JPH0846424A - Balanced oscillator and high frequency device using the same - Google Patents

Abstract

PURPOSE:To improve adjustment accuracy and to reduce spurious radiation or reception by forming first and second inductance by a coil and a printed pattern and oppositely arranging them to provide mutual inductance between them. CONSTITUTION:On a printed board 107, an IC 101 provided with a balanced type oscillation circuit 71, a coil 66 for adjustment composed of the coil connected between the first output terminal 62 of the IC 101 and a first ground pattern 111, a tuning pattern 70 composed of the printed pattern connected between a second output terminal 64 and a second ground pattern 112 and a serial circuit of vari-cap diodes 67 and 69 whose cathodes are connected each other between the first output terminal 62 and the second output terminal 64 are connected. Thus, the mutual inductance M generated between the coil 66 for the adjustment and the pattern 70 is varied by inclining the coil 66 for the adjustment towards the tuning pattern 70 and an oscillation frequency is adjusted without almost breaking the balance of a tuning circuit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a balanced oscillator and a high frequency device using the balanced oscillator.

[0002]

2. Description of the Related Art A conventional balanced oscillator will be described below.

A conventional oscillator is constructed as shown in FIG. That is, on a printed circuit board 507, an IC 501 including a balanced oscillation circuit and the IC 501.
The first output terminal 508 and the first ground pattern 511 of
And a second adjustment coil 506 provided between the second output terminal 510 of the IC 501 and the second ground pattern 512.
And the first output terminal 508 and the second output terminal 510.
And a series circuit of two varicap diodes 503 and 504 having cathodes connected to each other.

A resistor 502 is provided between the connection point 513 of the two varicap diodes 503 and 504 and the voltage control terminal 509 of the IC 501.

The adjustment of the oscillation frequency is performed by the first method.
Adjusting coil 505 and the second adjusting coil 506
This was done by adjusting the interval between and to change the mutual inductance.

11 (a), 11 (b), 11 (c), and 11 (d), the manner of adjustment by the adjustment coil in the conventional oscillator will be described.

FIG. 11A shows the state of FIG. 10 seen from the upper surface A, and FIG. 11B shows the state of FIG. 10 seen from the side surface B.

In FIGS. 11A and 11B, the ground pattern 557 of the printed board 507 is a metal frame 55.
5, the substrate 507 is provided with a first adjusting coil 505 and a second adjusting coil 506, the metal frame 555 is covered with covers 554 and 558,
The cover 554 is provided with a cover hole 551 for coil adjustment.

At this time, the first adjusting coil 505 and the second adjusting coil 506 are arranged with their winding axes in substantially the same direction, and the first adjusting coil 505 is also used.
And the outer diameter P of the second adjustment coil 506 is substantially the same, and the first adjustment coil 505 and the second adjustment coil 506 are
Is set to about 1/2 of the outer diameter P of the first adjusting coil 505 so as to have mutual inductance M.

FIGS. 11 (c) and 11 (d) show a state after adjustment by these two adjusting coils.

In FIGS. 11 (c) and 11 (d), the first
If the adjustment coil 505 is tilted toward the second adjustment coil 506 to adjust the distance between the two, the mutual inductance of both the first adjustment coil 505 and the second adjustment coil 506 will be ΔM. The oscillation frequency can be adjusted while maintaining the balance of the oscillator.

Specifically, the first adjusting coil 50 is used.
The variable range of the oscillation frequency by 5 is about 35 MHz, which is a sufficient value for the actually required variable range of 10 MHz, but mutual mutual inductance M is large and the change ΔM in mutual inductance during coil adjustment is large. As a result, the amount of change in frequency becomes large and it is difficult to finely adjust the oscillation frequency.

As one of the improvement methods, FIG. 11 (b)
In, it is conceivable to widen the distance U between the first adjusting coil 505 and the second adjusting coil 506. For example, the variable range of the oscillation frequency by the first adjusting coil 505 is about 35 MHz from the conventional value. From the experiment, the first adjustment coil 505 and the second adjustment coil 505 can be reduced to 1/2.
The distance U between the adjusting coils 506 must be increased from 0.5 times to 1.25 times, or about 2.5 times, the outer diameter P of the first adjusting coil 505.

That is, it occupies a large space on the printed circuit board as compared with the conventional example. Further, the radiation of the oscillating component from the adjustment coil deteriorates the performance, for example, by lowering the sensitivity of the BS tuner or increasing the noise amount.

