JPH02308478A - Bit error rate measuring method - Google Patents

Abstract

PURPOSE:To accurately evaluate an optical recording medium including an effect due to the pattern of a recording signal by recording and inspecting the signal equivalent to the signal recorded on the optical recording medium at an actually working state. CONSTITUTION:A recording operation is performed by setting a readout start address of a pattern ROM 107 with a controller 113. The recording signal 111 outputted from the ROM 107 is recorded on the optical recording medium 101. Next, the inspection of a bit error is performed by setting the readout start address of the ROM 107 for inspection with the controller 113. Part of code data read out from the medium 101 and outputted from a data discriminator 105 is inputted to a mark detector 109, and a SYNC mark is detected at the detector. Reproducing data is compared with data in the ROM 107 setting the detection of the mark as a trigger, and the data for which noncoincidence is obtained is counted with an error counter 110 as an error. Thus, a bit error rate can be obtained by dividing the counted number of errors by the amount of data to be inspected.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention focuses light such as a laser into a minute spot,
The present invention relates to a method for measuring the bit error rate of an optical recording medium on which information is recorded.

[Prior Art] Conventionally, when measuring the bit error rate of an optical recording medium, first a signal of a constant frequency is recorded. Next, the bit error rate was determined by reproducing this portion and comparing it with the originally recorded data. An example of this is shown in FIG.

In FIG. 4, numeral 41 is a reproduction signal from an optical recording medium on which data of a constant frequency is recorded, and numeral 42 is a signal obtained by converting this signal back into code data. If there are defects caused by dust, scratches, etc. on the optical recording medium,
This reproduced signal is disturbed and an error occurs in that part. That is, the conventional bit error rate measurement method counts the number of defects on an optical recording medium.

[Problem to be solved by the invention] Generally, when recording information on an optical recording medium, various modulation methods are used, and only signals of a certain frequency are recorded as shown in Figure 4. Instead, a signal containing a mixture of multiple frequencies is recorded. An example of this is shown in FIG. In FIG. 5, 51 is a reproduced signal from an optical recording medium on which a modulated signal is recorded, and 52 is a signal obtained by converting this signal back into code data. In optical recording, as the interval between recorded bits becomes shorter, the amplitude of the reproduced signal becomes smaller, as seen in this figure. Now, let us say that the minimum amplitude is a, the maximum amplitude is b, and b/a is called the degree of modulation. If this modulation degree becomes too small, it becomes impossible to detect whether data exists or not, and an error occurs. When a modulated signal is recorded in this way, errors may occur depending on the pattern. However, conventional bit error rate measurement methods do not detect this type of error because recording is performed only at a fixed frequency. The present invention is intended to solve these problems.The purpose of the present invention is to perform recording using the modulation method used in actual recording, and to reproduce this data in order to reproduce data under actual usage conditions. The object of the present invention is to provide a method for measuring bit error rate.

[Means for Solving the Problems] The bit error rate measurement method of the present invention includes an optical recording medium, an optical pickup for recording and reproducing information on the optical recording medium, and a method for measuring data from a reproduced signal of the optical recording medium. A data discriminator for extracting the
In a configuration having an OM, bit errors are detected by comparing reproduced data and data in the ROM.

[Example] The present invention will be explained below based on the drawings.

FIG. 1 is a block diagram of the bit error measurement method of the present invention. 102 is an optical pickup that records and reproduces information on the optical recording medium 101. optical pickup 102
The analog reproduced signal 103 obtained from the above is binarized by a waveform shaper 104. A specific example at this time is shown in FIG. 21 is an analog reproduced waveform, and by performing peak detection from this waveform, a binarized waveform 22 is obtained. The clock extracted from this binarized data is the waveform 23, and at the rising edge of this clock,
By reading the waveform of 22, code data 24 is obtained. In FIG. 1, a clock extractor 106 extracts the clock waveform 23.
The part that obtains the code data 24 based on this clock is 1
05 is a data discriminator. Before explaining the next part of FIG. 1, an example of the physical format of an optical recording medium will be explained based on FIG. 3. In optical recording media, track addresses, sector addresses, etc. are formed in advance on the medium using uneven bits. In FIG. 3, the portion shown at the top is the sector format. Multiple sectors are grouped together to form a track. 31 is a preformat section formed of the above-mentioned uneven bits, and 33 is a user recording section in which the user records data. 32 is a gap part that separates 31 and 33, and 34 is a gap part that separates sectors.

