JPH02289915A - Fm envelope waveform inspecting device for magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To improve the accuracy of inspection by determining the increase and decrease of the area of reproducing FM envelope waveforms for a basic waveform. CONSTITUTION:The data on the reproducing FM envelope waveform for one frame stored in a waveform memory section and the data on the reference waveform for one frame are respectively divided to small sections at prescribed intervals in synchronization with a control signal to determine the areas of every small sections and to determine the increase and decrease of the area of the reproducing FM envelope waveform for the reference waveform. Namely, the partial area ratio of the reproducing FM envelope waveform for the area of the reference waveform or the increase or decrease of the partial area is determined in an inspection processing section 4 from the data on the reproducing FM envelope waveform for one frame stored in the waveform memory section 3 and the data on the reference waveform for one frame stored previously in the waveform memory section 3. The ratio of the overall area of the corresponding waveforms or the increase or decrease of the overall area is determined in this case and the results of the analysis, etc., are displayed on a display part 5. The analysis of NG is exactly executed in this way and the quality inspection of a magnetic recording and reproducing device 7 to be tested is exactly executed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a magnetic recording and reproducing device, or a magnetic recording and reproducing device that performs quality inspection after manufacturing and assembling a rotary head, etc. by analyzing a reproduced FM envelope waveform. FM
This invention relates to an envelope waveform inspection device.

[Conventional technology]

After the manufacturing and assembly of a magnetic recording/reproducing device, a rotary head, etc. is completed, its quality is inspected. This quality inspection is performed by analyzing the reproduced FM envelope waveform obtained by reproducing the test magnetic tape with the assembled magnetic recording/reproducing device or rotating head (hereinafter referred to as the magnetic recording/reproducing device under test). It is being done. Important quality inspection items include the roller system, tape guide, video search, and rotating hand of the magnetic recording/reproducing device.

The example shown in FIG. 4 is well known and
This is the inspection equipment used. Here, the outline of the inspection will be explained based on FIG. 4 as follows.

The magnetic tape 126 for testing is transferred to the magnetic recording/reproducing device 27 under test.
Load. Based on the mode switching signal from the outside, the magnetic recording/reproducing device under test operates in each switched operation mode. Operating modes include play, stop,
There are video search, fast rewind, fast forward, etc.

As shown in FIG. 4, when a tracking operation signal is applied to the magnetic recording/reproducing device under test 27 from the outside by manually adjusting a variable resistor for adjusting the tracking operation voltage (not shown),
The device 27 outputs a reproduced FM envelope waveform that changes accordingly. This reproduced FM envelope waveform is then observed with an oscilloscope 28. The test results are obtained by measuring the levels of the maximum peak-to-peak value A and the minimum peak-to-peak value B for each frame in the above-mentioned reproduced FM envelope waveform, and calculating the ratio of the minimum value B to the maximum value A, or the maximum It is evaluated based on the level difference between the key A and the minimum value B. That is, by evaluating the magnitude of these ratios or level differences (both of which represent the flatness of the waveform), the roller system, tape guide, video search, or rotation (not shown) in the magnetic recording/reproducing device 27 under test is evaluated. The quality of heads, etc. is inspected.

[Problem to be solved by the invention]

In the conventional configuration described above, the test results are evaluated by determining the level difference between the maximum value and the minimum value of the reproduced FM envelope waveform, or the ratio of the minimum value to the maximum value, from the measurement results. Therefore, the reproduction F which is the output of the magnetic recording and reproducing device under test
Since minute changes such as the shape of the M envelope waveform, waveform drop, or slope become unclear, the cause of the test failure is not revealed, and the N of the test result is
It becomes difficult to analyze G, and the quality deteriorates significantly.

In addition, even if data of the maximum and minimum values of many peak-peak values are collected in the reproduced FM envelope waveform and the test results are evaluated based on the average value, the number of data points to be collected and the points to be collected cannot be selected. etc. remain a problem.

Furthermore, during the inspection, the tracking operation must be performed manually.
This must be done quickly, and the associated complicated measurement of the reproduced FM envelope waveform is also done manually.

These operations require considerable skill, making it difficult to simplify quality inspection and save labor, leading to problems such as increased overall costs.

