JPS6016122Y2 - atomic oscillator - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an atomic oscillator that controls the frequency of a voltage-controlled crystal oscillator based on the transition frequency between hyperfine structure levels in the ground state of a cesium atom.

An atomic oscillator is known as a high-precision oscillator. For example, a cesium atomic oscillator uses cesium atoms (C5133).
Transition frequency between hyperfine structure levels in the ground state of
92.631... Controls the frequency of the voltage controlled oscillator based on MHz, 10-12 to 10-
It has a signal accuracy of 13 digits and is used as a primary standard for time and frequency.

Furthermore, high-precision crystal oscillators currently have a frequency accuracy of 10-8.
Although this has improved to a certain extent, there is a significant difference compared to the atomic oscillator mentioned above.

In order to configure an atomic oscillator, it is necessary to generate the transition frequency of cesium atoms.For this reason, conventionally, as shown in FIG. 1, when the output frequency is 5 MHz, a 5 MHz voltage controlled oscillator 11 is provided. The output frequency of this voltage controlled oscillator 11 is multiplied by a multiplier 12 to 9180 MH2, and the frequency synthesizer 13 including a crystal oscillator that operates in synchronization with the voltage controlled oscillator 11 is multiplied to 12.63177159.
A frequency of M H2 is generated, synthesized by the synthetic modulator 14 to obtain a frequency of 9192.63177159 MHz, and phase modulated by the output of the low frequency oscillator 15, and the output is applied to the atomic oscillator 16. The detection amplifier 17 detects and amplifies the output corresponding to the resonance characteristic, and the phase detector 18 detects the phase of the detection signal using the modulation signal, thereby detecting the deviation of the output frequency of the composite modulator 14 from the transition frequency. Therefore, the voltage controlled crystal oscillator 11 is controlled thereby.

. However, since the transition frequency has a fraction such as 9192.63177 MHz, it cannot be obtained by simply multiplying the desired integer output frequency. It has been established that

Furthermore, although this crystal oscillator must be synchronized with the voltage controlled crystal oscillator 11, there is a possibility that this synchronization may be lost under various conditions.

The present invention aims to generate fractional frequencies without providing a crystal oscillator outside the voltage controlled oscillator, and to solve the problem of out-of-synchronization.

Examples will be described in detail below. FIG. 2 is a block diagram of the main parts of the embodiment of the present invention, in which 21 is a voltage controlled crystal oscillator, 22 is a multiplier, 23 is a combiner, 24 is a multiplier,
25 is a modulator.

When the output frequency of the voltage controlled crystal oscillator 21 is 5 MHz, the multiplier 22 multiplies it by 18 to 90 MHz, and the synthesizer 23 uses 5 MH 2 and 90 MHz to make it 12 MHz.
．． 63177159MHz, and the multiplier 24 multiplies 90MHz by 102 to obtain 9180MH2, and the modulator 25 generates 9180+12.63177159=
The transition frequency of a cesium atom of 9192.63177159 (MHz) is obtained.

FIG. 3 is a block diagram of the synthesizer 23, and the input 5f
'viHz is divided into 1/2 by the frequency divider 31, multiplied by 5 by the multiplier 32, to 12.5rvfHz, and the input 90MHz is divided by 1/683 by the frequency divider 33.
The frequency is divided into 0.13177159MHz.

The modulator 34 has the aforementioned 12.5 MHz and 0.1317 MHz.
Since 7159 MHz is input, 12.63177159 MHz is output from the output terminal 35, which becomes one input of the modulator 25 in FIG.

When the voltage-controlled crystal oscillator 21 has an output frequency of 10 MHz, the multiplier 22 is configured to multiply the frequency by 9, and the frequency divider 31 is configured to divide the frequency by 4, so that the transition frequency of the cesium atom can be adjusted as in the previous embodiment. It is something that can be output.

As explained above, the present invention is applicable to 5MHz, IOMH
The output of the voltage controlled crystal oscillator 21 with an integer frequency such as 2 is multiplied by 18 times, 9 times, etc. by the first multiplier 22, and the input frequency of the first multiplier 22 is divided by the frequency divider 31. Multiplication by multiplier 32, output frequency divider 3
By frequency division by 3 and modulation by modulator 34, 12.63177159M H is a fraction of the transition frequency of cesium atoms.
2 is combined in a synthesizer 23, and the output of the first multiplier 22 is converted to 9180 MHz, which is an integer fraction of the transition frequency, to the second multiplier 24.
9192.6317715 by modulator 25.
9MHz, and by multiplying, dividing, and modulating the output of the voltage controlled crystal oscillator 21, it is possible to create a fractional frequency from an integer frequency, so there is no synchronization loss as in the conventional example. , the operation can be stabilized, and a voltage-controlled crystal oscillator for synthesizing fractional frequencies is not required, resulting in an economical configuration.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of main parts of a conventional atomic oscillator, FIG. 2 is a block diagram of main parts of an embodiment of the present invention, and FIG. 3 is a block diagram of a synthesizer. 11.21 is a voltage controlled crystal oscillator, 12, 22.24.
32 is a multiplier, 13 is a frequency synthesizer, 14 is a synthesis modulator, 15 is a low frequency oscillator, 16 is an atomic resonator, 17 is a detection amplifier, 18 is a phase detector, 23 is a synthesizer, 25.3
4 is a modulator, and 31.34 is a frequency divider.

Claims (1)

[Scope of utility model registration request] In an atomic oscillator that controls a voltage-controlled crystal oscillator with an integer frequency based on the transition frequency between hyperfine structure levels in the ground state of a cesium atom, the output frequency of the voltage-controlled crystal oscillator with the rectified frequency is multiplied. first multiplier,
Modulating a first signal obtained by dividing and multiplying the output frequency of the voltage controlled crystal oscillator and a second signal obtained by dividing the output frequency by the first multiplier. a synthesizer for creating a frequency of a fraction of the transition frequency, a second multiplier for multiplying the output of the first multiplier, and adding the output of the second multiplier and the output of the synthesizer. An atomic oscillator comprising a modulator that outputs the transition frequency.