1. An atomic cell comprising:
metallic atoms;
a first substrate having a concave portion which is opened on one surface side thereof;
a second substrate that is bonded to the one surface side of the first substrate, and forms an inner space where the metallic atoms are sealed, together with the first substrate;
a communication hole that communicates with the inner space; and
a sealing portion that is disposed at a position that overlaps a bonding portion of the first substrate and the second substrate in a plan view seen in a direction where the first substrate and the second substrate are overlapped to block the communication hole by fusion.
2. The atomic cell according to claim 1,
wherein the sealing portion is positioned to be closer to the first substrate than a surface of the second substrate on a side opposite to the first substrate.
3. An atomic cell manufacturing method comprising:
preparing a stacked structure that includes a first substrate having a concave portion which is opened on one surface side thereof, a second substrate that is bonded to the one surface side of the first substrate and forms an inner space together with the first substrate, and a communication hole that has an opening portion which is disposed at a position that overlaps a bonding portion of the first substrate and the second substrate in a plan view seen in a direction where the first substrate and the second substrate are overlapped and is opened outside and through which the inner space communicates with an external space, and
sealing the inner space by blocking the opening portion of the communication hole by fusion in a state where metallic atoms are introduced in the inner space.
4. The atomic cell manufacturing method according to claim 3,
wherein in the preparing of the stacked structure, the first substrate includes a third substrate having a through hole that is penetratingly formed in a thickness direction, and a fourth substrate that is bonded to one surface of the third substrate and forms the concave portion together with the third substrate.
5. The atomic cell manufacturing method according to claim 4,
wherein in the preparing of the stacked structure, the second substrate and the fourth substrate include glass, respectively, and the third substrate includes silicon.
6. The atomic cell manufacturing method according to claim 3,
wherein in the preparing of the stacked structure, the opening portion of the communication hole is provided in the second substrate.
7. The atomic cell manufacturing method according to claim 3,
wherein in the preparing of the stacked structure, the stacked structure has a protruding cylindrical portion that surrounds the opening portion of the communication hole.
8. The atomic cell manufacturing method according to claim 3,
wherein in the preparing of the stacked structure, the communication hole includes a first hole provided in the first substrate, and a second hole that communicates with the first hole and is provided in the second substrate.
9. The atomic cell manufacturing method according to claim 3,
wherein in the sealing of the inner space, the fusion is performed using flame.
10. The atomic cell manufacturing method according to claim 3,
wherein in the sealing of the inner space, the fusion is performed using laser.
11. The atomic cell manufacturing method according to claim 3,
wherein in the preparing of the stacked structure, the stacked structure includes plural sets of the inner space and the communication hole.
12. The atomic cell manufacturing method according to claim 11,
wherein after the sealing of the inner space, the stacked structure is individualized for each set of the inner space and the communication hole.
13. A quantum interference device comprising:
the atomic cell according to claim 1;
a light output section that outputs excitation light for exciting the metallic atoms; and
a light detecting section that detects the excitation light that passes through the atomic cell.
14. A quantum interference device comprising:
the atomic cell according to claim 2;
a light output section that outputs excitation light for exciting the metallic atoms; and
a light detecting section that detects the excitation light that passes through the atomic cell.
15. An atomic oscillator comprising the atomic cell according to claim 1.
16. An atomic oscillator comprising the atomic cell according to claim 2.
17. An electronic device comprising the atomic cell according to claim 1.
18. An electronic device comprising the atomic cell according to claim 2.
19. A moving object comprising the atomic cell according to claim 1.
20. A moving object comprising the atomic cell according to claim 2.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method of handling time drift during packet reception, said method comprising the steps of:
using a first sampling time to obtain a first sequence of hard decision symbols for decoding contents of a first portion of said received packet;
determining if a degradation in a reliability of the first sequence of hard decision symbols has occurred using an error checking code;
wherein the determining step is performed response to an end of a reception of the packet;
switching to a second sampling time if degradation in the reliability of the first sequence of symbols has been determined; and
responsive to switching to said second sampling time, using said second sampling time to obtain a second sequence of hard decision symbols for decoding contents of a second portion of said received packet.
2. The method of claim 1, wherein said second sequence is more reliable than said first sequence for decoding said second portion of the packet.
3. The method of claim 1, wherein a sync word is used to select said first and second sampling times.
4. The method of claim 1, wherein a determination of a particular sampling time is made by using the error checking code.
5. The method of claim 4, wherein the error checking code is a cyclic redundancy check (CRC) code.
6. The method of claim 5, wherein said degradation is indicated by the CRC code not checking for the first sampling time.
7. The method of claim 1, wherein said degradation is indicated by a difference between corresponding symbols of said first and second sequences at one sampling instant.
8. The method of claim 4, wherein the determination of the particular sampling time is performed responsive to an end of the reception of the packet.
9. The method of claim 5, wherein if said CRC results in lack of a valid code word, a retransmission is requested.
10. The method of claim 1, wherein said degradation results from time drift.
11. The method of claim 1, wherein said decision symbols are subject to baseband processing.
12. The method of claim 1, wherein an adequacy of a selected sampling time is determined by evaluating a signal to noise ratio.
13. The method of claim 1, wherein a plurality of sampling times are used throughout said packet.
14. The method of claim 1, wherein said first sampling time is used at the beginning of a packet.
15. The method of claim 1, wherein said first sequence of hard decision symbols are obtained by correlating received signals with a known sync word.
16. A method of handling time drift during packet reception, said method comprising the steps of:
using a first sampling time to obtain a first sequence of hard decision symbols for decoding contents of a first portion of said received packet;
determining if a degradation in a reliability of the first sequence of hard decision symbols has occurred using an error checking code;
wherein the determining step is performed responsive to at an end of a reception of the packet;
switching to a second sampling time if degradation in the reliability of the first sequence of symbols has been determined;
responsive to switching to said second sampling time, using said second sampling time to obtain a second sequence of hard decision symbols for decoding contents of a second portion of said received packet;
determining if a degradation in a reliability of the second sequence of hard decision symbols has occurred using the error checking code;
wherein the determining step is performed responsive to the end of the reception of the packet;
switching to a third sampling time if degradation in the reliability of the second sequence of symbols has been determined; and
responsive to switching to said third sampling time, using said third sampling time to obtain a third sequence of hard decision symbols for decoding contents of a third portion of said received packet.
17. The method of claim 16, wherein said third sequence is more reliable than said first sequence for decoding contents of the third portion of the packet.