JPH11196344A - Television tuner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve image interference characteristic at a low band by surely attenuating a signal of image frequency corresponding to a received signal not only at a high band but also at a low band. SOLUTION: A peaking circuit 26 having a switch diode 28 and a peaking coil 27 is provided between a signal transmission line 30 for connecting a secondary turning circuit 3b to a mixer 2 and the ground, one end of the diode 28 is connected to the transmission line 30 and the coil 27 is connected to the ground. A 1st capacitance means 36 is provided between the other end side of a high band tuning coil 4 of a primary tuning circuit 3a and the transmission line 30, a 2nd capacitance means 37 is provided between the other end side of the tuning coil 4 of the circuit 3a and the other end of the diode 28, and at the time of receiving a television signal of a high band, the diode 28 is electrically conducted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a television tuner in which a tuning circuit can be switched between a high band and a low band, and more particularly to an image signal and a low band for a high band television signal. A television tuner for attenuating an image signal with respect to a band television signal.

[0002]

2. Description of the Related Art FIG. 5 is a circuit diagram for explaining a conventional television tuner. In FIG. 5, between the high-frequency amplifier 51 and the mixer 52, an interstage double-tuned circuit (hereinafter, referred to as a "multi-tuned circuit") is provided.
53) is provided. The primary tuning circuit 53a includes a high-band tuning coil 54 and a low-band tuning coil 55 connected in series to each other by one end, and a high-band tuning coil 54 and a low-band tuning coil 55 connected in series. It has a varactor diode 56 connected in parallel. The varactor diode 56 has its anode grounded and its cathode connected to the other end of the high-band tuning coil 54 via a DC blocking capacitor 57. Similarly, the secondary tuning circuit 53b also includes a high-band tuning coil 58 and a low-band tuning coil 59 connected in series with one end, and a high-band tuning coil 58 and a low-band tuning coil 58 connected in series. A varactor diode 60 is connected in parallel with the tuning coil 59. The varactor diode 60 has its anode grounded and its cathode connected to the other end of the high band tuning coil 58 via a DC blocking capacitor 61. The other ends of the low-band tuning coils 55 and 59 are connected to one end of a coupling coil 62, and the other end of the coupling coil 62 is grounded by a DC blocking capacitor 63.

The connection point between the high-band tuning coil 54 and the low-band tuning coil 55 in the primary tuning circuit 53a is connected to the cathode of a switch diode 64, whose anode is a DC blocking capacitor. Similarly, the connection point between the high-band tuning coil 58 and the low-band tuning coil 59 in the secondary tuning circuit 53b is also connected to the cathode of the switch diode 66 and its anode. Are grounded by a DC blocking capacitor 67.

[0004] Then, the switch diode 64
The switch diode 66 is connected to the high band switching terminal 69 via the resistor 70, and the anode of the switch diode 66 is similarly connected to the high band switching terminal 69 via the resistor 70. A connection point between the coupling coil 62 and the DC blocking capacitor 63 is connected to a low band switching terminal 72 via a resistor 71. In addition, varactor diodes
The tuning voltage from the tuning voltage terminal 73 is applied to the cathode of the varactor diode 60 via the resistor 74. Similarly, the tuning voltage from the tuning voltage terminal 73 is also applied to the cathode of the varactor diode 60 by the resistor 75. Is applied via the

[0005] A peaking circuit 76 is provided between the double tuning circuit 53 and the mixer 52. Peaking circuit 7
6 is DC-blocked from the double tuning circuit 53 by a DC blocking capacitor 77 and DC-blocked from the mixer 52 by a DC blocking capacitor 78. The peaking circuit 76 has a configuration in which a peaking coil 79, a switch diode 80, and a DC blocking capacitor 81 are connected in series, and the peaking coil 79 is connected to DC blocking capacitors 77, 78. DC blocking capacitor 81
Is grounded at one end. The cathode of the switch diode 80 is connected to the low band switching terminal 72 via the resistor 82, and the anode is connected to the high band switching terminal 69 via the resistor 83. The inductance of the peaking coil 79 is set to resonate with the frequency of the low-band television signal of the high-band television signal in cooperation with the input capacitance 84 of the mixer 52.