[Means to solve the problem]

In order to solve the above problems, an FM envelope waveform inspection device for a magnetic recording/reproducing device according to the present invention has three non-modulated FM envelope waveform inspection devices.
Based on the test magnetic recording medium on which the 7MHz reference waveform is recorded and the mode switching signal from the inspection processing section, drive the magnetic recording/reproducing device under test for each operating mode and synchronize with its servo system. A reproduction FM that outputs a control signal and changes according to the control signal from the inspection processing section when the test magnetic recording medium is reproduced.
A driving interface section that outputs an envelope waveform, an analog processing section that amplifies the above-mentioned reproduced FM envelope waveform, samples and holds its peak-to-peak value for each frame, and converts it into a digital signal, and a standard for one frame in advance. A waveform storage unit that stores waveform data and one frame of reproduced FM envelope waveform data converted into a digital signal by an analog processing unit in synchronization with the control signal, and a control that performs tracking operations. In addition to outputting a mode switching signal corresponding to each operation mode, in synchronization with the control signal, one frame's worth of reproduced FM envelope waveform data and one frame's worth of data stored in the waveform storage section are outputted. An inspection process that performs quality inspection analysis by dividing the reference waveform data into small sections at predetermined intervals, determining the area of each small section, and determining the increase or decrease in the area of the reproduced FM envelope waveform with respect to the reference waveform. Department and
The present invention is characterized in that it includes a display section that displays the analysis results in the test processing section and monitors the reproduced FM envelope waveform.

[For production]

According to the above configuration, the test magnetic recording medium on which the reference waveform is recorded is loaded into the magnetic recording/reproducing device under test. The reference waveform is then reproduced and output from the drive interface unit as a reproduced FM envelope waveform that changes according to the control signal. In the analog processing section, the reproduced FM envelope waveform is amplified, its peak-to-peak value is sampled and held for each frame, and is further converted into a digital signal and output to the waveform storage section.

In the inspection processing section, one frame's worth of reproduced FM envelope waveform data stored in the waveform storage section and one frame's worth of reference waveform data stored in advance are divided into small sections at predetermined intervals, and each The area of each small section is determined, and the increase/decrease in the area of the corresponding small section of the reproduced FM envelope waveform with respect to the reference waveform and the increase/decrease in the area of the entire waveform are determined. Then, the analysis results and the like are displayed on the display section. Furthermore, the reproduced FM envelope waveform is monitored as necessary. As described above, the quality inspection of the magnetic recording/reproducing device under test is performed.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

As shown in FIG. 1, the FM envelope waveform inspection device for a magnetic recording/reproducing device according to the present invention mainly includes a drive interface section 1, an analog processing section 2, a waveform storage section 3, an inspection processing section 4, and a display section 5. It has become.

The drive interface unit 1 drives the magnetic recording/reproducing device 7 under test in each operation mode based on a mode switching signal from the inspection processing unit 4, which will be described later, and outputs a control signal for synchronizing with the servo system. ing. Also,
When the drive interface unit 1 reproduces the magnetic tape 6 as a test magnetic recording medium, it outputs a reproduced FM envelope waveform that changes according to a control signal from the test processing unit to the analog processing unit 2, which will be described later.

In addition, the above control signal is Capsun FC signal? , head switch pulse, etc., and the magnetic recording/reproducing device under test 7
This is a signal for synchronizing with the servo system (not shown) inside. Further, the above control signal is a signal for performing a tracking operation. The control signal will be explained as follows based on FIG.

As shown in FIG. 2, the setting range (0% to 100%) corresponding to the scale (0% to 100%) of the variable resistor for adjusting the tracking operation voltage (not shown) installed in the magnetic recording/reproducing device 7 under test is shown.
■1,■~Vffl. A control signal corresponding to the tracking operation voltage of X) is supplied by the inspection processing section 4 to the drive interface section 1.

The magnetic recording/reproducing device 7 under test is connected to the input of the drive interface section 1, and the output of the interface 1 is connected to the input of the buffer amplifier 8 in the analog processing section 2, as shown in FIG. There is. As shown in FIG.
o, and an A/D conversion circuit 11.

Since the reproduced FM envelope waveform from the drive interface section 1 is a weak signal, it is amplified by the buffer amplifier 8. The peak-to-peak value of this amplified reproduced FM envelope waveform is held in a peak-to-peak value hold circuit 9 for each frame, and further sampled and held in a sample-and-hold circuit 10. The output of the circuit 10 is converted into a digital signal by an A/D conversion circuit 11 and outputted to the waveform storage section 3 as a reproduced FM envelope waveform for one frame. Note that the above signal processing in the analog processing section 2 is performed in synchronization with the above control signal.

The waveform storage unit 3 stores in advance one frame's worth of reference waveform data, and also stores the reproduced FM envelope waveform data converted into the digital signal described above in synchronization with the control signal for each frame. Ru. The inspection processing unit 4 can access the above data as appropriate. The reference waveform is recorded in advance on the magnetic tape 6, and is an unmodulated signal having a frequency of, for example, 3 or 7 MIIz. The reason why an unmodulated signal is used as a reference waveform is to perform precise waveform analysis. That is, when a frequency-modulated signal is used, precise waveform analysis cannot be performed because the rotating magnetic head reproducing amplifier (not shown) in the magnetic recording/reproducing device under test 7 has frequency characteristics.

