Crestron QM-FTCC Operations & Installation Manual page 43

Crestron QM-FTCC
Operations & Installation Guide – DOC. 6313B
QuickMedia™ FlipTop Computer Center
Auto Compensation with a Self-Peaking Receiver
Crestron's innovative self-peaking audio circuit eliminates the need to peak the audio
signal.
Without self-peaking, the same peak and boost values are applied equally to the
video and audio signals. When these signals travel the same path, this arrangement is
satisfactory. However, when video and audio travel to a receiver from different
paths, cable lengths are unequal. The self-peaking feature eliminates the need to hunt
for peak and boost values by allowing the receiver to read the ID, input
compensation and microphone EQ from the audio channel regardless of the peaking
and boost values applied. Then using the transmitter ID, the receiver recalls the
preset containing the proper peak and boost settings for the video and implements the
correct input compensation and microphone EQ settings.
QM devices that do not have self-peaking include:
•
QM-RMCRX
•
QM-MD7x2
•
QM-MD5x1
•
TPMC-15-QM
•
TPMC-17-QM
Switchers
The QM-MD7x2 and the QM-MD5x1 terminate and re-initialize the audio path
within the unit, however, they pass the video untouched. This creates different path
lengths for the video and audio. This difference in path length creates different peak
and boost levels for audio and video. In the initial QM receivers the video and audio
circuits, peak/boost have the same settings for the audio and video. The initial QM
receivers cannot accommodate different settings and may experience difficulties
resolving the signals.
The QM-MD8x8 and QM-MD4x2 are simply analog switches. When audio-
breakaway is implemented, the audio and video paths are likely to be different. For
receivers without self-peaking audio, a probable conflict exists. For receivers with
self-peaking, auto compensation is still problematic when audio-breakaway is done
since the transmitter ID is that of the audio source and the video source is from a
different device with a different transmitter ID.
The self-peaking audio circuit resolves the problem of unequal cable lengths.
Because no audio setting is required, the video can have an independent peak/boost
as set by the program.
QM-AE Audio Extractor
The QM-AE is an audio-only device. The QM cable loops through the QM-AE from
the input connector to the output connector. The QM-AE taps only the audio signals
of the QM cable. The QM-AE is a self-peaking receiver, so peaking is not required.
QuickMedia™ FlipTop Computer Center: QM-FTCC • 39