Versions Compared

Key

  • This line was added.
  • This line was removed.
  • Formatting was changed.

...

The lowest tone frequency specified in below is 0.0001Hz (0.1mHz). This is 30 times lower than the bandwidth of a Type I clock.  It has a period of almost 2.8 hours, and hence requires a test time at least that long.   While Table 13 of G.812 is extends as low as 0.000012Hz (12µHz), which has with a period of over 23 hours . However, the longest observation interval specified in the MTIE mask (Figure 3) is 10000s, equivalent to a tone frequency of 0.000032Hz (32µHz).  Therefore it is sufficient to make 32µHz the lowest tone frequency in the testthe test time would be extremely long, and being so far into the pass-band it is very unlikely that either the wander tolerance or wander transfer would be any different.

The possible input signals for a Type I G.8266 clock are SyncE Option 1, 2048kHz, or 2048kbit/s (E1).

...

5000

Frequency

(Hz)

Amplitude

(ns)

Test Time

(Cycles)

Test Time

(s)

Max. Gain

(dB)

Max. Output Amplitude (ns)

1

750

300

300

-50.5

38

0.32

750

96

300

-40.6

43

0.01

750

30

300

-10.8

251

0.043

750

13

302

-23.1

88

0.032

1000

10

313

-20.6

129

0.016

2000

5

313

-14.7

404

0.01

2000

3

300

-10.8

610

0.0032

2000

3

938

-3.3

1403

0.0008

2000

12

12502500

0.2

2082

0.00032

5000

1

3125

0.2

5152

0.0001

5000

1

10000

0.2

5152

0.000032

1

31250

0.2

5152

The filtering characteristic expected from the clock is shown in the following diagram. While there is no minimum gain specified, the frequency response is expected to be fairly close to the maximum. Appendix II of G.812 suggests the result should be within 2% of the mask for long observation intervals.

...

Tone Frequencies for G.8266 Type II and Type III Clocks

...

Frequency

(Hz)

Amplitude

(ns)

Test Time

(Cycles)

Test Time

(s)

Max. Gain

(dB)

Max. Output Amplitude (ns)

4

300

1200

300

-72.0

36

1.26

301

377

300

-62.0

36

0.4

303

120

300

-52.0

36

0.126

308

38

302

-42.0

38

0.04

325

12

300

-32.0

44

0.0126

380

4

318

-22.0

66

0.004

550

3

750

-12.3

169

0.00143

1000

3

2100

-4.8

609

0.0004

1007

1

2500

0.2

1066

0.0001260001

10291037

1

795010000

0.2

1088

0.00004

1097

1

25000

0.2

1158

 The The filtering characteristic expected from the clock is shown in the following diagram. While there is no minimum gain specified, the frequency response is expected to be fairly close to the maximum. Appendix II of G.812 suggests the result should be within 2% of the mask for long observation intervals.

...