The output of the waveform storage section 3 is connected to the inspection processing section 4. The inspection processing section 4 outputs a control signal for performing the 1. lassoking operation and a mode switching signal corresponding to each operation mode to the drive interface section 1.

In addition, in synchronization with the control signal, one frame's worth of reproduced FM envelope waveform data and one frame's worth of reference waveform data stored in the waveform storage unit 3 are divided into small sections at predetermined intervals, and each The area of each small section is determined, and the increase/decrease in the area of the corresponding small section of the reproduced FM envelope waveform with respect to the reference waveform and the increase/decrease in the area of the entire corresponding waveform are determined.

For example, as shown in FIG. 3, the inspection processing section 4 performs tracking operation by changing the control signal between the reference waveform indicated by the broken line in the figure and the reproduced FM envelope waveform indicated by the solid line in the figure. The associated reproduced FM envelope waveform is sequentially subjected to peak-to-peak value hold, sample hold, and A/D conversion for each frame, and the waveform data is stored in the waveform storage section 3. Here, for example, the inspection processing unit 4 determines a section [p+ . p6] is determined as described below, and from the area of each small section, minute changes in the shape of the reproduced FM envelope waveform become clear, as described below.

That is, apart from the area surrounded by the enrobe of the reference waveform and the time axis in the small section (P,, P..1), the reproduced FM envelope waveform and the time axis in the same small section (Pi, P..,) Let S′. be the area surrounded by sl
By analyzing the increase or decrease of , with respect to S, it is possible to clarify changes such as the shape of a partial waveform, a slight drop in a partial waveform, or a slight slope of a partial waveform. Become.

Also, ΣS+=S (+=1 to 6), Σfurnace. 1S(i-
1 to 6), by analyzing S'/S,
It becomes possible to clarify changes in the overall waveform shape or the overall waveform slope. For example, S”/
By analyzing S, it is possible to check the parallelism between the magnetic tape 6 and the height of a guide roller (not shown) in the magnetic recording/reproducing device 7 under test with respect to the winding of the magnetic tape 6 around the rotating head. That is, the height of the guide roller can be adjusted. Furthermore, it is also possible to inspect the assembly condition of the outlet and inlet of the tape guide (not shown) in the magnetic recording/reproducing device 7 under test. Furthermore, by analyzing the rise of the reproduced FM envelope waveform, inspections such as video searches can be performed. Incidentally, the greater the value of i, that is, the number of points in the divided small sections, the higher the accuracy, and the value of i can be set arbitrarily.

Note that the inspection processing section 4 supplies a mode switching signal and a control signal to the drive interface section 1. Furthermore, the inspection processing section 4 performs stable control of the servo system of the apparatus based on the above control signal so that a stable reproduced FM envelope waveform can be obtained.

The analysis results of the inspection processing section 4 are output to the display section 5. Furthermore, the inspection processing section 4 can also monitor the reproduced FM envelope waveform as appropriate.

According to the above configuration, the magnetic tape 6 is loaded and played back in the magnetic recording/playback device 7 under test. At this time, the reproduced FM envelope waveform is output to the analog processing section 2 via the drive interface section 1 based on the tracking operation accompanying the change in the control 1/roll signal from the inspection processing section 4 .

In the analog processing section 2, a reproduced FM envelope waveform that changes according to the above-mentioned control signal is amplified by a buffer amplifier 8. This amplified reproduced FM envelope waveform is transmitted to a peak-to-peak value hold circuit 9 for each frame.
The signal is then sampled and bolded by the sample and hold circuit 10, and further converted into a digital signal by the A/D conversion circuit 11 and stored in the waveform storage section 3.

In this way, the inspection processing unit 4 uses data of one frame of reproduced FM envelope waveform stored in the shape storage unit 3 and one frame of reference waveform data stored in the waveform storage unit 3 in advance. In addition to finding the partial area ratio or increase/decrease in the partial area of the reproduced FM envelope waveform to the area of the reference waveform, the overall area ratio of the corresponding waveform or the increase/decrease in the overall area is determined. The analysis results are displayed on the display unit 5. As a result, NG analysis can be performed accurately, and the quality inspection of the magnetic recording/reproducing device 7 to be tested can be performed accurately.

