Dolby Laboratories DM100 Instrukcja Użytkownika Pobierz pdf

Monitor Modes

The DM100 allows for the monitoring of individual channels within

an input bitstream, as well as a downmix to a stereo (Lt/Rt, Lo/Ro)

or mono output. This is controlled in the Output Ch Map menu.

Decode FFormat ((Autodetect):

Identifies and decodes the incoming

data stream automatically. When the DM100 is not in Autodetect

mode, a flashing LED (Dolby

Digital, Dolby E, or PCM) indicates that

the incoming data stream does not match the chosen decode mode.

Dolby EE MMonitoring:

In addition to downmixing, the DM100 allows

the metadata parameter dialnorm to be applied to content being

decoded with Dolby E. This unique feature allows the user to test

this important parameter prior to Dolby Digital encoding,

providing a safeguard against improper metadata authoring.

Dolby DDigital MMonitoring:

The DM100 can apply and monitor dynamic

range control using the RF and Line mode profiles within the

incoming Dolby Digital data stream. Line, RF, and Custom modes are

provided under the DD Compression menu. Custom disables dynamic

range compression, except when listening to a downmix.

Power-Up Functions

Factory RReset:

Press and hold [Enter] during power-up; follow

displayed instructions.

Software UUpgrade:

Press and hold [Setup] during power-up; press

[Esc] to abort.

Level Display Functions

The input level for each audio channel, as well as Dynamic Range

Control levels for Dolby Digital Line and RF modes, can be displayed

in numeric (default) or bar graph form. While in numeric display mode,

the DM100 displays levels for both RMS (on the left) and peak (on the

right) of the selected channel. To toggle between a numeric or bar

graph display, press [Enter] when viewing the appropriate status

screen. All status level displays remain in the last mode selected.

DM100 Bitstream Analyzer Quick Start Guide Issue 2

Dolby E (DE) Position

When the DM100 is supplied with a video reference, the Dolby E

MD status screens can display both Dolby E video frame rate and

information about the position of the start of the Dolby E frame

boundary. For seamless switching and editing of Dolby E

bitstreams, it is important that the start of the Dolby E frame is

correctly aligned to the video frame. The Dolby E frame is in danger

of corruption if the measured DE position is less than 11 or greater

than 30 lines for 29.97 fps (NTSC) bitstreams, or less than 7 and

greater than 35 lines for 25 fps (PAL) bitstreams.

Channel Status Bit Modification

The DM100 is capable of changing status bits present in the first and

third bytes of the AES channel status data. This feature can override

improperly authored audio streams. This allows any equipment that

may view such bits as illegal to accept AES3 streams and to allow

equipment testing. When changing AES3 status bits, the selected

decode mode LED flashes slowly.

AES3 MMode:

Professional/Consumer bit.

Audio MMode:

Audio/Non-Audio bit.

Pro EEmphasis:

J.17/50/15-us Emphasis bit. (Reserved bits are

included for future functionality.)

Pro FFreq MMode:

Locked/Unlocked bit.

Pro/Consumer SSample FFreq:

32/44.1/48 kHz bit.

Consumer CCopyright:

Yes/No bit.

Consumer AAdditional IInfo:

Pre-Emphasis bit.

Pass TThrough AAll:

All AES status bits pass through the DM100 unchanged.

Timecode/TS Delay Word

The DM100 displays the timecode and time stamp delay word from

the incoming bitstreams. The time stamp delay word is a setting

within a Dolby Digital encoder that carries delay information to

downstream devices, such as broadcast transmission equipment.

The delay word is displayed in milliseconds, where a positive value

indicates an advance and a negative value, a delay.

Generator Modes

The DM100 is capable of storing and generating a number of test

signals. The DM100’s output can be locked to internal 48 kHz clock,

the digital input, or 48 kHz derived from the reference video input.

Depending on the type of test signal selected, some setup menus may

be hidden.

