Wohler AMP2A-VTR User's Guide download pdf (Page 64)

Bitstream Detection

The unit will now mute an input pair if it detects the presence of a non-

PCM stream (such as a Dolby or DTS bitstream) on that pair. The unit

detects bitstreams with two methods:

A. Preamble detection

B. Not-Audio AES Channel status flag is asserted

In terms of Method A, encoded bitstreams contain key data sequences

that identify the type of encoding used. These sequences are known as

preambles (see the SMPTE 337 and 338 standards). This unit can only

detect 16-bit preambles. For example, a 20-bit Dolby E stream would be

passed as PCM audio, instead of being flagged as an encoded stream.

This method is always employed.

In terms of Method B, the upstream equipment must either assert or

de-assert this flag. Unfortunately, not all equipment does this correctly.

In those cases where the channel status flag is set incorrectly, you may

need to disable this method of bitstream detection. This can be done

using the setup menu item A Vld Det. When enabled (Ena), Method B

is used to detect bitstreams. When disabled (Disa), Method B is not

used to detect bitstreams. If your unit is muting PCM streams, set this

item to Disa. If encoded bitstreams are getting through to the speakers,

set this item to Ena.

1 2 ... 59 60 61 62 63 64 65 66 67 68 69 ... 73 74

No comments

Wohler AMP2A-VTR User's Guide Page 64