Atomic oscillator and manufacturing method of the atomic oscillator

Patent metadata

Field	Value
Publication number	US-9130579-B2
Application number	US-201414199305-A
Country	US
Kind code	B2
Filing date	Mar 6, 2014
Priority date	Mar 27, 2013
Publication date	Sep 8, 2015
Grant date	Sep 8, 2015

Abstract

An atomic oscillator includes an atomic cell in which an atom is enclosed, a magnetic field generation part to apply a magnetic field to the atomic cell, a reference oscillator which is controlled based on an atomic resonance signal outputted from the atomic cell and generates a reference signal, and a fractional N-PLL which receives the reference signal to generate a signal including a resonance frequency of the atom, in which when a maximum digit of the resonance frequency adjustable by the magnetic field generation part is a boundary digit, the fractional N-PLL can adjust at least a digit one digit higher than the boundary digit.

First claim

What is claimed is:

1. An atomic oscillator comprising:
an atomic cell in which an atom is enclosed;
a magnetic field generation part to apply a magnetic field to the atomic cell;
a reference oscillator that is controlled based on an atomic resonance signal outputted from the atomic cell and generates a reference signal; and
a fractional N-PLL that receives the reference signal to generate a signal including a resonance frequency of the atom, wherein
when a maximum digit of the resonance frequency adjustable by the magnetic field generation part is a boundary digit, the fractional N-PLL is operable to adjust the resonance frequency at least a digit that is one digit higher than the boundary digit,
the fractional N-PLL includes an n-bit decimal setting part to determine a decimal part of a frequency division ratio, and
when a bit number of the decimal setting part is n, a phase comparison frequency is f PFD , the resonance frequency is f ΔE , and an adjustable ratio of the magnetic field generation part to the resonance frequeny is R M ,following equation is satisfied

f
PFD

2
n

≤

f

Δ
⁢

⁢
E

×

R
M

.

2. The atomic oscillator according to claim 1 , wherein the fractional N-PLL includes a decimal setting part of at least 25 bits.

3. The atomic oscillator according to claim 1 , wherein the fractional N-PLL is operable to adjust at least remaining digits of the resonance frequency which are higher than the boundary digit.

4. A manufacturing method of an atomic oscillator including an atomic cell in which an atom is enclosed, a magnetic field generation part as a coil to apply a magnetic field to the atomic cell, a reference oscillator that is controlled based on an atomic resonance signal outputted from the atomic cell and generates a reference signal, and a fractional N-PLL that includes an n-bit decimal setting part to determine a decimal part of a frequency division ratio and receives the reference signal to generate a signal including a resonance frequency of the atom, the method comprising:
determining n of a bit number of the decimal setting part of the fractional N-PLL, wherein when a maximum digit of the resonance frequency adjustable by the magnetic field generation part is a boundary digit, the fractional N-PLL can adjust at least a digit one digit higher than the boundary digit, and when a bit number of the decimal setting part is n, a phase comparison frequency is f PFD , the resonance frequency is f ΔE and an adjustable ratio of the magnetic field generation part to the resonance frequency is R M , following equation is satisfied

f
PFD

2
n

≤

f

Δ
⁢

⁢
E

×

R
M

.

5. The manufacturing method of the atomic oscillator according to claim 4 , further comprising:
giving an initial value to the n-bit decimal setting part of the fractional N-PLL; and
adjusting the value set in the decimal setting part.

6. The manufacturing method of the atomic oscillator according to claim 4 , further comprising
adjusting the current of the magnetic field generation part.

7. A manufacturing method of an atomic oscillator including an atomic cell in which an atom is enclosed, a magnetic field generation part as a coil to apply a magnetic field to the atomic cell, a reference oscillator that is controlled based on an atomic resonance signal outputted from the atomic cell and generates a reference signal, and a fractional N-PLL that includes an n-bit decimal setting part to determine a decimal part of a frequency division ratio and receives the reference signal to generate a signal including a resonance frequency of the atom, the method comprising:
determining at least one of a number of turns and a current of the magnetic field generation part such that the magnetic field generation part can adjust at least a digit not higher than a boundary digit of the resonance frequency, the boundary digit being a digit one digit lower than a minimum digit of the resonance frequency adjustable by the fractional N-PLL, and when a bit number of the decimal setting part is n, a phase comparison frequency is f PFD , the resonance frequency is f ΔE , and an adjustable ratio of the magnetic field generation part to the resonance frequency is R M , following equation is satisfied

f
PFD

2
n

≤

f

Δ
⁢

⁢
E

×

R
M

.

8. The manufacturing method of the atomic oscillator according to claim 7 , further comprising:
giving an initial value to the n-bit decimal setting part of the fractional N-PLL; and
adjusting the value set in the decimal setting part.

9. The manufacturing method of the atomic oscillator according to claim 7 , further comprising
adjusting the current of the magnetic field generation part.

Assignees

• Seiko Epson Corp

Inventors

• Maki Yoshiyuki

Classifications

• G04F5/145

  using Coherent Population Trapping · CPC title

• H03L7/26 Primary

  using energy levels of molecules, atoms, or subatomic particles as a frequency reference · CPC title

• Y10T29/4902

  Electromagnet, transformer or inductor · CPC title

• H03B17/00

  Generation of oscillations using radiation source and detector, e.g. with interposed variable obturator · CPC title