Coustic XM6 Manuel d'utilisateur télécharger pdf (Page 28)

To be ANSI/TIA-470.130-C

5.4.4 Headset Send Linearity 387

The CPE shall meet either the sinusoidal stimulus requirement or the artificial speech stimulus 388

requirement. 389

5.4.4.1 Requirement (Sinusoidal Stimulus) 390

The send linearity response curves for the -20 dB and +10 dB levels with respect to the reference 391

level (-4.7 dBPa) measured in 5.4.2, using a 2.7 km artificial line, shall be within the values listed in 392

Table 4, for the R40 frequencies 300 Hz to 3150 Hz. The Mouth simulator shall have an output 393

distortion less than 2 % THD at +5.3 dBPa. 394

395

Table 4 – Send linearity requirements (Sinusoidal) 396

Level from Reference

Frequency Response

Tolerance

-20 dB +/- 3.0 dB

+10 dB +/- 2.0 dB

397

5.4.4.2 Method of Measurement 398

The following steps shall be taken: 399

1. Determine the reference linearity response from the 2.7 km artificial line measurement in 5.4.2. 400

2. Perform a frequency response measurement at the -20 dB relative source level (-24.7 dBPa) and 401

determine the linearity response versus the reference. 402

3. Perform a frequency response measurement at the +10 dB relative source level (+5.3 dBPa) and 403

determine the linearity response versus the reference. 404

405

5.4.4.3 Requirement (Artificial Speech Stimulus) 406

The send linearity response for the -10 dB and -20 dB levels shall be measured with respect to the 407

Reference level (-4.7 dBPa) measured in 5.4.2, using a 2.7 km artificial line. The tolerance values 408

listed in Table 5 shall be applied for frequencies from 300 Hz to 3150 Hz. 409

410

Table 5 – Send linearity requirements (Artificial Speech) 411

Level from Reference

Frequency Response

Tolerance

-20 dB +/- 3.0 dB

-10 dB +/- 2.0 dB

412

5.4.4.4 Method of Measurement 413

The following steps shall be taken: 414

1. Determine the reference linearity response from the 2.7 km artificial line measurement in 5.4.2. 415

2. Perform a frequency response measurement at the -10 dB relative source level (-14.7 dBPa) and 416

determine the linearity response versus the reference. 417

3. Perform a frequency response measurement at the -20 dB relative source level (-24.7 dBPa) and 418

determine the linearity response versus the reference. 419

420

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Coustic XM6 Manuel d'utilisateur Page 28

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