JPH07312522A - Adjustment device for voltage controlled oscillator - Google Patents

Abstract

PURPOSE:To realize the adjustment device for the voltage controlled oscillator by which the center frequency is adjusted with high accuracy. CONSTITUTION:In the adjustment device for a voltage controlled oscillator whose resonance circuit is formed by connecting one terminal of a strip line 14 to ground and connecting the other terminal to a resonance capacitor 3 and an oscillation active element 1, the effective length of the strip line is changed by cutting off any of plural ground pattern lines 10, 11, 12 interconnecting the long side of the strip line and an earth pattern. Thus, the oscillated frequency range of the voltage controlled oscillator is roughly adjusted thereby. Furthermore, the the oscillated frequency range of the voltage controlled oscillator is fine-adjusted by changing the thickness of at least one of adjustment lands 15, 16 provided on a resonance circuit and to change the thickness of the pattern through the adhesion of a conductor such as solder so as to change the inductive component of the resonance circuit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adjusting device for a voltage controlled oscillator (hereinafter referred to as VCO) used in mobile communication equipment and the like.

[0002]

2. Description of the Related Art Conventionally, a VCO circuit used in a mobile communication device such as a mobile phone is constructed, for example, as shown in FIG. This prior art is basically based on a Colpitts type oscillation circuit using a grounded collector type oscillation amplifier, in which a part of the capacitor is replaced with a varactor diode 1 to form a VCO. A stripline resonator 2 is used as the resonance inductor L.

This VCO has a resonance circuit section composed of a varactor diode 1, an inductor (L) 2, and a capacitor (C1) 3, a capacitor (C2) 4, and a capacitor (C
3) It can be regarded as a combination of an oscillation amplifier unit composed of 5, a capacitor (C4) 6, a resistor (R2) 7 and a transistor 8.

Here, the equivalent capacitance when looking at the oscillation amplifier section from the point A is CAMP, the capacitance of the varactor diode 1 is CVD,
If the equivalent inductance of the stripline resonator 2 is L, the oscillation frequency f0 of the VCO is

[0005]

[Equation 1]

It is represented by CVD is varactor diode 1
Since it changes according to the tuning voltage VT applied to one end of the resistor via the resistor (R1) 9, f0 can be changed according to VT.

Now, it is necessary to adjust the variable range of the VCO so that it oscillates in a necessary frequency range according to the system used. VC with low oscillation frequency or narrow variable range
In the case of O, the oscillation frequency can be adjusted by replacing the capacitor (C1) 3 with a trimmer capacitor or connecting a trimmer capacitor in parallel with the varactor diode 1. However, when the oscillation frequency is as high as about 1.6 GHz and the variable range requires a wide range of 20 MHz or more, such as a personal handyphone system (PHS) or a personal digital cellular system (PDC), deterioration of the Q value due to the trimmer capacitor occurs. As a result, there are problems that the oscillation stop phenomenon occurs and the variable range cannot be secured due to variations in parts. Therefore, the VCO used in the above system is generally a stripline resonator 2
The center frequency is adjusted by changing the equivalent inductance value L by adjusting the length of.

FIG. 5 shows an example of the pattern layout of the VCO. The stripline resonator 2 has a ground pattern 10,
Grounding is provided at 11 and 12, and a stub pattern 13 is added on the left side of the grounding pattern 10. The stub pattern 13 can be cut at any position such as P1, P2 and P3.

When adjusting the center frequency, the ground pattern 1
The frequency is adjusted by cutting 0, 11, 12 to change the resonator length or cutting a part of the stub pattern 13 to change the stub length.

[0010]

However, in the conventional VCO as described above, the pitches of the cut points P1 to P3 of the ground patterns 10, 11, 12 and the stub pattern 13 are adjusted in order to accurately adjust the center frequency. It was necessary to set it up in detail. For example, in the VHS for PHS, it is necessary to suppress the variation of the center frequency to several MHz, but in order to realize this, the pitch of the cut points P1 to P3 of the ground patterns 10, 11, 12 and the stub pattern 13 should be 100 μm or less. Must be set. Therefore, conventionally, these cuttings have been performed by laser trimming.

