KR20050020852A - Tuner for enable receving broadcasting of all type - Google Patents

Abstract

PURPOSE: A tuner capable of receiving broadcast signals of all broadcasting modes is provided to receive the broadcasting signals of all broadcasting modes using a single tuner by varying passband characteristics of video and audio saw filers, a sound trap filter and a sound pass filter in response to the broadcasting modes. CONSTITUTION: A tuner includes a tuning unit(110) and an IF demodulator(120). The tuning unit includes a tuner module(112) for filtering only an RF signal of one channel from RF signals received from an antenna(111) and converting the RF signal into an IF(Intermediate Frequency) signal, a controller(113) for providing corresponding channel data for generating an oscillating signal and outputting a switching signal in response to an input broadcasting standard, a video saw filter(115) whose passband characteristic is varied with an input signal to filter a video frequency among signals output from the tuner module, an audio saw filter(116) whose passband characteristic is varied with an input signal to filter an audio frequency among the signals output from the tuner module, the first switch(117) for varying the passband characteristics of the video and audio saw filters. The IF demodulator includes an IF detector(121) for detecting an IF signal including a video signal and an audio signal input from the video and audio saw filters to remove a frequency component from the IF signal, a sound trap filter(122) whose passband characteristic is varied with an input signal to trap only a sound signal among signals output from the IF detector and output a video signal, a sound pass filter(123) whose passband characteristic is varied with an input signal to pass only an audio signal among the signals output from the IF detector, and the second switch(124) for varying the passband characteristics of the sound trap filter and the sound pass filter.

Description

Tuner that can receive broadcasts of all methods {TUNER FOR ENABLE RECEVING BROADCASTING OF ALL TYPE}

The present invention relates to a tuner, and more particularly, to a tuner capable of receiving broadcasts in all manners so that any broadcast in the world can be received by one tuner.

In general, a tuner is a device that receives an RF signal (radio frequency signal) through an antenna, converts it into an IF signal (intermediate frequency signal), detects it, and separates it into a video signal and an audio signal to output it.

On the other hand, since the tuner receives a wideband RF signal, the tuner divides the reception band into a VHF band and a UHF band to select a signal.

This tuner is described with reference to FIG. 1 as follows.

1 is a block diagram schematically showing the configuration of a conventional tuner.

Referring to FIG. 1, a conventional tuner 10 is divided into a tuner unit 20 and an IF demodulation unit 30.

The tuner unit 20 filters only the RF signal of one desired channel among the numerous channels inputted through the antenna 21 by the tuner module 22, converts it into an IF signal required by a broadcasting method, and outputs the trap circuit 23. ) Traps adjacent channel frequency components and filters and outputs a specific frequency from the saw filter 24. In this case, an oscillation signal is required to downconvert an RF signal, which is a high frequency signal, to an IF signal, which is a low frequency signal. The IF signal is a value obtained by subtracting the RF signal from the oscillation signal. Since the IF signal is fixed for each broadcasting method and the input RF signal is different for each channel, the oscillation signal for each channel is different, and the controller 25 provides corresponding channel data to generate the oscillation signal.

The IF demodulator 30 detects the IF signal including the input video signal and the audio signal from the IF detector 31 to remove and output a frequency component. The sound trap filter 32 and the audio pass filter 33 Each outputs a desired base signal (video / audio).

On the other hand, the global broadcasting system is divided into NTSC, PAL, SECAM, NTSC is divided into NTSC M, NTSC JPN, PAL is divided into PAL B / G, PAL D / K, PAL I, and SECAM is again divided into SECAM L, It is divided into SECAM L '.

If you look at the IF signal for each broadcasting method, NTSC M = 45.75MHz, NTSC JPN = 58.75MHz, PAL (CHINA) = 38.0MHz, PAL (CCIR) = 38.9MHz, other PAL = 39.0MHz, SECAM L = 38.9MHz, SECAM L '= 33.9 MHz.

In addition, there are gaps between video and color frequencies and gaps between video and audio frequencies for each broadcasting system. NTSC M and NTSC JPN have 3.58MHz for video and color, and 4.5MHz for video and audio, and PAL B / G. , PAL D / K, PAL I, SECAM L, SECAM L 'is 4.43MHz in video and color, PAL D / K, SECAM L, SECAM L' is 6.5MHz difference in video and audio, PAL B / G is Video and audio are 5.5MHz, PAL I video and audio is 6.0MHz difference.

Therefore, in some cases, the tuner and demodulator are used in common by similar method, but in case of the broadcasting method with different frequency, the parts are not shared, so multiple tuners must be used to receive all the world broadcasts. Therefore, there is a problem that the product volume is increased, and the manufacturing cost is increased.

Accordingly, an object of the present invention is to solve the above problems, and the reception of all broadcasts is controlled by one tuner by varying the passband characteristics of the video and audio saw filters, the sound trap filters, and the sound pass filters according to the broadcast method. To make it possible.

