KR100216755B1 - Audio output method of hifi vcr - Google Patents

Abstract

The present invention relates to a method of controlling an audio output mode of a hi-fi vias, and more particularly, to an audio output mode control method for a hi-fi tape, .

To this end, the present invention comprises a first step of checking a hi-fi audio signal in a reproduction mode and setting an audio signal output mode to a hi-fi mode if a signal of a predetermined level or higher is input; A second step of comparing the count value of the hi-fi audio signal with a predetermined number of counts if the level of the hi-fi audio signal falls below a predetermined value in the first step; And a third step of forcibly switching the audio signal output mode to the normal mode when the value counted in the second step exceeds a predetermined number or if the hi-fi signal is not input in the first step, and displaying the state to the outside .

Description

How to control the audio output of HiFi Vsial

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method for controlling audio output when a hi-fi tape is reproduced in a high fidelity video cassette recorder (hereinafter referred to as a hi-fi vial) The present invention relates to a method of controlling an audio output mode of a HiFi Vial to eliminate an inconvenience of a consumer when viewing a hi-fi tape by automatically controlling the output of an audio signal reproduced from the audio head according to the reproduction state of the hi-fi tape.

In general, a hi-fi VCR is a VCR which is capable of processing other information on a normal audio track. The VCR is used to record and reproduce an audio signal by focusing on a rotary head used for recording or reproducing a video signal. In particular, in a VHS type HiFi VCR, two audio heads in addition to two video heads are installed in a rotary drum, and an audio signal is FM-modulated and recorded. The audio signal is recorded in advance in the thickness direction of the tape .

Since the carrier wave of the audio signal is set to be lower in frequency than the carrier wave of the luminance signal, the audio head gap is wider than the video head gap and can magnetize to the depth portion of the magnetic layer of the tape. Also, The video signal is recorded on the tape surface and the magnetizing force is reduced in the deep portion of the tape. Therefore, the audio signal remains and the two kinds of signals coexist do.

Therefore, the reproduced output is reduced by about 12 dB because the surface layer portion of the audio signal is erased at the time of reproducing the audio signal. However, since FM modulation is used, the influence of noise is not a problem.

In order to realize such a hi-fi system, a reproduction signal processing circuit of a conventional hi-fi VCR includes an audio head 10 for recording or reproducing a normal audio signal on a tape and an audio signal in an FM- And a rotary audio head 20 for recording or reproducing audio signals. Each of the preamplifiers 11 and 21 for amplifying a signal reproduced from the audio head at a constant level is provided for each audio head, A hi-fi audio signal processing unit (22) and a normal audio signal processing unit (12) for processing and outputting an audio signal from the pre-amplified signal and outputting a hi-fi audio signal A hi-fi / normal detector 23 for judging whether or not the hi-fi / Are switched according to an output of 23 has a signal processing flow made by the output switching unit 13 and outputting the two select an audio signal processor.

A preamplifier 31 for amplifying a signal read from the video head at a predetermined level, and a preamplifier 31 for reading the video signal read from the video head 30 An FM luminance signal detection unit 32 and a color signal detection unit 33 for separately detecting an FM luminance signal and a color signal from the pre-amplified signal, and an FM luminance signal and a color signal detected in the above- And a video signal processing unit 34 for finally outputting the video signal.

The recording frequency of each signal in the HiFi VCR having such a configuration is 0.629 ± 0.5 [MHz] for the video signal and 1.3 [MHz] for the right audio signal in the case of the National Television System Committee (NTSC) , The left audio signal is 1.7 [MHz] and the video signal luminance signal is 1.1 ~ 7 [MHz]. In the case of PAL (Phase Alternation by Line), the color signal frequency of the video signal is 0.627 ± 0.5 [MHz] The right audio signal is recorded in the frequency band of 1.4 [MHz], the left audio signal is recorded in the frequency band of 1.8 [MHz], and the luminance signal is recorded in the frequency band of 1.1 to 7 [MHz].

Recording frequency bandwidth of video signal and audio signal by NTSC system and PAL system Type Signal type NTSC system PAL system Color signal 0.629 ± 0.5 MHz 0.627 ± 0.5 MHz Voice signal (right) 1.3MHz 1.4MHz Voice signal (left) 1.7MHz 1.8MHz Luminance signal 1.1 to 7 MHz 1.1 to 7 MHz

2, an audio signal is FM-modulated between the color signal recording frequency band of the video signal and the luminance signal recording frequency band in both the NTSC system and the PAL system, as shown in the spectrum analysis result of FIG. 2 as an example of the NTSC system .

