19
M4DDC User Manual
HD Lock is required for the M4DDC to correlate the Main Program – Analog and HD-1 Digital audio
streams. The HD Radio
TM
icon at the top of this screen acts as an HD Lock indicator. If this is not
present the M4DDC has not acquired HD Lock and cannot build a correlation.
TimeLock Processing Window
TimeLock
TM
processing data is displayed in a
RED
font if HD-1 or MPS input is NOT present or if the
TimeLock algorithm hasn’t built a correlation between Analog and Digital that is greater than the user
set correlation threshold. Once both conditions are valid the font will turn
GREEN
indicating that
TimeLock Correction located within TimeLock / Level Lock Settings (no longer shaded out) is available
now.
Data is expressed in samples and time (Msec) for both pre and post correction. If TimeLock Correction
is not enabled the post processing data will read N/A. Audio phase is either ‘IN’ or ‘Out’. Post
processing will display N/A if Audio Phase Correction is disabled.
Figure 14
The slide graph represents HD-1 fixed in time while the Analog stream is measured drifting ahead or
behind HD-1. The Analog slide marker is represented in a
GREEN
in our example above. This
indicates that a correlation was built that is equal to or higher than the set Correlation Threshold. Any
correlation that is lower than this set amount will be indicated in
RED
Time moves from right to left.
The red or green Analog marker will drift ahead (left) or behind (right) of the HD-1 stream. Left
indicates that the Analog stream is ahead of HD-1 and is represented by (-) negative samples. Right
indicates Analog is behind HD-1 and is represented by (+) samples. A messages is displayed above
the slide graph at all times explaining how many samples are required to adjust the Analog stream until
the diversity delay is zero.
Time
Message indicating the adjustments
necessary to align both audio streams
to equal zero diversity delay.
