JP3132297B2 - Balance type oscillator and high frequency device using it - Google Patents

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 same.

[0002]

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

A conventional oscillator is configured as shown in FIG. That is, on a printed circuit board 507, an IC 501 including a balanced oscillation circuit, and the IC 501
First output terminal 508 and first ground pattern 511
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 a connection point 513 between the two varicap diodes 503 and 504 and a voltage control terminal 509 of the IC 501.

The adjustment of the oscillation frequency is performed by the first
Adjustment coil 505 and the second adjustment coil 506
This is done by adjusting the distance between them and varying the mutual inductance.

FIGS. 11 (a), 11 (b), 11 (c) and 11 (d) show how adjustment is performed by adjusting coils in a conventional oscillator.

FIG. 11A shows a state in which FIG. 10 is viewed from the upper surface A, and FIG. 11B shows a state in which FIG.

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

At this time, the first adjusting coil 505 and the second adjusting coil 506 are arranged with the winding axes substantially in the same direction, and the first adjusting coil 505
The outer diameter P of the first adjustment coil 506 and the second adjustment coil 506 are substantially the same.
Are set to about １ ／ of the outer diameter P of the first adjusting coil 505 so that mutual inductance M is provided.

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

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

More specifically, the first adjusting coil 50
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. However, the mutual inductance M is large, and the mutual inductance change ΔM during coil adjustment is small. As a result, the amount of change in the frequency becomes large, and it is difficult to finely adjust the oscillation frequency.

As one of the improvement methods, FIG.
It is conceivable to increase the interval U between the first adjusting coil 505 and the second adjusting coil 506 in, for example, the variable range of the oscillation frequency by the first adjusting coil 505 is reduced from the conventional 35 MHz to about 35 MHz. According to experiments, the first adjusting coil 505 and the second
The distance U between the adjustment coils 506 must be increased to about 2.5 to 1.25 times the outer diameter P of the first adjustment coil 505.

That is, more space is occupied on the printed circuit board than in the conventional example. In addition, the radiation of the oscillating component from the adjustment coil has deteriorated the performance, for example, by lowering the sensitivity of the BS tuner or increasing the amount of noise.

Further, when one adjusting coil is adjusted by the adjusting rod, the other adjusting coil corresponds to the other adjusting coil.
It is necessary to further increase the coil adjusting cover hole 551 for adjusting the two adjusting coils 505 and 506 by about twice or more. Unnecessary radiation and jumping in by the cover hole 551 affect the outside of the BS tuner. Receive or give.

[0016]

In such a conventional configuration, the radiation of the oscillating component from the adjusting coils 505 and 506 causes, for example, a decrease in the sensitivity of the BS tuner or an increase in the amount of noise, thereby deteriorating the performance. Was.

At the time of adjustment, an adjusting rod is inserted into the cover hole 551 for adjusting the coil, and the two adjusting coils 505, 5
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.

For this reason, the cover hole 551 is large for adjusting the coil, but must be small in order to cause unnecessary radiation and interference due to diving, which is a problem to be solved. Accordingly, it is an object of the present invention to provide a device having high adjustment accuracy and less unnecessary radiation and diving.

[0019]

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

[0020]

According to this structure, the first inductance is formed by a winding coil and the second inductance is formed by a printed pattern.
It is possible to adjust the oscillation frequency without having to worry about the other adjustment coil as before, and the amount of change to the oscillation frequency during coil adjustment can be reduced, so that oscillation can be performed with less man-hours and with high accuracy The frequency can be adjusted.

Furthermore, them to the surface opposite to the ground pattern with the second inductance on the printed pattern
If, reducing unnecessary radiation from the second printed pattern
It is possible to make.

[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 one embodiment of the present invention.

In FIG. 1, the BS tuner 14 comprises a down converter 12 and a demodulator 13. The down-converter section 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 to an output of the mixer 3. Consists of

The demodulation unit 13 includes a phase comparator 5 connected to the IF amplifier 4, a loop amplifier 6 connected to the phase comparator 5, 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. The output of the second oscillator 9 Input to the container 5.

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

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

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

First, the balanced oscillation circuit 71 will be described. Transistors 53 and 54 form a differential amplifier circuit, and both emitters are connected to ground terminal 63 through 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 a second output terminal 64 via a capacitor 58, and the second output terminal 64 is connected to the base of the transistor 54 via a capacitor 57.

