KR100233523B1 - Multipurpose evaluation signal generator of optical disc reproduction system - Google Patents

Abstract

The present disclosure relates to an apparatus for testing the performance of components constituting an optical disc reproducing system, and relates to an apparatus capable of generating various evaluation signals using a modeled channel. The present invention can generate a desired optical recording reproduction signal without a system for generating an actual optical reproduction signal, and independently configures a protocol for adjusting channel data and control data, while changing channel characteristics while generating channel data. The present invention provides an advantage of testing the operating characteristics of each component constituting the optical disc reproducing system.

Description

Multi-purpose evaluation signal generator of optical disc playback system

Recently, the development environment of the optical recording and reproducing apparatus has been changed so that the development of the media and the system can be carried out not only in the apparatus for exclusive use of the reproduction but also in the recording and reproducing system. Therefore, timely securing the signal source necessary for the production evaluation of the system has become a very important factor in the development. Accordingly, a multipurpose evaluation signal generator is needed to provide various experimental environments until the performance of media is stabilized.

However, it is difficult to provide the above-mentioned multi-purpose evaluation signal generator because it is virtually impossible to have a measurement experiment apparatus suitable for the environment of such high-tech products from the beginning of development due to the advancement of various devices. Therefore, the present invention is to implement an optical disk simulation apparatus to meet the changes of the development conditions and to be suitable for the development environment of the high density optical disk in the future. Accordingly, the present invention is a multi-purpose evaluation signal of an optical disc reproducing system capable of testing the performance of each device constituting the optical disc reproducing system by generating a desired optical recording reproducing signal without a system for generating an optical reproducing signal by modeling an optical recording channel. Present the generator.

1 is a conceptual diagram for explaining the channel data and control data protocol of the present invention.

2 is a block diagram showing a multi-purpose evaluation signal generating apparatus of the optical disc reproducing system applied to the present invention.

3 is a configuration diagram showing in detail the RF signal generator 40 shown in FIG.

* Explanation of symbols for main parts of the drawings

10: software processing unit 20: interface unit

30: data downloading unit 40: RF signal generation unit

50: internal equalizer and PLL section

A feature of the present invention for achieving the technical problem as described above is in the apparatus for testing the performance of each of the components constituting the optical disc playback system, performing A / V encoding, ECC encoding, modulation, etc. A software program for processing a software program capable of adjusting characteristics, and outputting a channel characteristic adjustment signal for setting various formats to enable various simulations, and an optical channel previously stored in a memory according to the channel characteristic adjustment signal inputted from the software processor. A data downloading unit that reads the modeled channel data and outputs channel data for testing the operation and correction capability of the modulator and the ECC decoder according to a transmission rate control signal applied from the outside, and the channel data from the data downloading unit. Filter corresponding to impulse response of optical channel And an internal equalizer and a PLL unit for generating a signal for testing the operation characteristics of the PLL and the equalization based on the RF signal. It is a multipurpose evaluation signal generator.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Before describing the apparatus of the present invention, first, the modeling of the optical disc channel to be applied to the present invention will be briefly described.

The optical disc channel is generally modeled by MTF (Modulation Transfer Function) characteristic curve. There are many ways to model this MTF channel. Trigonometric Model applied to the present invention is represented by the following equation.

In the formula (1), r and sin θ are given by the following equation.

In Equation (2) described above, λ represents a laser wavelength, NA represents an aperture ratio, and Ω represents a spatial frequency.

1 is a conceptual diagram illustrating a data protocol and a control data protocol applied to the present invention. FIG. 1 (a) is a conceptual diagram showing a channel data string for explaining the channel data protocol, and FIG. 1 (b) is a conceptual diagram showing a control data string for explaining the control data protocol.

