KR101762949B1 - Circuit for Filter Switching - Google Patents

Circuit for Filter Switching Download PDF

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Publication number
KR101762949B1
KR101762949B1 KR1020100118676A KR20100118676A KR101762949B1 KR 101762949 B1 KR101762949 B1 KR 101762949B1 KR 1020100118676 A KR1020100118676 A KR 1020100118676A KR 20100118676 A KR20100118676 A KR 20100118676A KR 101762949 B1 KR101762949 B1 KR 101762949B1
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KR
South Korea
Prior art keywords
signal
saw filter
filter unit
diode
electrically connected
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KR1020100118676A
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Korean (ko)
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KR20120057094A (en
Inventor
윤영욱
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엘지이노텍 주식회사
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Priority to KR1020100118676A priority Critical patent/KR101762949B1/en
Publication of KR20120057094A publication Critical patent/KR20120057094A/en
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Publication of KR101762949B1 publication Critical patent/KR101762949B1/en

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Abstract

The present invention relates to a filter switching circuit.
A filter switching circuit according to an embodiment of the present invention receives a first signal from a switching Saw filter unit and a CTR stage and provides an input signal to a first input terminal of a switching Saw filter unit and a second input terminal of a switching Saw filter unit, And a signal controller for receiving a second signal different from the first signal and providing a reference signal to a second input terminal of the switching saw filter unit.

Description

[0001] The present invention relates to a filter switching circuit,

The present invention relates to a filter switching circuit.

The DVB-T broadcasting system has a channel bandwidth of 7 MHZ at 300 MHz or lower and a channel bandwidth of 8 MHz at 300 MHz or higher. Therefore, the DVB-T tuner was used by switching the Saw Filter to IF out and 7 / 8MHz.

Conventionally, in the Saw Filter Switching circuit, Saw Filter Switching was operated by controlling ON or OFF of the P5 terminal of the MOPLL IC.

On the other hand, in most of the Saw filters, the switching circuit operates, whereas in some Saw Filters, the switching circuit does not operate properly, and the Group delay characteristic and the filter characteristic are deteriorated .

It is an object of the present invention to provide a filter switching circuit capable of deteriorating Group Delay characteristics and Filter characteristics by disposing a signal control unit according to an embodiment.

The filter switching circuit according to the embodiment includes a switching Saw filter unit; And a second diode connected in series with the first diode. The first diode receives the first signal from the CTR terminal and receives the input signal to the first input terminal of the switching saw filter unit and the second input terminal of the switching saw filter unit A signal controller for receiving a second signal different from the first signal from the CTR stage and providing a reference signal to a second input of the switching saw filter unit; And a voltage distributor for dividing the voltage provided to the Vcc stage and applying a different voltage to the first input terminal of the switching Saw filter unit and the second input terminal of the switching Saw filter unit, The anode terminal of the second diode is electrically connected in common to the cathode terminal of the first diode and the second input terminal of the switching Saw filter section, 2 diode is electrically connected to a reference voltage source, and the voltage divider has one end of the first resistor electrically connected to the CTR stage, the other end of the first resistor is electrically connected to the Vcc stage, The other end of the second resistor is electrically connected to the Vcc terminal, and the third terminal of the third resistor is electrically connected to the third input terminal, One end of the resistor may be electrically connected to the VTR stage, and the other end of the third resistor may be electrically connected to the second input terminal.

The filter switching circuit according to the embodiment has an effect that the group delay characteristic and the filter characteristic can be deteriorated by arranging the signal control portion.

In addition, the filter switching circuit according to the embodiment has an effect that the reliability of the product can be improved by disposing the signal control unit to deteriorate the group delay characteristic and the filter characteristic.

1 is intended to describe a filter switching circuit according to an embodiment of the present invention.
FIG. 2 and FIG. 3 illustrate the operation of the filter switching circuit according to an embodiment of the present invention.

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

FIG. 1 is for explaining a filter switching circuit according to an embodiment of the present invention, and FIGS. 2 and 3 are for explaining the operation of a filter switching circuit according to an embodiment of the present invention.

