KR100194037B1 - Tape running speed detection circuit and method of image signal processing device - Google Patents

Abstract

1. TECHNICAL FIELD OF THE INVENTION The invention described in the claims belongs to a tape traveling speed detection field of an image signal processing apparatus.

2. The technical problem to be solved by the present invention is to provide a circuit and a method for detecting a tape running speed accurately without error while having a simple configuration.

3. Summary of the Invention The tape travel speed detecting circuit of the improved image signal processing apparatus comprises: means for generating a jog pulse synchronized with the head switching pulse; And means for detecting the running speed of the tape by counting the number of jog pulses applied during the period of the head switching pulse and comparing the counting value with a preset tape regeneration mode value.

4. Significant use of the invention: detection of tape running speed of video signal processing apparatus.

Description

Tape running speed detection circuit and method of image signal processing device

1 is a conventional tape traveling speed detection circuit diagram.

2 is a traveling speed detection circuit diagram of a tape according to the present invention.

3 is a control flowchart for detecting a traveling speed of a tape according to the present invention.

The present invention relates to a video signal processing apparatus such as a video cassette tape recorder, a camcorder, and the like, and more particularly, to a circuit and a method for detecting a traveling speed of a tape.

In general, recent video signal processing apparatuses, for example, 8 millimeter camcorders, have adopted a multifunction mode to satisfy various needs of users. In the multifunction mode, also called the jog mode, the running speed and running direction of the tape used as the recording medium are varied according to the user's command. For example, FF, REW, FPS, RPS and ED (-) modes.

The conventional tape travel speed detecting circuit which detects the speed of Standard Play (hereinafter referred to as SP) or Long Play (hereinafter referred to as LP) when performing the jog mode is as shown in FIG. .

Referring to FIG. 1, the signal output from the preamplifier 2 connected to the drum motor is provided to the envelope detector 4. The envelope detector 4 detects an envelope of the signal and applies its output to the comparator 6. The comparator 6 compares the output of the reference signal REF and the envelope detector 4 with each other and provides the corresponding difference signal to the lowpass filter 8. The low pass filter 8 converts the difference signal into a DC voltage and provides it to the jog comparator 10. The jog comparator 10 compares the DC voltage with the applied jog signal and outputs a logic high or low level signal to the microcomputer 12. The microcomputer 12 determines the play of the current tape as the standard play (SP) or the long play (LP) according to the low or high level signal and appropriately matches the capstan motor driver 14 to determine the speed accordingly. Supply double speed voltage. However, since the circuit of FIG. 1 determines the play of the current tape according to the output signal of the jog comparator 10, an error frequently occurs. This problem is because the variation of the pickup envelope level varies depending on the type and condition of the tape, and the output level of the low pass filter 8 has a relatively small margin due to the AGC characteristic deviation of the envelope detector.

As described above, since the playback mode of the tape is determined based on an analog signal having a relatively small margin, a detection error is frequently used, and thus the reliability of the tape traveling speed detection circuit of the image signal processing apparatus cannot be guaranteed.

Accordingly, an object of the present invention is to provide a tape traveling speed detection circuit and method of an improved image signal processing apparatus that can solve the above-mentioned conventional problems.

Another object of the present invention is to provide a tape traveling speed detecting circuit and method of an image signal processing apparatus capable of accurately detecting a tape playing mode.

It is another object of the present invention to provide a tape traveling speed detection circuit of an image signal processing apparatus which can simplify a circuit component.

The present invention for achieving the above object is a means for generating a jog pulse synchronized with the head switching pulse in the image signal processing apparatus; And means for detecting the running speed of the tape by counting the number of jog pulses applied during the period of the head switching pulse and comparing the counting value with a preset tape regeneration mode value. The means for generating the jog pulse may include a preamplifier for amplifying a signal applied from a drum motor, a detector for detecting an envelope of a signal output from the preamplifier, and comparing the output of the detector with a preset reference signal. Comprising a comparator for outputting a jog pulse, the detection means may be a microprocessor connected to the key input unit and connected to the drive unit for driving the capstan motor.

In the video signal processing apparatus according to the present invention, a method for detecting a running speed of a tape is counted in the jog mode, and counts the number of jog pulses applied during the head switching pulse, and compares the counting value with a preset tape regeneration mode value. It is characterized by detecting the running speed of the tape.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The circuits and methods of one preferred embodiment of the present invention will now be described with reference to the accompanying circuit drawings. In the following description, the detailed items for such configurations are described in detail in order to provide a more thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced without these specific details. In addition, well-known structures and operations of the basic blocks are not described in detail in order not to obscure the present invention.