In the laser trimming method, the equipment cost is high and the unit cost of the VCO is increased, and since the trimming adjustment direction is one direction, it is impossible to adjust the trimming once excessively and the yield is high. There was a problem of lowering.

[0012]

SUMMARY OF THE INVENTION The present invention solves the above problems of the prior art by connecting one end of a stripline to ground and the other end to a resonance capacitor and an active element for oscillation. In a voltage-controlled oscillator adjusting device that constitutes a resonance circuit, a plurality of ground / ground pattern lines that connect the long side of the strip line and an earth pattern, and a conductor such as solder that is provided on the resonance circuit. At least one or more adjustment lands for changing the thickness of the pattern by
Roughly adjusting the oscillation frequency range of the voltage-controlled oscillator by cutting the ground pattern line and changing the effective length of the strip line, and changing the thickness of the adjustment land by soldering to change the inductor component of the resonance circuit. It is characterized in that the oscillation frequency range is finely adjusted by changing it.

[0013]

[Function] The effective length of the strip line is changed by cutting the ground pattern line, the oscillation frequency range is roughly adjusted, and the inductor of the resonance circuit is changed by changing the amount of solder attached to the adjustment land. Then, the oscillation frequency range is finely adjusted.

[0014]

EXAMPLES Examples of the present invention will be described below. FIG. 1 is a circuit diagram of a voltage control oscillator adjusting device according to the present invention, and FIG. 2 is a pattern layout diagram thereof. The same components as those of the conventional technique shown in FIG. 4 are designated by the same reference numerals, and the description thereof will be omitted.

The stripline resonator 14 is grounded by the ground pattern lines 10, 11 and 12. 1
5 and 16 are capacitors (C1) 3 which are part of the resonance circuit section
The adjustment lands are formed on both sides of the adjustment land, and the thickness is changed by attaching solder to the adjustment lands to adjust the oscillation frequency range as described later.

The ground pattern lines 10, 11, 12 are VC
It is arranged for coarse adjustment of the O center frequency. That is, the length of the stripline resonator 14 is changed by sequentially cutting the ground pattern lines 10, 11 and 12, and the center frequency is changed accordingly. V for PHS
In the case of CO, if the space between the ground pattern lines 10, 11 and 12 is 0.4 mm, the center frequency changes by 20 to 30 MHz every time one pattern is cut. By this coarse adjustment, the frequency is adjusted to be lower than and close to the target center frequency.

The ground pattern for coarse adjustment may be constructed as shown in FIG. That is, 17a, 18a, and 19a are first short-circuit lands formed by being led out from the stripline resonator 14, and these short-circuit lands 17 are formed.
Second shorting lands 17b, 18b, 19b are formed at positions facing a, 18a, 19a, respectively. The rough adjustment of this embodiment is performed by the first short-circuit lands 17a, 18
a, 19a and the second short circuit lands 16b, 17b, 18
This is done by bridging b and b with conductors 19, respectively.

The adjustment lands 15 and 16 are arranged for fine adjustment of the VCO center frequency. The adjustment land 1
If the inductances of 5 and 16 are LR1 and LR2, the oscillation frequency fo is

[0019]

[Equation 2]

[0020]

When a conductor such as solder is attached on the adjustment lands 15 and 16, the thickness of the adjustment lands 15 and 16 increases, and as a result, the inductance of the adjustment lands slightly decreases. The inductance value at this time is LR1 '＋ LR
2 ',

[0022]

[Equation 3]

Considering f1 ² such that

[0024]

[Equation 4]

The following holds. That is, the VCO frequency f0 'when the inductance value is changed to LR1' + LR2 'is

[0026]

[Equation 5]

The relationship of [1] is satisfied and the inductance value is LR1.
Increases more than + LR2.

