KR19980058140A - Apparatus and method for processing high frequency signal in CD-ROM drive - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high frequency signal processing apparatus and method in a CD-ROM drive, and more particularly, to use in a CD player that can simultaneously play a 1x speed audio CD and a 4x speed video CD. A high frequency signal processing apparatus in a CD-ROM drive including a com, a cutoff frequency converter, a filter, an amplifier, and the like, and a high frequency signal processing method in the CD-ROM drive using the apparatus are presented.

Description

Apparatus and method for processing high frequency signal in CD-ROM drive

1 is a view showing the configuration of the present invention,

2 is a flowchart showing a process of controlling the operation of the present invention.

Explanation of symbols for main parts of the drawings

1: micro-com 2: cutoff frequency converter

3: filter 4: amplifier

Q: Transistor FET: Field Effect Transistor

C, C _f : Capacitor R: Resistance

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high frequency signal processing apparatus and method in a compact disk (hereinafter referred to as a CD) -ROM drive. In particular, when playing a CD in a CD-ROM drive capable of playing CDs of different speeds, The present invention relates to an apparatus and a method for processing a high frequency signal according to the double speed of each CD.

In general, there are CDs of 1x and 4x speeds, 1x speed is mainly used for general audio CD, and 4x speed is mainly used for video CD. Currently, a CD player that can simultaneously play an audio CD of 1x speed and a video CD of 4x speed has been developed, and accordingly, it automatically adjusts the play speed according to each CD type and plays the adjusted CD. There is a need for a device for processing high frequency signals at double speed.

In view of the above, the present invention adjusts the speed at which a CD is automatically played according to the type of CD to be played, and processes the high frequency signal in a CD-ROM drive for processing a high frequency signal according to the adjusted play speed of the CD. It is an object to present an apparatus and method.

That is, the microcomputer determines the type of CD, determines the play speed of the CD based on the determination result, and outputs a control signal; A cut-off frequency converter comprising two transistors turned on / off by a control signal output from the microcomputer and a capacitor, the cutoff frequency converter converting a cutoff frequency of the filter by turning on / off by the control signal of the microcomputer; A filter consisting of one capacitor and one resistor and filtering the input signal after the cutoff frequency is converted by the state of the cutoff frequency converter; A high frequency signal processing device is implemented in a CD-ROM drive which is composed of an amplifying unit which receives and amplifies a signal output from a filter.

In addition, when the type of CD is determined by the microcomputer and the play speed of the CD is determined based on the determination result, the control signal is output by the control signal output from the microcomputer, and the transistor and the capacitor which determine the cutoff frequency are turned on / off. It is turned off, and the cutoff frequency is adjusted by turning on / off of the transistor and the capacitor, and different high frequency signals can be processed by adjusting the cutoff frequency as described above.

When described in detail with reference to the drawings as follows.

1 is a diagram showing the configuration of the present invention. The micro-comb 1 determines the type of CD, determines the play speed of the CD based on the determination result, and outputs a control signal. A cut-off frequency converter 2 for turning on / off a signal to convert the cut-off frequency of the filter 3, and a filter for filtering the input signal after the cut-off frequency is converted by the state of the cut-off frequency converter 2 ( 3) and an amplifier 4 for receiving and amplifying and outputting the signal output from the filter 3; In the above description, the cutoff frequency converter 2 includes two transistors Q and FET and one capacitor C _f that are turned on and off by a control signal output from the microcomputer 1, and a filter 3. ) Consists of one capacitor (C) and one resistor (R).

FIG. 2 is a flowchart showing a process of controlling the operation of the present invention. In FIG. 1, the operation process performed in the microcomputer 1 is shown. The TOC (Table Of Contact) information of the CD being played is shown in FIG. A first step (S1) of reading the stored portion); A second step (S2) of reading a subcode from the TOC read in the first step (S1); A third step S3 of diagnosing the subcode read in the second step S2; A fourth step (S4) of setting an arbitrary integer N (a number representing a double speed) to 1 when the subcode diagnosis result in the third step (S3) is an audio CD; A fifth step (S5) of setting and outputting a control terminal (output terminal for controlling the blocking frequency converter) to a low value after the fourth step (S4); A sixth step (S6) of moving the cutoff frequency to a lower frequency after the fifth step (S5); A seventh step (S) of setting an arbitrary integer N (a number representing a double speed) to 4 when the subcode diagnosis result in the third step (S3) is a video CD; An eighth step (S8) of setting and outputting a control terminal (output terminal for controlling the blocking frequency converter) to a high value after the seventh step (S7); A ninth step S9 of moving the cutoff frequency to a higher frequency after the eighth step S8; After the sixth step (S6) and the ninth step (S9) consists of a tenth step (S10) for reproducing the CD to operate sequentially.

When the low signal is output from the microcomputer 1 through the above process, the transistor Q is turned off, the field effect transistor FET is turned on, and the cutoff frequency of the filter 3 becomes a low frequency. When the high signal is output from the com 1, the transistor Q is turned on, the field effect transistor FET is turned off, and the cutoff frequency of the filter 33 becomes a high frequency.

In the above, when the low signal is output from the micro-comb 1, the cutoff frequency becomes 1 / 2πγ (C + C _f ) and becomes a low frequency. When the high signal is output from the micro-comb 1, the frequency is 1. It becomes / 2πγC and becomes high frequency.

The present invention provides a high frequency signal processing apparatus and method in the CD-ROM drive as described above, so that different types of CDs having different double speeds can be played in one CD player.

Claims (3)

A microcomputer (1) for judging the type of CD, determining the play speed of the CD based on the determination result, and outputting a control signal; It consists of two transistors (Q, FET) and one capacitor (C _f ) turned on / off by the control signal output from the micro-com (1), and on / off by the control signal of the micro-com (1) A cutoff frequency converter 2 for turning off the cutoff frequency of the filter 3; A filter (3) consisting of one capacitor (C) and one resistor (R), for filtering the input signal after the cutoff frequency is converted by the state of the cutoff frequency converter (2); And amplifying part (4) for receiving and amplifying and outputting the signal output from the filter (3). When the micro-comm 1 determines the type of CD and determines the play speed of the CD based on the determination result and outputs the control signal, the transistor for determining the cutoff frequency by the control signal output from the micro-com 1 (Q, FET) and capacitor C _f are turned on / off, and the cutoff frequency is adjusted by turning on / off of transistors Q, FET and capacitor C _f , and by adjusting the cutoff frequency as described above. A high frequency signal processing method in a CD-ROM drive characterized by processing different high frequency signals. The process of claim 2, wherein the process of outputting a control signal by determining the type of CD in the microcomputer 1 reads the TOC of the CD being played, extracts the subcode, and diagnoses the subcode. In the case of an audio CD, an arbitrary integer N (number of double speeds) is set to 1, the control terminal (output terminal for controlling the cutoff frequency converter) is set to a low value, and the cutoff frequency is moved to a lower frequency. If the subcode diagnosis result is a video CD, an arbitrary integer N (the number representing the double speed) is set to 4, and the control terminal (output terminal for controlling the cutoff frequency converter) is set to a high value and output. In the CD-ROM drive, characterized in that the step of moving the cutoff frequency to a high frequency, the process of playing a CD after the cutoff frequency shift Frequency signal processing method.