Error Log - Lexicon PCM 81 - REV 2 User Manual

PCM 81
Upon loss of lock, or reception of non-audio data, the PCM 81 will
mute the digital input and display the following messages when
Word Clock or Dig In Status is selected:
Word Clock
Not Locked
Out of Range
Non Audio: 44.1

Error Log

The following errors are continuously logged and are available for
review by pressing Load/✱ from the Dig In Status display and using
ADJUST to scroll through the error list:
• Validity: A Validity error indicates that the Validity bit
was set in a frame of incoming data and that
the data attached to it may be corrupted. This
bit may also be sent when the transmitting
device is paused.
• Confidence: The PCM 81 is detecting excessive jitter or
noise on the digital audio line. No data has
been corrupted, but corrective action should
be taken.
• SlipSample: Indicates that a single sample is misaligned
with the window defined by the Word Clock.
This may occur when an external master
changes sample rate, or when it is just
powering up, but should not occur in normal
operation.
• CRC: Indicates a Cyclic Redundancy Check error in
the incoming data.
Dig In Status
No Lock (Int 44.1)
No Lock (Int 44.1)
Non Audio: 44.1
• Parity, Indicate that at least one bit (and therefore at
Biphase: least one audio sample) was corrupted.
Parity, Biphase, and Confidence errors are most often caused by
inappropriate cabling. Be sure to use 75Ω video-grade cable, kept
as short as possible — standard audio cable will not work reliably.
Each error is reported by name, with the number of occurrences of
that particular type of error.
The display might show, for example "CRC: 4752". As many as
9999 instances of each error can be shown. If the number of actu-
al errors exceeds 9999, the display will indicate ">9999". A special
symbol (n) before the error type indicates the most recently
received error.
Press Load/✱ from the Dig In Status display and use ADJUST to scroll through the Error Log.
A typical Error Log display showing that the
last error received was a CRC error ( I CRC)
and that there have been more than (>)
9999 instances of CRC errors since Word
Clock was last set to Ext.
To clear the Error Log, reselect Ext from the Control Mode Word
Clock display. This will cause the PCM 81 to attempt to lock to the
current external source and will reset the Error Log. The log is also
cleared on power up, and whenever it relocks (Auto Lock On).
Basic Operation
✱
I
2-7