Further, between the primary tuning circuit 53a and the secondary tuning circuit 53b, more specifically, the other end of the high band tuning coil 54 of the primary tuning circuit 53a, the DC blocking capacitor 77 and the DC blocking capacitor 78 peaking. A small-capacity capacitor 85 is connected between the connection point to the coil 79. Since the capacitor 85 has a small capacity, it is constituted by using conductor electrodes formed on a printed circuit board (not shown) constituting a television tuner, for example.
This capacitor 85 forms a parallel resonance circuit together with the high-band tuning coil 54 in the primary tuning circuit 53a and the high-band tuning coil 58 in the secondary tuning circuit 53b when receiving a high-band television signal. It traps (attenuates) an image signal corresponding to a television signal, and its resonance frequency is a television signal having a higher frequency among high-band television signals, for example, a channel W of the United States specification (frequency is about 300 MHz). Is set so as to coincide with the image frequency (about 386 MHz).

In the above configuration, when a high-band television signal is received, a switch diode is applied by a switching voltage applied to a high-band switching terminal 69.
When the dual tuning circuit 53 is set to receive a high-band television signal and the low-band television signal is received, the switching voltage applied to the low-band switching terminal 72 is set. Thus, the switch diodes 64 and 66 are both non-conductive, and the double tuning circuit 53 is set to a state for receiving a low-band television signal. The tuning voltage applied to the tuning voltage terminal 73 causes the double tuning circuit 53 to tune to a desired frequency.

On the other hand, when a high band television signal is received, the switch diode of the peaking circuit 76 is used.
Is turned on. As a result, a parallel tuning circuit is formed by the peaking coil 79 and the input capacitance 84 of the mixer 52, and tunes to the lower frequency of the high-band television signal, and The level of the television signal is prevented from lowering. The frequency characteristics (transmission characteristics) at the input end of the mixer 52 at the time of reception of the high-band channel W are as shown by curve A in FIG. 4. At approximately 300 MHz, the maximum transmission level is reached. About three times the frequency
Attenuates at 86 MHz. This attenuated frequency is the trap frequency Ft1, which is just the image frequency (386 MHz).
z). The trap frequency Ft1 is based on the parallel resonance frequency of the capacitor 85 and the high-band tuning coil 54 in the primary tuning circuit 53a and the high-band tuning coil 58 in the secondary tuning circuit 53b.

[0009]

However, in the conventional television tuner, when the double tuning circuit 53 is switched to the low band receiving state, the high band tuning coil 54 in the primary tuning circuit 53a and the low band tuning coil are connected. The tuning 55 for the band is connected in series with the tuning coil 58 for the high band and the tuning coil 5 for the low band in the secondary tuning circuit 53b.
9 is in series. Therefore, these four tuning coils 5
A capacitor 85 is connected in parallel to the entirety of 4, 55, 58, 59 to form a parallel resonance circuit. for that reason,
The resonance frequency of this parallel resonance circuit has become lower, and the frequency has become lower than the frequency of an image signal for a low-band television signal. For example, in the low-band channel B (frequency is about 130 MHz), the image frequency is approximately 219 MHz, but as shown in curve B in FIG. 4, the resonance frequency of the parallel resonance circuit, that is, the trap frequency Ft2 is About 153 MHz, 21
It is not sufficiently attenuated at an image frequency of 9 MHz.
For this reason, the image interference characteristic in the low band has been deteriorated.

Therefore, the television tuner of the present invention reliably attenuates the image frequency signal with respect to the received signal not only in the high band but also in the low band, thereby achieving image interference characteristics in the low band. The aim is to improve.

[0011]

In order to solve the above-mentioned problems, a television tuner according to the present invention comprises a high-band tuning coil and a low-frequency tuning coil connected in series with each other by one end.
A primary tuning circuit having a tuning coil for a band, a double tuning circuit having a secondary tuning circuit having a tuning coil for a high band and a tuning coil for a low band connected in series by one end, and the secondary tuning circuit. , A switch diode and a peaking coil connected in series with each other, and connected between a signal transmission line connecting the secondary tuning circuit and the mixer and a grant. A switching circuit having one end connected to the signal transmission line and the peaking coil connected to the ground, and a high-band tuning coil of the primary tuning circuit and a switch. The connection point between the band tuning coil and the connection point between the high band tuning coil and the low band tuning coil of the secondary tuning circuit is a high band television signal; Grounded when receiving, providing a first capacitance means between the other end of the high-band tuning coil of the primary tuning circuit and the signal transmission line, and providing other than the high-band tuning coil of the primary tuning circuit. A second capacitance means is provided between the end and the other end of the switch diode so that the switch diode conducts when a high-band television signal is received.