Features of the present invention for achieving the above object,

In the tuner,

In the tuner,

A tuner module which filters only an RF signal of a desired channel among RF signals received from an antenna, converts the IF signal required by a broadcasting method, and outputs the converted IF signal;

A controller for providing corresponding channel data for generating an oscillation signal to the tuner module and outputting a switching signal according to an input broadcast method;

A video saw filter for varying a passband characteristic according to a signal input from the outside and filtering and outputting a video frequency among signals output from the tuner module;

An audio saw filter for varying a passband characteristic according to a signal input from the outside and filtering and outputting a video frequency among signals output from the tuner module;

A tuner unit including a first switch that is switched to a switching signal output from the controller and outputs an output signal having a different level to vary pass band characteristics of the video saw filter and the audio saw filter;

An IF detector which detects an IF signal including a video signal and an audio signal input from the video saw filter and the audio saw filter and removes frequency components;

A sound trap filter for varying passband characteristics according to a signal input from the outside and trapping only a sound signal among signals output from the IF detector to output a video signal;

A sound pass filter for varying a passband characteristic according to a signal input from the outside and passing only an audio signal among signals output from the IF detector, and outputting an audio signal;

And an IF demodulator including a second switch that is switched to a switching signal output from the controller and outputs an output signal having a different level to vary passband characteristics of the sound trap filter and the audio pass filter.

Here, the tuner module is

Outputs an IF signal of 38.0MHz or 38.9MHz.

Here also the controller,

Even if the RF signal for each broadcasting method is input, data is set and stored in advance so that the same IF signal can be output.

Here, between the tuner module and the video saw filter and the audio saw filter,

A trap circuit for trapping adjacent channel frequency components among the signals output from the tuner module is further provided.

Hereinafter, a configuration of a tuner capable of receiving broadcasts according to the present invention will be described in detail with reference to FIG. 2.

2 is a block diagram schematically showing the configuration of a tuner capable of receiving broadcasts according to the present invention.

2, the tuner 100 capable of receiving broadcasts according to the present invention includes a tuner 110 and an IF demodulator 120.

The tuner unit 110 includes an antenna 111, a tuner module 112, a controller 113, a trap circuit 114, a video saw filter 115, an audio saw filter 116, and a first saw. It consists of a switch 117.

The antenna 111 receives an RF signal.

The tuner module 112 filters the RF signal of one desired channel among the RF signals received from the antenna 111 and converts the RF signal into an IF signal of 38.0 MHz or 38.9 MHz.

The controller 113 provides the channel data for generating the oscillation signal to the tuner module 112, outputs a switching signal according to the input broadcasting scheme, and outputs the same IF signal even if an RF signal corresponding to each broadcasting scheme is input. The data is set and stored in advance for output.

The trap circuit 114 traps adjacent channel frequency components of the signals output from the tuner module 112.

The video saw filter 115 filters and outputs a video frequency among signals output from the trap circuit 114 by varying passband characteristics according to a signal input from the first switch 117 to be described below.

The audio saw filter 116 filters and outputs a video frequency among signals output from the trap circuit 114 by varying passband characteristics according to a signal input from the first switch 117.

The first switch 117 is configured of a transistor, and outputs a low / high signal under the control of the controller 113 to vary the pass band characteristics of the video saw filter 115 and the audio saw filter 116.

The IF demodulator 120 includes an IF detector 121, a sound trap filter 122, a sound path circuit 123, and a second switch 124.

The IF detector 121 detects an IF signal including a video signal and an audio signal input from the video saw filter 115 and the audio saw filter 116 to remove unnecessary frequency components.

The sound trap filter 122 has a passband characteristic that varies according to a signal input from the second switch 124 to be described below, and outputs a video signal by trapping only a sound signal among signals output from the IF detector 121.

The sound pass filter 123 varies the pass band characteristic according to the signal input from the second switch 124 and passes only the audio signal among the signals output from the IF detector 121 to output the audio signal.

The second switch 124 is composed of a transistor and outputs a low / high signal under the control of the controller 113 to vary the passband characteristics of the sound trap filter 122 and the audio pass filter 123.

Hereinafter, an operation of a tuner capable of receiving broadcasts according to the present invention will be described in detail with reference to FIGS. 2 to 5.

3 is a graph illustrating a pass band characteristic of a video saw filter in a tuner capable of receiving broadcasts according to the present invention, and FIG. 4 is a PAL pass of an audio saw filter in a tuner capable of receiving broadcasts according to the present invention. FIG. 5 is a graph showing band characteristics, and FIG. 5 is a graph showing SECAM L 'pass band characteristics of an audio saw filter in a tuner capable of receiving broadcasts according to the present invention.

First, in the present invention, the IF signal is assumed to be 38.9 MHz.

In this state, if only the RF signal of one desired channel through which the RF signal is input through the antenna 111 is filtered and converted into an IF signal of 38.9 MHz, the trap circuit 114 traps and outputs adjacent channel frequency components. .

On the other hand, the controller 113 allows the high or low signal to be output from the first switch 117 according to the broadcasting method.