As shown, the channel data and control data protocols consist of 8-bit contiguous data sequences and have independent protocols. Therefore, control data can be generated in the middle of generating channel data. Each protocol starts with a start code and ends with an end code. It consists of information about the size and a string of data. The size field of the channel and control code consists of 2 bytes and represents the total data size field read by the I / F module unit 41. The data of the control code consists of 4 bytes. The upper 2 bytes and the lower 2 bytes each contain a function address and a function data. Signals generated according to the control code protocol (Fig. 1 (b)) are the coefficients and signal-to-noise ratios of the filters corresponding to the optical disc channels, the attenuation coefficients of the signals and noise corresponding to the SNR, and the like. The control signal protocol is extensible to add factors such as jitter components. It is also distinguished from the channel data protocol for signal generation.

The channel data protocol used for generating the data sequence of the optical disc channel and the control data protocol used for generating the control signal are separate protocols. Therefore, even when channel data is generated by the channel data protocol, various parameters can be converted by the control code protocol. That is, even when channel data is generated, the amount of interference between symbols can be adjusted according to the change in channel impulse response and the degree of noise generation can be adjusted.

Now, referring to FIGS. 2 and 3, the multipurpose evaluation signal generating apparatus of the optical disc reproducing system according to the present invention will be described in detail. FIG. 2 is a block diagram showing a multi-purpose evaluation signal generator of the optical disc reproducing system applied to the present invention. FIG. 3 is a block diagram showing the RF signal generator 40 shown in FIG.

First, the apparatus for generating the optical recording / reproducing signal so that the optical disc simulation can be performed is largely composed of software means and hardware means. As shown in FIG. 2, the apparatus of the present invention includes a software processor 10 for performing A / V encoding, ECC encoding, and modulation. In addition, the software processing section 10 generates a control signal to each component constituting the optical disc playback system, and outputs a channel characteristic adjustment signal. An interface unit 20 is configured at the rear end of the software processing unit 10, and transmits a control signal and a channel characteristic adjustment signal input from the software processing unit 10 to the next stage. In addition, the apparatus of the present invention is a data download unit 30 for storing the data received from the software processing unit 10 in the memory, and receives the channel data therefrom to filter with a filter corresponding to the impulse response of the optical channel and noise In addition, it is composed of an RF signal generator 40 for generating an RF signal. In addition, it includes an internal equalizer and a PLL unit 50 for generating a test signal for experimenting the characteristics of the detector connected to the equalizer and the PLL unit.

In FIG. 1, the software processor 10 performs A / V encoding, ECC encoding, modulation, and the like, and processes a software program that can adjust channel characteristics. Here, A / V encoding, ECC encoding, and modulation are determined according to the format of the signal, and the software processing unit 10 outputs a channel characteristic adjustment signal for setting various formats to enable various simulations. The data downloading unit 30 receives the channel characteristic adjustment signal from the software processing unit 10 through the interface unit 20, reads the corresponding channel data from the memory (not shown), and connects the modulator and the ECC decoder to the rear end. Will output Accordingly, the operation of the modulator and the ECC decoder and the ECC decoder and the correction capability can be measured. At this time, the data downloading unit 30 varies the transmission speed of the channel data according to the transmission rate control signal applied from the outside according to the user's selection and outputs it to the modulator and the ECC decoder. In addition, the RF signal generator 40 receives the channel data from the memory of the data downloading unit 30 and outputs the RF signal through filtering and D / A conversion to the equalizer and the PLL unit connected to the rear stage. It can be used to find the operation and optimum parameters of the PLL section. On the other hand, in order to test the operation of the detector connected to the equalizer and the rear end of the PLL unit, an accurate PLL signal is required. Accordingly, in order to obtain the correct PLL signal, the internal equalizer and the PLL unit 50 receive the RF signal applied from the RF signal generator 40 and perform equalizing and PLL to output the correct PLL signal to the detector.

2 is a block diagram showing the RF signal generator 40 shown in FIG. The RF signal generator 40 includes an I / F module unit 41 for processing a signal interface between the data downloading unit 30 and the RF signal generator 40. The system controller 42 receives the channel data and control data converted to the TTL level from the I / F module unit 41 (see FIG. 1) and generates a channel data string, and the filtering unit 44 and the adder ( 45). The noise generator 43 artificially adds noise necessary for filtering. The filter 44 is composed of two or more digital filters. The adder 45 adds the data filtered through the filter 44 and the noise applied from the noise generator 43. The D / A converter 46 converts the digital signal added by the adder 45 into an analog signal. The LPF and the gain control unit 47 filter the analog signal input from the D / A converter 46 with a local pass filter (LPF) and adjust the gain and offset to output the final RF signal.