Further, the television tuner of the present invention comprises:
A first conductive electrode connected to the signal transmission line and a second conductive electrode connected to the other end of the switch diode; And a third conductor electrode connected to the high-band tuning coil of the primary tuning circuit and disposed opposite the first conductor electrode, and a high-band tuning coil of the primary tuning circuit. A fourth conductor electrode connected to the second conductor electrode and disposed opposite to the second conductor electrode is formed on the printed circuit board, and the first capacitance means is connected to the first conductor electrode and the third conductor electrode. And the second capacitance means is composed of the second conductor electrode and the fourth conductor electrode.

Further, the television tuner of the present invention comprises:
A first conductive electrode connected to the signal transmission line and a second conductive electrode connected to the other end of the switch diode; Forming a third conductive electrode connected to the high-band tuning coil of the primary tuning circuit and disposed opposite to the first conductive electrode on the printed circuit board; One capacitance means is constituted by the first conductor electrode and the third conductor electrode, and the second capacitance means is constituted by the second conductor electrode and the third conductor electrode.

[0014]

FIG. 1 is a circuit diagram for explaining a television according to the present invention. In FIG. 1, an interstage double tuning circuit (hereinafter simply referred to as double tuning circuit) 3 is provided between the high-frequency amplifier 1 and the mixer 2. The primary tuning circuit 3a includes a tuning coil for high band 4 and a tuning coil for low band 5 connected in series by one end.
And a varactor diode 6 connected in parallel to the high-band tuning coil 4 and the low-band tuning coil 5 connected in series. Varactor diode 6
The anode is grounded, and the cathode is connected via a DC blocking capacitor 7 to the other end of the tuning coil 4 for high band. Similarly, the secondary tuning circuit 3b also includes a high-band tuning coil 8 and a low-band tuning coil 9 connected in series to each other by one end, and a high-band tuning coil 8 and a low-band tuning coil 8 connected in series. A varactor diode 10 is connected in parallel with the tuning coil 9. The varactor diode 10 has its anode grounded and its cathode connected to the other end of the high-band tuning coil 8 via a DC blocking capacitor 11. The other ends of the low-band tuning coils 5 and 9 are connected to one end of a coupling coil 12, and the other end of the coupling coil 12 is grounded by a DC blocking capacitor 13.

The connection point between the high-band tuning coil 4 and the low-band tuning coil 5 in the primary tuning circuit 3a is connected to the cathode of the switch diode 14, and its anode is a DC blocking capacitor. Similarly, the connection point between the high-band tuning coil 8 and the low-band tuning coil 9 in the secondary tuning circuit 3b is also connected to the cathode of the switch diode 16 and its anode. Are grounded by a DC blocking capacitor 17.

Then, the switch diode 14 is turned on.
The anode of the switch diode 16 is connected to the high band switching terminal 17 via the resistor 20 in the same manner. A connection point between the coupling coil 12 and the DC blocking capacitor 13 is connected to a low band switching terminal 22 via a resistor 21. In addition, varactor diodes
A tuning voltage from a tuning voltage terminal 23 is applied to a cathode of the node 6 through a resistor 24, and similarly, a varactor diode is connected.
The tuning voltage from the tuning voltage terminal 23 is also applied to the cathode of the node 10 via the resistor 25.

A peaking circuit 26 is provided between the double tuning circuit 3 and the mixer 2. That is, the peaking circuit 26 has a peaking coil 27, a switch diode 28, and a DC blocking capacitor 29 connected in series to each other, and the secondary tuning circuit 3b of the double tuning circuit 3 and the mixer 2 Is connected between the signal transmission path 30 and the ground. The peaking circuit 26 is connected to the secondary tuning circuit 3b of the double tuning circuit 3 by a DC blocking capacitor 31.
The DC current is blocked by the DC blocking capacitor 32 from the mixer 2. The cathode of the switch diode 28 is connected to the DC blocking capacitors 31 and 32, and one end of the DC blocking capacitor 29 is grounded. The cathode of the switch diode 28 is connected to the low band switching terminal 2 via the resistor 33.
2 and a connection point between the peaking coil 27 and the DC blocking capacitor 29 is connected to the high band switching terminal 19 via the resistor 34. Peaking coil 27
Is set so as to resonate with the frequency of the low-band television signal of the high-band television signal in cooperation with the input capacitance 35 of the mixer 2.