If the broadcast method is NTSC M, NTSC JPN method, a high signal is output from the first switch 117 so that the video saw filter 115 operates as an inter-carrier saw filter to pass video, color, and audio IF signals. As shown in Fig. 3, when the broadcast method is PAL or SECAM L method, a low signal is output from the first switch 117 to pass the image IF signal through 38.9 MHz and the color IF signal through 34.47 MHz, and the broadcast method is SECAM L '. In this method, a low signal is output from the first switch 117 so that the image IF signal passes through 33.9 MHz and the color IF signal passes through 38.33 MHz.

As shown in FIG. 4, the audio saw filter 116 has a passband characteristic varying according to a signal output from the first switch 117, so that the PAL B / G method is 33.9 MHz, and the PAL I method is 33.9 MHz and PAL. If the D / K, SECAM L scheme 32.9MHz, SECAM L 'scheme passes the voice IF signal of 40.4MHz as shown in FIG. In the NTSC M and NTSC JPN schemes, the voice IF signal is passed from the video saw filter 115.

On the other hand, when the video, color, and audio IF signals are output from the video saw filter 115 and the audio saw filter 116 and input to the IF detector 121 of the IF demodulator 120, the IF detector 121 receives the input video signal. Detect and output IF signal including and audio signal to remove frequency component.

At this time, the controller 113 allows the high or low signal to be output from the second switch 124 according to the broadcasting method.

Thus, if the passband characteristics of the sound trap filter 122 and the audio pass filter 123 are varied to 4.4 MHz / 5.5 MHz / 6.0 MHz / 6.5 MHz according to the broadcasting method, the signals are output as desired base signals (video / audio). .

Therefore, the tuner section filters the video and audio signals respectively, and adds a switch for varying the pass band characteristics of the saw filter and the saw filter whose pass band characteristics are changed, and the pass band of the sound trap filter and the sound pass filter in the IF demodulation unit. By adding a switch for varying the characteristics, it is possible to receive all broadcasts with one tuner by varying the pass band characteristics of the saw filter, the sound trap filter, and the sound path filter according to the broadcast band.

As described above, according to the tuner capable of receiving broadcasts according to the present invention, the tuner transmits a single tuner by varying the passband characteristics of the video and audio saw filters, the sound trap filter, and the sound pass filter according to the broadcast method. The reception of the broadcast may be possible.

1 is a block diagram schematically showing a configuration of a conventional tuner

2 is a block diagram schematically showing the configuration of a tuner capable of receiving broadcasts according to the present invention;

3 is a graph illustrating a passband characteristic of a video saw filter in a tuner capable of receiving broadcasts according to the present invention.

4 is a graph illustrating PAL passband characteristics of an audio saw filter in a tuner capable of receiving broadcasts according to the present invention.

5 is a graph showing the SECAM L 'passband characteristics of an audio saw filter in a tuner capable of receiving broadcasts according to the present invention.

<Description of the symbols for the main parts of the drawings>

110: tuner portion 111: antenna

112: tuner module 113: controller

114: Trap Circuit 115: Video Saw Filter

116: audio saw filter 117: first switch

120: IF demodulator 121: IF detector

122: sound trap filter 123: sound pass circuit

124: second switch

Claims (4)

In the tuner, A tuner module which filters only an RF signal of a desired channel among RF signals received from an antenna, converts the IF signal required by a broadcasting method, and outputs the converted IF signal; A controller for providing corresponding channel data for generating an oscillation signal to the tuner module and outputting a switching signal according to an input broadcast method; A video saw filter for varying a passband characteristic according to a signal input from the outside and filtering and outputting a video frequency among signals output from the tuner module; An audio saw filter for varying a passband characteristic according to a signal input from the outside and filtering and outputting a video frequency among signals output from the tuner module; A tuner unit including a first switch that is switched to a switching signal output from the controller and outputs an output signal having a different level to vary pass band characteristics of the video saw filter and the audio saw filter; An IF detector which detects an IF signal including a video signal and an audio signal input from the video saw filter and the audio saw filter and removes frequency components; A sound trap filter for varying passband characteristics according to a signal input from the outside and trapping only a sound signal among signals output from the IF detector to output a video signal; A sound pass filter for varying a passband characteristic according to a signal input from the outside and passing only an audio signal among signals output from the IF detector, and outputting an audio signal; And an IF demodulator including a second switch that is switched to a switching signal output from the controller and outputs an output signal having a different level to vary pass band characteristics of the sound trap filter and the audio pass filter. Tuner capable of broadcast reception. The method of claim 1, The tuner module, Tuner capable of receiving broadcasts of all types, characterized by outputting an IF signal of 38.0MHz or 38.9MHz. The method of claim 1, The controller, Tuner capable of receiving broadcasts according to the above-mentioned method, wherein data is set and stored so that the same IF signal can be output even if an RF signal for each broadcasting method is input. The method of claim 1, Between the tuner module and the video saw filter and the audio saw filter, And a trap circuit for trapping adjacent channel frequency components among the signals output from the tuner module.