KR100262777B1 - High-frequency modulator built-in tv tuner - Google Patents

Abstract

The present invention provides an RF modulator with no bit disturbance in the display screen resulting from leakage of harmonics of a signal between the RF modulator 1 and the TV tuner 2 which are assembled and integrated in one metal box body. It is to provide a built-in TV tuner.

To this end, a crystal oscillator connected to the box body 14, the wiring board 11 provided in the box body, the first phase synchronous loop circuit 3 provided on the wiring board and the first phase synchronous loop circuit ( A TV tuner 21 having an RF modulator 1 having 3c), an input 12 provided on the wiring board, and a second phase synchronous loop circuit 10, and the crystal oscillator and the second phase synchronization. In order to connect the loop circuit, a wiring pattern 17 formed on the wiring board is provided, and a ground pattern 15 is provided between the wiring pattern and the input unit.

Description

TF modulator tuner TV tuner

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a TV (TV) tuner with a built-in RF (high frequency) modulator, and more particularly, to an RF modulator with a TV tuner incorporating an RF modulator and a TV tuner used in video equipment such as a video tape recorder (VTR).

Recently, in video equipment such as a VTR, an RF modulator-type TV tuner in which an RF modulator and a TV tuner are assembled into one metal box body and integrated.

FIG. 2 is a schematic diagram showing an example of a configuration in which such a conventional RF modulator built-in TV tuner, that is, an RF modulator and a TV tuner are integrally assembled into one metal box body.

As shown in Fig. 2, in the TV tuner built-in RF modulator, a single wiring board 11 is arranged in a box body 14 which is made entirely of one metal material, and the RF modulator 1 is placed on the wiring board 11. ) And the TV tuner unit 2.

The RF modulator section 1 includes a first phase locked loop (PLL) circuit 3, a first RF amplifier 5, a divider 6, a second RF amplifier 7, a mixer 8, and the like. The first phase synchronous loop (PLL) circuit 3 includes a first reference oscillator 3a and a first voltage controlled oscillator VCO (not shown). The first reference oscillator 3a is provided. The reference oscillator 3c for reference frequency setting is connected, and the first reference oscillator 3b is constituted by the first reference oscillator 3a and the crystal oscillator 3c. The first reference oscillator 3b also oscillates at a frequency of 4 MHz, for example.

On the other hand, the TV tuner unit 2 includes at least an input unit 12, a third RF amplifier 13, and a second phase locked loop (PLL) circuit 10, and the second phase locked loop (PLL). The circuit 10 includes a second reference oscillator circuit 10a and a second voltage controlled oscillator (VCO) not shown. And the crystal oscillator 3c provided in the RF modulator 1 and the second reference oscillation circuit 10a of the second phase locked loop (PLL) circuit 10 are provided on the wiring board 11. The second reference oscillator 10b oscillating at, for example, 4 MHz by the crystal oscillator 3c and the second reference oscillation circuit 10a is connected in a pattern 17.

Thus, the crystal oscillator 3c is shared by the first phase locked loop (PLL) circuit 3 of the RF modulator section 1 and the second phase locked loop (PLL) circuit 10 of the TV tuner section 2. In the TV tuner 2, the crystal oscillator 3c for setting the reference frequency is not disposed. Although not shown in the input unit 12, a coil constituting an antenna tuning circuit for selecting a reception signal or an intermediate frequency trap circuit for removing an external signal having the same frequency as the intermediate signal is disposed on the wiring board 11. It is.

On the wiring board 11, a first ground pattern 15 is provided on both the RF modulator 1 and the TV tuner 2 while being close to the box 14.

The wiring pattern 17 is disposed between the first ground pattern 15, the input 12 of the TV tuner 2, and the third RF amplifier 13. The second ground pattern 16 is provided between the RF modulator 1 and the TV tuner 2, and the RF modulator 1 and the TV tuner are formed by the second ground pattern 16. (2) is electrically shielded, respectively.

In addition, the first ground pattern 15 and the second ground pattern 16 are electrically connected to the box body 14 to become a ground potential.

An opening 16a in which the second ground pattern 16 is separated is formed at a predetermined position of the second ground pattern 16, and is disposed on the side of the RF modulator 1 through the opening 16a. The wiring pattern 17 which connects the crystal oscillator 3c which exists and the 2nd reference oscillation circuit 10a of the 2nd phase locked loop (PLL) circuit 10 of the TV tuner part 2 are arrange | positioned.

In addition, the wiring pattern 17 connecting the crystal oscillator 3c and the second phase locked loop (PLL) circuit 10 has the first ground pattern 15 and the input portion 12 of the TV tuner 2. ) And the third RF amplifier 13 are turned around, and thus are arranged in the vicinity of the input unit 12 and the third RF amplifier 13.

