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G.8266 Tone Frequencies for Tolerance and Transfer

The following table tables proposes the tone frequencies and amplitudes to be applied at the input, the attenuation due to the filter, and the tone amplitude expected at the output.

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The lowest tone frequency specified in Table 13 of G.812 is 0.000012Hz (12µHz), which has 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 this the lowest tone frequency in the test, reducing the overall test time from 36 hours to about 13 hours.

Table 1: Tone Frequencies for G.8266 Type I Clocks

The parameters used to generate this table were:

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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

1

1250

0.2

2082

0.00032

5000

1

3125

0.2

5152

0.0001

5000

1

10000

0.2

5152

0.000032

5000

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.

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

The parameters used to generate this table were:

  • Maximum bandwidth: 1mHz

  • Minimum bandwidth: none

  • Maximum gain peaking: 0.2dB

  • Noise generation allowance: ±35ns
    (half the peak-to-peak high-frequency time error defined in clause 8.2)

  • At least two points per decade

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

0.000126

1029

1

7950

0.2

1088

0.00004

1097

1

25000

0.2

1158

 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.

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