The voltage applied to the voltage supply terminal 61 is applied to the transistor 5 via 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 adjusting 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; And a series circuit of varicap diodes 67 and 69 having their cathodes connected to the second output terminal 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 adjustment 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 a main part of the second oscillator according to the present invention shown in FIG. In FIG. 3, an IC 10 including a balanced oscillation circuit 71 is provided on a printed circuit board 107.
1, an adjustment coil 66 composed of a winding coil connected between the first output terminal 62 of the IC 101 and the first ground pattern 111, a second output terminal 64 and a second ground pattern 112, A tuning pattern 70 consisting of a printed pattern connected between the first output terminal 6
A series circuit of varicap diodes 67 and 69 having their cathodes connected to each other is connected between the second output terminal 64 and the second output terminal 64.

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

Next, how the oscillation frequency is adjusted by the adjusting coil 66 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.

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

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 interval Q from the adjusting coil 66 to the outside of the tuning pattern 70 is equal to the aforementioned value. It should be equal to or less than the outer diameter P of the adjusting coil 66.

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

Thus, the mutual inductance M generated between the adjustment coil 107 and the tuning pattern 70 is reduced by tilting the adjustment coil 107 toward the tuning pattern 70. The variation can be varied by ΔM at a time, and as a result, the oscillation frequency can be adjusted without almost losing the balance of the tuning circuit.

In FIGS. 4C and 4D, FIG.
7A and 7B show a state after adjusting the adjustment coil by tilting the adjustment coil toward a set of tuning patterns.

4 (a), 4 (b), 4 (c) and 4 (d), the tuning pattern 7
0 to the outside diameter P of the adjusting coil 66.
A description will be given of a case where the value is set to about 1/2 of the value.

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

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

Further, as is apparent from FIG. 4A, only one adjustment coil 66 is visible from the adjustment cover hole 251. Since the adjustment coil 66 is tilted for adjustment, adjustment is easy. In addition, the size of the adjustment cover hole can be reduced, and unnecessary radiation and dive can be improved.

In FIGS. 5A and 5B, FIGS.
(B) shows a case where an earth pattern is provided on the opposite surface of the printed pattern constituting the inductance of the tuning circuit.

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

On the printed circuit board 107, the adjusting coil 66 and the tuning pattern 70 are placed 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.

Thus, the level of unnecessary radiation emitted from the inductance of the tuning pattern 70 is reduced.

FIG. 6 is a perspective view of a main part of the second oscillator according to the present invention shown in FIG. 2, showing a case where the shape of a printed pattern constituting a tuning pattern is different.

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

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

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.

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

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

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

More specifically, the tuning pattern portion 410 farthest from the adjusting coil 66 is positioned substantially parallel to the direction of the winding of the adjusting coil 66, and one of the tuning pattern portions 410 This tuning pattern part 4
A tuning pattern portion 409 is connected in a direction substantially perpendicular to the direction of the adjusting coil 66, and a tuning pattern portion 408 is formed substantially perpendicular to the tuning pattern portion 410 at the other end of the tuning pattern portion 410. Adjustment coil 6
Connect in the direction of 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 substantially P ≧ R.
In addition, the length S of the tuning pattern portion 410 is substantially P ≦ S.

Thus, the tuning pattern portion 40
8 and 409 and 410 all have mutual inductance with the adjusting coil 66,
By setting R and S, the frequency adjustment range and adjustment accuracy at the time of coil adjustment can be selected.

FIGS. 8 and 9 show a case in which the shape of the tuning pattern composed of 408, 409 and 410 of FIG. 7A according to an embodiment of the present invention is different.

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

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

Thus, the mutual inductance between the adjusting coil 66 and the tuning pattern 454 becomes
The mutual inductance in FIG. 7A, which is one embodiment of the present invention, can be larger than that of FIG. 7A, and the frequency adjustment range and the adjustment accuracy at the time of coil adjustment can be selected.

In FIG. 9, an adjustment cover hole 251 is provided in the metal cover 254, and an adjustment coil 66 composed of a winding coil and a tuning pattern 454 composed of a spiral print pattern are 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 substantially equal to or smaller than the outer diameter P of the adjusting coil 66.