Further, when one adjusting coil is adjusted by the adjusting rod, the other adjusting coil is touched.
It is necessary to further increase the cover hole 551 for adjusting the coil for adjusting the two adjusting coils 505 and 506 by more than about two times, and the unnecessary radiation and jumping due to the cover hole 551 affect the outside of the BS tuner. Receive and give.

[0016]

In such a conventional structure, the radiation of the oscillating component from the adjusting coils 505 and 506 deteriorates the performance, for example, by lowering the sensitivity of the BS tuner or increasing the noise amount. It was

Further, at the time of adjustment, an adjusting rod is put in the cover hole 551 for adjusting the coil and the two adjusting coils 505, 5 are provided.
Since the oscillation frequency is adjusted by changing the mutual inductance according to the interval of 06, the adjustment coil on the adjusted side is deformed, and the amount of change to the oscillation frequency at the time of coil adjustment is large and it is difficult to match the predetermined oscillation frequency. It was hanging.

Therefore, the cover hole 551 is large for adjustment of the coil, and on the other hand, it has to be small in order to cause interference due to unnecessary radiation and diving, which is a problem to be solved. Therefore, it is an object of the present invention to provide a device with high adjustment accuracy and less unwanted radiation and diving.

[0019]

In order to achieve this object, in the tuning circuit of the oscillator of the present invention, the first inductance is an adjusting coil composed of a winding coil, and the second inductance is a tuning composed of a printed pattern. The first inductance and the second inductance are opposed to each other so as to have mutual inductance.

[0020]

According to this structure, the first inductance is the winding coil and the second inductance is the printed pattern. Therefore, the adjustment coil seen from the cover hole has only one coil.
The oscillation frequency can be adjusted without worrying about the other adjustment coil as in the past, and the amount of change to the oscillation frequency when adjusting the coil can be reduced, so oscillation can be performed accurately with less man-hours. The frequency can be adjusted.

Further, by using the second inductance as a printed pattern and the opposite surface as a ground pattern, unnecessary radiation from the printed pattern of the second inductance can be reduced.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a BS tuner according to an embodiment of the present invention.

In FIG. 1, the BS tuner 14 comprises a down converter 12 and a demodulator 13. The down converter unit 12 includes an RF amplifier 2 connected to an input terminal 1, a mixer 3 to which the RF amplifier 2 and the first oscillator 8 are input, and an IF amplifier 4 connected to an output of the mixer 3. Consists of.

The demodulation section 13 includes a phase comparator 5 connected to the IF amplifier 4, a loop amplifier 6 connected to the phase comparator 5, and a video amplifier 7 connected to the loop amplifier 6. It comprises a low-pass filter (hereinafter referred to as LPF) 10 connected to the output of the loop amplifier 6 and the second oscillator 9 connected to the output of the LPF 10, and the output of the second oscillator 9 is compared with the phase comparator. Input to the vessel 5.

The output of the video amplifier 7 is connected to the output terminal 11. Next, the operation will be described. An input signal from the BS antenna is amplified by the RF amplifier 2 through the input terminal 1 and is then input to the mixer 3.

The signal input to the mixer 3 is frequency-converted by the first oscillator 8 and the IF amplifier 4
After being amplified by the phase comparator 5, the loop amplifier 6, the LPF 10, and the second oscillator 9, the demodulation unit 13 demodulates the demodulated component, and the demodulation component is amplified by the video amplifier 7 and It is output from the output terminal 11.

FIG. 2 is a detailed view of the second oscillator 9. FIG. 2 shows a balanced oscillator circuit 71 and a tuning circuit 72 that determines the oscillation frequency.

First, the balanced oscillator circuit 71 will be described. The transistors 53 and 54 form a differential amplifier circuit, and the emitters thereof are both connected to the ground terminal 63 through the constant current source 60.

The collector of the transistor 54 is connected to a first output terminal 62 via a capacitor 55, and the first output terminal 62 is connected to the base of the transistor 53 via a capacitor 56.

Further, the collector of the transistor 53 is connected to the second output terminal 64 via the capacitor 58, and the second output terminal 64 is connected to the base of the transistor 54 via the capacitor 57.

The voltage applied to the voltage supply terminal 61 is applied to the transistor 5 via the resistors 51 and 52, respectively.
3 and 54, and the output of the amplifier circuit 59 of the loop amplifier is connected to the voltage control terminal 65.