First, FIG. 2 is a tape traveling speed detection circuit diagram according to the present invention. Referring to FIG. 2, the preamplifier 2, the envelope detector 4, the comparator 6, and the capstan motor driving unit 14, the key input unit 22, and the microcomputer having the same configuration as those of FIG. 1. 20) is shown. In FIG. 2, line L4 is a power supply line of a capstan motor that controls the running of the tape, and line L5 is a line of frequency generation signal according to the rotation of the motor. The line L2 is a line for providing a signal for the microcomputer 20 to control the driving unit 14, and the line L3 is a line for providing the frequency generation signal applied to the microcomputer 20. Line L1 is an input line of key data provided from the key input unit 22, line L6 is an output line of a signal generated from the drum motor, and line L7 is amplified by the preamplifier 2. Output line of the signal. Line L8 is the output line of the envelope detector 4 and line L9 is the output line of the jog pulse output from the comparator 6.

The microcomputer 20 of FIG. 2 stores a program for programming a flow chart as shown in FIG. 3. Accordingly, the number of jog pulses applied during the period of the head switching pulse in the jog mode is counted and the counting value is counted. Compares the preset tape playback mode value with the tape to detect the running speed of the tape.

Hereinafter, with reference to Figure 3, the process of detecting the traveling speed of the tape in accordance with the principles of the present invention will be described in detail.

Step 300 of FIG. 3 is performed after the microcomputer 20 receives the power-on key data from the key input unit 22. In step 300, the microcomputer 20 sets the speed flag as SP. In operation 302, the microcomputer 20 checks a current function to determine whether the microcomputer 20 is in jog mode in operation 304. If it is determined that the jog mode, the microcomputer 20 performs step 306 to determine whether a head switching pulse has been detected in step 308. In this case, the low transition edge of the head switching pulse is used as the synchronization signal counting the jog pulse. That is, the present invention uses the basic principle that the jog pulses generated at the time of SP and LP differ from one another during the head switching pulse. For example, in the case of 11 times speed, the number of jog pulses during one head switching pulse section is 7 at the SP and 14 at the LP. When the section of the first head switching pulse starts in step 308, the microcomputer 20 continuously counts the jog pulse applied through the comparator 6 until the section of the switching pulse ends. The steps for performing this operation are steps 310, 312, 314, and 316.

After performing the above steps to count the number of jog pulses, the microcomputer 20 enters step 318 and compares whether the counting value is within a preset value in step 320. For example, if the K value is set to 7 and the tolerance a value is set to 1, it is checked whether the counting value is between 6 and 8. Therefore, when the counting value of the jog pulse and the preset tape play mode value are compared in operation 320, operation 324 or operation 322 is determined according to the result. That is, if the comparison result is correct, the microcomputer 20 stores the SP in the speed flag in step 324, or stores the LP in step 322 and initially sets the SP in step 300 in the SP. Update the. That is, if the count value is not between k-a and k + a, the speed flag is replaced with LP and set to LP speed. However, if the count value is between k-a and k + a, the speed flag is kept at SP. In operation 326, the microcomputer 20 performs control according to a corresponding mode as the driving speed of the tape is detected.

According to the present invention as described above, the configuration of the detection circuit of the present invention is simpler than that of the conventional FIG. 1 by detecting the SP and the LP by the above-described method. In addition, the present invention has the effect of accurately detecting the tape reproducing mode without error by detecting SP or LP by counting jog pulses.

Claims (4)

A tape traveling speed detection circuit of a video signal processing apparatus, comprising: means for generating a jog pulse synchronized with a head switching pulse; And means for detecting the running speed of the tape by counting the number of jog pulses applied during the period of the head switching pulse and comparing the counting value with a preset tape regeneration mode value. Travel speed detection circuit. The apparatus of claim 1, wherein the means for generating the jog pulse comprises: a preamplifier for amplifying a signal applied from a drum motor, a detector for detecting an envelope of a signal output from the preamplifier, and a preset output of the detector. And a comparator for outputting jog pulses in comparison with a reference signal. The method of claim 1, wherein the means for detecting the traveling speed of the tape is implemented by a microprocessor connected to a key input unit and connected to a driving unit for driving a capstan motor, and performs a control operation according to the detected traveling speed. Tape running speed detection circuit. A tape traveling speed detection method of an image signal processing apparatus, comprising: counting the number of jog pulses applied during a head switching pulse in a jog mode, comparing the counted value with the preset tape reproduction mode value Tape running speed detection method comprising the step of detecting the running speed of the tape.