Further, between the primary tuning circuit 3a and the secondary tuning circuit 3b, more specifically, the other end of the high-band tuning coil 4 of the primary tuning circuit 3a, a DC blocking capacitor 31, a DC blocking capacitor 32, and a switch diode. A first capacitor 36, which is a small-capacity first capacitance means, is connected between a connection point of the cathode 28 and the cathode (that is, a cathode which is one end of the switch diode 28). ing. further,
Between the other end of the high-band tuning coil 4 of the primary tuning circuit 3a and the anode which is the other end of the switch diode 28, a second capacitor 37, which is a small-capacity second capacitance means, is provided. It is connected. Since the capacitance values of the first capacitor 36 and the second capacitor 37 are small, they can be formed by using, for example, conductor electrodes formed on a printed circuit board constituting a television tuner. is there.

That is, as shown in FIG. 2, on a printed circuit board 40 on which at least the double tuning circuit 3 and the peaking circuit 26 are formed, a first diode connected to a cathode of a switch diode 28 is provided. Conductor electrode 41 and switch diode 2
8, a third conductor electrode 43 connected to the other end of the high-band tuning coil 4 in the primary tuning circuit 3a, and a high-band tuning coil as well. 4th conductive electrode 4 connected to the other end of 4
4 and the first conductor electrode 41 and the third conductor electrode 4
3 constitutes a first capacitance means which becomes the first capacitor 36, and a second capacitor 37 which becomes the second capacitor 37 by causing the second conductor electrode 42 and the fourth conductor electrode 44 to face each other. The second capacitance means is constituted. With this configuration, the first capacitance means 36 and the second capacitance means 37 can be configured without using discrete parts (individual parts).
Can be downsized. Also, because it is composed of conductor electrodes,
Capacitance means having an extremely small capacitance value can be provided. In this case, the fourth conductor electrode 44 is deleted, and as shown in FIG.
And the second conductor electrode 42 are opposed to each other to constitute a first capacitance means by the first conductor electrode 41 and the third conductor electrode 43, and the second conductor electrode and the third conductor electrode 43 May constitute the second capacitance means. This eliminates the need for the fourth conductor electrode 44, so that the area of the printed circuit board 40 can be reduced. With the above configuration, when the switch diode 28 is turned on, the primary tuning circuit 3a and the secondary tuning circuit 3b of the double tuning circuit 4 are connected in a state where the first capacitor 36 and the second capacitor 37 are connected in parallel. When the switch diode 30 is off, the primary tuning circuit 3a and the secondary tuning circuit 3b are connected.
And only the first capacitor 36 is connected between them.

In the above configuration, when a high-band television signal is received, the switch diode is switched by the switching voltage applied to the high-band switching terminal 19.
And the connection points of the high-band tuning coil 4 and the low-band tuning coil 5 in the primary tuning circuit 3a are connected to the ground at high frequency.
By connecting the connection point between the high-band tuning coil 8 and the low-band tuning coil 9 in the secondary tuning circuit 3b to the high frequency ground, the double tuning circuit 3 is set to a state for receiving a high-band television signal. Become. Also,
Since the switch diode 28 of the king circuit 26 conducts, a parallel tuning circuit is formed by the peaking coil 27 and the input capacitance 35 of the mixer 2, and tunes to the lower frequency of the high band television signal. , The level of a low-frequency television signal input to the mixer 2 is prevented from lowering. At this time, the first capacitor 36 and the second capacitor 37 are connected in parallel, and the high-band tuning coil 4 in the primary tuning circuit 3a and the high-band tuning coil in the secondary tuning circuit 3b are connected. A first capacitor 36 and a second capacitor 37 connected in series and connected in parallel to the series-connected high-band tuning coils 4 and 8 are connected in parallel to form a parallel resonance circuit. In this case, the sum of the capacitance value of the first capacitor 36 and the capacitance value of the second capacitor 37 is determined by the image of the parallel resonance circuit with respect to the high frequency television signal of the high band television signals. -Set to the frequency of the digital signal.

