Dolby Laboratories | DM100 | DM100 Bitstream Analyzer Quick Start Guide

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DM100 Bitstream Analyzer Quick Start Guide
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 Format (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 E Monitoring: 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 Digital Monitoring: 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 Reset: Press and hold [Enter] during power-up; follow
displayed instructions.
Software Upgrade: Press and hold [Setup] during power-up; press
[Esc] to abort.
Dolby E (DE) Position
DE Guard Band
Line 14
DE Frame Rate
29.97 fps
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.
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.
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 Mode: Professional/Consumer bit.
Audio Mode: Audio/Non-Audio bit.
Pro Emphasis: J.17/50/15-us Emphasis bit. (Reserved bits are
included for future functionality.)
Pro Freq Mode: Locked/Unlocked bit.
Pro/Consumer Sample Freq: 32/44.1/48 kHz bit.
Consumer Copyright: Yes/No bit.
Consumer Additional Info: Pre-Emphasis bit.
Pass Through All: All AES status bits pass through the DM100 unchanged.
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.
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 Digital/Dolby E Streams: 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 Position: Sets the video line number where the internally
generated Dolby E test stream begins.
DD Ch Select: Allows the internally generated Dolby Digital stream
to be carried on either or both channels of an AES pair.
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 •
Dolby and the double-D symbol are trademarks of Dolby Laboratories. All other trademarks remain the property of their respective owners. © 2003 Dolby Laboratories, Inc.
S03/13398/14655 Part No. 91749
DM100 Bitstream Analyzer Quick Start Guide Issue 2
Latency Measurement Mode
The DM100 can measure the latency of audio equipment. At userdefined 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.
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.
Mon/Gen Buttons
Mon: Resets internal settings to quickly allow monitoring of input
Gen: Turns the generator on and brings up the Gen Stream Sel menu.
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Setup Menu
Gen Control
Monitor Control
Pass Through
Dolby E
Decode Format
Dolby Digital
Output Mode
L=Ls R=Rs
Dolby E Prog Sel
DE Dialogue Lev
DD Stream Select
Gen Stream Sel
L=Lt R=Rt
PCM Waveform
Only when generating PCM
White Noise
PCM Frequency
Only in PCM Sine or Square mode
Stream 0-7
PCM Sweep Min F
Only in PCM Sweep mode
AES3 Ch Select
Channel 1+2
Channel 2
Channel 1
Line Mode
DD Compression
Pass Through
Pass Through
J.17 Emph
50/15-us Emph
Freq Mode
Sample Freq
20 Hz-20 kHz
DAC on Non-Audio
Optical Output
Logging Output
Pass Through
32 kHz
Unit Name
Passthru Ch Swap
10 min
Power Management
PCM Channel
Only when generating PCM
30 min
LCD Backlight
Firmware Upgrade
Pass Through
Reserved (5 7)
Additional Info
2 ch 50/15us
Reserved (1 3)
2 10 sec
2ch No Pre-Emph
If out mode is latency test
Pass Through
Line 2 623
32 kHz
Only when generating Dolby E
Sample Freq
Channel 1 + 2
Channel 2
Pass Through
Channel 1
Validity Bit
Status Menu
44.1 kHz
48 kHz
Dolby Digital X
3/2L 448 kbps
Dolby E MD
ENTER to View
Dolby Digital MD
ENTER to View
AES3 Status
ENTER to View
Input Level
ENTER to View
Main Screen
Dolby E Metadata Screen
Dolby Digital Metadata Screen
AES3 Status Screen
Input Level Screen
ENTER to View
Video Ref.
29.97 fps
Time Code 29 Dly
00:00:00:00 N/A
Error Stats
ENTER to View
Firmware Version
Generator Status Screen
Video Frame Rate Screen
Time Code Screen
Error Stats Screen
Firmware Version Screen
Pass Through All
DM100 Bitstream Analyzer Quick Start Guide Issue 2
Contrast Adjust
Cons Chan Status
5 min
Pass Through
60 0 dBFS
My DM100
15 min
Internal 48 kHz
Not Indicated
1 10 sec
Upload Bitstream
Video Ref 48 kHz
Only when generating PCM
Only when generating Dolby Digital
Gen Clock Source
38.4 kbps
19.2 kbps
Digital Input
Freq Sweep
Only in PCM Sweep mode
DD Ch Select
01 04
Pass Through
48 kHz
DE Position
Not Indicated
44.1 kHz
Noise Burst Rate
115.2 kbps
RS 232 Baud Rate
Save Preset
No Emphasis
Only in PCM Sweep mode
PCM Amplitude
Input Select
Reserved (5)
PCM Sweep Max F
PCM Sweep Time
01 04
Reserved (1 3)
RF Mode
Headphone Mode
Pro Chan Status
Pink Noise
Audio Mode
Program 1 8
System Settings
Recall Preset
A/V Freq Drift
L=Lo R=Ro
I/O Control
Pass Through
AES3 Mode
Latency Test
Output Ch Map
User Presets
AES3 Output
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