be repeated to swap the memories back. Similarly, whenever the source ID page is
displayed the results are immediately compared with the pass/fail tolerance if one is in use
(see section 5.1). This allows memory recall and memory status operations to be used to
check quickly whether each set of results would pass the current tolerance.
Usually the unit can hold six complete sets of results in memories 0 to 5 (memory 0 being
the main or working memory). However, the number of results memories is reduced
when user tolerances are defined (section 5.6) or when the unit is configured for multiple
results compartments (section 4.18). In either case, the range of memory numbers
available is always shown (as in fig 3.13).
3.6 Cyclic Identification Character
A cyclic identification character (A-Z) is transmitted by the LA101 with the serial number
(as FSK) and printed out with the sequence results, as shown:
LINDOS AUDIO SEQUENCE TEST
SOURCE 6548A
...
LINDOS AUDIO SEQUENCE TEST
SOURCE 6548B
This letter advances through the alphabet each time a sequence is run (returning to A after
Z), and helps in sorting out a day’s tests. It may be set to any letter using the LA101
sequence editor (section 4.3), and it is reset to A when the sequence memory is cleared (or
if the SOURCE ID is deleted entirely).
3.7 Test Level Test level for sequences Measuring gain Gain measurement Relative level Sensitive inputs Reference level
Sequence tests operate at a test level which is normally 0dBu but it can be changed to suit
the application. A typical example would be when testing a microphone input where a
test level of -60dBu might be selected. Similarly, a fixed-gain tape recorder might be
tested by setting a test level that produced exactly 0VU on its meters.
To set a test level other than 0dBu first select the desired level in manual mode on the
LA101 and then press
. The letters TL will now appear to indicate that a test level
has been set, and all sequences will be output relative to this level, unless the maximum
output level of the LA101 is exceeded, in which case an error message appears and the
sequence stops. To cancel the test level setting press
again in manual mode, or
more simply tap
to reset the LA101. Sequences usually begin with a test level
segment, and the result (under the heading ‘TL OUT’) indicates the measured test level,
(out of the system under test). If the LA101 test level was 0dBu, then TL OUT represents
the gain of the system.
If a sequence is always being used at a particular level then the sequence definition can be
modified to make it automatically set the test level when it is run (see section 4.21) and
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3. Sequence Testing
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