KR20020066634A - Connecting structure of double conversion type tuner - Google Patents

Abstract

PURPOSE: A connection structure of a double conversion type tuner is provided to prevent collision between oscillating frequencies by forming the first local oscillator of the first IF portion and the second local oscillator of the second IF portion, independently. CONSTITUTION: The first printed circuit board is adhered to the first sash portion(110). The first printed circuit board is formed with the first IF portion and an inductor of a band pass filter. The second printed circuit board is adhered to the second sash portion(120). The second IF portion is formed in the second printed circuit board. A plurality of shielding panels(130) are installed on a boundary portion between the first sash portion(110) and the second sash portion(120) in order to shield interference phenomena of local oscillators. A fixing groove(131) is formed in the shielding panel(130). A lead-through capacitor(140) is installed in the fixing groove(131) of the shielding panel(130) in order to connect electrically the first IF portion with the second IF portion.

Description

CONNECTING STRUCTURE OF DOUBLE CONVERSION TYPE TUNER}

The present invention relates to a chassis structure of a tuner, and more particularly, the primary local oscillator and the primary local oscillator of the secondary IF unit and the secondary local oscillator of the secondary IF unit are structurally completely separated from unnecessary primary oscillation frequency and secondary oscillation. The collision structure of the frequency relates to a connection structure of a double conversion type tuner which prevents bits from being output at the output of the final output frequency of 44 MHz due to collision of frequencies.

As shown in FIG. 1, a general double conversion tuner 10 includes a first IF unit 20, a band pass filter 30, and a second IF unit 40.

The primary IF unit 20 includes an AGC 21, a tracking filter 22, an RF amplifier 23, an RF filter 24, a primary mixer 25, and a primary local oscillator 26. And the primary PLL 27.

The AGC 21 automatically adjusts the output of the video signal at all times even when the magnitude of the high frequency signal of 44 to 860 MHz that is induced by the antenna ANT changes. The tracking filter 22 removes noise included in the signal of the high frequency band received by the antenna ANT and passes only the desired high frequency (RF) signal. The RF amplifier 23 amplifies the high frequency signal passed through the tracking filter 22. The RF filter 24 selects a desired high frequency signal (860 MHz) from the high frequency signals amplified by the RF amplifier 23. The primary mixer 25 mixes the high frequency signal selected by the RF filter 24 and the oscillation frequency generated by the primary local oscillator 26 to output the primary IF frequency. The primary local oscillator 26 generates a predetermined oscillation frequency according to the control voltage of the primary PLL 27 at the time of channel tuning and outputs it to the primary mixer 25. The primary phase locked loop (PLL) 28 stores channel data therein and outputs a control voltage to the primary local oscillator 26 according to external control.

The band pass filter 30 is connected to the output terminal of the primary mixer 25 of the primary IF 20 to pass only a signal of a predetermined band among the primary IF frequencies output from the primary mixer 25. Here, the band pass filter 30 is composed of an inductor and a capacitor.

The secondary IF unit 40 includes a primary IF amplifier 41, a primary IF filter 42, a secondary mixer 43, a secondary local oscillator 44, a secondary PLL 45, And a second order IF filter 46.

The primary IF amplifier 41 amplifies the primary IF frequency signal output from the band pass filter 30. The primary IF filter 42 passes only the desired IF frequency signal among the primary IF frequency signals amplified and output from the primary IF amplifier 41. The secondary mixer 43 mixes the primary IF frequency signal amplified by the primary IF filter 42 and the oscillation frequency generated by the secondary local oscillator 44 to output the secondary IF frequency. The secondary local oscillator 44 generates a predetermined oscillation frequency according to the control voltage of the secondary PLL 45 at the time of channel tuning and outputs it to the secondary mixer 43. The secondary phase locked loop (PLL) 45 stores channel data therein and outputs a control voltage to the secondary local oscillator 44 according to external control. The secondary IF filter 46 passes only signals of a desired band among the secondary IF frequency signals output from the secondary mixer 43.

The tuner 10 of the double conversion method uses the AGC 21 of the primary IF 20, the tracking filter 22, the RF amplifier 23 and the desired channel among the TV signals input from the antenna ANT. When a certain tuning waveform is made by the RF filter 24, it is converted to the first IF frequency (1038 MHz) while passing through the first mixer 25, and passes through the band pass filter 30, so that only a signal of a predetermined region is passed. Passed. Then, after passing through the primary IF amplifier 41 and the primary IF filter 42, it is again converted to the final IF frequency (44 MHz) while passing through the secondary mixer 43 and the secondary IF filter 46 Outputs through).

On the other hand, the double conversion tuner is provided with a primary IF unit 20 and a secondary IF unit 40 on one printed circuit board (not shown), respectively, which are fixed to one chassis (not shown). .

However, in the conventional double conversion tuner connection structure, the primary local oscillator and the secondary local oscillator are formed adjacent to one printed circuit board so that the oscillation signal of the primary local oscillator and the oscillation signal of the secondary local oscillator collide with each other. When the sea tuner is operated, a collision frequency (Beat) is output when a final output frequency of 44 MHz is output.

Accordingly, an object of the present invention is to solve the above problems, and to assemble the primary IF portion and the secondary IF portion on each printed circuit board, each primary IF portion assembled to the chassis formed independently by the blocking panel The primary printed circuit board and the secondary IF unit are assembled, and the first IF unit and the secondary IF unit are electrically connected to each other by a through capacitor forming a band pass filter. The secondary local oscillator of the IF unit is mechanically independent to prevent each oscillation frequency from colliding.

1 is a block diagram showing the configuration of a conventional double conversion type tuner.