The first ground pattern 15, the second ground pattern 16, and the wiring pattern 17 are formed by etching copper foil on the wiring board 11.

In the above configuration, the TV signal from the input terminal 4 provided on the side of the RF modulator 1 receives the first amplifier 5, the splitter 6, the second amplifier 7, the mixer 8, and the like. Via the input terminal 9 to the TV receiver (not shown), the TV signal distributed by the distributor 6 is input to the TV tuner 2.

In the modulation circuit, in which the video signal from the video signal input terminal 3d and the audio signal from the audio signal input terminal 3e are not shown, a carrier wave from the first phase locked loop (PLL) circuit 3 is used. It modulates and is guided to the output terminal 9 via the mixer 8 as an RF signal.

The first phase locked loop (PLL) circuit 3 of the RF modulator 1 is used for setting the frequency of the carrier wave and the second phase locked loop (PLL) circuit 10 of the TV tuner 2. ) Is used for tuning.

However, in the conventional TV tuner built-in RF modulator, the first phase locked loop (PLL) circuit 3 of the RF modulator 1 and the second phase locked loop (PLL) circuit 10 of the TV tuner 2 are provided. On the wiring pattern 17 provided for sharing the crystal oscillator 3c, the first reference oscillator 3b of the first phase locked loop (PLL) circuit 3 of the RF modulator 1 and the TV tuner unit ( The reference wave of each oscillation signal of the second reference oscillator 10b of the second phase locked loop (PLL) circuit 10 of 2) and its harmonics flow, and this wiring pattern 17 is connected to the TV tuner unit 2. Harmonics of the reference frequency signals of the first reference oscillator 3b and the second reference oscillator 10b flowing on the wiring pattern 17 because they are disposed in the vicinity of the input unit 12 and the third RF amplifier 13. Is easily transferred to the coil of the input unit 12, and the transferred harmonics cause distortion in each circuit of the TV tuner unit 2. And is something that is causing the problem is a bit disturbing when the display screen.

The present invention solves this problem, and its object is to provide a TV tuner with an RF modulator without causing bit interference on the display screen.

1 is a schematic diagram showing the configuration of an embodiment of a TV tuner built-in RF modulator according to the present invention;

2 is a schematic diagram showing the configuration of a conventional TV tuner built-in RF modulator.

※ Explanation of code for main part of drawing

1: RF modulator section 2: TV tuner section

3: 1st phase synchronous loop (PLL) circuit

3a: first reference oscillation circuit

3c: crystal oscillator 5, 7, 13: RF amplifier

10: second phase locked loop (PLL) circuit

10a: second reference oscillator circuit 11: wiring board

12: input unit 14: box body

15: first ground pattern 16: second ground pattern

17: wiring pattern

A TV tuner with an RF modulator according to the present invention includes a box, a wiring board provided in the box, a first phase synchronous loop circuit provided on the wiring board, and a reference frequency set connected to the first phase synchronous loop circuit. An RF modulator section having a quartz crystal oscillator, an input unit provided on the wiring board, and a TV tuner section having a second phase locked loop circuit, and on the wiring board for connecting the quartz crystal and the second phase locked loop circuit. It has a wiring pattern formed in the ground pattern is provided between the wiring pattern and the input unit.

In the TV tuner built-in RF modulator of the present invention, the wiring pattern is provided between the ground pattern and the box body.

(Example)

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

1 is a schematic diagram showing the configuration of a TV tuner built-in RF modulator according to an embodiment of the present invention.

In addition, in FIG. 1, the same code | symbol is attached | subjected about the structure similar to the structure shown in the prior art example of FIG.

As shown in Fig. 1, the first ground pattern 15 of the TV tuner built-in RF modulator according to the embodiment of the present invention has openings 15a and 15b toward the RF modulator section 1 and the TV tuner section 2, respectively. Is provided between the first ground pattern 15 and the box body 14, the configuration is different from the conventional RF modulator built-in TV tuner shown in FIG. As for the configuration of the conventional TV tuner built-in RF modulator.

In this case, in the RF tuner built-in TV tuner according to the embodiment of the present invention, the first ground pattern 15 is provided on both the RF modulator 1 and the TV tuner 2, and the box body ( It is installed close to 14).

One end of the wiring pattern 17 is passed through the opening 15a and into the RF modulator 1 to be connected to the crystal oscillator 3c of the RF modulator 1, and the wiring pattern 17 The other end of the < RTI ID = 0.0 >) < / RTI > is passed through the opening 15b and in the TV tuner section 2 so that the second reference oscillation circuit 10a of the second phase locked loop (PLL) circuit 10 of the )

Thus, the first reference oscillator 3b of the first phase locked loop (PLL) circuit 3 is formed by the crystal oscillator 3c and the first reference oscillator circuit 3a disposed on the RF modulator 1 side. And a second reference oscillator of the second phase locked loop (PLL) circuit 10 by the crystal oscillator 3c and the second reference oscillator circuit 10a connected through the wiring pattern 17. 10b) is configured.