The output processing operation for the hi-fi audio signal during reproduction of the hi-fi tape recorded as described above is performed by reproducing the audio signal in the frequency-modulated state in the hi-fi rotary audio head 21, amplifying the audio signal through the pre- In the normal detector 23, when the level of the pre-amplified audio signal is higher than or equal to about 200 mV (slightly different for each IC or model), the controller 23 controls the switching unit 13 to recognize the high- A hi-fi audio signal can be automatically output when there is reproduction of an audio signal. When the voltage level of the FM-modulated audio reproduction signal is 200 mV or less, the hi-fi / normal detection unit 23 switches to the normal state unconditionally. If the voltage level is 200 mV or more, So that the operation of changing the position is continued.

However, in the existing hi-fi VISIR that detects and controls the output of the hi-fi audio signal as described above, the hi-fi signal can not be detected due to worn or tape-like noise due to a large number of times of use of the tape during reproduction of the hi-fi tape, Since the output level of the audio signal itself is also hi-fi and sometimes normal, it is often audible to listen to hi-fi audio signals. In this state, if the user does not want to listen, It has to be made into a normal state, so that there was a lot of inconvenience.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and it is an object of the present invention to provide a microprocessor which checks the level of a reference signal for recognizing a hi-fi signal, counts a case where a value falls below a predetermined value, Audio output of the hi-fi Vial is controlled so as to automatically select the audio output to be a forced monaural when the audio signal is abnormal or the signal level fluctuates, thereby eliminating the inconvenience of the consumer listening to the reproduced audio signal upon reproduction of the hi-fi tape And a mode control method.

According to an aspect of the present invention, there is provided a method for controlling a hi-fi system, the method comprising: checking a hi-fi audio signal in a playback mode and setting an audio signal output mode to a hi-fi mode if a signal of a predetermined level or higher is input; A second step of comparing the count value of the hi-fi audio signal with a predetermined number of counts if the level of the hi-fi audio signal falls below a predetermined value in the first step; And a third step of forcibly switching the audio signal output mode to the normal mode when the value counted in the second step exceeds a predetermined number or if the hi-fi signal is not inputted in the first step, and displaying the state to the outside The present invention provides a method of controlling an audio output mode of a HiFi Vsial.

1 is a block diagram of a reproduction signal processing circuit for hi-fi Vials

2 is a graph showing a result of spectral analysis of a general NTSC recording frequency

3 is a block diagram of a reproduction signal processing circuit for hi-fi Vials according to the present invention

4 is a flowchart illustrating an audio output mode control method according to an embodiment of the present invention.

DESCRIPTION OF THE REFERENCE NUMERALS

10: audio head 11, 21, 31:

12: Normal audio signal processing unit 13: Output switching unit

20: rotating audio head 22: hi-fi audio signal processor

30: video head 32: FM luminance signal detector

33: Color signal detection unit 34: Video signal processing unit

41: key input unit 42: microprocessor

43: OSD processing section 44: VFD display section

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method of controlling an audio output mode of a Hi-Fi Vsial according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 3 is a block diagram of a reproduction signal processing circuit for a hi-fi Vial according to the present invention. As shown in the figure, the audio signal processing apparatus includes an audio head 10 for recording or reproducing a normal audio signal on a tape, And a video head 30 for recording or reproducing a video signal on a tape, and the signals reproduced from the audio head and the video head are respectively supplied to a constant level And preamplifier units 11, 21, and 31 for amplifying are provided for each of the heads.

A normal audio signal processing unit 12 for processing the pre-amplified signal into an audio signal and outputting the processed audio signal; and a control unit 12 for detecting a hi-fi audio level from a reproduced signal in the FM state pre- And a hi-fi audio signal processor 22 for outputting a hi-fi signal H according to the determination result to the microprocessor, and a hi-fi audio signal processor 22 controlled by an operation command of the microprocessor.

When the hi-fi audio signal processor 22 is connected to the hi-fi audio signal processor through the data line DATA to check the hi-fi signal H of the hi-fi audio signal processor 22 in the playback mode, The microprocessor 42 forcibly switching the operation mode of the Hi-Fi audio IC to the normal mode when the level of the Hi-Fi audio signal falls below a predetermined value, And an output switching unit (13) switched according to a hi-fi signal output from the hi-fi audio IC to select and output the two audio signal processing units.

The microprocessor 42 is configured to scan the key input unit 41 for an interface with an external user. The microprocessor 42 recognizes that the hi-fi selection key is pressed through the key input unit, It is preferable to be configured to be forcedly switched to the normal mode.