Next, the portion shown below is a detailed diagram of the user recording section 33. 35 is a VFO for clock synchronization
Part 36 is a 5YNC mark that detects synchronization confirmation, and 3
7 is a part for recording user data. Above,
Having finished explaining the physical format of the optical recording medium, the remaining portions of FIG. 1 will now be explained. First, before measuring the bit error rate, it is necessary to record data in the area to be inspected on the optical recording medium.

When performing a recording operation, the controller 113 sends a signal to the address switch 112 to select the pattern RO of 107.
Set the reading start address of M for recording. The data sent out from the pattern ROM at this time is the data in the portions 35 to 37 in FIG. pattern RO
The recording signal 111 output from the optical pickup 102
and recorded on the optical recording medium 101. next,
Bit error checking will be explained. Regarding the part that converts the playback signal from the optical recording medium into code data,
As stated before. And controller 113
sends a signal to the address switch 112 to set the reading start address of the pattern ROM 107 for inspection. At this time, the data sent out from the pattern ROM is only the portion 37 in FIG. Part of the code data output from the data discriminator 105 enters the mark detector 109, where the 5YNC mark 36 shown in FIG. 3 is detected. Using this 5YNC mark detection as a twagger, the data comparator 108 compares the reproduced data and the data in the pattern ROM, and the data that do not match is counted as an error by the error counter 110. As a method for detecting errors, for example, exclusive OR of the data in the pattern ROM and the reproduced data from the data discriminator 105 may be performed. By dividing the number of errors thus counted by the number of data to be inspected, the bit error rate can be obtained.

In this inspection method, any modulation method and any data may be recorded in the user data section 37 in FIG. 3, and the measurement can be performed using data of the user's preference. Therefore, it is best to write a pattern that is most difficult to detect into the ROM and inspect it under actual use conditions.

[Effects of the Invention] As described above, when the bit error rate inspection method of the present invention is used, a signal equivalent to the signal recorded on an optical recording medium in actual use is recorded and inspected, so that the recorded signal is Accurate evaluation of optical recording media including effects due to patterns can be performed. In addition, bit error inspection is performed using the pattern ROM.
Since this is done in

[Brief explanation of drawings]

Figure 1 is a block diagram of the bit error rate measurement method of the present invention, Figure 2 is a waveform diagram for each block shown in Figure 1, and Figure 3 is the layout of the physical format of the optical recording medium. 4 is a reproduced waveform diagram of the conventional bit error rate measurement method, and FIG. 5 is a reproduced waveform diagram of a modulated signal. 101... Optical recording medium 102... Optical pickup 103... Reproduction signal 104... Waveform shaper 105... Data discriminator 106... Black extractor 107... Pattern ROM 108...・Data comparator 109...Mark detector 110...Error counter 111...Record signal 112...Address switch 113...Controller 21...Analog reproduction waveform 22...Binarization Waveform 23...Clock 24...Code data 31...Blower format section 32.34...Gap section 33...User recording section 35...VFO section 36...5YNC section 37... User Data Department and above Applicant: Seiko Epson Co., Ltd. Representative Patent Attorney Kizobe Meiki (and 1 other person) 31 Nibrifuo 1 Matsuto Department 32, 34: Gap Department 33: User Record Department 35: VFO Department 36: 5YNC Department 37: User Data section Figure 3 Figure 4 Figure 5 Figure 4e

Claims (1)

[Claims] an optical recording medium; an optical pickup for recording and reproducing information on the optical recording medium; a data discriminator for extracting data from a reproduction signal of the optical recording medium; A method for measuring a bit error rate, characterized in that, in a configuration having a ROM for performing comparison with data, a bit error is detected by comparing the reproduced data with data in the ROM.