Referring to FIG. 1, the filter switching circuit 100 according to an embodiment of the present invention includes a switching Saw filter unit 110, a signal controller 120, and a voltage distributor 130.

The switching saw filter unit 110 is operated to have a channel bandwidth of 7 MHZ at 300 MHz or lower and a channel bandwidth of 8 MHZ at 300 MHz or higher by receiving a predetermined signal from the CTR stage or the IF stage. The switching Saw filter unit 110 receives an input signal or a reference signal provided through a signal control unit 120 to be described later and turns on or off. At this time, the switching saw filter unit 110 may include a MOPLL IC.

The signal controller 120 receives the first signal or the second signal from the CTR terminal and provides the input signal or the reference signal to the switching saw filter unit 110. That is, the signal controller 120 receives the first signal from the CTR terminal and inputs the input signal to the first input terminal Input1 of the switching saw filter unit 110 and the second input terminal Input2 of the switching saw filter unit 110 And provides a reference signal to the second input terminal Input2 of the switching saw filter unit 110 by receiving a second signal different from the first signal from the CTR terminal. Here, the reference signal may be substantially equal to the ground voltage (GND).

At this time, the signal controller 120 includes a first diode D1 and a second diode D2 connected in series with the first diode D1. That is, the signal controller 120 is easily configured by the first diode D1 and the second diode D2. Accordingly, the anode terminal A of the first diode D1 is electrically connected to the first input terminal Input1 of the switching Saw filter unit 110, and the anode terminal A of the second diode D2 is electrically connected to the first input terminal And the cathode terminal K of the first diode D1 and the second input Input2 of the switching saw filter unit 110 are electrically connected in common.

The voltage divider 130 divides the voltage supplied to the Vcc stage and outputs different voltages to the first input Input1 of the switching Saw filter unit 110 and the second input Input2 of the switching Saw filter unit 110 It is to take. The voltage divider 130 includes at least one resistor R1, R2, and R3.

A different voltage is applied to the first input terminal Input1 of the switching saw filter unit 110 and the second input terminal Input2 of the switching saw filter unit 110 through the voltage distributor 130, The first signal and the second signal that are stable can be supplied to the signal control unit 120, thereby remarkably reducing malfunction of the signal control unit 120.

The connection relationship of the filter switching circuit 100 according to an embodiment of the present invention described above is as follows.

The other end of the first capacitor C1 is connected to one end of the second resistor R2 and the other end of the fourth resistor R4 is connected to the other end of the first diode D1. And the first input terminal Input 1 of the switching saw filter unit 110 are electrically connected in common. One end of the fourth resistor R4 is electrically connected to the reference voltage source GND.

The CTR stage is electrically connected to one end of the third resistor R3 of the first resistor R1 and the other end of the third resistor R3 is connected to the cathode terminal K of the first diode D1, The anode terminal A of the diode D2 and the second input terminal Input2 of the switching saw filter unit 110 are electrically connected in common. The cathode terminal K of the second diode D2 is electrically connected to the third input terminal Input3 of the switching saw filter unit 110 and the reference voltage source GND.

The VCC stage is electrically connected in common to the other end of the second resistor R2 of the first resistor R1.

The operation of the filter switching circuit 100 electrically connected in this way is as follows.

Referring to FIG. 2, a first signal is provided from a CTR stage. Referring to FIG. 3, a second signal is provided from a CTR stage.

First, when the first signal is provided from the CTR stage, a voltage of about 1 V is applied to the first input terminal Input1 of the switching saw filter unit 110 by the voltage distributor 130, And a voltage of about 0.3 V is applied to the second input terminal Input2 by the voltage distributor 130. [ The first diode D1 operates so that the first input terminal Input1 of the switching saw filter unit 110 and the second input terminal Input2 of the switching saw filter unit 110 are electrically connected to each other, Is supplied.