Note that the inspection target of the present invention is not limited to the reproduced FM envelope waveform obtained by reproducing the magnetic recording/reproducing device, but can also be applied to inspection and analysis of general FM envelope waveforms and envelopes of general waveforms. It is possible.

〔Effect of the invention〕

As described above, the FM envelope waveform inspection device for a magnetic recording/reproducing device according to the present invention has a non-modulated 3. 7MHz
Control that drives the magnetic recording/reproducing device under test for each operating mode and synchronizes it with its servo system based on the test magnetic recording medium on which the reference waveform of is recorded and the mode switching signal from the inspection processing section. output a signal, and
When a test magnetic recording medium is reproduced, there is a drive interface section that outputs a reproduction FM envelope waveform that changes according to a control signal from the inspection processing section, and a drive interface section that amplifies the reproduction FM envelope waveform and outputs it for each frame. An analog processing section that samples and bolds peak-to-peak values and converts them into digital signals, and a reproduction FM that stores one frame's worth of reference waveform data in advance and converts it into a digital signal by the analog processing section. A waveform storage section in which envelope waveform data is stored in synchronization with the control signal, and a control signal that adjusts the correlation between the test magnetic recording medium and the magnetic recording/reproducing device under test, and is compatible with each operation mode. At the same time, in synchronization with the control signal, one frame's worth of reproduced FM envelope waveform data and one frame's worth of reference waveform data stored in the waveform storage section are divided into small sections at predetermined intervals. an inspection processing unit that performs quality inspection analysis by dividing each subsection, determining the area of each subsection, and determining an increase/decrease in the area of the reproduced FM envelope waveform with respect to the reference waveform, and displaying the analysis results of the inspection processing unit; The configuration includes a display unit that monitors the reproduced FM envelope waveform.

As a result, since a non-modulated reference waveform is used, the reproduction characteristics of the rotary head reproduction amplifier become independent of frequency, which enables precise measurement of the reproduction FM envelope waveform and improves inspection accuracy. Also, play FM
The shape of the envelope waveform, the drop in the waveform, or
Since minute changes such as the slope of the waveform become clear, it becomes easier to analyze NG test results. Furthermore, since precise waveform analysis can be performed without manual measurement, the cause of inspection defects becomes clear and quality is reliably improved.

Furthermore, since tracking operations can be performed automatically using control signals without human intervention, inspections can be easily performed without requiring any skill. Therefore, quality inspection can be simplified and labor can be saved, and overall costs can be reduced.

312I is a diagram showing the relationship between the reference waveform and the reproduced FM envelope waveform.

FIG. 4 shows a conventional example, and is a block diagram showing the configuration of the conventional example.

1 is a drive interface section, 2 is an analog processing section, 3
4 is a waveform storage unit, 4 is a test processing unit, 5 is a display unit, 6 is a magnetic tape, and 7 is a magnetic recording/reproducing device to be tested.

[Brief explanation of drawings]

1 to 3 show one embodiment of the present invention. FIG. 1 is a block diagram showing the configuration of an FM envelope waveform inspection device for a magnetic recording repopulation device according to the present invention. FIG. 2 is a diagram showing the relationship between the variable resistor scale for tracking operation voltage adjustment and the tracking operation voltage. Taste/Musashi

Claims (1)

[Claims] 1. A test magnetic recording medium on which an unmodulated 3.7 MHz reference waveform is recorded, and a magnetic recording medium to be tested for each operation mode based on a mode switching signal from an inspection processing section. Drives the playback device and outputs a control signal to synchronize with its servo system, and outputs a playback FM envelope waveform that changes according to the control signal from the test processing section when playing back the test magnetic recording medium. A drive interface section, an analog processing section that amplifies the above-mentioned reproduced FM envelope waveform, samples and holds its peak-to-peak value for each frame, and converts it into a digital signal, and one frame's worth of reference waveform data is stored in advance. and a waveform storage section in which one frame of reproduced FM envelope waveform data converted into a digital signal by the analog processing section is stored in synchronization with the control signal, and a control signal for performing a tracking operation is output. In addition, it outputs a mode switching signal corresponding to each operation mode, and in synchronization with the control signal, outputs one frame's worth of reproduced FM envelope waveform data and one frame's worth of reference waveform data stored in the waveform storage unit. an inspection processing unit that performs quality inspection analysis by dividing the reproduced FM envelope waveform into small sections at predetermined intervals, calculating the area of each small section, and calculating the increase or decrease in the area of the reproduced FM envelope waveform with respect to the reference waveform; 1. An FM envelope waveform inspection device for a magnetic recording/reproducing device, comprising a display section for displaying analysis results in the section and for monitoring a reproduced FM envelope waveform.