JPH06112734A - Oscillator - Google Patents

Abstract

PURPOSE:To provide a crystal oscillator which can suppress the generation of the noise spectrum due to the indirect transmission of vibrations and secures the highly stable working with low noises by covering the casing of the oscillator with a vacuum-sealed metallic casing and providing the posts onto the inner wall of the metallic casing. CONSTITUTION:A metallic casing 2 which can be vacuum-sealed is provided together with the elastic posts 3 which are set on each surface of the inner wall of the casing 2 and fix a crystal oscillator casing 1, and a hermetic terminal 11. When the oscillator 4 is put in an acoustic environment, the direct transmission of the air vibrations caused by the sound waves is prevented by the casing 2 to the oscillator 4. At the same time, the indirect transmission of the air vibrations caused by the sound waves is prevented by the posts 3 to the oscillator 4 via the casing 2, the casing 1 and a printed board 5. In such a constitution, the noise spectrum generated by the sounds can be suppressed. Thus it is possible to reduce the noises and to ensure the highly stable working of the oscillator 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oscillator used as a signal source for radar equipment.

[0002]

2. Description of the Related Art FIG. 5 is a sectional view of a conventional oscillator for a radar device, and FIG. 6 is an external view thereof. In the figure, 1
Is an oscillator housing, 4 is a crystal oscillator, and 5 is a printed circuit board that realizes an electronic circuit that drives the crystal oscillator 4 to generate electrical transmission.

Next, the operation will be described. A crystal oscillator 4 is driven by an electronic circuit formed on a printed circuit board 5, oscillates a frequency determined by the crystal oscillator 4, is amplified and multiplied as needed, and then is a stable, low-noise high-frequency signal. Is output.

[0004]

As shown in FIG. 7, the signal oscillated by the oscillator configured as described above spreads the spectrum due to the phase noise due to the characteristics of the crystal unit 4, electronic circuit parts and the like. However, when the above-mentioned oscillator is placed in an environment where sound waves having acoustic frequency components as shown in FIG. 8 exist, oscillation is caused by a piezoelectric effect which is a reversible conversion action of mechanical vibration and electrical vibration. The crystal oscillator 4 that is being vibrated is directly vibrated by the air vibration caused by the sound wave, and is also indirectly vibrated via the housing and the substrate to give a phase modulation to the original oscillation frequency signal. As shown in FIG. 9, there is a problem that a noise spectrum is generated at a frequency that is separated from the oscillation frequency by an acoustic frequency component.

SAW (Surface Accou)
The oscillator using a stic wave) device also has the same problem as described above because it uses the reversible conversion action of mechanical vibration and electrical vibration.

The present invention has been made in order to solve the above problems, and it is an influence of direct vibration propagation of air vibration of sound waves existing in the environment where the oscillator is placed and indirect through the housing and the printed circuit board. The purpose of the present invention is to realize a highly stable and low-noise oscillator by suppressing the generation of a noise spectrum due to the influence of the propagation of dynamic vibration.

[0007]

An oscillator according to the present invention covers a crystal oscillator casing with a vacuum-sealed metal casing,
Moreover, the above-mentioned crystal oscillator is fixed through the columns of the elastic body attached to each surface of the inner wall of the metal housing.

Further, the crystal oscillator casing is covered with a metal casing,
Moreover, the metal housing is fixed by being closely adhered and wrapped with the elastic sound absorbing material attached to the entire inner wall of the metal housing.

The SAW oscillator housing having the same problem as the crystal oscillator is covered with a vacuum-sealed metal housing, and the pillars of elastic body are attached to each surface of the inner wall of the metal housing. The SAW oscillator is fixed.

Further, the housing of the SAW oscillator is fixed by covering the housing with a metal housing and closely wrapping it with an elastic sound absorbing material attached to the entire inner wall of the metal housing.

[0011]

In the oscillator configured as described above, the vacuum-sealed metal housing prevents direct propagation of air vibration due to sound waves to the crystal unit, and is attached to each surface of the inner wall of the metal housing. By fixing the crystal oscillator through the elastic column, the indirect vibration of air vibration caused by sound waves to the crystal unit through the metal housing and the printed circuit board is prevented, and the noise spectrum The effect of suppressing the occurrence is obtained.

