JPS6042481Y2 - UHF tuner resonator device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a resonator device using a microstrip line used in a UHF tuner of a television receiver.

Generally, a UHF tuner for a television receiver has a resonator using a microstrip transmission line in each of an antenna stage, a high frequency stage, a mixer stage, and a local oscillator stage.

Conventionally, as shown in FIG.
The F tuner has a laminated plate 2 installed inside an outer frame cover 1, and on the surface of this laminated plate 2 are formed an antenna stage microstrip transmission line 3, a high frequency stage microstrip transmission line 4, a mixer stage microstrip transmission line 5, and a local oscillator stage. A microstrip transmission line 6 is formed, and a ground pattern 7 is commonly formed on the back surface of the laminated plate 2.

Next, FIG. 2 shows an equivalent circuit of the first resonator 8 using the antenna stage microstrip transmission line 3 and the second resonator 9 using the high frequency stage microstrip transmission line 4.

That is, the antenna stage microstrip transmission line 3 is represented by inductances 10 and 11 and capacitance 12,
A termination capacitor consisting of a variable capacitance diode 13 and a series capacitor 14 is connected to the end of the antenna stage microstrip transmission line 3.

The inductances 10 and 11, the capacitance 12, and the terminating capacitance cause resonance at a desired frequency.

Similarly, the high frequency stage microstrip transmission line 4 is represented by inductances 15, 16 and capacitance 17,
A variable capacitance diode 18 and a series capacitor 19 are connected to its terminal end.
A terminating capacitor consisting of the following is connected.

It is resonated at a desired frequency by the inductance I L 16 SEI 7 and the termination capacitance.

Therefore, when the copper foil of the laminate 2 is used for the ground pattern 7, the copper foil is thin and the copper foil is scraped by the insertion holes of the parts, resulting in a circuit that has impedance with respect to the original ground. When a common ground pattern 7 is used for
The first resonator 8 and the second resonator 9 are coupled by the resistor 22, and the signals of each transmission line 3, 4 commonly move through the back ground pattern 7, so that each transmission line 3,
It becomes a connection between 4.

Similarly, transmission lines 5 and 6 are also coupled.

However, there are drawbacks such as an increase in local oscillation leakage voltage from the antenna and unstable operation of the high frequency amplifier circuit due to the coupling of the microstrip transmission lines in each stage of the UHF tuner.

The present invention was developed in view of the above points, and by allowing a resonant current to flow through each stage of the UHF tuner, it is possible to improve the local oscillation leakage voltage generated at the antenna terminal, and also to improve the local oscillation leakage voltage generated at the antenna terminal. It is an object of the present invention to provide a resonant device for a UHF tuner that can stabilize amplification.

Embodiments of the present invention will be described in detail below with reference to FIGS. 3 and 4.

That is, as shown in FIGS. 3a and 3b, a laminated plate 32 is attached within the outer frame 31 of the UHF tuner of the television receiver, and an antenna stage microstrip transmission line 33 is mounted on the surface of this laminated plate 32. , a high frequency stage microstrip transmission line 34, a mixer stage microstrip transmission line 35, and a local oscillator stage microstrip transmission line 36 are formed.

A first ground pattern 3 is provided on the back surface of the fjt layer plate 32 corresponding to the antenna stage microstrip transmission line 33.
7 is formed, the high frequency stage microstrip transmission line 34 and the mixer stage microstrip transmission line 35.
A second ground pattern 38 is formed on the back surface of the laminate 32 corresponding to the local oscillator stage microstrip transmission line 36, and a third ground pattern is formed on the back surface of the laminate 32 corresponding to the local oscillator stage microstrip transmission line 36.

Thus, the outer frame 31 is used as a reference earth electrode,
Each of the back ground patterns 37, 38, and 39 is grounded through soldering points 40 to 45, forming a circuit that is not directly connected to the back ground pattern.

That is, each transmission line 33. 34. By providing each ground pattern 37, 38, 39 for 35, 36, the antenna circuit is connected to the line 3 for the outer frame 31.
3 and pattern 37, between lines 34 and 35 and pattern 38 between stages, and between line 36 and pattern 39 in the local oscillation circuit, the coupling is small.

Furthermore, considering the case where the transmission line 34 has a positive charge, the second ground pattern 38 has a negative charge with respect to the reference outer frame 31.

At this time, the first ground pattern 37 has a negative charge caused by the transmission line 34 and a positive charge caused by the second ground pattern 38, and since the two cancel each other out, the first ground pattern 3
7 is not affected by the charges moving on the transmission line 34.

In other words, the coupling between the transmission lines 33 and 34 is smaller than in the conventional case.

FIG. 4 is an equivalent circuit of a first resonator 46 using an antenna stage microstrip transmission line 33 and a second resonator 47 using a high frequency stage microstrip transmission line 34.

That is, the antenna stage microstrip transmission line 33
is represented by inductances 48, 49 and capacitance 50, and a variable capacitance diode 51 is placed at the end of this transmission line 33.
A terminating capacitor consisting of a series capacitor 52 is connected, and the inductances 48, 49, capacitor i50, and terminating capacitor resonate at a desired frequency.

The first earth pattern 37 is represented by a capacitor 53 and a resistor 54, and the resonant current of the first resonator 46 is
flows.

Similarly, the high frequency stage microstrip transmission line 34
is represented by an inductance 55, 56 and a capacitance 57, and is resonated at a desired frequency by a terminal capacitance consisting of a variable capacitance diode 58 and a series capacitor 59 connected to the terminal end of the transmission line 34.

This resonant current flows through a capacitor 60 and a resistor 61 representing the second ground pattern 38.

Therefore, the resonant currents of each resonator 46, 47 do not flow through the same circuit, but through separate resistors 54, 61, resulting in reduced coupling.

Similarly, the mixer stage microstrip transmission line 35
The coupling of the resonator using the local oscillator stage and the resonator using the local oscillator stage microstrip transmission line 36 is reduced.

The above-mentioned effects of the present invention can be remotely achieved by basically making only the ground pattern of the local oscillator stage independent, and are included in the present invention.

As described above, according to the present invention, by reducing the coupling between the resonators in each stage of the UHF tuner, the local oscillation leakage voltage generated at the antenna terminal can be improved, and the amplification in the high frequency amplifier circuit can be stabilized. It is possible to provide a resonator device for a UHF tuner that can perform the following steps.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing a conventional UHF tuner resonator device, Fig. 2 is an equivalent circuit diagram showing a part of the resonator device in Fig. 1, and Fig. 3a shows an embodiment of the present invention. FIG. 3 is a cross-sectional view of FIG. 3A, and FIG. 4 is an equivalent circuit diagram showing a part of FIG. 3. 31...Outer frame, 32...Laminated plate, 33...Antenna stage microstrip transmission line, 34...High frequency stage microstrip transmission line, 35・・・・・・Mixer stage micros) I
J-tsubu transmission line, 36... Local oscillator stage microstrip transmission line, 37... First earth pattern, 38... Second earth pattern, 3
9...Third earth pattern.

Claims (1)

[Scope of utility model registration request] A U in which a substrate is provided within an outer frame, a plurality of microstrip transmission lines constituting resonators are formed on the surface of this substrate, and a ground pattern is formed on the back surface of the substrate.
1. A resonator device for a UHF tuner, characterized in that the ground pattern is separated corresponding to the resonator formed by the microstrip transmission line.