Next, the tuning circuit 72 will be described.
An adjustment coil 66 provided between the first output terminal 62 and the ground pattern, a tuning pattern 70 provided between the second output terminal 64 and the ground pattern, the first output terminal 62 and the first pattern. It is composed of a series circuit of varicap diodes 67 and 69 whose cathodes are connected between the two output terminals 64.

Further, a resistor 68 is provided between the connection point between the two varicap diodes 67 and 69 and the voltage control terminal 65.

With the above configuration, the transistor 53
And 54 form a balanced oscillation circuit, and positive feedback is applied by the capacitors 55, 56, 57 and 58,
The oscillation frequency is mainly determined by the adjusting coil 66, the tuning pattern 70, and the two varicap diodes 67 and 69 in the tuning circuit 72.

FIG. 3 is a perspective view of an essential portion of the second oscillator according to the present invention shown in FIG. In FIG. 3, an IC 10 including a balanced oscillator circuit 71 on a printed circuit board 107.
1, an adjusting coil 66 composed of a winding coil connected between the first output terminal 62 of the IC 101 and the first ground pattern 111, the second output terminal 64, and the second ground pattern 112. A tuning pattern 70 composed of a print pattern connected between the first output terminal 6 and the tuning pattern 70.
A series circuit of varicap diodes 67 and 69 having cathodes connected to each other is connected between 2 and the second output terminal 64.

A resistor 68 is provided between the voltage control terminal 65 and the connection point 113 between the two varicap diodes 67 and 69.

Next, how the adjusting coil 66 adjusts the oscillation frequency will be described with reference to FIG. FIG. 4A shows FIG.
Is viewed from the upper surface A of the cover, and FIG. 4B is a view of FIG. 3 viewed from the side surface B.

In FIGS. 4A and 4B, the metal frame 255 is connected to the ground pattern 257 of the printed board 107 by soldering, and the upper surface is covered with the metal covers 254 and 258. A cover hole 251 for coil adjustment is provided in 254.

At this time, the direction of the winding axis of the adjusting coil 66 and the tuning pattern 253 are positioned substantially parallel to each other, and the distance Q from the adjusting coil 66 to the outside of the tuning pattern 70 is the above. It is equal to or less than the outer diameter P of the adjusting coil 66.

However, at this time, it is considered that the adjusting coil 66 does not float above the printed circuit board 107.

As a result, the mutual inductance M generated between the adjusting coil 107 and the tuning pattern 70 is reduced by tilting the adjusting coil 107 toward the tuning pattern 70. The amount of change can be varied by ΔM, and as a result, the oscillation frequency can be adjusted without breaking the balance of the tuning circuit.

In FIGS. 4 (c) and 4 (d), FIG.
9B and 9B show the state after the adjustment coil is tilted toward the set of tuning patterns for adjustment.

4 (a), (b), (c), and (d), the tuning coil 66 to the tuning pattern 7 are used.
The distance Q to the outside of 0 is the outer diameter P of the adjusting coil 66.
The case of setting about 1/2 of the above will be described.

With this setting, the mutual inductance M between the adjusting coil 66 and the tuning pattern 70 is increased.
Can be reduced to about 1/2 of that of the conventional example, and the change ΔM in mutual inductance can be reduced to 1/2 of that of the conventional example. Further, the variable range of the oscillation frequency by the adjusting coil 66 at that time is about 18 MHz, which is sufficient for the actually required variable range of 10 MHz.

That is, the sensitivity to the frequency change by the adjusting coil can be set to about 1/2 of the conventional example, and the oscillation frequency can be adjusted with high accuracy.

Further, as is clear from FIG. 4A, only one adjustment coil 66 can be seen through the adjustment cover hole 251, and the adjustment coil 66 is tilted for adjustment, so that adjustment is easy. In addition, the adjustment cover hole can be made smaller, and unnecessary radiation and diving can be improved.

In FIGS. 5A and 5B, as shown in FIGS.
The case where the ground pattern is provided on the surface opposite to the printed pattern forming the inductance of the tuning circuit is shown in FIG.

In FIGS. 5A and 5B, the metal frame 255 is a ground pattern 307 of the printed circuit board 107.
Is connected by soldering to the metal frame 255
Is covered with metal covers 254 and 258, and a cover hole 251 for coil adjustment is provided in the metal cover 254.