Further, the sound absorbing material attached to the entire inner wall of the metal housing prevents direct propagation of air vibration due to sound waves to the crystal unit, and the elasticity of the sound absorbing material suppresses air vibration due to sound waves. The effect of suppressing the indirect propagation of vibration to the crystal unit through the metal casing and the printed circuit board and suppressing the generation of the noise spectrum due to the sound can be obtained.

Also in the oscillator using the SAW device, the vacuum-sealed metal housing prevents direct propagation of air vibrations due to sound waves to the SAW device, and each surface of the inner wall of the metal housing. By fixing the SAW oscillator via the elastic column attached to the S, the S
The effect of suppressing the indirect propagation of vibration to the AW device and suppressing the generation of a noise spectrum due to sound can be obtained.

Further, the sound absorbing material attached to the entire inner wall of the metal housing prevents direct propagation of air vibration due to sound waves to the SAW device, and the elasticity of the sound absorbing material causes the metal of air vibration due to sound waves. It is possible to obtain the effect of suppressing the indirect propagation of vibration to the SAW device via the housing and the printed circuit board and suppressing the generation of a noise spectrum due to sound.

[0015]

EXAMPLES Example 1. FIG. 1 is a sectional view showing an embodiment of the present invention. In FIG. 1, 1, 4 and 5 are parts corresponding to those of a conventional device, and 2 is a metal housing capable of vacuum sealing,
Reference numeral 3 is a column of an elastic body for fixing the crystal oscillator arranged on each surface of the inner wall of the metal housing 2, and 11 is a hermetic terminal.

In the oscillator configured as described above,
When the oscillator is placed in an environment where sound is present, air vibration caused by the sound wave is prevented from directly propagating to the crystal oscillator 4 by the vacuum-sealed metal housing 2, and each inner wall of the metal housing 2 is blocked. Indirect propagation of air vibrations due to sound waves to the metal oscillator 2 and the crystal oscillator oscillator 1 and the crystal oscillator 4 via the printed circuit board 5 by the elastic column 3 for fixing the crystal oscillator oscillator 1 mounted on the surface. This suppresses the generation of noise spectrum due to sound, and realizes a highly stable and low noise oscillator.

Example 2. FIG. 2 is a sectional view showing another embodiment of the present invention. In FIG. 2, 1, 4 and 5 are the same parts as those of the conventional device and the first embodiment, 6 is a metal housing, and 7 is arranged so as to enclose and fix the crystal oscillator 1 on the entire inner wall of the metal housing 6. Elastic sound absorbing material,
Reference numeral 12 is a through terminal.

In the oscillator configured as described above, the acoustic sound absorbing material 7 that wraps and fixes the crystal oscillator 1 blocks the direct propagation of air vibration due to sound waves to the crystal oscillator 4, and Elasticity blocks the indirect vibration propagation to the crystal unit 4 through the metal housing and the printed circuit board of air vibration caused by sound waves, and suppresses the generation of noise spectrum due to sound, realizing a highly stable and low noise oscillator. To be done.

Example 3. SAW device 9 as shown in FIG.
Also in the oscillator configured by the SAW oscillator using the above, when the oscillator is placed in the environment where the sound exists, the air vibration caused by the sound wave is directly propagated to the SAW device 9 by the vacuum-sealed housing 2. Of the SAW oscillator housing 8 attached to each surface of the inner wall of the metal housing 2 by the elastic pillar 3 for fixing the SAW oscillator housing 8 and the SAW oscillator housing 8 and the printed circuit board 10 which are air-vibrated by sound waves. Indirect propagation to the SAW device 9 via the is blocked, generation of a noise spectrum due to sound is suppressed, and a highly stable and low noise oscillator is realized.

Example 4. SAW device 9 as shown in FIG.
Also in the oscillator configured by the SAW oscillator using the, when the oscillator is placed in an environment where sound exists, the acoustic sound absorbing material 7 that surrounds and fixes the SAW oscillator housing 8 causes air vibration caused by sound waves. Prohibition of vibration propagation to the SAW device directly or indirectly via the printed circuit board 10 suppresses the generation of a noise spectrum due to sound, and realizes a highly stable and low noise oscillator.