When the second signal is provided from the CTR stage, a voltage of about 1 V is applied to the first input terminal Input 1 of the switching saw filter unit 110 by the voltage distribution unit 130, And a voltage of about 0.8 V is applied to the second input (Input 2) by the voltage distributor 130. Accordingly, the first diode D1 does not operate and the second diode D2 operates. Accordingly, the second input (Input2) of the switching Saw filter unit 110 and the third input (Input3) of the switching Saw filter unit 110 are electrically connected and the reference signal is supplied.

As described above, the second input terminal Input2 of the switching saw filter unit 110 is connected to the AC GND and the DC GND (second input terminal) by using the first diode D1 and the second diode D2 constituting the signal control unit 120, It is possible to compensate for the deterioration of the Group Delay characteristic and the Filter characteristic.

That is, AC GND and DC GND are stably operated at the second input (Input 2) of the switching saw filter unit 110 through the first diode (D 1) and the second diode (D 2) It is possible to prevent the deterioration of the Group Delay characteristic and the Filter characteristic from occurring.

It will be understood by those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. Therefore, it should be understood that the above-described embodiments are to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than the foregoing description, It is intended that all changes and modifications derived from the equivalent concept be included within the scope of the present invention.

100: Filter switching circuit 110: Switching Saw filter unit
120: Signal control unit 130: Voltage distribution unit

Claims (6)

A switching saw filter unit;
And a second diode connected in series with the first diode. The first diode receives the first signal from the CTR terminal and receives the input signal to the first input terminal of the switching saw filter unit and the second input terminal of the switching saw filter unit A signal controller for receiving a second signal different from the first signal from the CTR stage and providing a reference signal to a second input of the switching saw filter unit; And
And a voltage distributor for distributing a voltage provided to the Vcc stage so that different voltages are applied to the first input terminal of the switching Saw filter unit and the second input terminal of the switching Saw filter unit,
Wherein the signal control unit is configured such that the anode terminal of the first diode is electrically connected to the first input terminal of the switching Saw filter unit and the anode terminal of the second diode is connected to the cathode terminal of the first diode and the second input terminal of the switching Saw filter unit, The cathode terminal of the second diode is electrically connected to the reference voltage source,
Wherein the voltage divider has a voltage dividing section that has one end of the first resistor electrically connected to the CTR stage, the other end of the first resistor being electrically connected to the Vcc terminal, one end of the second resistor being electrically connected to the first input terminal, The other end of the second resistor is electrically connected to the Vcc stage, the one end of the third resistor is electrically connected to the VTR stage, and the other end of the third resistor is electrically connected to the second input terminal.
The method according to claim 1,
Further comprising a first capacitor electrically connected at one end to the IF stage and electrically connected at the other end to the first input terminal.
The method according to claim 1,
Wherein the first diode is operated when the first signal is provided to the signal control unit, and the second diode is operated when the second signal is provided.
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KR1020100118676A 2010-11-26 2010-11-26 Circuit for Filter Switching KR101762949B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
KR1020100118676A KR101762949B1 (en) 2010-11-26 2010-11-26 Circuit for Filter Switching

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
KR1020100118676A KR101762949B1 (en) 2010-11-26 2010-11-26 Circuit for Filter Switching

Publications (2)

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KR20120057094A KR20120057094A (en) 2012-06-05
KR101762949B1 true KR101762949B1 (en) 2017-07-28

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Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2682010B2 (en) * 1988-05-30 1997-11-26 日本電気株式会社 Antenna shared circuit

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100328492B1 (en) * 1999-12-10 2002-03-16 송재인 Three band tracking filter for digital satellite broadcasting tuner
KR20080051609A (en) * 2006-12-06 2008-06-11 엘지이노텍 주식회사 Switching circuit of if saw filter
KR20090022004A (en) * 2007-08-29 2009-03-04 엘지이노텍 주식회사 Switching circuit of if saw filter

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2682010B2 (en) * 1988-05-30 1997-11-26 日本電気株式会社 Antenna shared circuit

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