KR19980023363U - PAL signal receiving circuit - Google Patents

Abstract

The present invention relates to a PAL receiver having different image and color and audio carrier frequencies according to PAL-B / G, PAL-B / H, PAL-I / I, PAL-I and PAL-B / G schemes. An image detector (2) having an image carrier frequency band according to the PAL-I / I scheme and detecting an image signal; A color detector (3) having a frequency band of 4.43 MHz higher than a carrier frequency of the image detector (2) and detecting the color signal; Frequency of 5.5, 6.0, 6.5 MHz band higher than the carrier frequency of the image detector 2 according to PAL-B / G, PAL-B / H, PAL-I / I, PAL-I and PAL-B / G An audio detector 4 is provided for selectively detecting the audio signal by providing a band.

That is, according to the present invention, the type of filter for detecting PAL video, color, and audio signals is greatly reduced, thereby simplifying the manufacturing process of the PAL receiver, thereby improving production efficiency.

Description

PAL signal receiving circuit

The present invention relates to a PAL type receiver, and more particularly, to a PAL type signal receiving circuit capable of receiving broadcast signals for each type of PAL type.

In addition to the NTSC system used in Korea and the United States, there are a PAL system developed in Germany and a SECAM system developed in France. Although the PAL and SECAM methods have a lot in common with the NTSC method, the major difference is the transmission of the color difference signal and the multiplexing of the color difference signal and the luminance signal.

In addition, the PAL method is classified into various methods as shown in the following [Table].

T-1

As shown in [Table], PAL schemes have different video carriers, color carriers, and voice carrier schemes. Therefore, when manufacturing PAL receivers, filters for video and color audio carrier frequencies must be configured according to these schemes. . Therefore, considerable care is required in the manufacture of the PAL receiver, and the manufacturing process has become a cause of complexity.

The present invention has been devised to solve such a problem, and an object of the present invention is to simplify the manufacturing process by reducing the types of filters for detecting video, color, and audio signals when manufacturing a PAL receiver. To provide a receiving circuit.

PAL signal reception circuit according to the present invention, according to the PAL-B / G, PAL-B / H, PAL-I / I, PAL-I and PAL-B / G system, different image and color and audio carrier frequency A PAL receiver having an image carrier, comprising: an image detector having an image carrier frequency band according to the PAL-I / I scheme and detecting an image signal; A color detector having a frequency band of 4.43 MHz higher than a carrier frequency of the image detector and detecting the color signal; According to PAL-B / G, PAL-B / H, PAL-I / I, PAL-I and PAL-B / G, a band of frequencies 5.5, 6.0 and 6.5 MHz higher than the carrier frequency of the image detector is selectively And an audio detector for detecting an audio signal.

1 is a block diagram showing an embodiment of a PAL signal reception circuit according to the present invention;

2 is a block diagram showing another embodiment of a PAL signal reception circuit according to the present invention;

* Description of the symbols for the main parts of the drawings *

1: SAW filter 2: image detector

3: color detection unit 4: audio detection unit

The above object and various advantages of the present invention will become more apparent from the preferred embodiments of the invention described below with reference to the accompanying drawings by those skilled in the art.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention.

1 is a PAL signal reception circuit according to a preferred embodiment of the present invention, and is composed of a SAW filter unit 1, an image detector 2, a color detector 3, and an audio detector 4.

In such a configuration, the SWA filter unit 1 is applied with an intermediate frequencyized PAL broadcast signal. That is, a broadcast signal of a predetermined channel tuned by an antenna and a tuner configured in a PAL receiver is intermediateized and applied to the SAW filter unit 1, and the SAW filter unit 1 is applied to the predetermined channel from the input signal. Only the broadcast signal is filtered and output.

The broadcast signal of the SAW filter unit 1 is applied to the image detector 2, the color detector 3, and the audio detector 4, respectively, and is separated into an image signal and an audio signal. At this time, as described above, the PAL audio signal has various video carriers, color carriers, and voice carrier frequencies as shown in the table. Conventionally, in order to detect an image signal and an audio signal according to the broadcasting method, the image detector 2, the color detector 3, and the audio detector 4 are used using various filters according to the carrier frequency band as described above. .

However, the inventors of the present invention realize that there is no problem in reconstruction, that is, image quality, of all PAL broadcast signals even if the video signals are detected using only the PAL-I / I video carrier frequency (38.9 MHz) filter. It became. That is, the image detection unit 2 can be configured by fixing with a 38.9 MHz filter.

As described above, when the filter of the image detector 2 is determined to be a 38.9 MHz filter, the filter of the color detector 3 is configured using only one filter having a frequency of 4.43 MHz higher than the image carrier frequency as shown in [Table]. It can be seen that.

On the other hand, it can be seen that three types of filters should be used as shown in [Table] to detect the voice signal.

For example, P + 5.5 MHz filters should be used for PAL-B / G and PAL-B / H schemes, and P + 6.0 MHz filters should be used for PAL-I / I and PAL-I schemes. something to do. Therefore, in order to receive these types of broadcast signals, the audio detector 4 can be configured with a filter corresponding thereto.

However, in the case of PAL-B / G, it can be seen that two filters of P + 5.5 and P + 6.6 MHz are used. Also in this case, as shown in FIG. 2, the P + 5.5 MHz filter for the PAL-B / G and PAL-B / H schemes and a separate P + 6.0 MHz filter are connected in parallel to configure the audio detector 4. It can be.

In addition, as described above, the audio detector 4 should be configured with a filter having various bandwidths for each PAL method. When the audio detector 4 is configured to change the bandwidth by using a variable capacitor or the like, one variable filter is used. It will be readily apparent to those skilled in the art that all audio signals in the PAL scheme can be received.

That is, in the present invention, by configuring the image detector 2 as a 38,9 MHz filter, the color detector 3 can be configured as one type (P + 4.43) filter, and three types (P + 5.5, The filter audio detection unit 4 of P + 6.0 and P + 6.5 can be configured.

As described above, according to the present invention, the type of filter for detecting PAL video, color, and audio signals is greatly reduced, thereby simplifying the manufacturing process of the PAL receiver, thereby improving production efficiency.

Claims (1)

In the PAL receiver having different image, color and audio carrier frequencies according to PAL-B / G, PAL-B / H, PAL-I / I, PAL-I and PAL-B / G schemes, An image detector (2) having an image carrier frequency band according to the PAL-I / I scheme and detecting an image signal; A color detector (3) having a frequency band of 4.43 MHz higher than a carrier frequency of the image detector (2) and detecting the color signal; According to the PAL-B / G, PAL-B / H, PAL-I / I, PAL-I and PAL-B / G, the band of 5.5, 6.0, 6.5 HMZ is higher than the carrier frequency of the image detector 2 And a audio detector (4) for selectively detecting the audio signal by providing a frequency band.