Английская Википедия:Digital milliwatt

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Версия от 10:12, 27 февраля 2024; EducationBot (обсуждение | вклад) (Новая страница: «{{Английская Википедия/Панель перехода}} {| class=wikitable style="float:right;" |+ align="bottom" style="caption-side:bottom;text-align:left;" | Code sequence of the digital milliwatt in μ-law and A-law encodings.<ref name=att/> ! rowspan=2|Word<br>number || colspan=2|Hexadecimal code |- | μ-law || A-law |- | 1 || 1e || 34 |- | 2 || 0b || 21 |- | 3 || 0b || 21 |- | 4 || 1e || 34 |-...»)
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Code sequence of the digital milliwatt in μ-law and A-law encodings.[1]
Word
number
Hexadecimal code
μ-law A-law
1 1e 34
2 0b 21
3 0b 21
4 1e 34
5 9e b4
6 8b a1
7 8b a1
8 9e b4

In digital telephony, the digital milliwatt is a standard test signal that serves as a reference for analog signal levels in the telecommunications network.[2] When decoding the digital milliwatt, a PCM decoder produces a sinusoidal signal with a frequency of Шаблон:Val with one milliwatt in power (Шаблон:Val, a reference for dBm0).

The digital milliwatt signal is encoded by eight 8-bit words corresponding to one pulse-code modulated cycle of the signal, sampled 8000 times per second. It is typically stored in read-only memory (ROM) in the telecommunication equipment.[1]

The digital milliwatt signal is often generated in instruments in place of separate test equipment. It has the advantage of being tied in frequency and amplitude to the relatively stable digital clock signal and power (voltage) supply, respectively, that are used by the digital channel bank.

References

Шаблон:Reflist

Шаблон:FS1037C

  1. 1,0 1,1 AT&T, Digital Channel Bank Requirements And Objectives, Publication No. 43801 (December 1978). page A6.
  2. Anttalainen T., Introduction to Telecommunications Network Engineering, Artech House (2003).