The RF signal generator 40 shown in FIG. 2 corresponds to the output signals of the pickup and the reproduction amplifier from the perspective of the actual optical disc reproduction system.

The operation of the RF signal generator 40 having the above configuration will be described in more detail.

First, the I / F module unit 41 converts the channel data and the control data generated in the data downloading unit 30 into a TTL level signal and outputs them to the system controller 41 and the noise generator 43. The system controller 42 generates a channel data string based on the channel data, and outputs a control signal for setting coefficients of a filter for modeling an optical disc channel for filtering the channel data string. Here, the filter coefficients and the channel data are received from the software processor 10 shown in FIG. The noise generator 42 generates an additive white Gaussian noise by a pseudo random noise generation method and outputs the added white Gaussian noise to the adder 45. The filter 44 receives the filter coefficient and the control signal applied from the system controller 42 to set and filter the filter coefficients corresponding to the channel data sequence and the impulse response. The filtering unit 44 filters the set filter coefficients and adds interference between channel data symbols. Thus, the amount of intersymbol interference depends on the impulse response of the modeled channel. The adder 45 adds the data filtered by the filter 44 and the noise generated by the noise generator 43 according to the gain control signal of the system controller 42. The D / A converter 46 converts an 8-bit digital signal applied from the adder 45 into an 256-level analog signal and outputs it. The LPF and gain controller 47 filters the analog signal applied from the D / A converter 46 into the Nyquist band and adjusts gain and offset to output the final RF signal.

As described above, the present invention generates an RF signal without actually generating an optical recording / reproducing signal to configure an optical disk reproducing system such as an operation test of an equalizer, a PLL, an operation test of a detector, an operation of a modulator, and an ECC decoder. The operating characteristics of each component can be tested. In addition, by independently configuring the protocols for adjusting the channel data and control data necessary for generating the evaluation signal, that is, the RF characteristics, the operation characteristics of each component constituting the optical disc reproducing system while changing the characteristics of the channel during channel data generation. It provides an advantage for testing.

Claims (3)

In the apparatus for testing the performance of each of the components constituting the optical disc playback system, A / V encoding, ECC encoding, modulation, etc., processing a software program that can adjust the channel characteristics, various simulations A software processing unit for outputting a channel characteristic adjustment signal for setting various formats so as to be possible; To read the channel data modeling the optical channel pre-stored in the memory according to the channel characteristic adjustment signal input from the software processing unit, and to test the operation and correction capability of the modulator and ECC decoder according to the transmission rate control signal applied from the outside. A data downloading unit for outputting channel data; An RF signal generator which receives the channel data from the data downloader, filters the filter corresponding to an impulse response of the optical channel, and adds noise to generate an RF signal; And an internal equalizer and a PLL unit for generating a signal for testing the operation characteristics of the equalizer and the PLL based on the RF signal. The RF signal generator of claim 1, further comprising: an I / F module for receiving channel data from the data downloading unit and converting the channel data to a predetermined level; A system controller which receives the channel data converted by the I / F module, generates a channel data sequence, and controls a filtering unit and an adding unit; A noise generator for adding noise required for filtering; A filtering unit filtering the channel data sequence according to a filtering coefficient setting control signal applied from the system controller to give inter-symbol interference to the channel data signal; An adder configured to add noise data applied from the noise generator and filtered data applied from the filtering unit according to a gain signal applied from the system controller; A D / A converter converting the analog signal input from the adder into a digital signal; And an LPF and a gain control unit for filtering the analog signal inputted from the D / A converter by LPF, adjusting gain and offset, and outputting a final RF signal. The multipurpose evaluation signal of an optical disc reproducing system according to claim 1, wherein the software processing unit independently configures protocols for generating channel data and control data so as to vary channel characteristics even during channel data generation. Generator.