KR0174913B1 - The secam color deflection compensation apparatus - Google Patents

Abstract

The present invention relates to an apparatus for compensating for distortion of Secam color when a broadcast signal is received by a Phase Alternation by Line (PAL) -B / G and a Sekam-L dual system. In the prior art, since the Secam-L color is frequency-modulated and transmitted when receiving a broadcast signal by the PAL-B / G and the Secam-L dual system, it appears as color level (+) distortion of the frequency band during the demodulation process. Therefore, there was a drawback that the red drag phenomenon appeared on the screen. Accordingly, in the present invention, a filter for passing an arm-B / G video signal and a filter for passing a Secam-L video signal when the filter is operated in parallel with the filter. Therefore, there is an effect of compensating for the distortion of the Secam color when the broadcast signal is received by the PAL-B / G and Sekam-L dual systems.

Description

Device that compensates for distortion of Secam color

1 is a block diagram showing an embodiment of broadcast signal reception according to the prior art.

2 is a block diagram showing an embodiment of an apparatus for compensating for distortion of Secam color according to the present invention.

* Explanation of symbols for main parts of the drawings

32, 34: first and second filter 36: switching unit

The present invention Secam (SEquential Couleur Memoire (SECAM) is a device for compensating for distortion of color, and specifically, distortion of Secam color when receiving broadcast signals by Phase Alternation by Line (PAL) = B / G and Secam-L dual system. To a compensating device.

1 is a block diagram showing an embodiment of a broadcast signal reception according to the prior art, a tuner (tuner tuner) 12, an amplification and filtering unit 14, a signal detector 16, a demodulator 18, voice It is composed of a trap (voice trap) 20, and a buffer (22).

In the figure, the tuner 12 receives each broadcast signal by a plurality of broadcast stations from a preset antenna. Subsequently, the tuner 12 tunes only a specific broadcast signal as the user selects a specific channel. Thereafter, the tuner 12 converts the tuned broadcast signal into an intermediate frequency (IF) and provides it to the amplification and filtering unit 14. At this time, the tuner 12 uses a separate local oscillator (LO) to convert to the intermediate frequency. That is, mixing the tuned broadcast signal with the local oscillation frequency signal from the local oscillator produces an intermediate frequency.

The amplification and filtration section 14 then amplifies the output of the tuner 12. In addition, the amplification and filtering unit 14 restricts the frequency band and passes only signals of a specific frequency band including the image signal to the signal detection unit 16.

Subsequently, the signal detector 16 detects an image signal from the output of the amplification and filtering unit 14 using a voltage controlled oscillator (VCO) and provides it to the demodulator 18. At this time, the voltage controlled oscillator changes the oscillation frequency to a control voltage.

The demodulator 18 demodulates the original video signal from the output of the output of the signal detector 16 and provides it to the audio trap unit 20. In this case, since the Secam-L color is transmitted by frequency modulation (Frequency Modulation: FM), the distortion of the frequency band appears as color level (+) distortion during the demodulation process.

Here, the arm color signal is amplitude modulated (AM), and the subcarrier frequency of the arm color signal is 4.43 MHz. And the secam color signal is frequency modulated, and the subcarrier frequencies of the secal color signal are 4.25 MHz and 4.406 MHz. That is, the secam color transmits one horizontal signal alternately using two subcarrier frequencies. In this case, for each Secam color, there is a level specification of color, and the frequency thereof reaches a band of about 4.7 MHz. If these specifications are not met, that is, if the ratios of D' _R and D' _B do not match, it is caused by color level (+) distortion of the frequency band during demodulation. Thus, a red drag phenomenon appears on the screen. At this time, the D ' _R is 476mV, D' _B is 168mV, when D ' _R divided by D' _B should be about 2.8.

The voice trap unit 20 then removes the voice signal portion from the output of the demodulator 18 and provides the remaining signal to the buffer 22. That is, the voice trap unit 20 grounds and removes the voice signal portion using a filter that can pass the voice signal portion. The reason for causing the audio trap section 20 to remove the audio signal portion in this way is to prevent the audio signal portion from interfering with the video signal.

Next, the buffer 22 temporarily stores the output of the voice trap unit 20 and outputs it. At this time, the temporary storage period of the buffer 22 is appropriate to the operation of the system.

Therefore, in the conventional technique, since the Secam-L color is frequency-modulated and transmitted when receiving a broadcast signal by the PAL-B / G and the Secam-L dual system, the color level (+) distortion of the frequency band during the demodulation process. Appears. Therefore, there is a drawback in that a red drag phenomenon appears on the screen.

The present invention has been made to solve the drawbacks of the prior art, and to configure a filter that passes the arm-B / G video signal and a filter that passes the Secam-L video signal when operating in parallel with the filter It is an object of the present invention to provide an apparatus for compensating for distortion of Secam color.

According to an aspect of the present invention, there is provided an apparatus for compensating for distortion of a secam color in an image signal, the apparatus comprising: a first filter configured to pass an arm-B / G image signal in the image signal; A second filter configured to pass a Secam-L video signal in the video signal when the first filter and the input / output are operated in parallel; And a switching unit configured to switch the output of the second filter to an output terminal of the first filter when the video signal is a Secam-L video signal so that the first and second filters operate in parallel with input and output. It features.

When described in detail by the accompanying drawings an embodiment of the present invention as follows.

FIG. 2 is a block diagram showing an embodiment of an apparatus for compensating for distortion of Secam color according to the present invention, and includes first and second filters 32 and 34 and a switching unit 36.

In the figure, the first filter 32 passes an arm-B / G video signal among the video signals provided from the demodulator 18 as shown in FIG. In this case, the first filter 32 may be selectively configured by arranging a resistor, a coil, and a capacitor to configure the circuit by a conventional technique.

Next, when the second filter 34 operates in parallel with the first filter 32 and the input / output, the second filter 34 passes the Secam-L video signal in the video signal provided from the demodulator 18. In this case, the second filter 34 may selectively configure a resistor, a coil, and a capacitor to configure a circuit by a conventional technique. That is, when the bands of the signals passed by the first and second filters 32 and 34 are respectively added, they are equal to the bands of the Secam-L video signal.

In addition, the switching unit 36 switches the output of the second filter 34 to the output terminal of the first filter 32 according to the selection signal. That is, when the current broadcast signal is a Secam-L video signal, the switching unit 36 switches by the selection signal to switch the output of the second filter 34 to the output terminal of the first filter 32. Therefore, the first and second filters 32, 34 operate in parallel with the input and output. In addition, the output according to the parallel operation of the first and second filters 32 and 34 is provided to the voice trap unit 20 as shown in FIG.

As described above, the present invention is configured to configure a filter for passing an arm-B / G video signal and a filter for passing a Secam-L video signal when the filter is operated in parallel. Therefore, there is an effect of compensating for the distortion of the Secam color when the broadcast signal is received by the PAL-B / G and Sekam-L dual systems.

Claims (1)

An apparatus for compensating for distortion of secam color in an image signal, comprising: a first filter (32) for passing an eight-B / G image signal in the image signal; A second filter 34 configured to pass a Secam-L video signal in the video signal when the first filter 32 and the input / output are operated in parallel; When the video signal is a Secam-L video signal, the output of the second filter 34 is switched to the output terminal of the first filter 32 so that the first and second filters 32 and 34 are connected to input and output. Device for compensating for distortion in Secam color comprising a switching section (36) for operating in parallel with respect.