Thus, the mutual inductance between the adjusting coil 66 and the tuning pattern 474 becomes
The mutual inductance in FIG. 7A, which is one embodiment of the present invention, can be larger than that of FIG. 7A, and the frequency adjustment range and the 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 an adjusting coil composed of a winding coil, and the second inductance is a tuning pattern composed of a microstrip line. The first and second inductances are formed so as to be opposed to each other so as to have a mutual inductance, and the adjustment coil is adjusted by tilting toward the inductance.

As a result, the number of adjusting coils as viewed from the cover hole becomes one, and the adjustment can be performed without worrying about the other coil as in the conventional case. An effective design against disturbance is possible.

Further, the back side of the printed circuit board is grounded.
If the turn, the configuration of tuning circuit consisting of a tuning pattern consisting of a microstrip line and the adjustment coil, can set the amount of change in optimal mutual inductance during adjustment, it is possible to better adjust the system of oscillation frequency .
The leakage of the oscillation component from the tuned circuit by using a microstrip line to a tuning circuit can be greatly reduced.

As described above, by employing the present invention, it is possible to provide a high-frequency device having a low-cost and excellent balance-type oscillator.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a BS tuner according to one 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. 3,
3B is a top view of the cover as viewed from the top A, and FIG. 3B is a cross-sectional view as viewed from the side B of FIG. 3 before adjustment by the coil of FIG. (D) is a cross-sectional view of the state after adjustment by the coil of FIG. 3 as viewed from the side surface B 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.

7A shows a state before adjustment by the coil of FIG. 6,
6B is a cross-sectional view of the state before adjustment by the coil of FIG. 6 as viewed from the side surface B of the cover.

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

[Explanation of symbols]

 Reference Signs List 1 input terminal 9 second oscillation circuit 11 output terminal 12 down converter section 13 demodulation section 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

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-4-806 (JP, A) JP-A-3-214906 (JP, A) JP-A-63-67031 (JP, A) JP-A-6-670 291548 (JP, A) JP-A-6-291549 (JP, A) JP-A-4-290005 (JP, A) JP-A-61-162127 (JP, U) JP-A-59-31205 (JP, U) (58) Field surveyed (Int.Cl. ⁷ , DB name) H03B 5/00-5/28 H04B 1/26 H03H 7/01

Claims (4)

(57) [Claims] 1. A pre-mounting device mounted in a metal frame.
A balanced oscillation circuit mounted on a printed circuit board, a tuning circuit connected to the output side of the balanced oscillation circuit ,
And a metal cover over the metal frame.
The balanced oscillation circuit forms a differential amplifier circuit.
First and second transistors, and the first and second transistors
Transistor emitter connected and ground
A constant current source connected to the second transistor;
A first capacitor connected between the first output terminal and the first output terminal.
A capacitor; the first output terminal; and the first transistor.
A second capacitor connected between the
The collector of the first transistor and the second output terminal
A third capacitor connected between the second capacitor and the second output terminal
Connected between the transistor and the base of the second transistor.
A fourth capacitor, a power supply terminal and the first transformer.
A first resistor connected between the transistor and the collector of the transistor;
The power supply terminal and a collector of the second transistor
And a second resistor connected between said tuning circuit, said first output terminal and the adjustment coil consisting of a winding coil connected to the between the first ground, the first Output 2
A tuning pattern consisting of a printed pattern connected between a terminal 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 adjusting coil and the tuning pattern, and the adjusting cover is provided on the cover.
A balanced type oscillator having a cover hole and adjusting the mutual inductance with the adjusting coil from the cover hole to enable adjustment of the oscillation frequency. 2. A balanced oscillator according to claim 1, wherein a tuning pattern comprising a printed pattern is formed on one side of the printed circuit board, and an earth pattern is provided on the opposite side. 3. An input terminal, a down-converter connected to the input terminal, a demodulator connected to an output of the down converter, and an output terminal connected to an output of the demodulator. A high-frequency device provided with the balanced oscillator according to claim 1 in the demodulation unit. 4. An input terminal, a down converter connected to the input terminal, a demodulator connected to an output of the down converter, and an output terminal connected to an output of the demodulator. A high-frequency device provided with the balanced oscillator according to claim 2 in the demodulation unit.