An FM luminance signal detecting unit 32 and a color signal detecting unit 33 for separately detecting an FM luminance signal and a color signal from the preamplified signal read from the video head and detecting the corresponding character according to a control signal of the microprocessor; And a VFD display section 44 for displaying a hi-fi operation state using the VFD or VFD driving IC. The FM luminance signal and the color signal detected in the above are demodulated as original signals And a video signal processing section 34 for superimposing or selecting the text screen of the OSD processing section on the video signal and finally outputting the selected video screen.

FIG. 4 is a flowchart of a control operation performed by the microprocessor of FIG. 3 in connection with its peripheral circuit. As shown in FIG. 4, the first step is performed when the reproduction mode is selected. (S42, S43) of checking whether a hi-fi signal (H) of a predetermined level or higher is input from the hi-fi audio signal processing section if the mode is the playback mode, And setting the audio signal output mode to the high-fidelity mode (S44).

The second step is performed when the level of the hi-fi audio signal falls below a predetermined value in the first step. The counting step S45 is performed each time the level of the hi-fi audio signal is lower than a predetermined value. Step S46.

The third step is performed when the count value exceeds a predetermined number in the second step or the hi-phi signal H is not input in the first step, and the count value is initialized, A step of forcibly switching the mode to the normal mode (S47), and a step (S48) of externally displaying a message informing the switching state.

And a step (S49) of checking the state in which the hi-fi selection key is depressed without immediately ending the third step, and a step (S50) of controlling the audio output mode according to the selection result It is preferable that the microprocessor is configured to again check the intention of the user and to control the audio output mode by providing the user with the opportunity to select the audio output mode again by having four steps.

The operation of the present invention having the above-described structure will now be described.

First, in the present invention, the level of a reproduced FM signal, which is a reference signal for recognizing a hi-fi signal, is defined as a constant voltage or higher (200 mV is set in the present invention as an example) ) Counts the number of falling times, and when the count value exceeds a predetermined count value, or when there is a change in the hi-fi audio signal level, the audio output line is automatically selected as the forced normal mode.

That is, when the reproduced FM signal read from the rotary audio head 30 is input to the hi-fi audio signal processing unit 22, it undergoes carrier adjustment through a band-pass filter or the like. At this time, when a normal level is reached, the hi-fi audio signal processor 22 configured by the hi-fi audio IC outputs a hi-fi signal and is transmitted to the microprocessor 42. Since the hi-fi signal is currently being input from the microprocessor 42 A command to perform a hi-fi operation is given via the data line DATA and controls the VFD or VFD driver IC to turn on the hi-fi segment as serial data via the VFD display 44 of the logic section.

At this time, in the Hi-Fi audio IC according to the tape state, if the reproduced FM signal can not be detected when the frequency is 200 mV or less, the hi-fi signal is not outputted. Therefore, the microprocessor 42 outputs the hi-fi signal through the hi-fi audio signal processor 22 The number of times that the current level falls below a predetermined level (S45) and the number of times the high / low count value of the hi-fi signal is predetermined (which is set to about three times in the present invention, for example) When the check is made (Y branch in S46), control is performed so as to normally operate through the data line unconditionally (S47).

When it is recognized that the hi-fi signal has fallen more than the predetermined number of times (Y branch in S46), the microprocessor 42 forcibly switches the output mode of the hi-fi audio IC to the normal mode (S47) (S48), and then checks the key input state (S49). If the user desires to view the still image in the hi-fi mode If there is a consumer (Y branch of S49), control is made to return to the previous state by inputting a specific key (especially a hi-fi mode selection key).

According to the method of controlling the audio output mode of the hi-fi vial according to the present invention, when there is no hi-fi signal several times according to the state of the tape, the user is forced to dynamically switch to the normal mode Accordingly, it is useful to pursue the convenience of the user.

Claims (2)

A first step of checking a hi-fi audio signal in a reproduction mode and setting an audio signal output mode to a hi-fi mode if a signal of a predetermined level or higher is input; A second step of comparing, when the level of the hi-fi audio signal falls below a predetermined value in the first step, whether the count value increases more than a predetermined number of times while counting; And a third step of forcibly switching the audio output mode to the normal mode and displaying the state to the outside when the count value exceeds a predetermined number in the second step . The method as claimed in claim 1, further comprising the step of: after the display of the third step, re-assigning an audio output mode selection opportunity by a user to control an audio output mode according to a user's intention. Output mode control method.