At this time, since the first ground pattern 15 is disposed between the wiring pattern 17, the input unit 12 of the TV tuner 2, and the third RF amplifier 13, the wiring pattern 17 is connected to the input unit 12. The third RF amplifier 13 is arranged in a position separated from the conventional by the first ground pattern 15. In other words, the first ground pattern 15 separates the wiring pattern 17 from the input unit 12 and the like. The input part 12 in which the harmonics of the signal of the reference frequency of the 1st reference oscillator 3b and the 2nd reference oscillator 10b which flow on the wiring pattern 17 by the arrangement | positioning of the wiring pattern 17 are arrange | positioned coils, etc. B) less transition to the third RF amplifier 13 or the like.

In addition, since the wiring pattern 17 is disposed between the first grounding pattern 15 and the box body 14, the wiring pattern 17 flows on the wiring pattern 17 even when the wiring pattern 17 is fitted to a member having a ground potential. Even if harmonics are radiated, they are absorbed by the box body 14 made of a metal material, and the number of transitions to the input unit 12, the third RF amplifier 13, etc., in which the coil or the like is disposed, is less.

The TV tuner built-in RF modulator according to the embodiment of the present invention having the above configuration operates as follows.

First, the case of operating the RF modulator 1 will be described. The oscillation signal output from the first voltage controlled oscillator VOC (not shown) is controlled by the first reference oscillator 3b using the crystal oscillator 3c. The frequency stabilizes.

At this time, the oscillation signal (carrier) output from the first voltage controlled oscillator VCO is modulated by the video signal supplied to the video signal input terminal 3d and the audio signal supplied to the audio signal input terminal 3e and thus the mixer ( 8) is entered. The RF signal supplied from the distributor 6 via the second RF amplifier 7 is also input to the mixer 8. The antenna output terminal 9 is supplied as an RF output signal to an antenna input terminal (not shown) of the television receiver.

Next, a description will be given of the case where the TV tuner unit 2 is operated. The local oscillation signal output from the second voltage controlled oscillator VCO (not shown) is a crystal oscillator 3c provided on the RF modulator unit 1 side. And the frequency is stabilized by the second reference oscillator 10b including the second reference oscillator circuit 10a of the second phase locked loop (PLL) circuit 10.

At this time, the TV broadcast signal supplied through the input unit 12 and the third RF amplifier 13 is tuned by the local oscillation signal output from the second voltage controlled oscillator VCO, and the intermediate frequency corresponding to the tuned TV broadcast signal is selected. (IF) signal is obtained.

The intermediate frequency signal corresponding to the tuned TV broadcast signal is supplied from the intermediate frequency signal output terminal 10c to the intermediate frequency signal processing circuit (not shown) of the next stage.

Further, in the embodiment of the present invention, the crystal oscillator 3c when the crystal oscillator 3c for setting the reference frequency is shared between the first phase locked loop circuit 3 side and the second phase locked loop circuit 10 side. Has been described with respect to the embodiment in which the RF modulator unit 1 is disposed, the crystal oscillator 3c may be arranged on the TV tuner unit 2 side.

As described above, according to the present invention, a wiring pattern connecting the crystal oscillator on the RF modulator side and the second reference oscillation circuit of the second phase locked loop circuit on the TV tuner side is separated from the input portion of the TV tuner by the first ground pattern. Since the harmonics of the oscillation signal of the reference oscillator flowing through the wiring pattern are less likely to be transferred to the coil of the input unit, as compared with a TV tuner with a built-in RF modulator integrated in a conventional metal box, the oscillation frequency signal of the input unit is difficult. There is an effect that problems such as bit interference are unlikely to occur between and.

Further, according to the present invention, since the wiring pattern is provided between the first ground pattern and the box body, harmonics radiated from the wiring pattern because the wiring pattern is sandwiched between the first ground pattern and the box body which are ground potentials. Since it is absorbed by the box body, the transition to the coil or the like is further reduced, which has a remarkable effect that the problem such as bit interference is less likely to occur.

Claims (2)

An RF modulator section having a box body, a wiring board arranged in the box body, a first phase locked loop circuit provided on the wiring board, and a crystal oscillator for setting a reference frequency connected to the first phase locked loop circuit; A TV tuner section having an input section provided on a wiring board and a second phase locked loop circuit, and a wiring pattern formed on the wiring board for connecting the crystal oscillator and the second phase locked loop circuit; An RF modulator built-in TV tuner, wherein a ground pattern is provided between the input parts. The method of claim 1, And the wiring pattern is provided between the ground pattern and the box body.