described for the two signal processing devices in the CUE signal recording / reproducing system. However, even if the analog digital conversion circuit, the delay circuit, and the digital analog conversion circuit exist for each system, if the output of one digital analog conversion circuit is returned to the other analog digital conversion circuit, The same effect can be realized.

Further, in the above embodiment, the case where there are two systems of the analog digital conversion circuit, the delay circuit and the digital analog conversion circuit has been described.
The present invention is not limited to this, and one system may be used. In this case as well, if the output of the digital-to-analog conversion circuit is returned to the analog-to-digital conversion circuit, the same effect as the above-described embodiment can be realized.

Furthermore, in the above-described embodiment, the present invention is applied to the one in which an analog signal is converted into a digital signal, delayed by digital signal processing, and converted again into an analog signal, but the digital signal processing is not limited to this. No
For example, various digital signal processing such as digital filter processing may be applied.

Further, in the above-mentioned embodiment, the repeating pattern of the maximum value and the minimum value of the digital analog conversion is used as the test pattern data TDATA, but the test pattern is not limited to this, and it may be changed according to the contents of the digital signal processing. You may make it use the data of a predetermined pattern.

Further, in the above-mentioned embodiment, the present invention is applied to the CUE signal recording / reproducing system of the digital audio tape recorder, but the present invention is not limited to this, the point is that an analog signal is once converted into a digital signal and predetermined. It is suitable for wide application to a signal processing device which is configured to perform the digital signal processing, and convert it into an analog signal for output again.

[0035]

As described above, according to the present invention, the digital
Output analog signal sent from the analog conversion means
As an input analog signal of analog digital conversion means
Folds back and digitally outputs predetermined digital signal for test
Input to signal processing means or digital analog conversion means
And sent from the analog digital conversion means.
Sent from the input digital signal or digital signal processing means
Output digital signal and digital signal for test
According to the issue, analog digital conversion means, digital
The operation of the signal processing means and digital analog conversion means
By diagnosing, the digital signal processing unit
And even if the analog signal processing unit is mixed, this
Signal processing that can easily diagnose whether the entire operation is normal
The device can be realized.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a digital audio tape recorder according to the present invention.

FIG. 2 is a timing chart for explaining a self-diagnosis operation of the digital audio tape recorder shown in FIG.

[Explanation of symbols]

1 ... Digital audio tape recorder, 2 ... Input amplifier circuit, 3, 5, 15 ... Selector, 4 ... Analog digital conversion circuit, 6 ... Delay circuit, 7 ... Interface, 8 ... System control circuit , 9 ... Digital analog conversion circuit, 10 ... PWM modulation circuit, 1
1 ... Recording amplification circuit, 12 ... Head, 13 ... Magnetic tape, 14 ... Reproduction amplification circuit, 16 ... PWM demodulation circuit, 17 ... Output amplification circuit, 19 ... Test signal generation circuit, 20 ... Test signal detection circuit.

Claims (4)

[Claims] 1. An analog digital conversion means for analog-digital converting an input analog signal and sending it, and a digital signal processing means for applying predetermined digital signal processing to the input digital signal sent from the analog digital converting means and sending it. And a digital-analog conversion means for converting the output digital signal sent from the digital signal processing means into a digital-analog and sending the digital signal, the output analog signal sent from the digital-analog conversion means is converted into the analog-digital signal. Folding back as the input analog signal of the converting means, inputting a predetermined test digital signal to the digital signal processing means, and detecting the input digital signal sent from the analog digital converting means, The operation of the analog digital conversion means, the digital signal processing means, and the digital analog conversion means is self-diagnosed by the input digital signal and the test digital signal which are the detection results. Signal processing device. 2. An analog digital conversion means for converting an input analog signal into an analog digital signal and sending the analog signal, and a digital signal processing means for applying a predetermined digital signal processing to the input digital signal sent from the analog digital conversion means and sending the digital signal. And a digital-analog conversion means for converting the output digital signal sent from the digital signal processing means into a digital-analog and sending the digital signal, the output analog signal sent from the digital-analog conversion means is converted into the analog-digital signal. Folding back as the input analog signal of the converting means, inputting a predetermined test digital signal to the digital analog converting means, and detecting the output digital signal sent from the digital signal processing means, The operation of the analog digital conversion means, the digital signal processing means, and the digital analog conversion means is self-diagnosed by the output digital signal and the test digital signal which are the detection results. Signal processing device. 3. A signal processing device in which the analog digital converting means, the digital signal processing means, and the digital analog converting means are combined in at least two systems, and the first digital analog converting means sends the first digital analog converting means. The output analog signal is folded back as the second input analog signal of the second analog digital conversion means, and a predetermined test digital signal is input to the first digital signal processing means, and at the same time, the second analog digital signal is input. The second input digital signal sent from the conversion means or the second output digital signal sent from the second digital signal processing means is detected, and the second input digital signal or the second input digital signal obtained by the detection result is detected. 2 above output digital signal and above test digital Signal processing, the operation of the second analog digital conversion means, the first or second digital signal processing means, and the first digital analog conversion means is self-diagnosed. apparatus. 4. The first and second analog digital conversion means, the first and second digital signal processing means,
4. The signal processing apparatus according to claim 3, wherein the first and second digital analog conversion means are shared in a time division manner as needed.