PCM:

Pink Noise, White Noise, Sine, Square, and Silence (AES

Black) waveforms. Amplitude is adjustable on all PCM waveforms

(except silence), and the frequency of sine signals can be fixed or

swept over a maximum of ten seconds. The PCM stream can be

carried on either or both channels of an AES pair.

Hint:

Pressing [Shift] increases frequency in 1,000 Hz steps.

Dolby DDigital/Dolby EE SStreams:

Up to 200 bitstreams can be stored in

the unit at one time. The supplied CD-ROM contains several

thousand additional bitstreams which can be uploaded into the

DM100. When generating Dolby E streams, the clock should be

referenced to video.

DE PPosition:

Sets the video line number where the internally

generated Dolby E test stream begins.

DD CCh SSelect:

Allows the internally generated Dolby Digital stream

to be carried on either or both channels of an AES pair.

DE Guard Band

Line 14

DE Frame Rate

29.97 fps

Dolby Laboratories, Inc. 100 Potrero Avenue • San Francisco, CA 94103-4813 • Telephone 415-558-0200 • Fax 415-863-1373

Wootton Bassett • Wiltshire SN4 8QJ • England • Telephone (44) 1793-842100 • Fax (44) 1793-842101 • www.dolby.com

S03/13398/14655 Part No. 91749

DM100 Bitstream Analyzer Quick Start Guide

Latency Measurement Mode

The DM100 can measure the latency of audio equipment. At user-

defined intervals, the DM100 generates a short burst of white noise,

and measures the time it takes for the signal to return. To perform

this measurement, select Latency Test from the Gen

Control/Output Mode setup menu. Connect the DM100’s Digital

Out to the equipment to be measured, and the output of that

equipment to the DM100’s Digital In. The time interval between

the noise bursts can be set in the Gen Control/Noise Burst Rate

setup menu. The measured latency can then be read in the

Generator status menu. Press [Enter] to display the measured

latency in either audio samples or milliseconds.

Audio/Video Frequency Drift Mode

The DM100 can determine if an AES digital audio or reference

signal is frequency-locked to a video black burst reference signal.

The unit locks to the video reference, then measures the frequency

difference between the Digital In and the video reference. To

perform this measurement, select A/V Freq Drift from the Gen

Control/Output Mode setup menu. Connect a 29.97 or 25 fps video

reference to the DM100’s V Ref input, and the test AES signal to

the DM100’s Digital In. The measured frequency drift between the

AES and video signals can be read in the Generator status menu as

a continuous counter. The display counts the frequency difference

in AES samples: a positive number indicates the AES input signal is

faster than the video reference. Therefore, if the two signals are

locked, the display will read “0 samples.” Pressing [Enter] resets

the counter.

SMPTE 337M Status

The AES3 Status/337M Status menu contains information about

the headers used to identify non-audio bitstreams in AES3 signals.

Pa Alignment indicates the channel (Left or Right) where the

header begins. The Error Stats/Pa Alignment menu counts the

number of times the alignment is in error. Pa Spacing measures the

number of AES3 samples between successive headers. Correct

values should be constant—Dolby Digital: 1536; Dolby E (NTSC):

1601/2; Dolby E (PAL): 1920.

Mon/Gen Buttons

Mon:

Resets internal settings to quickly allow monitoring of input

streams.

Gen:

Turns the generator on and brings up the Gen Stream Sel menu.

Logging Mode

When the Logging Output is enabled, a subset of DM100 status

values is output as ASCII text from the RS-232 port. A standard

terminal program can display this. In addition, the currently

selected status menu item is output.

pa_td_0302_DM100StartGuide.qxd 3/11/2003 6:35 AM Page 1

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Podsumowanie treści

Strona 1 - 29.97 fps

Monitor ModesThe DM100 allows for the monitoring of individual channels withinan input bitstream, as well as a downmix to a stereo (Lt/Rt, Lo/Ro)or mo

Strona 2 - Setup Menu

Input SelectSample FreqFreq ModeMain ScreenDolby E Metadata ScreenInput Level ScreenGenerator Status ScreenVideo Frame Rate ScreenTime Code ScreenErro

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