Lambda SR1, Руководство по эксплуатации, Страница: 106 / 317

SR1 Operation Manual 106
© 2014 Stanford Research Systems
Lock Indicator should glow green indicating a successful lock. If the indicator does not glow green,
check that the correct clock is selected, the expected frequency is correct, and the external clock
signal is free of excessive noise and jitter. If lock is not checked, SR1 uses its own internal crystal
oscillator as a clock source. The phase lock loop attenuates jitter of the reference signal by 6 dB/octave
above 5 Hz.
AES Reference Controls
The Terminate checkbox terminates the rear panel AES Ref In XLR connector with a110 resistor.
Reference In Digital Input Delay displays the measured time interval between the z-preambles of
the AES reference input (rear panel AES Ref In) and the front panel digital audio input.
The AES Reference Status indicators indicate the current status of the AES Reference input.
Status
Condition Meaning
CRC For AES/EBU digital audio streams an 8-bit CRC code is generated from the
received channel status bits in each block and compared to the value stored in the
last byte of the channel status block. Red indicates a CRC mismatch.
Lock Green indicates that the digital audio receiver is locked to an input data stream. Red
indicates no lock.
Validity Red indicates that the validity bit has been set in one of the received sub-frames
Confidence Red when either the Unlock or Bi-phase error is detected.
Coding Bi-phase error. A valid digital audio signal remains at the same amplitude for no
greater than two Unit Intervals (UIs), except during preambles. A red indicator
indicates that this condition has been violated.
Parity Each digital audio subframe contains a parity bit which summarizes the parity of the
remainder of the bits in the subframe. Red indicates that the received parity bit does
not match the parity computed in the remainder of the subframe.
Reference Out->Main Output delay sets the delay between the AES Reference Out z-preamble and
the main Digital Audio output z-preamble. The delay may be set between 0 and 127.5 UI (128 UI would
be 1 complete digital audio frame) in .5 UI intervals.