KR20100022313A - Tuning circuit in tuner - Google Patents
Tuning circuit in tuner Download PDFInfo
- Publication number
- KR20100022313A KR20100022313A KR1020080080934A KR20080080934A KR20100022313A KR 20100022313 A KR20100022313 A KR 20100022313A KR 1020080080934 A KR1020080080934 A KR 1020080080934A KR 20080080934 A KR20080080934 A KR 20080080934A KR 20100022313 A KR20100022313 A KR 20100022313A
- Authority
- KR
- South Korea
- Prior art keywords
- capacitor
- inductor
- tuning circuit
- tuner
- switching element
- Prior art date
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Classifications
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
- H03H7/01—Frequency selective two-port networks
- H03H7/0115—Frequency selective two-port networks comprising only inductors and capacitors
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03J—TUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS
- H03J3/00—Continuous tuning
- H03J3/02—Details
- H03J3/16—Tuning without displacement of reactive element, e.g. by varying permeability
- H03J3/18—Tuning without displacement of reactive element, e.g. by varying permeability by discharge tube or semiconductor device simulating variable reactance
- H03J3/185—Tuning without displacement of reactive element, e.g. by varying permeability by discharge tube or semiconductor device simulating variable reactance with varactors, i.e. voltage variable reactive diodes
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03J—TUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS
- H03J5/00—Discontinuous tuning; Selecting predetermined frequencies; Selecting frequency bands with or without continuous tuning in one or more of the bands, e.g. push-button tuning, turret tuner
- H03J5/24—Discontinuous tuning; Selecting predetermined frequencies; Selecting frequency bands with or without continuous tuning in one or more of the bands, e.g. push-button tuning, turret tuner with a number of separate pretuned tuning circuits or separate tuning elements selectively brought into circuit, e.g. for waveband selection or for television channel selection
- H03J5/242—Discontinuous tuning; Selecting predetermined frequencies; Selecting frequency bands with or without continuous tuning in one or more of the bands, e.g. push-button tuning, turret tuner with a number of separate pretuned tuning circuits or separate tuning elements selectively brought into circuit, e.g. for waveband selection or for television channel selection used exclusively for band selection
- H03J5/244—Discontinuous tuning; Selecting predetermined frequencies; Selecting frequency bands with or without continuous tuning in one or more of the bands, e.g. push-button tuning, turret tuner with a number of separate pretuned tuning circuits or separate tuning elements selectively brought into circuit, e.g. for waveband selection or for television channel selection used exclusively for band selection using electronic means
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N5/00—Details of television systems
- H04N5/44—Receiver circuitry for the reception of television signals according to analogue transmission standards
- H04N5/50—Tuning indicators; Automatic tuning control
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Input Circuits Of Receivers And Coupling Of Receivers And Audio Equipment (AREA)
Abstract
The present invention relates to a tuning circuit of a tuner.
The present invention includes an inductor and a capacitor connected to a switching element, a fixed capacitive element connected between the inductor and the capacitor, and a variable capacitive element connected to the switching element.
Description
The present invention relates to a tuning circuit of a 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.
An antenna of a multimedia A / V device (eg, analog television, digital television, etc.) receives various high frequency signals having UHF, VHF High, and VHF Low frequency bands. These high frequency signals are input tuned by the tuner's input tuning circuit.
An input tuning circuit that tunes the VHF low frequency is configured as shown in FIG.
As shown in FIG. 1, the VHF low input tuning circuit is connected to the gate G1 of the switching element TR1 (for example, the FET) in the order of the inductor L1, the varistor diode VD1, and the capacitor C1. The capacitor C2 is connected in parallel with the varactor diode VD1 between the inductor L1 and the capacitor C1.
A varistor diode VD2 and a capacitor C3 are connected between one end of the varistor diode VD1 and a ground terminal, and an inductor L1, a varactor diode VD1, and a varactor diode VD2 are connected. One end of the inductor L2 is connected to the contact point, and the other end of the inductor L2 is grounded.
In addition, a resistor R1 is connected in parallel between the contact point between the capacitor C1 and the capacitor C2 and the gate G1 of the switching element TR1, and between the varistor diode VD1 and the capacitor C1. The resistors R2 and R3 are connected to each other, and a resistor R4 is connected between the contacts of the resistors R2 and R3 and the contacts of the varistor diode VD2 and the capacitor C3.
In the conventional VHF low input tuning circuit configured as described above, when a signal is input through an antenna or a cable, the signal is passed through the capacitor C1 by the varistor diodes VD1 and VD2 and the capacitors C2 and C3. By tuning the tuning frequency, it is tuned to a particular channel.