An adjustment coil 66 and a tuning pattern 70 are placed on the printed circuit board 107 in the same positional relationship as in FIGS. 4A and 4B, and the ground pattern 307 is provided on the opposite surface of the tuning pattern 70. To form a microstrip line.

As a result, the level of unnecessary radiation emitted from the inductance of the tuning pattern 70 is reduced.

FIG. 6 is a perspective view of an essential part of the second oscillator according to the present invention shown in FIG. 2, showing a case where the shapes of the print patterns forming the tuning pattern are different.

In FIG. 6, on a printed circuit board 357, an IC 101 including a balanced oscillation circuit, and this IC
The adjustment coil 66 connected between the first output terminal 62 of 101 and the ground pattern 111, and the second output terminal 6
4 and a ground pattern 112, and a tuning pattern 356, and varicap diodes 67 and 69 having cathodes connected in series between the first output terminal 62 and the second terminal 64. To do.

A resistor 68 is provided between the voltage control terminal 65 and the connection point 113 between the two varicap diodes 67 and 69.

The manner in which the oscillation frequency is adjusted by the adjusting coil 66 will be described with reference to FIGS. 7 (a) and 7 (b).

FIG. 7A is a view of FIG. 6 viewed from the upper surface A of the cover, and FIG. 7B is a view of FIG. 6 viewed from the side surface B.

In FIGS. 7A and 7B, the metal frame 255 is the ground pattern 4 of the printed circuit board 357.
07 is connected by soldering, and 408, 409, 4
A case where the earth pattern 407 is placed on the opposite surface of the substrate of the tuning pattern 356 made of 10 or the like is shown.

The metal frame 255 is a metal cover 25.
8 and 254, the metal cover 254 is provided with a cover hole 251 for coil adjustment.

At this time, the U-shaped tuning pattern 356 of 408 to 410 is provided so as to face the tuning coil 66.

Specifically, the tuning pattern portion 410 farthest from the adjustment coil 66 is positioned substantially parallel to the winding direction of the adjustment coil 66, and one of the tuning pattern portions 410 is provided on one side. This tuning pattern part 4
10, a tuning pattern portion 409 is connected in the direction of the adjustment coil 66 substantially at a right angle to 10, and a tuning pattern portion 408 is provided at the other end of the tuning pattern portion 410 at a substantially right angle to the tuning pattern portion 410. Adjustment coil 6
Connect in direction 6.

At this time, the relationship between the outer diameter P of the winding portion of the adjusting coil 66 and the dimension R from the adjusting coil 66 to the outside of the tuning pattern portion 410 is approximately P ≧ R.
Further, the length S of the tuning pattern portion 410 is approximately P ≦ S.

As a result, the tuning pattern portion 40
8 and 409 and 410 all have mutual inductance with the adjusting coil 66,
By setting the R and S, it is possible to select the frequency adjustment range and the adjustment accuracy when adjusting the coil.

FIG. 8 and FIG. 9 show the case where the shapes of the tuning patterns composed of 408, 409 and 410 of FIG. 7 (a) which are one embodiment of the present invention are different.

In FIG. 8, a cover hole 251 for adjustment is provided in the metal cover 254, and an adjustment coil 66 made of a winding coil and a zigzag tuning pattern 454 made of a printed pattern are provided.

At this time, the dimension V from the adjusting coil 66 to the outside of the tuning pattern 454 is set to be substantially equal to or less than the outer diameter P of the adjusting coil 66.

As a result, the mutual inductance between the adjusting coil 66 and the tuning pattern 454 is
It can be set larger than the mutual inductance shown in FIG. 7A, which is an embodiment of the present invention, and the frequency adjustment range and adjustment accuracy at the time of coil adjustment can be selected.

In FIG. 9, a cover hole 251 for adjustment is provided in the metal cover 254, an adjustment coil 66 made of a winding coil and a tuning pattern 454 made of a spiral print pattern are provided, and the central portion thereof is provided. Connect to ground pattern 475.

At this time, the dimension W from the adjusting coil 66 to the outside of the tuning pattern 474 is set to be substantially equal to or less than the outer diameter P of the adjusting coil 66.

As a result, the mutual inductance between the adjusting coil 66 and the tuning pattern 474 becomes
It can be set larger than the mutual inductance shown in FIG. 7A, which is an embodiment of the present invention, and the frequency adjustment range and adjustment accuracy at the time of coil adjustment can be selected.