Accordingly, the frequency characteristic (transmission characteristic) at the input end of the mixer 2 when receiving a high-band television signal (for example, channel W in the United States) is as follows:
As shown in curve A of FIG.
The transmission level becomes the maximum at z and attenuates at the image frequency of about 386 MHz. This attenuated frequency is the trap frequency Ft1, which is just the image frequency (38
6 MHz).

On the other hand, when a low-band television signal is received, both the switch diodes 14 and 16 are turned off by the switching voltage applied to the low-band switching terminal 22, and the high-level signal in the primary tuning circuit 3a is turned on. The band tuning coil 4 and the low band tuning coil 5 are connected in series, and similarly, the high band tuning coil 8 and the low band tuning coil 9 in the secondary tuning circuit 3b are connected in series. The tuning circuit 3 is set to receive a low-band television signal, and the switch diode 28 of the peaking circuit 26 is turned off. Then, the peaking circuit 26 is disconnected from the signal transmission line 30 connecting the secondary tuning circuit 3b and the mixer 2. At this time, the high-band tuning coil 4 and the low-band tuning coil 5 in the primary tuning circuit 3a and the high-band tuning coil 8 in the secondary tuning circuit 3b are used.
And the low-band tuning coil 9 are connected in series. The series-connected high-band tuning coil 4, low-band tuning coil 5, high-band tuning coil 8, and low-band tuning coil 9 are connected in series. The first capacitor 36 for the whole
Are connected in parallel to form a parallel resonance circuit. In this case, the capacitance value of the first capacitor 36 is a high-range television signal (for example, channel B) of the low-band television signals whose resonance frequency of the parallel resonance circuit is low.
Of the image signal with respect to (approximately 219 MHz)
It is set so that

As a result, the frequency characteristic (transmission characteristic) at the input end of the mixer 2 at the time of receiving the low-band channel B is as shown by curve B in FIG.
The transmission level becomes maximum at 0 MHz, and attenuates at about 219 MHz, which is the image frequency. This attenuated frequency is the trap frequency Ft2, which exactly matches the image frequency (219 MHz).

The tuning voltage terminal 23 is used for both receiving a high-band television signal and receiving a low-band television signal.
Is tuned to a desired frequency by the tuning voltage applied to the double tuning circuit 3.

[0025]

As described above, according to the television tuner of the present invention, the switch diode and the peaking coil are provided between the grant and the signal transmission line connecting the secondary tuning circuit and the mixer. A switching circuit having one end connected to the signal transmission line.
The king coil is connected to the ground, the first capacitance means is provided between the high-band tuning coil of the primary tuning circuit and the signal transmission path, and the other end of the high-band tuning coil of the primary tuning circuit is connected to the switch diode. The second capacitance means is provided between the other end of the switch and the switch diode when the high band television signal is received, so that when the high band television signal is received. Is
The frequency of the image signal to be attenuated by the first capacitance means and the second capacitance means is set, and the image signal to be attenuated by the first capacitance means when a low-band television signal is received. Frequency can be set. Therefore,
The image signal for the high band television signal and the image signal for the low band television signal can be effectively attenuated.

Further, the television tuner of the present invention comprises:
A first conductor electrode connected to a signal transmission line, having a printed circuit that forms a double tuning circuit and a peaking circuit,
A second conductor electrode connected to the other end of the switch diode; and a third conductor electrode connected to the high-band tuning coil of the primary tuning circuit and arranged opposite to the first conductor electrode. Forming a fourth conductor electrode connected to the high-band tuning coil of the primary tuning circuit and facing the second conductor electrode on a printed circuit board, and forming the first capacitance means as the first capacitor means. Since the second capacitance means is composed of the second conductor electrode and the fourth conductor electrode, the first capacitance means and the second capacitance means are used without using components. And a capacitance means. Therefore, the size of the tuner can be reduced.