That is, the varistor diodes VD1 and VD2 are variable capacitive elements whose capacitance is changed by the tuning voltage VT, also called variable capacitance diodes, and acting as capacitors to form an LC tuning circuit, thereby providing a desired frequency band. To receive.
However, when a strong signal (for example, about 45Mhz ~ 140Mhz) is input in the VHF low band, a strong electric field signal flows into the VHF low input tuning circuit, and thus, when an analog device is selected for twice the channel selection, In the case of screen noise and a digital device, screen cracking occurs.
The present invention prevents screen noise and cracking caused by the inflow of the strong electric field signal.
A tuning circuit of a tuner according to an embodiment of the present invention includes an inductor and a capacitor connected to a switching element, a fixed capacitive element connected between the inductor and a capacitor, and a variable capacitive element connected to the switching element. Can be.
The present invention can reduce the inflow of the strong field signal by configuring a series connected varistor diode between the signal input terminal and the switching element, through which the strong field signal is mainly introduced, by a capacitor, thereby preventing the occurrence of screen noise or cracking. .
Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.
2 is a VHF low input tuning circuit diagram in accordance with a preferred embodiment of the present invention.
As shown in FIG. 2, the VHF low input tuning circuit according to the embodiment of the present invention includes the inductor L10, the capacitor C100, and the capacitor C10 in order of the switching element TR10 (eg, the FET). The capacitor C20 is connected in series with the gate G1, and is connected in parallel with the capacitor C100 between the inductor L10 and the capacitor C10.
The varistor diode VD10 and the capacitor C30 are connected between one end of the capacitor C100 and the ground terminal, and an inductor is connected to the inductor L10 and the capacitor C100 and the varactor diode VD10. One end of the L20 is connected and the other end of the inductor L20 is grounded.
In addition, a resistor R10 is connected in parallel between the contact point between the capacitor C10 and the capacitor C20 and the gate G1 of the switching element TR10, and the resistor diode VD10 and the capacitor C30 One end of the resistor R30 is connected therebetween, and the other end of the resistor R30 is connected in parallel with the resistor R20.
In the VHF low input tuning circuit according to the embodiment of the present invention configured as described above, when a signal is input through an antenna or a cable, the signal is passed through the capacitor C10 and the capacitor C100 and the varistor diode VD10. The tuning frequency is varied by the capacitors C20 and C30, thereby tuning to a specific channel.
Here, the varistor diode VD10 is a variable capacitive element whose capacitance is changed by the tuning voltage VT, and serves as a capacitor to form an LC tuning circuit, thereby receiving a desired frequency band.
As described above, the present invention is composed of a capacitor C100 connected in series between a signal input terminal and a switching element in which a strong electric field signal mainly flows, thereby reducing the inflow of the strong electric field signal, thereby reducing screen noise or cracking. It can prevent occurrence.
By eliminating the series connected varistor diode and the resistor R2 connected to the varistor diode, the configuration can be simplified, and thus manufacturing cost can be reduced.
In addition, the varistor diode is driven by a tuning voltage, so that the noise can be reduced by deleting the series connected varistor diode.
As described above, in the detailed description of the present invention, specific embodiment (s) have been described, but various modifications are possible without departing from the scope of the present invention.
Therefore, the scope of the present invention should not be limited to the described embodiment (s), but should be defined by the claims below and equivalents thereof.
1 is a conventional VHF low input tuning circuit diagram.
2 is a VHF low input tuning circuit in accordance with a preferred embodiment of the present invention.
<Description of the code used in the main part of the drawing>
VD10: varistor diodes C10, C20, C30, C100: capacitors
L10, L20: Inductor R10, R20, R30: Resistor
TR10: switching element
Claims (6)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1020080080934A KR20100022313A (en) | 2008-08-19 | 2008-08-19 | Tuning circuit in tuner |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1020080080934A KR20100022313A (en) | 2008-08-19 | 2008-08-19 | Tuning circuit in tuner |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| KR20100022313A true KR20100022313A (en) | 2010-03-02 |
Family
ID=42174898
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| KR1020080080934A KR20100022313A (en) | 2008-08-19 | 2008-08-19 | Tuning circuit in tuner |
Country Status (1)
| Country | Link |
|---|---|
| KR (1) | KR20100022313A (en) |
-
2008
- 2008-08-19 KR KR1020080080934A patent/KR20100022313A/en not_active Application Discontinuation
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A201 | Request for examination | ||
| E902 | Notification of reason for refusal | ||
| E601 | Decision to refuse application |