2 is a perspective view schematically showing a connection structure of a double conversion type tuner according to the present invention;

3 is a rear view of FIG. 2.

<Explanation of symbols for main parts of the drawings>

110: first chassis 120: second chassis

130: blocking panel 131: fixing groove

140: through capacitor 150: insulating member

Features of the present invention for achieving the above object,

A primary IF section comprising an AGC, a tracking filter, an RF amplifier, an RF filter, a primary mixer, a primary local oscillator, and a primary PLL; A band pass filter; Double-conversion tuner including a 1st IF amplifier, a 1st IF filter, a 1st IF amplifier, a 2nd mixer, a 2nd local oscillator, a 2nd PLL, and a 2nd IF section consisting of a 2nd IF filter. To

A first chassis unit to which the first printed circuit board on which the primary IF unit and the inductor of the band pass filter are mounted is assembled;

A second chassis to which the second printed circuit board equipped with the secondary IF unit is assembled;

The first chassis and the second chassis are formed of a single panel, and have a structure independent by a plurality of blocking panels, and a through capacitor electrically connecting the first chassis and the second chassis to the blocking panel. The through capacitor is electrically connected to the inductor of the band pass filter and the primary IF amplifier of the secondary IF unit.

Here, the through capacitor is fixed by an insulating material so as to be electrically separated from the blocking panel.

Hereinafter, the configuration and operation of the connection structure of the double conversion type tuner according to the present invention will be described in detail with reference to FIG. 2.

2 is a perspective view schematically illustrating a connection structure of a double conversion type tuner according to the present invention, and FIG. 3 is a rear view of FIG. 2.

2, the chassis 100 of the double conversion tuner according to the present invention includes a first chassis 110, a second chassis 120, a blocking panel 130, and a through capacitor 140. do.

The first chassis 110 is attached with a first printed circuit board (not shown) in which the inductor of the first IF unit and the band pass filter described above are attached, and the second chassis 120 is assembled with the secondary IF unit. A second printed circuit board (not shown) is attached. Here, the primary local oscillator of the primary IF unit is located at a portion of the first chassis 110 in the drawing of FIG. 2, and the secondary local oscillator of the secondary IF unit is located at a portion b of the second chassis 120. Position them so that they are completely separated from each other. Here, the first chassis 110 and the second chassis 120 are preferably formed of one panel, and may be connected to each other in a separated state. Here, the first printed circuit board and the second printed circuit board are provided with a fixing hole (not shown) having a pattern formed such that the through capacitor 140 is fixed to electrically connect the inductor and the secondary IF amplifier of the secondary IF unit.

The plurality of blocking panels 130 are installed to form a boundary between the first chassis 110 and the second chassis 120 to block the occurrence of interference by the oscillation frequency of each local oscillator. Here, each of the blocking panels 130 has a fixing groove 131 formed therein, and the blocking panel 130 is formed to have a certain gap with the first chassis 110 and the second chassis 120. .

The through capacitor 140 is fixedly installed in the fixing groove 131 of the blocking panel 130 and electrically connects the primary IF unit and the secondary IF unit. Meanwhile, when the through capacitor 140 is fixed to the blocking panel 130, the through capacitor 140 is fixed by the insulating member 150 to be insulated from the metal blocking panel 130.

Therefore, the primary local oscillator of the primary IF unit is fixed to the first chassis, is installed on the second chassis of the secondary local oscillator of the secondary IF unit, and the first chassis and the second chassis are blocked by a blocking panel. When the primary IF unit and the secondary IF unit are electrically connected to each other through the pass-through capacitor of the band pass filter, the collision frequency between the unnecessary primary oscillation frequency and the secondary oscillation frequency collides and the final output frequency of 44 MHz is output. You can block the bit from being output.

As described above, according to the connection structure of the double conversion type tuner according to the present invention, the primary IF unit and the secondary IF unit are assembled on each printed circuit board, and each primary is independently formed by a chassis. The primary local oscillator of the primary IF unit by installing the printed circuit board of the IF unit and the printed circuit board of the secondary IF unit, and electrically connecting the primary IF unit and the secondary IF unit with through capacitors forming a band pass filter. By independent of the secondary local oscillator of the secondary IF unit and the secondary IF unit, unnecessary collision of the primary oscillation frequency and the secondary oscillation frequency collides, thereby preventing the output of the bit at the output of the final output frequency of 44 MHz.

Claims (3)

A primary IF section comprising an AGC, a tracking filter, an RF amplifier, an RF filter, a primary mixer, a primary local oscillator, and a primary PLL; A band pass filter; Double-conversion tuner including a 1st IF amplifier, a 1st IF filter, a 1st IF amplifier, a 2nd mixer, a 2nd local oscillator, a 2nd PLL and a 2nd IF part consisting of a 2nd IF filter. To A first chassis unit to which the first printed circuit board on which the primary IF unit and the inductor of the band pass filter are mounted is assembled; A second chassis to which the second printed circuit board equipped with the secondary IF unit is assembled; The first chassis and the second chassis are formed of a single panel, and have a structure independent by a plurality of blocking panels, and a through capacitor electrically connecting the first chassis and the second chassis to the blocking panel. And the through capacitor is electrically connected to the inductor of the band pass filter and the primary IF amplifier of the secondary IF unit. The method of claim 1, The through capacitor, Connection structure of a double conversion type tuner, characterized in that fixed by the insulating material to be electrically separated from the blocking panel. The method of claim 1, The first printed circuit board and the second printed circuit board, Connection structure of a double conversion type tuner, characterized in that the fixing hole is fixed to the through capacitor is formed.