Further, the television tuner of the present invention comprises:
A first conductor electrode connected to a signal transmission line, having a printed circuit that forms a double tuning circuit and a peaking circuit,
A second conductor electrode connected to the other end of the switch diode; and a third conductor electrode connected to the high-band tuning coil of the primary tuning circuit and arranged opposite to the first conductor electrode. Is formed on a printed circuit board, the first capacitance means is constituted by a first conductor electrode and a third conductor electrode, and the second capacitance means is constituted by a second conductor electrode and a third conductor electrode. Therefore, the number of conductor electrodes constituting the first capacitance means and the second capacitance means is reduced, and the size of the tuner can be further reduced.

[Brief description of the drawings]

FIG. 1 is a circuit diagram illustrating a television tuner of the present invention.

FIG. 2 is an image in the television tuner of the present invention.
FIG. 4 is an explanatory diagram for explaining a configuration of a trap capacitor for attenuating a signal.

FIG. 3 is an image in the television tuner of the present invention.
FIG. 4 is an explanatory diagram for explaining a configuration of a trap capacitor for attenuating a signal.

FIG. 4 is a transmission characteristic diagram of the television of the present invention.

FIG. 5 is a circuit diagram illustrating a conventional television tuner.

FIG. 6 is a transmission characteristic diagram of a conventional television.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 High frequency amplifier 2 Mixer 3 Double tuning circuit 3a Primary tuning circuit 3b Secondary tuning circuit 4,8 Tuning coil for high band 5,9 Tuning coil for low band 6,10 Varactor diode 7,11,13,15 , 17, 29, 31, 32 DC blocking capacitor 12 Coupling coil 14, 16, 28 Switch diode 18, 20, 21, 24, 25, 33, 34 Resistance 19 High band switching terminal 22 Low band switching terminal 23 Synchronization Voltage terminal 26 Peaking circuit 27 Peaking coil 30 Signal transmission line 35 Input capacitance 36 First capacitor 37 Second capacitor 40 Printed circuit board 41 First conductor electrode 42 Second conductor electrode 43 Third conductor electrode 44 Fourth conductor electrode

Claims (3)

[Claims] 1. A primary tuning circuit having a high-band tuning coil and a low-band tuning coil connected in series to each other by one end, and a high-band tuning coil and a low-band tuning coil connected in series to each other by one end. A double tuning circuit having a secondary tuning circuit having a tuning coil;
A signal transmission line connecting the secondary tuning circuit and the mixer, the mixer including a mixer connected to the secondary tuning circuit, a switch diode and a peaking coil connected in series to each other, and a grant And a peaking circuit connected between the signal line and one end of the switch diode, the peaking coil being connected to the ground, and a high band of the primary tuning circuit. The connection point between the tuning coil for low band and the tuning coil for low band and the connection point between the tuning coil for high band and the tuning coil for low band of the secondary tuning circuit are used when receiving a high band television signal. Grounding, providing a first capacitance means between the other end of the high-band tuning coil of the primary tuning circuit and the signal transmission line, and the other end of the high-band tuning coil of the primary tuning circuit and the A second capacitive means provided between the other end of the switch diode and the switch diode to conduct when a high-band television signal is received; . 2. A switch according to claim 1, further comprising a printed circuit which forms the double tuning circuit and the peaking circuit, wherein the first conductive electrode is connected to the signal transmission line and the other end of the switch diode. A second conductor electrode connected thereto, a third conductor electrode connected to the high-band tuning coil of the primary tuning circuit and arranged opposite to the first conductor electrode, and Forming a fourth conductor electrode connected to the tuning coil for high band and arranged opposite to the second conductor electrode on the printed circuit board, and forming the first capacitance means on the first conductor; 2. The television tuner according to claim 1, wherein the first and second conductors are constituted by an electrode and the third conductor electrode, and the second capacitance means is constituted by the second conductor electrode and the fourth conductor electrode. -Na. 3. A switch according to claim 1, further comprising a printed circuit for forming said double tuning circuit and said peaking circuit, wherein said first conductor electrode is connected to said signal transmission path and said other end of said switch diode. The connected second conductor electrode and a third conductor electrode connected to the high-band tuning coil of the primary tuning circuit and arranged opposite to the first conductor electrode on the printed circuit board. Formed, the first capacitance means is constituted by the first conductor electrode and the third conductor electrode, and the second capacitance means is constituted by the second conductor electrode and the third conductor electrode. The television tuner according to claim 1, wherein the television tuner is configured.