Conversely, by removing the conductors on the adjustment lands 15 and 16, the inductance value becomes larger than LR1 + LR2 and the VCO frequency decreases.

As described above, since the VCO frequency can be adjusted with an accuracy equal to or lower than the rate of change of the inductance value, the fine adjustment range can be set by appropriately determining the ratio of the pattern area of the adjustment lands 15 and 16 and the area where the conductor is attached. I can decide.

The solder is attached and removed by the ground pattern 1
Unlike 0, 11, and 12 cutting, continuous control is possible, so that frequency adjustment can be performed continuously. Further, since the frequency can be adjusted freely in both the upper and lower directions, the yield will not be lowered due to excessive adjustment unlike the conventional case.

In the case of PHS, since a frequency shift of about 30 MHz is possible by this fine adjustment, a conductor is attached if the frequency is adjusted to the closest lower frequency than the target center frequency by the coarse adjustment of the resolution of 20 to 30 MHz described above. Accurate frequency adjustment is completed.

The fine adjustment lands are not limited to the positions in FIGS. 1 and 2, but may be any number on the connection of the stripline resonator 14, the capacitor (C1) 3 and the varactor diode 1, and the number thereof is arbitrary. Can be set to.

[0033]

As described above, according to the adjusting device for a voltage controlled oscillator according to the present invention, the center frequency can be adjusted accurately without using expensive equipment, and in the fine adjustment step, the conductor is attached. Since the increase and decrease of the center frequency can be freely controlled by performing both the work of removing the VCO and the process of removing the VCO, there is an effect that the VCO can be provided without lowering the yield as in the conventional case.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an adjusting device for a voltage controlled oscillator according to the present invention.

FIG. 2 is a pattern layout diagram of a voltage controlled oscillator adjustment device according to the present invention.

FIG. 3 is a pattern layout diagram showing another embodiment of the present invention.

FIG. 4 is a circuit diagram of a voltage-controlled oscillator adjusting device according to the prior art.

FIG. 5 is a pattern layout diagram of a voltage controlled oscillator adjusting device according to a conventional technique.

[Explanation of symbols]

1 Oscillation Active Element (Varactor Diode) 3 Resonance Capacitor (Capacitor C1) 10, 11, 12 Ground Pattern Line 14 Stripline Resonator 15, 16 Adjustment Land 17a, 18a, 19a First Shorting Land 17b, 18b, 19b Second short circuit land

Claims (2)

[Claims] 1. An adjusting device for a voltage controlled oscillator, wherein a resonance circuit is configured by grounding one end of a strip line and connecting the other end to a resonance capacitor and an active element for oscillation, wherein a long side of the strip line is provided. And a plurality of ground pattern lines for connecting the ground pattern to the ground pattern, and at least one or more adjustment lands provided on the resonance circuit for changing the pattern thickness by attaching a conductor such as solder. , The ground pattern line is cut and the effective length of the strip line is changed to roughly adjust the oscillation frequency range of the voltage controlled oscillator, and the thickness of the adjustment land is changed by soldering to change the inductance component of the resonance circuit. Adjustment device for a voltage controlled oscillator, characterized in that the oscillation frequency range is finely adjusted by changing Place 2. An adjusting device for a voltage controlled oscillator, wherein a resonance circuit is constituted by grounding one end of a strip line and connecting the other end to a resonance capacitor and an active element for oscillation, wherein a long side of the strip line is provided. At least one or more first short-circuiting lands, a second short-circuiting land electrically connected to the ground pattern at a position facing the first short-circuiting land, and on the resonance circuit. At least one land for changing the thickness of the pattern by attaching a conductor such as solder, and electrically connecting the opposing first and second shorting lands to each other. By roughly adjusting the oscillation frequency range of the voltage controlled oscillator by changing the effective length of the line, and changing the thickness of the land by soldering. A fine tuning of the oscillation frequency range is performed by changing the inductance component of the resonance circuit.