[0069]

As described above, according to the tuning circuit of the oscillator of the present invention, the first inductance is the adjusting coil made of the winding coil, and the second inductance is the tuning pattern made of the microstrip line. While being formed, the first and second inductances are arranged so as to face each other so as to have mutual inductance, and the adjustment coil is tilted toward the inductance for adjustment.

As a result, the number of adjustment coils seen from the cover hole is one, and adjustment can be performed without having to worry about the other coil as in the conventional case, so that the adjustment cover hole can be made small and unnecessary radiation or jumping can occur. An effective design for interference is possible.

Furthermore, the configuration of the tuning circuit including the tuning pattern made of the microstrip line and the adjustment coil makes it possible to set the optimum variation amount of the mutual inductance at the time of the adjustment, and the oscillation frequency can be adjusted with high accuracy. By using a microstrip line for the tuning circuit, the leakage of oscillation components from the tuning circuit can be greatly reduced.

As described above, by adopting the present invention, it is possible to provide a high frequency device having an excellent balanced oscillator at low cost.

[Brief description of drawings]

FIG. 1 is a block diagram showing a BS tuner according to an embodiment of the present invention.

FIG. 2 is a circuit diagram of a second oscillator of the BS tuner.

FIG. 3 is a perspective view of a main part of a second oscillator of the BS tuner.

4 (a) shows a state before adjustment by the coil of FIG.
The top view of the cover of FIG. 3 seen from the upper surface A is a state before adjustment by the coil of FIG. 3, and the cross-sectional view of the side view B of FIG. 3 is a state after adjustment by the coil of FIG. 3D is a top view seen from the upper surface A of the cover of FIG. 3, (d) is a cross-sectional view seen from the side surface B of FIG. 3 after adjustment with the coil of FIG.

5A is a top view of another embodiment corresponding to FIG. 4A, and FIG. 5B is a cross-sectional view of another embodiment corresponding to FIG. 4B.

FIG. 6 is a perspective view of a main part of a second oscillator of the BS tuner.

7 (a) shows a state before adjustment by the coil of FIG.
The top view seen from the upper surface A of the cover (b) is a cross-sectional view seen from the side surface B of the cover before adjustment by the coil of FIG.

FIG. 8 is a top view of another embodiment of the tuning pattern.

FIG. 9 is a top view of another embodiment of the tuning pattern.

FIG. 10 is a perspective view of a main part of a second oscillator of a conventional BS tuner.

11A is a top view of the state before adjustment by the coil of FIG. 10, viewed from the upper surface A of the cover, and FIG. 11B is a state of the state before adjustment by the coil of FIG. 10, viewed from the side surface B of the cover. Sectional view (c) is a top view showing a state after adjustment with the coil of FIG. 11 (a). (D) is a sectional view showing a state after adjustment with the coil of FIG. 11 (b).

[Explanation of symbols]

 1 Input Terminal 9 Second Oscillation Circuit 11 Output Terminal 12 Down Converter 13 Demodulator 62 First Output Terminal 64 Second Output Terminal 66 Adjustment Coil 67 Varicap Diode 69 Varicap Diode 70 Tuning Pattern 71 Balanced Type Oscillation circuit 72 Tuning circuit

Claims (4)

[Claims] 1. A balanced oscillation circuit and a tuning circuit provided on an output side of the balanced oscillation circuit, wherein the tuning circuit is provided between a first output terminal of the balanced oscillation circuit and a first ground. An adjusting coil formed of a wound coil connected to the first and second terminals, a tuning pattern including a printed pattern connected between a second output terminal of the balanced oscillator circuit and a second ground, and A capacitance connected between the first output terminal and the second output terminal, a mutual inductance is provided between the adjustment coil and the tuning pattern, and the mutual inductance is provided by the adjustment coil. Balanced oscillator that can adjust the oscillation frequency by changing the inductance. 2. The balanced oscillator according to claim 1, wherein a tuning pattern composed of a printed pattern is formed on one surface of the printed circuit board, and an earth pattern is arranged on the opposite surface side. 3. An input terminal, a down converter section connected to this input terminal, a demodulation section connected to this down converter section, and an output terminal connected to this demodulation section. A high frequency device provided with the balanced oscillator according to claim 1. 4. An input terminal, a down converter section connected to this input terminal, a demodulation section connected to this down converter section, and an output terminal connected to this demodulation section. A high frequency device provided with the balanced oscillator according to claim 2.