[0021]

As described above, according to the present invention, the crystal oscillator is fixed and held inside the vacuum-sealed metal housing by the column of the elastic body. Therefore, the direct influence of the air vibration by the sound wave is obtained. Also, by suppressing the indirect influence via the metal housing and the printed circuit board, it is possible to prevent generation of a noise spectrum due to sound and realize a highly stable and low noise oscillator.

Further, since the crystal oscillator is configured so as to be fixed and held by being wrapped in an elastic sound-absorbing material inside the metal housing, the direct influence of air vibration caused by sound waves and the indirect operation via the metal housing and the printed circuit board are provided. By suppressing these effects, it is possible to prevent the generation of a noise spectrum due to sound and realize a highly stable and low noise oscillator.

Further, even when the crystal oscillator is replaced with a SAW oscillator and a similar configuration is adopted, it is possible to prevent generation of a noise spectrum due to sound and realize a highly stable and low noise oscillator.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

FIG. 2 is a sectional view showing Embodiment 2 of the present invention.

FIG. 3 is a sectional view showing Embodiment 3 of the present invention.

FIG. 4 is a sectional view showing Embodiment 4 of the present invention.

FIG. 5 is a sectional view showing a conventional oscillator.

FIG. 6 is an external view showing a conventional oscillator.

FIG. 7 is a diagram showing an oscillation signal of an oscillator.

FIG. 8 is a diagram showing acoustic frequency components existing in an environment where an oscillator is placed.

9 is a diagram showing an oscillation signal when the oscillator is affected by the acoustic frequency component of FIG.

[Explanation of symbols]

 1 Crystal Oscillator Housing 2 Vacuum Sealable Metal Housing 3 Elastic Column 4 Crystal Resonator 5 Printed Circuit Board Realizing Crystal Oscillator 6 Metal Housing 7 Elastic Sound Absorbing Material 8 SAW Oscillator Housing 9 SAW Resonator 10 SAW Oscillator Printed circuit board that realizes 11 Hermetic terminal 12 Through terminal

Claims (4)

[Claims] 1. A vacuum-sealed first metal housing, a hermetic terminal mounted on the wall surface thereof, and a plurality of elastic pillars mounted on each surface of the inner wall of the first metal housing. , A second metal housing fixed by the column of the elastic body, and a crystal resonator and an electronic circuit for driving the crystal resonator and electrically oscillating by being fixed inside the second metal housing by screwing. An oscillator characterized by being configured with a crystal oscillation circuit board having the same. 2. A first metal housing, a through terminal attached to the wall surface of the first metal housing, an elastic sound-absorbing material sheet attached to the entire inner wall of the first metal housing, and a sound-absorbing material sheet in close contact with the sound absorbing material sheet. A crystal oscillation circuit having a second metal housing fixed by the above-mentioned operation, and a crystal resonator and an electronic circuit fixed inside the second metal housing by screwing and driving the crystal resonator to generate electric oscillation. An oscillator characterized by comprising a substrate. 3. A vacuum-sealed first metal housing, a hermetic terminal mounted on the wall surface thereof, and a plurality of elastic pillars mounted on each surface of the inner wall of the first metal housing. , A second metal housing fixed by the column of the elastic body, and a second SAW (Surface Acoustic W) which is fixed inside the second metal housing by screwing.
ave) An oscillator comprising a device and a SAW oscillator circuit board having an electronic circuit for driving the device to generate electric oscillation. 4. A first metal housing, a through terminal attached to a side surface of the first metal housing, an elastic sound-absorbing material sheet attached to the entire inner wall of the first metal housing, and a sound-absorbing material sheet in close contact with the sound absorbing material sheet. A SAW oscillation circuit having a second metal housing fixed by the above-mentioned method, and a SAW device and an electronic circuit for driving the SAW device and generating electrical oscillation by being fixed inside the second metal housing by screwing. An oscillator characterized by comprising a substrate.